Any experienced engine tuners able to assist?

[benno505]

Hi Guys,

trying to tune my new engine, i.e timing & dialing in the dual quad carbs. here is the details let me know if you need anymore

440 - 505 stroker chrysler motor.
manual car
MSD pro billet dizzy (no vac advance) MSD 6AL ignition & blaster 2 coil
[email protected] lunati hyd cam, 10.1 compression.

dual quad edelbrock 600cfm.

my main question is trying to work out where to get the timing perfect, i set it at 14 intial and it started and idled not too bad, but from here i dont really know what to do.

also on adjusting my carbs they are set up as 1:1 (not progressive) i have the idle screws both adjusted 1/2 turn in and all 4 idle mixture screws at 2 1/4 turns out. it is responsive and does not seem to bog down much but it is overfueling as i have fouled the plugs, i had a vac gauge on it and it was reading around 10-13 jumping back and forth.

if anyone could tell me step by step on how to get this running perfect would be greatly appreciated.

[sam 74]

i try to run as much initial timming as possible, usually i use a 12* stop bushing in the dist and 22 to 25 initial timming. when i had a dual quad on my 470 i ran 2 holley 660s and ran about 1 turn out on the adjustments, you can try this setup and see if it works for you, i also ran 1 to 1 on the carbs. with a 256* @ 50 roller cam and 11 to 1 comp.

[Ron Sutton]

Hi Benno,

I can help you dial in the fuel curve & ignition tuning, but being long distance, you'll need to do things to make it like I'm there.

First off, the cam has a lot of duration for a 10-1 compression engine. That is part of the reason it is running so rich. The valve is open a long time, but the cylinder pressure is low, so it's not efficient. Regardless, you can optimize it & have a nice running package.

We're going to want to dial in the timing curve first, then move to fuel ... fine tune the fuel curve at the jet level ... then tweek the timing a little again ... and finally dial in the idle circuits.

Let's start with the distributor. I also run a MSD Pro Billet distributors, but there are a few versions.
What is yours?
How does your control advance?
What it is set at now?

While we're at it, answer these for me ...
1. Have you been driving it .. or just running it in the garage?
2. If you have been driving it, how does it run at ...
a. Idle ?
b. Cruise rpm (2000 +/-) ?
c. mid range 3500+
d. Top end 5000+
3. How does it accelerate?
4. How does the engine run after you let the rpms come down to an idle after a 3500+ rpm blast?

5. What spark plugs are you running?
* If you have actually driven the car ... pull them out (all 8) and post a photo looking down at them. Keep them in order, so I can tell which is #1, #2, etc.

6. HAS THE ENGINE BACK FIRED? Even once? If yes, you will need to pull the power valves & check them.

7. What jets are in all 8 corners of the carbs?
b. Are there power valves on the secondaries too? ... or just on the primary sides of the 2 carbs?
* We'll get to shooter, pumps & cams later?

8. Are the carbs identical in every way ?

[benno505]

7741177412
Hi Benno,

I can help you dial in the fuel curve & ignition tuning, but being long distance, you'll need to do things to make it like I'm there.

First off, the cam has a lot of duration for a 10-1 compression engine. That is part of the reason it is running so rich. The valve is open a long time, but the cylinder pressure is low, so it's not efficient. Regardless, you can optimize it & have a nice running package.

We're going to want to dial in the timing curve first, then move to fuel ... fine tune the fuel curve at the jet level ... then tweek the timing a little again ... and finally dial in the idle circuits.

Let's start with the distributor. I also run a MSD Pro Billet distributors, but there are a few versions.
What is yours?
How does your control advance?
What it is set at now?

While we're at it, answer these for me ...
1. Have you been driving it .. or just running it in the garage?
2. If you have been driving it, how does it run at ...
a. Idle ?
b. Cruise rpm (2000 +/-) ?
c. mid range 3500+
d. Top end 5000+
3. How does it accelerate?
4. How does the engine run after you let the rpms come down to an idle after a 3500+ rpm blast?

5. What spark plugs are you running?
* If you have actually driven the car ... pull them out (all 8) and post a photo looking down at them. Keep them in order, so I can tell which is #1, #2, etc.

6. HAS THE ENGINE BACK FIRED? Even once? If yes, you will need to pull the power valves & check them.

7. What jets are in all 8 corners of the carbs?
b. Are there power valves on the secondaries too? ... or just on the primary sides of the 2 carbs?
* We'll get to shooter, pumps & cams later?

8. Are the carbs identical in every way ?

Hi Ron,
thanks for the help.

I have the MSD 8546 billet dizzy, it is as it was from out of the box nothing changed, has the standard blue bushing and silver springs.
I am not sure about the control advance, centrifugal I am guessing?

it is set at 14* initial and I think it came in at *40 total or close to that anyway

1. I drove the car about 10klm to the gas station, it ran well but would not start after refilling unless I had pedal flat to floor, then I drove the car about 30klm and ran good then after that I could feel the engione starting to miss like a spark plug lead fell off, I checked and all good so I guessed it might be a dead plug.

2. when driving it actually went not to bad the throttle was very responsive, but it did feel like there was not a lot of power, I figured this might be because I was running the motor in.
a. it idled not to bad at 850rpm a little jumpy.
b. & c. it seemed to run not to bad like I said was pretty responsive on and off the throttle but definetly lacking some power for a stroker.
d. I never got it that high as running the motor in.

3. accelerated pretty well no bogging or spluttering until I killed 3 plugs.

4. it ran fine after after 3500rpm, it did runon a couple of times after shut off when hot though.

5. spark plugs are NGK BCPR6EIX-11 iridiums, I took 1 picture of a plug as all look identical, but I did give the plugs a clean as I was oping this might fix the dead plug, they all were black and slightly wet from fuel and the reek of fuel, attached photo.

6. the engine started backfiring after the plugs failed.

7. I have not touched the carbs in anyway they are as they are from the box, part no. edelbrock #1404, and they are identical in every way. here is the owners manual http://www.edelbrock.com/automotive_new/mc/carbs_acc/pdf/carb_owners_manual.pdf


I was reading today that a cam of that size requires from 18-20* initial and around 35-38 total, so I am guessing a bush change in the dizzy is in order.

thanks for the help
Ben

[Ron Sutton]

i try to run as much initial timming as possible, usually i use a 12* stop bushing in the dist and 22 to 25 initial timming. when i had a dual quad on my 470 i ran 2 holley 660s and ran about 1 turn out on the adjustments, you can try this setup and see if it works for you, i also ran 1 to 1 on the carbs. with a 256* @ 50 roller cam and 11 to 1 comp.

Benno,
What Sam says here would be a good starting point for timing ... if you can run that much initial without detonation ... but MSD doesn't offer a 12 degree stop bushing.

Sam,
Are you running a MSD ignition ... and custom make a stop bushing ... or is it a different brand of distributor?


P.S. I run MSD's Pro Billit E-curve distributor, so practically any curve is possible.

[Ron Sutton]

Hi Ron,
thanks for the help.

I have the MSD 8546 billet dizzy, it is as it was from out of the box nothing changed, has the standard blue bushing and silver springs.
I am not sure about the control advance, centrifugal I am guessing?

It is centrifugal with weights, springs & an advance stop bushing. With the standard blue bushing and silver springs it limits "around" 21 degrees of advance.

it is set at 14* initial and I think it came in at *40 total or close to that anyway
Did you check this? If you set it at 14 degrees initial ... it should have 35+/- degrees total with the standard blue bushing and silver springs. Please recheck this, as we will want to both "Sure & Accurate".


1. I drove the car about 10klm to the gas station, it ran well but would not start after refilling unless I had pedal flat to floor,
It is simply way too rich & flooding.

then I drove the car about 30klm and ran good then after that I could feel the engione starting to miss like a spark plug lead fell off, I checked and all good so I guessed it might be a dead plug.
Yup, yup ... fouled a spark plug ... maybe more than 1.

2. when driving it actually went not to bad the throttle was very responsive, but it did feel like there was not a lot of power, I figured this might be because I was running the motor in.
When "breaking in" a new engine, they will build a "little less" power due to less true compression ... until the rings seat properly & the sharp honing edges on the cylinder walls flatten out a little. But this is maybe 6-10% less power at most. It should run GOOD. But break-in is not the issue ... fuel curve is.

a. it idled not to bad at 850rpm a little jumpy.
With this cam, you should run the idle around 900+ rpm.

b. & c. it seemed to run not to bad like I said was pretty responsive on and off the throttle but definetly lacking some power for a stroker.
d. I never got it that high as running the motor in.
OK

3. accelerated pretty well no bogging or spluttering until I killed 3 plugs.
OK

4. it ran fine after after 3500rpm, it did runon a couple of times after shut off when hot though.
Yup ... too much fuel ... plus you may have the carb butterflys open too much. Our goal will be to get it to idle better & higher (900 rpm) with less butterfly opening by leaning it out & advancing the timing at idle.

5. spark plugs are NGK BCPR6EIX-11 iridiums, I took 1 picture of a plug as all look identical, but I did give the plugs a clean as I was oping this might fix the dead plug, they all were black and slightly wet from fuel and the reek of fuel, attached photo.
Wow ... that is a HOT plug ... and you're fouling them! Your baby is WAY TOO RICH. These plugs will hinder your ability to optimize this engine. The plug runs hot, stays hot and the tip projects into the chamber. That is just inviting detonation. When you try to advance the timing & lean the fuel curve to optimize power, idle quality, acceleration, part throttle cruising, etc ... these plugs will cause detonation with optimum timing & A/F ratio. You need to change them.

6. the engine started backfiring after the plugs failed.
Yup ... unburnt fuel igniting after the fact. When I asked this question I wrongly "assumed" you were running Holley carbs ... which if they backfire from being rich ... rips the diaphragm in the powervalve(s) ... making the carb run 6 jet sizes richer per powervalve ... compounding the over rich problem. BUT the Edelbrock powervalve is not of the diaphragm design, so it doesn't blow out.

7. I have not touched the carbs in anyway they are as they are from the box, part no. edelbrock #1404, and they are identical in every way. here is the owners manual http://www.edelbrock.com/automotive_new/mc/carbs_acc/pdf/carb_owners_manual.pdf
First, if you truly have part # 1404, they are 500cfm carbs, not 600cfm. Is this correct?

Again, when I asked this question, I wrongly "assumed" you were running Holley carbs, which would have 4 jets in each carb, 1 for each barrel.

As an over generalization, tuners & racers prefer Holleys, because they are so tunable ... and Non-Tuners tend to prefer Edlebrocks, based on the old Carter line, because they are simpler, more & fail proof. As a 35 year racer & tuner, I can know what every circuit on a Holley does & how to modify it to correct any part of the fuel curve. I have NO experience tuning Edelbrock carbs. But tuning is tuning. I understand how the Carter/Edelbrock works & will be able to guide you correctly. Just the methods are different with the Carter/Edelbrock.


I was reading today that a cam of that size requires from 18-20* initial and around 35-38 total, so I am guessing a bush change in the dizzy is in order.
I would agree with that if the compression was 12-1. But for the engine to be "optimum" you will need as much initial timing as you can run without killing starters or causing light load detonation. As Sam suggested, if you could lock out the distributor advance to 12 degrees & run 24+/- degrees of initial timing, your baby will purr like a kitten.

But, we don't know how much timing it will accept, until we test it, on your engine, your car & the gas available to you.

Which brings me to this question ... Do you have gasoline options? If so what are they?
Is Ethanol readily available to you in your area of the world?

--------------------------------------------------------

OK, next step ...

We need to work on the timing, but the carbs are SO RICH, we need to jet them down some before we can proceed & we need to get new spark plugs.

1. Please do not try to reuse the fouled spark plugs. You'll be wasting everyone's time. Buy 2 sets of new spark plugs. Don't buy Iridium yet, because you need to be able to read them & throw them away. Once you "color up" a set of plugs with an engine that is too rich ... you can not lean the engine & re-read them. You need new plugs each time.

When you have your engine dialed in, then spend the bucks on Iridium plugs. I think the NGK BKR8EIX plugs will be optimum once you have the fuel & ignition optimum.

For now, we need 1 step hotter than optimum, so they don't foul as easily, yet 1 step colder than what you currently have. Buy either, NGK BCPR7ES, NGK BCPR7ES-11 or Autolite 3922. Gap them at .035" (for now) and install a new set, along with the tuning changes outlined below. Keep the 2nd set, for round 2 of your engine tuning.

2. Buy 2 of the CALIBRATION KITS, for these carbs, from Edelbrock, Part# 1486.

3. One of your issues is ... as vacuum jumps around, it is affecting the metering rods that go into the jets. The metering rod springs WANT to push the metering rod up & out of the jet, which richens the engine. Vacuum is what "pulls" down against the metering rod spring to keep the engine running correctly leaner at low speeds. The big cam duration reduces vacuum at all levels, and the metering rod spring, in this off the shelf carb for "most" applications, is too stiff for the low vacuum you have. You need a softer spring. How soft? To get it optimum, you'll need to test. To be sure, we're not having metering rod pop-up problems, let's start with the blue springs.

4. The engine is too rich across the board, so you need to jet it down/leaner "some" now ... and maybe more later. You need to stay on the "slightly rich" side ... but currently you're on the "flooding the spark plug" extreme side of rich. From the Edelbrock calibration kit, install the #1422 (.083") jets on the primary side of both carbs.

*This will get you "closer in the ball park" on jetting, so you can dial in some timing.

5. For now, until we find out if there is a way to limit the advance on your distributor more, install the black timing advance stop, which should limit the advance around 18 degrees. Then set the initial timing at 20 degrees. CHECK TO MAKE SURE THE TOTAL TIMING is 38 degrees. Adjust the initial timing if needed, but for now, don't exceed 38 degrees.

*While you're doing this, the goal is to warm the engine up. Once the engine is warm, you can tune the idle & idle mixture

6. What does the engine idle at now? If it is above 900 rpm, adjust the idle screws down (evenly) to achieve 900 rpm.

** Tip: The more you can close the butterflies & achieve the proper idle rpm, the better, because when the butterflies are open to far, they expose the idle transfer slot too much, contributing to a rich, rough idle.

7. Hook a manifold vacuum gauge to a intake manifold vacuum port. Pick a side & adjust the idle A/F mixtures screws on both carbs (slowly & the same) until you achieve the highest vacuum # (it will be shaky ... do your best). You will need to tap the throttle after each adjustment & see where it lands (both idle rpm & vacuum). Keep tuning until you get the highest vacuum. Go to the other side & do the same.

What's the rpm at now? If it is above 900 rpm, adjust the idle screws down (evenly) to achieve 900 rpm.

Start over & adjust all 4 idle A/F mixtures screws ... again & again ... until you have reached the highest vacuum. Each time the idle rpm comes up above 900, adjust it down. Be patient & persistent & you will end up with good idle quality & off-idle responsiveness.

8. Now go drive it & pay attention to how it runs at ...
* Each rpm range
* Under light acceleration
* Under medium acceleration

If you hear or feel pinging, bring it back home.

9. Pull the spark plugs & post 1 photo online of ALL 8 plugs, so I can see the heads ... write a report about how it runs as outlined above ... and we'll keep tuning from there.

Ron Sutton



thanks for the help
No worries.

Ben

Ron Sutton

[benno505]

Ron i really appreciate this, i will not be able to get the plugs until tomorrow and the jet kit i only have one at the moment, i will have to order another one from the states.
and sorry yes the carbs are the 500cfm not 600 #1404.

the gasoline we have here is 91, 95, 98 octane and we can get race fuel, but very expensive. we dont have any ethanol fuel here as i am in a small mining town. i have 98 octane in at the moment.
i also thought i would let you know, the carbs i removed the choke actuators and blade.

i will get this stuff and get back to you soon once i start making some changes,
thanks again
Ben

when changing the A/F screws to get highest vacuum to i do a little turn on each of the 4 screws or just work on 1 carb at a time?

[Ron Sutton]

Ron i really appreciate this, i will not be able to get the plugs until tomorrow and the jet kit i only have one at the moment, i will have to order another one from the states.
No worries. We'll work on it when you get the parts.

and sorry yes the carbs are the 500cfm not 600 #1404.
Ok. Cool. Just needed to be sure.

the gasoline we have here is 91, 95, 98 octane and we can get race fuel, but very expensive. we dont have any ethanol fuel here as i am in a small mining town. i have 98 octane in at the moment.
Holy cow! If you octane is rated the same way ours is in America ... and you have 98 octane available to you ... that's awesome!! 98 will allow you to run the timing curve t this engine really needs. :yeah:

i also thought i would let you know, the carbs i removed the choke actuators and blade.
No worries.

i will get this stuff and get back to you soon once i start making some changes,
thanks again
Ben

Sounds Good, Ron Sutton

when changing the A/F screws to get highest vacuum to i do a little turn on each of the 4 screws or just work on 1 carb at a time?

Do a 1/8 turn on the same side of both carbs until you get the highest vacuum. Then do the same on the other side. Adjust the idle screws to keep the idle at 900 ... and repeat the process until you can't find any more vacuum ... then try 1/16 turns until it is optimum.

Lastly, if it were me, I would then make very small adjustments to each of the 4 & see if you can get any gain. If the manifold has perfect distribution, you won't find gain by tuning them individually. But if the manifold runners are slightly different, you might. :-)

[benno505]

thanks, talk soon

[benno505]

Hi Ron,
had another question, i changed to the black bushing, i will set initial to 19* after i make the carb changes, but what springs should i be looking at?
attached photo, my cams sweet spot is from 3000-6500
77471

[Ron Sutton]

A good baseline for your engine will be to have all the advance "in" by 3000 rpm. The 1 heavy silver spring & 1 light silver spring achieve that.

Stick with the 98 Octane fuel ... and once you lean the carb & test drive it ... we'll learn if you can advance the timing curve quicker or not. We want to advance the timing as much as the fuel will allow, to build more torque. You would run it locked at 36-38 if we could, like I do on mine, but it requires better fuel.


I'll preface this by saying "my engine is very different". It's a 410" small block Dart Chevy with 265 cam intake duration @.050 & 13.78-1 compression, that makes 730 hp on Ethanol.

I run my MSD Pro Billet E-Curve at 36 degrees with the advance locked out. It retards the timing 20 degrees (from 26 to to 16 degrees) to start. This is so it's not so hard on the starter. Then once it's started, the engine is 36 degrees all the time.

The cam is much bigger (which reduces cylinder pressure) & my compression is high (which of course, builds cylinder pressure). Overall my engine makes more cylinder pressure ... so I couldn't run 36 degrees locked in ... with 98 octane fuel. My engine is set up for 105 octane E85 for street driving & Ignite brand 114 Octane racing ethanol for track days.

The points to take from this comparison are, with big cams & lower cylinder pressure, the engine wants more timing, so advance it in as quickly as the fuel octane will allow. More timing will build torque, which your engine is currently soft on. When we get the fuel curve & timing "happy" ... you'll be happy too. It will idle better, take off better, accelerate better, etc.

[benno505]

ron I know I shouldn't of but I went and got some of the non iridium plugs you mentioned and put them in at .35 gap then I put the black bush in the dizzy and set the timing to 20* initial 38 total, and rpm to 950 but it was sort of surging from 950 -1050 ( I haven't put the other jets in yet as I am waiting for them to turn up) but starting was hard on the starter motor for a brief second and the engine when driving felt like it was surging slightly then when I shut it off it overran for a second. probably not best to go on this until I fix the carbs but I thought I would let you know, I just got impatient as I have been working on my car for 2 years and she is finally on the road.

[Ron Sutton]

Haha :lol:

Simply adjusting the idle up to 950 made the car more rich, because you're uncovering the transfer slot more. You will want to get the idle up to 900 rpm by leaning the carb.

Did you experience any detonation?

Pull the plugs & post a photo so I can see.

[sam 74]

Ron, the bushing was something a friend and myself were toying with, i'm sure any machine shop could make one. he measured the closest size MSD bushings and we went from there. unfortunately thats pretty much the only way i know of to get a taylored advance stop for the MSD. when i drag raced i did similar to what you do with your setup with the lockout at 37*, i ended up getting a retard box from MSD so i could use the 20* start retard, plus i added an NOS system and needed the 3 step retard, but a start retard and locked timming is something that could run well on the street when setup properly to do so.

[Ron Sutton]

Thanks for the update Sam.

The cool thing about the MSD Pro Billet E-curve distributor, is the start retard is built in. So is the rev limiter.

Take care.

[sam 74]

yeah the e curve is a pretty cool setup, it wasn't around when i did my ignition so i had to piece together everything from MSDs offerings, but it all worked out in the end and i'm a firm believer that if it aint broke don't fix it.

[benno505]

ron, my jets and springs turned up, just to clarify I need to put the .83 jets in? do I change the jet rod as well and the spring?
also I have put the black bush in the dizzy and 1 (silver) hard spring and 1 (silver) soft spring, doesn't matter which one goes on which side?

I will time it and take it for a spin tomorrow and post the pics of the plugs.

thanks

[Ron Sutton]

ron, my jets and springs turned up, just to clarify I need to put the .83 jets in? do I change the jet rod as well and the spring?
also I have put the black bush in the dizzy and 1 (silver) hard spring and 1 (silver) soft spring, doesn't matter which one goes on which side?

I will time it and take it for a spin tomorrow and post the pics of the plugs.

thanks


For the carb, you need to ...
a. Put in the .083 jets in the primaries of each carb
b. Leave the metering rod the same (for now)
c. Put in the blue metering rod springs.

For the distributor, you have already have it correct ...
* Black advance limiting bushing
* 1 soft & 1 heavy silver spring ... and no it does not matter which side.
* Set the initial timing at 20 degrees.

Then ... CHECK TO MAKE SURE THE TOTAL TIMING is 38 degrees. Adjust the initial timing if needed, but for now, don't exceed 38 degrees.

Then do the tuning plan I outlined for you ... test drive it ... post the results (so far) & show the spark plugs. Then we'll keep making small, safe steps until we get the timing & fuel curve happy.


Ron Sutton

[benno505]

Okay Ron,
.83 jets are in the primaries, the blue spring is in.
distributor black bushing in and 1 hard silver and 1 soft silver are in, timing set to 20* ( it was jumping between 20* & 21* not steady, when revved and held at 3000rpm it was at 34-35* total)
couldn't get idle lower than 1150 with idles back all the way out and I checked to see if butterflies closed which they were. it was hard to start on the alternator. and when I shut it off it overran and hissed.

but I took it for about 10 min drive and it felt pretty good it had a lot more throttle response and revved pretty well through the range and seem to shift easier. still feels like it could have some more power though.

I left the a/f screws at 2 turns out on all 4 for now.

here is the picture of the plugs they all look almost identical, so I only took pics of number 2 and number 5 let me know if you need them all.

77771
77772

[benno505]

also I found out today that our 98 octane is more like your guys 95 octane, I wonder if this has any effect

[benno505]

also ron, beacause there is 4 vacuum outlets on the front of the carbs (2 on each) and I only have 1 vac gauge should I be porting up to both ports at once or 2 ports on same side of car or all 4? out of the 2 ports on each carb 1 sits lower I don't know if this makes a difference?

really confusing myself here don't know where to start should just go injection haha

[Ron Sutton]

also I found out today that our 98 octane is more like your guys 95 octane, I wonder if this has any effect

95 octane will be fine. It just help me to have a reference.

[Ron Sutton]

also ron, beacause there is 4 vacuum outlets on the front of the carbs (2 on each) and I only have 1 vac gauge should I be porting up to both ports at once or 2 ports on same side of car or all 4? out of the 2 ports on each carb 1 sits lower I don't know if this makes a difference?

really confusing myself here don't know where to start should just go injection haha

Relax buddy ... it ain't nothing but a thang. Manifold vacuum is manifold vacuum, regardless of where you take it, and you only need 1 gauge plugged into 1 port at a time.

You should be able to move your vacuum gauge to either of the 2 ports on the carb & get the same reading. Edelbrock "could" be making this carb with a Ported Spark Vacuum** outlet. But hey ... it's easy enough to test ... so move your vacuum gauge around & see.

I have found on dual carb applications, that the manifold vacuum "can vary slightly" under each carb, when one carb is not tuned correctly. Obviously, manifold vacuum "averages out" inside the plenum. But in dual 4-barrel applications like yours, you should connect the vacuum gauge to the carb you are tuning.


** You always hear there is an exception to every rule. Here it is for manifold vacuum. In the early era of emissions controls, but before catalytic converters, engineers created a band-aid known as "ported spark vacuum" ... which provided manifold vacuum, but only when the throttle blades were open, so not at idle. You can always tell if you're plugged into a ported spark vacuum outlet, because it provides NO vacuum at idle. Do not use ported spark vacuum outlets for ... well ... anything. (I'm sure there is an exception to this rule too.)

[Ron Sutton]

Okay Ron,
.83 jets are in the primaries, the blue spring is in.
Good.


distributor black bushing in and 1 hard silver and 1 soft silver are in, timing set to 20* ( it was jumping between 20* & 21* not steady, when revved and held at 3000rpm it was at 34-35* total)
OK. Interesting. Sounds like the black bushing limited advance to 14° ... which is not bad. We just don't know exactly where your optimum timing curve is yet, until we finish all the tuning steps.


couldn't get idle lower than 1150 with idles back all the way out
This is good news. It puts us on the good side of the tuning equation & gives us lots of options to make it run optimum.

and I checked to see if butterflies closed which they were.
You checked HOW? by eyeball? More on this later.

it was hard to start on the alternator.
Hmmm. I don't understand. What are you trying to tell me?


and when I shut it off it overran and hissed.
No worries. But that condition gives me a clue where to start.


but I took it for about 10 min drive and it felt pretty good it had a lot more throttle response
It was way too rich before. Dropping the jets from .086" to .083" helped.

and revved pretty well through the range
Do you mean with no load? Or did you accelerate the car up through your full rpm range on your test drive?


and seem to shift easier.
Automatic? Automatics always shift better, when the engine runs cleaner & has more torque versus when the engine is struggling a before.


still feels like it could have some more power though.
You still have MANY tuning steps to go to optimize your engine package. You're just going the right direction now.


I left the a/f screws at 2 turns out on all 4 for now.
OK. Thanks for that info.

here is the picture of the plugs they all look almost identical, so I only took pics of number 2 and number 5 let me know if you need them all.
Thanks for the photos. The spark plugs look way better. Still work to do, but like I said, you still have many tuning steps to go to optimize your engine package.

In my next post, I'll explain the 3 methods for tuning idle & guide you on some steps.


I do need you to answer these questions, while I'm writing stuff up.

#1 and I checked to see if butterflies closed which they were.
You checked HOW? by eyeball? More on this later.

#2 it was hard to start on the alternator.
Hmmm. I don't understand. What are you trying to tell me?

#3 and revved pretty well through the range
Do you mean with no load? Or did you accelerate the car up through your full rpm range on your test drive?


Ron Sutton

[Ron Sutton]

There are three common methods of tuning idle.
1. Static ignition timing
2. Idle fuel adjustment screw*
3. Throttle blade opening (controlling volume of air)

* On some carbs, like the Holley 4165/4175 models, the amount of fuel for the idle circuit is preset & the “idle screw” adjusts the air, like an adjustable air bleed. You can always tell, because if you close the idle screws on these carbs the engine doesn’t die.

Each one of these methods work.

1. Less static ignition timing lowers idle / More static timing raises the idle.
2. Richening the Idle fuel screws lowers idle / Leaning them raises the idle.
3. Closing the throttle blades lowers idle / Opening them raises the idle.

But choosing the right one for the situation is key to a good running engine.

---------------------------------------------------------------------------------------------------------------------

You could easily lower the static timing … but that’s not ideal for your situation … so let’s not START there. You have an engine with a large duration cam & modest compression … along with a lower than optimum rod/stroke ratio due to the stroker crank. That baby needs the spark timing to come in earlier to run optimum. Having gasoline with 98 octane in Australia (similar to a 95 octane rating in the US) should allow you to be more aggressive with three areas … the static amount of timing … the timing advance curve … and total amount of timing.

You did not mention any detonation or knock on your test drives, so that supports your goal. But pay attention to this as we progress.

I say this to all car guys. The Ron Popiel “set it & forget it” philosophy works with $99 ovens & poor running performance cars. Optimizing anything … engine, suspension, driving, etc … takes time, focus & commitment to achieve optimum. It’s all about testing & tuning until you find the best combination. Knowledge & experience just get you there quicker.

77778

* Do they have Ron Popiel commercials in Australia?

If you want to achieve optimum engine performance, you will want to do a lot of tweaking back & forth on the timing & fuel curve, until your baby rocks. :git:

---------------------------------------------------------------------------------------------------------------------

You could VERY easily richen the idle mixture screws & the idle will come down. I suspect we may end up doing this “some”, but that is not where we need to start. This will be our 2nd idle tuning tool.

---------------------------------------------------------------------------------------------------------------------

We need to start by reducing the air available to the engine around the throttle blades. Your carbs were designed to provide the proper amount of air at idle … with just one carb. You have two … so more air is available to your engine at idle … raising the idle higher than it needs to be.

I know you said the throttle blades were “closed” … but “closed” is a subjective thing, that we need to quantify. There IS CLEARANCE around the blades. If not … the blades would wedge themselves into the throttle bore & “stick” closed. Not dangerous, but really irritating for the driver. Plus, if the blades were 100% closed & sealed, the engine couldn’t run.

We need to reduce the airflow at idle, so you need to close the blades slightly more than they are. We need to start by figuring out “exactly” how open the throttle blades are currently. Get a set of thin feeler gauges with the flexible brass blades. You need a set with blades: .0015”, .002”, .0025” & .003”.

To measure the throttle blade clearance:
With the engine off … open the throttle & put your feeler gauge against the backside wall of the primary throttle bore & close the throttle. Now slowly pull the feeler gauge up & out. Increase the thickness of the feeler gauge blade until you feel moderate resistance (hard to quantify … say 2-3#) as you pull up.

Now do the same thing on the front wall of the primary throttle bore. Repeat this with all 4 primary throttle blades. Write down the clearance to achieve moderate resistance … front & back … for all 4 primary throttle blades.

Post your results on the Forum & I’ll walk you through “how & how far” to tune this, providing we have enough range in the carb.

---------------------------------------------------------------------------------------------------------------------

After we dial in the throttle blade clearances … we’ll see where that puts the idle … and tune the idle fuel screws from there to achieve an idle around 900-1000 rpm. The final idle rpm you’re happy with … is often influenced by the cam profile.

I have race engines with big cams that sound like they’re loping along at a normal rpm idle, but really, the rpm is 1800. Your engine would sound like it’s racing at 1800 rpm. It probably sounds like that a little at 1150 rpm.

---------------------------------------------------------------------------------------------------------------------

Once the throttle blade clearances & idle fuel mixture is dialed in, we’ll work on tuning the engine’s driving performance at part throttle & full throttle throughout the rpm range … with fuel & timing tuning.

---------------------------------------------------------------------------------------------------------------------


If anyone has any questions, feel free to chime in on this thread.

Ron Sutton

[benno505]

Okay Ron,
.83 jets are in the primaries, the blue spring is in.
Good.


distributor black bushing in and 1 hard silver and 1 soft silver are in, timing set to 20* ( it was jumping between 20* & 21* not steady, when revved and held at 3000rpm it was at 34-35* total)
OK. Interesting. Sounds like the black bushing limited advance to 14° ... which is not bad. We just don't know exactly where your optimum timing curve is yet, until we finish all the tuning steps.


couldn't get idle lower than 1150 with idles back all the way out
This is good news. It puts us on the good side of the tuning equation & gives us lots of options to make it run optimum.

and I checked to see if butterflies closed which they were.
You checked HOW? by eyeball? More on this later.

it was hard to start on the alternator.
Hmmm. I don't understand. What are you trying to tell me?


and when I shut it off it overran and hissed.
No worries. But that condition gives me a clue where to start.


but I took it for about 10 min drive and it felt pretty good it had a lot more throttle response
It was way too rich before. Dropping the jets from .086" to .083" helped.

and revved pretty well through the range
Do you mean with no load? Or did you accelerate the car up through your full rpm range on your test drive?


and seem to shift easier.
Automatic? Automatics always shift better, when the engine runs cleaner & has more torque versus when the engine is struggling a before.


still feels like it could have some more power though.
You still have MANY tuning steps to go to optimize your engine package. You're just going the right direction now.


I left the a/f screws at 2 turns out on all 4 for now.
OK. Thanks for that info.

here is the picture of the plugs they all look almost identical, so I only took pics of number 2 and number 5 let me know if you need them all.
Thanks for the photos. The spark plugs look way better. Still work to do, but like I said, you still have many tuning steps to go to optimize your engine package.

In my next post, I'll explain the 3 methods for tuning idle & guide you on some steps.


I do need you to answer these questions, while I'm writing stuff up.

#1 and I checked to see if butterflies closed which they were.
You checked HOW? by eyeball? More on this later.

#2 it was hard to start on the alternator.
Hmmm. I don't understand. What are you trying to tell me?

#3 and revved pretty well through the range
Do you mean with no load? Or did you accelerate the car up through your full rpm range on your test drive?


Ron Sutton

#1 I checked by eyeball with the top of carb hat off and then again when I put it back on and then I undid the linkage and and moved the throttle back and forward then all the way back until bottomed out, I recalibrated the linkage ( it was slightly out before, good now though)

#2 when I started all 3 times the starter was clunking and struggling, this went away when I retarded it some.

3# I accelerated through the rpm range from 1000-5000, it accelerated much better and did not feel like it was struggling at all.

[benno505]

There are three common methods of tuning idle.
1. Static ignition timing
2. Idle fuel adjustment screw*
3. Throttle blade opening (controlling volume of air)

* On some carbs, like the Holley 4165/4175 models, the amount of fuel for the idle circuit is preset & the “idle screw” adjusts the air, like an adjustable air bleed. You can always tell, because if you close the idle screws on these carbs the engine doesn’t die.

Each one of these methods work.

1. Less static ignition timing lowers idle / More static timing raises the idle.
2. Richening the Idle fuel screws lowers idle / Leaning them raises the idle.
3. Closing the throttle blades lowers idle / Opening them raises the idle.

But choosing the right one for the situation is key to a good running engine.

---------------------------------------------------------------------------------------------------------------------

You could easily lower the static timing … but that’s not ideal for your situation … so let’s not START there. You have an engine with a large duration cam & modest compression … along with a lower than optimum rod/stroke ratio due to the stroker crank. That baby needs the spark timing to come in earlier to run optimum. Having gasoline with 98 octane in Australia (similar to a 95 octane rating in the US) should allow you to be more aggressive with three areas … the static amount of timing … the timing advance curve … and total amount of timing.

You did not mention any detonation or knock on your test drives, so that supports your goal. But pay attention to this as we progress.

I say this to all car guys. The Ron Popiel “set it & forget it” philosophy works with $99 ovens & poor running performance cars. Optimizing anything … engine, suspension, driving, etc … takes time, focus & commitment to achieve optimum. It’s all about testing & tuning until you find the best combination. Knowledge & experience just get you there quicker.

77778

* Do they have Ron Popiel commercials in Australia?

If you want to achieve optimum engine performance, you will want to do a lot of tweaking back & forth on the timing & fuel curve, until your baby rocks. :git:

---------------------------------------------------------------------------------------------------------------------

You could VERY easily richen the idle mixture screws & the idle will come down. I suspect we may end up doing this “some”, but that is not where we need to start. This will be our 2nd idle tuning tool.

---------------------------------------------------------------------------------------------------------------------

We need to start by reducing the air available to the engine around the throttle blades. Your carbs were designed to provide the proper amount of air at idle … with just one carb. You have two … so more air is available to your engine at idle … raising the idle higher than it needs to be.

I know you said the throttle blades were “closed” … but “closed” is a subjective thing, that we need to quantify. There IS CLEARANCE around the blades. If not … the blades would wedge themselves into the throttle bore & “stick” closed. Not dangerous, but really irritating for the driver. Plus, if the blades were 100% closed & sealed, the engine couldn’t run.

We need to reduce the airflow at idle, so you need to close the blades slightly more than they are. We need to start by figuring out “exactly” how open the throttle blades are currently. Get a set of thin feeler gauges with the flexible brass blades. You need a set with blades: .0015”, .002”, .0025” & .003”.

To measure the throttle blade clearance:
With the engine off … open the throttle & put your feeler gauge against the backside wall of the primary throttle bore & close the throttle. Now slowly pull the feeler gauge up & out. Increase the thickness of the feeler gauge blade until you feel moderate resistance (hard to quantify … say 2-3#) as you pull up.

Now do the same thing on the front wall of the primary throttle bore. Repeat this with all 4 primary throttle blades. Write down the clearance to achieve moderate resistance … front & back … for all 4 primary throttle blades.

Post your results on the Forum & I’ll walk you through “how & how far” to tune this, providing we have enough range in the carb.

---------------------------------------------------------------------------------------------------------------------

After we dial in the throttle blade clearances … we’ll see where that puts the idle … and tune the idle fuel screws from there to achieve an idle around 900-1000 rpm. The final idle rpm you’re happy with … is often influenced by the cam profile.

I have race engines with big cams that sound like they’re loping along at a normal rpm idle, but really, the rpm is 1800. Your engine would sound like it’s racing at 1800 rpm. It probably sounds like that a little at 1150 rpm.

---------------------------------------------------------------------------------------------------------------------

Once the throttle blade clearances & idle fuel mixture is dialed in, we’ll work on tuning the engine’s driving performance at part throttle & full throttle throughout the rpm range … with fuel & timing tuning.

---------------------------------------------------------------------------------------------------------------------


If anyone has any questions, feel free to chime in on this thread.

Ron Sutton

I redid my comp check it cme in at 9.8:1 if this also helps.

no ron commercials here mate

I will check the blades right now

[benno505]

ron, the smallest feeler gauge I have is .002 and it was very tight against all sides of the primaries

[Ron Sutton]

Is it a steel ... or brass feeler gauge?

[sam 74]

distributor black bushing in and 1 hard silver and 1 soft silver are in, timing set to 20* ( it was jumping between 20* & 21* not steady, when revved and held at 3000rpm it was at 34-35* total)

you may want to check to see if your advance weights are moving freely, i have found that some weights tend to stick from time to time, if that checks out you should try to check the total timming a little above 3000 and see if you get more advance, i have yet to see a bushing from MSD that isn't what its rated at, that doesn't mean it doesn't happen but i've never seen that happen before. you could always try the 2 light springs and see if that gets your advance in a little before or at 3000 rpm.

[Ron Sutton]

Hi Sam,

After we get the carb set, we may have to go the other way ... and advance the timing further. Can't say until we finish with carb.

[Ron Sutton]

Is it a steel ... or brass feeler gauge?

[benno505]

Is it a steel ... or brass feeler gauge?

I only have a stainless one, this no good? that is with idle screws all th way out

[benno505]

distributor black bushing in and 1 hard silver and 1 soft silver are in, timing set to 20* ( it was jumping between 20* & 21* not steady, when revved and held at 3000rpm it was at 34-35* total)

you may want to check to see if your advance weights are moving freely, i have found that some weights tend to stick from time to time, if that checks out you should try to check the total timming a little above 3000 and see if you get more advance, i have yet to see a bushing from MSD that isn't what its rated at, that doesn't mean it doesn't happen but i've never seen that happen before. you could always try the 2 light springs and see if that gets your advance in a little before or at 3000 rpm.

sam they move freely

[Ron Sutton]

I only have a stainless one, this no good? that is with idle screws all th way out

It won't flex around the curved throttle blade & barrel easily. It will always been tight ... even if there was .010" clearance. Do you have an auto parts store or tool store nearby?

[Ron Sutton]

Ben PM'd me the throttle blades had around .002" clearance & were all the same. So there is no room for adjusting here.

He's going to drop the initial timing to 16 degrees ... so it will start easier ... see what the idle is with this timing ... and adjust the idle fuel mixture next.

Ron Sutton

[benno505]

initial 16*, idle jumping between 900-915, give it a little squirt and it take a few seconds for it to return to idle, when shutoff it overran for about 2 secs

[Ron Sutton]

initial 16*, idle jumping between 900-915, give it a little squirt and it take a few seconds for it to return to idle, when shutoff it overran for about 2 secs

Hmmm. The only way a engine can "run on" is if it is getting air either through the carb(s) or a vacuum leak. You can test this by shutting it off & putting your hands over both choke horns. If it shuts off with no "run on" ... the engine was still sucking air through the carb. If it still "runs on" when you're blocking all the air to the carbs ... you have a vaccum or air leak.

Test it & let me know.

[benno505]

i did readjust the idle screws back in the get the desired 900 rpm, would that have anything to do with it

[benno505]

i will test that be right back

[Ron Sutton]

No.

But just so I'm informed ... I think you had the idle fuel adjustment screw out 2 full turns. Where did you adjust them to?

[Ron Sutton]

i did readjust the idle screws back in the get the desired 900 rpm, would that have anything to do with it

No.

But just so I'm informed ... what did you adjust the idle screw to?

[benno505]

just found a problem as the missus started the car i seen sparks goiung from the number 7 & 5 leads to the headers, ii got a big jump out of it haha, i will replace these i think.

taking the family out for a few hours, wont get back to the car until later, so will probably talk to you tomorrow,

anything else you want me to do in the meantime?

[benno505]

No.

But just so I'm informed ... what did you adjust the idle screw to?

haven't touched them there still at 2 turns out

[Ron Sutton]

just found a problem as the missus started the car i seen sparks goiung from the number 7 & 5 leads to the headers, ii got a big jump out of it haha, i will replace these i think.

taking the family out for a few hours, wont get back to the car until later, so will probably talk to you tomorrow,

anything else you want me to do in the meantime?

HaHa ... I wished I had seen that. If you're going to seriously hurt yourself ... do me a favor ... and ask your wife to video it. We all need a little laugh now & then.

No worries. Let us know when you have that fixed & we'll pick up from there.


Ron Sutton

[benno505]

done running a bit better haha, started it covered both choke horns it shut off, restarted it then turned it off and it didn't overrun

[Ron Sutton]

Cool. I thought you were taking the wife out to dinner?

[benno505]

actually taking the wife and son to the show in about 20 mins.

[Ron Sutton]

Actually ... I guess in your time zone ... lunch?

[benno505]

took her for a big drive today after I attempted tuning the A/F mixtures im I turned them in the vacuum got lower so I turned them out to 2.5 turns it didn't seem to get much higher than 5. and at 5 it was very steady needle on the gauge. went for the big drive and was hard to start had to hold throttle down and everytime I turned it off it overran really bad. but it did drive pretty well through the rpm range,
when putting around you can see fuel smoke coming out the exhaust when it is hot.

[Ron Sutton]

took her for a big drive today after I attempted tuning the A/F mixtures im I turned them in the vacuum got lower so I turned them out to 2.5 turns it didn't seem to get much higher than 5. and at 5 it was very steady needle on the gauge. went for the big drive and was hard to start had to hold throttle down and everytime I turned it off it overran really bad. but it did drive pretty well through the rpm range,
when putting around you can see fuel smoke coming out the exhaust when it is hot.

It's still too rich on the primary sides of the carbs & is most likely very rich on the secondary sides of the carbs. Did you experience any detontation?

[Ron Sutton]

Do a little "process of elimination" test for us, to narrow down the cause of run on. Set the timing at 10° & set the idle at 900rpm ... and shut it off a couple times. Then Set the timing at 20° ... and shut it off a couple times.

This will help me to understand if the run on is caused by the carbs still allowing too much air or preignition.

[benno505]

no detonation what so ever, and I had the rpm upto 5800 it picks up speed very quick with all 8 butterflies open,
I still haven't checked for vacuum leaks, was hoping you had an accurate way to do this.

when I was first driving around for the first 15 mins it was bogging a lot when I took off from the lights etc. I forgot to mention sorry, but after about 30-60 mins this sort of went away.

[benno505]

also Ron I want to put 2 x 2" spacers under the carbs to get the air cleaner in through the hole in my reverse cowl and lift the air cleaner away from the distributor, which type would you recommend and does this affect any tuning?

here is some pics for you.

77928

77929

77930

77931

[Ron Sutton]

Man, Ben, that car looks great. Awesome engine too.

Did you do the little "process of elimination" test for us?

... to narrow down the cause of run on. Set the timing at 10° & set the idle at 900rpm ... and shut it off a couple times. Then Set the timing at 20° ... and shut it off a couple times.

This will help me to understand if the run on is caused by the carbs still allowing too much air or preignition.

[Ron Sutton]

Also Ron I want to put 2 x 2" spacers under the carbs to get the air cleaner in through the hole in my reverse cowl and lift the air cleaner away from the distributor, which type would you recommend and does this affect any tuning?

That would be a good move. I like the "Super Sucker" spacers from HVH best, because they do a lot of testing & have developed units that increase the torque, throttle response, atomize the fuel better & improve the signal to the carb. Part #SS4150-2AL is the 2" tall "solid version" & #SS4150-2ALW is the lightweight version.

Yes, these will definitely affect the final carb tuning. But lets carry on with our tuning steps.

1. We need to confirm the cause of the "run on" ... either to much air past the throttle blades (have a cure for you) ... or vacuum leak (have a method to test for you) ... or there are hot spots in the cylinder causing pre-ignition (which is why I need to do the 10* & 20* timing tests).

2. You leaned the primaries ... but they will need more. This step will depend on the cause of the run-on.

3. We'll want to finalize static timing, timing advance amount & rate & total timing. Can't do this until #1 & #2 are done.

4. The secondaries should also be way too rich. Need 1-3 done to dial this in.

[benno505]

Ron,
Havent been able to do these tests yet and wont be able to get to them until tomorrow,
i will get the outcome to you.

you want me to do the timing test before i hunt for vac leaks?

thanks Ben

[Ron Sutton]

Thanks for the update. No hurry. I'm on your schedule.

Vacuum leak test first. With the engine running, spray carb cleaner (with the little nozzle tube) slowly along the edges of the intake manifold & carb mating surfaces. If the idle picks up anywhere, you have a leak.

Also ... with the engine running ... cap any vacuum hose, 1 at a time. If the idle picks up anywhere, you have a leak.

[benno505]

Okay thanks Ron,

what are you working on a 57 chev? got a build thread?

Ben

[Ron Sutton]

Top secret NASA/CIA spy stuff. :secret:

I'm designing a new car for myself ... less Pro Touring ... more Street Warrior for driving & competing in events like AutoX, Road course track day events, all-around street car competitions & Silver State Challenge, which my daughter is going to do with me.

I'll do a thread on it when I get it going.

[benno505]

Hi Ron,
thought I would also let you know the timing light I am using is the innova equus 3568 http://www.summitracing.com/parts/equ-3568/overview/

it has advance and retard buttons on the timing light, I am not really sure on what these do so I have left it at zero am I doing it wrong?

[benno505]

Okay mate, don't laugh at me but I found my vacuum leak. I was spraying carby cleaner all around everything and then when I got to the gap between the 2 carbs the revs were going mental, so I took a peak and there it is I forgot to put the big bung in the back of the carby, the hole was about half inch haha. fixed this.

I then set initial timing to 20*, turned it off then restarted it, the starter motor didn't like it it made a clunk but it did start easy, then when I shut it off it overran slightly.

I then set it to 10* it started okay, but it did not overrun, so I decided to take it for a spin and get it really warmed up, it felt like it had lost some power, and when I turned it off it overran again.
the rockers started making a ticking noise ( need to adjust after the engine break in) and when shifting between gears it was clunking the gears which it did not previously do ( I am guessing it doesn't like 10*)

[Ron Sutton]

Okay mate, don't laugh at me but I found my vacuum leak. I was spraying carby cleaner all around everything and then when I got to the gap between the 2 carbs the revs were going mental, so I took a peak and there it is I forgot to put the big bung in the back of the carby, the hole was about half inch haha. fixed this.
No worries. Glad you found it before we got too far.

I then set initial timing to 20*, turned it off then restarted it, the starter motor didn't like it it made a clunk but it did start easy, then when I shut it off it overran slightly.

I then set it to 10* it started okay, but it did not overrun, so I decided to take it for a spin and get it really warmed up, it felt like it had lost some power, and when I turned it off it overran again.
the rockers started making a ticking noise ( need to adjust after the engine break in) and when shifting between gears it was clunking the gears which it did not previously do ( I am guessing it doesn't like 10*)
I wasn't thinking we'd run it at 10* ... I just needed you to run a heat test.

My suggestion for initial timing will be to run as much as the starter will "happily" allow. This will make the engine run better at low rpms & idle. If you can't run enough timing due to your starter ... and you're unhappy with it ... you may want to look into an ultra high torque starter like I run.

For now, set the initial timing at 16*

If the lifters are "ticking" more than normal ... don't wait til later ... go ahead & adjust them now.

[Ron Sutton]

Hi Ron,
thought I would also let you know the timing light I am using is the innova equus 3568 http://www.summitracing.com/parts/equ-3568/overview/

it has advance and retard buttons on the timing light, I am not really sure on what these do so I have left it at zero am I doing it wrong?

You can leave it at zero & use it like a normal timing light & continue reading the timing marks on the timing tab.

If you want to use the advance feature, you preset it at the desired timing ... say 16 degrees for idle ... and you're looking for the timing marks to read "0" at the timing tab.


Please, please, PLEASE don't make the mistake I saw a racer do last year. He set pre-set the advance timing light at 36 degrees & then set the timing with the marks also reading 36 degrees (total timing). He had 72 degrees of timing advance. :hammer:

At that point, the spark is lighting the fire so early the burn reaches full force in the combustion chamber well before the piston reaches top dead center. Basically it is fighting itself inside the block. It would not rev past 4000 rpm on track. When they came & asked me for advice ... it was too late ... it had beat the bearings out of it. :crying:

[benno505]

Ron,
i have a powermaster XS torque starter i think there good for 18.1 compression.

i will set it to 16* this afternoon after i adjust the rockers. ( we are just finding a good initial at the moment aren't we? and then we will find total?)

i will use the timing light on '0'

will let you know the details.

[Ron Sutton]

Ron,
i have a powermaster XS torque starter i think there good for 18.1 compression.
Should work fine. The XS is a 200# torque starter. If you become unhappy with it later ... they make one called the Ultra that is 250# torque starter.

i will set it to 16* this afternoon after i adjust the rockers. ( we are just finding a good initial at the moment aren't we? and then we will find total?)
Yes. Just a starting point.

i will use the timing light on '0'

will let you know the details.

Sounds good.

[Scott Parkhurst]

Ron- you're doing a great job of walking him through the process long-distance. No easy feat!

Benno- Keep listening- he knows what's up! Wait til he tells you to crank up the acceleration pumps a bit. You won't believe the change...those big Mopars love a good pump shot.

[Ron Sutton]

Thanks Scott.

My only fear is missing something because I'm not there. But Ben & I are working it out.

[benno505]

thanks scott, got the rockers adjusted.

also asked similar questions on forbbodiesonly a mopar forum. few guys there with 505 and 512 strokers also with similar addons, they reckon they run 22-24 initial and 34-36 total all in at 3200rpm. but to get that they needed the custom bush from 4secondsflat.com.

maybe I need a better starter?

whats your thoughts ron

[Ron Sutton]

That is my recommendation too ... for an optimum setup. Remember, big cam engines need timing for a better idle & low end response. As I mentioned earlier, I run my advance "locked out" with 36 degrees initial & total. My MSD E-Curve distributor is set to drop the timing to 16 degrees for starting & I have a 250# torque starter.

You may want to see about a timing retard switch if MSD offers one. Then you could set the initial timing at 20-24 degrees ... retard it to 12-16 for starting ... and not worry about the starter.

When we get back to tuning the carb, You are going to need to adjust a linkage rod on the passenger side of the carb that limits how far the throttle blades close. As I mentioned earlier, your carbs were designed to idle with just 1 carb, and you have 2. Two are flowing too much air at idle & contributing to your "run on' problem. But the solution is 3-pronged, requiring more initial timing, leaner jetting & less air at idle.

[benno505]

okay, I did find something yesterday when tinkering, I pulled the linkage off and readjusted idles and linkage then put it back on, it seems that when the carb closest to driver was closed the front one was still slightly open, maybe causing me dramas, I have fixed this and fixed the lifters hopefully, going to set it to 19* today as we are going for a cruise, I will see how this goes and let you know.
I will look into those retard units.

[Ron Sutton]

Awesome. It really seemed like it had too much air available, contributing to the run on.

[benno505]

Ron,
my lifters are dead I think, ticking off there head even after adjusting, have o order some more.

20* @900 rpm, engine surging at low rpm, engine run on still. starting easier though and not to bad to drive.

going to order new lifters and the custom bushing from 4seconds flat next pay day.

talk soon.

[Ron Sutton]

Dang it. What do you think hurt your lifters?

[benno505]

no idea, took it for that 1 hr drive then next run they started ticking, I have been hearing some complaints about bad batches of comp cams lifters.
I am thinking about getting some of those Rhodes v max lifters, they sound like good quality, plus I bought 2 of those super sucker spacers you told me about.

when I set the initial timing and idle this morning at 20* @900 rpm then after going for a bit of a drive I got home and idle was at 1300rpm it changed after driving, I did not recheck the timing yet, maybe my dizzy is moving or I am having problems elsewhere.

[Ron Sutton]

Keep me informed & let me know when you're ready for guidance.

[benno505]

gremlins have been sorted,

engine run on is gone, it was because I had the butterflies open too much during idle
new lifters in ( I do need to readjust now there run in)
fuel pressure is back to normal set on 5.5-6 PSI.

I deburred and polished the inside of the carbs
I installed 2, 2" spacers under the carbs open hole for more plenum volume

Initial timing: 20*
Timing Total Advance: 38* @ 2800 rpm
Carb idle screws at: 1 turn in
Carb idle mixture screws at: 1 3/4 turns out
Idle at: 900rpm
Manifold vacuum at: 7-9 hg

waiting on custom bushes from fbo to raise intitial timing up and lower total

1 silver and 1 blue light springs in distributor

[Ron Sutton]

OK Ben,

Now that you have the gremlins fixed, let's get on with the tuning.

Let's work in this order:
1. Optimize the idle.
2. Put in new, colder spark plugs.
3. Do a thorough test drive to evaluate performance at each level for tuning.

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Optimizing Idle:

Make 1/8 turn adjustments on the idle fuel mixtures screws ... on the same side of both carbs ... until you get the highest vacuum. Then do the same on the other side. As the idle raises, adjust the idle screws down to keep the idle at 900. Repeat this process many times ... until you can't find any more vacuum ... then try 1/16 turns each direction. If it gets better ... keep that adjustment.

Lastly, if it were me, I would then make very small adjustments to each of the 4 idle screws ... individually ... to see if you can get any gain. If the manifold has perfect distribution, you won't find any gain by tuning them individually. But if the manifold runners are slightly different, you might. :)

Your end goal is the highest vacuum reading while keeping the idle at 900 rpm. Take note of your final numbers on all 4 idle screws for future reference.
*Readers, we do this slightly different for race cars. After we find optimum idle, we richen the idle screws 1/8 turn, even though the idle quality drops a tick.

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Put in a new set of spark plugs ... NGK BCPR7ES, NGK BCPR7ES-11 or Autolite 3922. Gap them at .035"
* You will probably need 1-2 more sets of these for tuning. Because once they color up from being too rich, we can't uncolor them. That's why I recommended the cheap plugs for tuning.

**Save the NGK BKR8EIX Iridium spark plugs for later.

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Now go drive it & pay attention to how it runs at ...

* Each rpm range: Idle to 1800 rpm, 2000-3000 rpm, 3000-5500 rpm

* Under light acceleration

* Under medium acceleration

* When you go from low rpm cruise rpm (1800) & open the throttle quickly to WOT ... does it bog then accelerate hard? ... does it feel strong or "soft"?

If you hear or feel pinging ... or if it gets too hot ... bring it back home.

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Post a detailed report of how it drove & I'll help you make carb tuning adjustments to improve it.

Pull all 8 spark plugs & post photos so I can see the tip, porcelain & outer ring of each. Keep them marked, so if I see something odd, I can tell you what to adjust & where.

It takes several rounds of tuning to get the fuel & timing curve of a new engine combination it optimum. But then it will be awesome for as long as you have it, barring serious weather or altitude changes.

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[Peter Mc Mahon]

I love this thread, thank you Ron and everyone else that chimes in. It's like a good book!

[Ron Sutton]

I love this thread, thank you Ron and everyone else that chimes in. It's like a good book!

You're welcome.

We got side tracked with some engine gremlins, but we got them all worked out. Now we're on to tuning.

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[benno505]

thanks Ron, I will have to postpone this for a moment as my vac gauge was destroyed by my 2 year old son. going to order one today.

1 question on the bottom of the carbs there is 2 vacuum ports, 1 is slightly higher then the other, but when hooking the gauge up to do the A/F mixtures, do I need to alternate between hookingit up each carb or can I do all the adjustments from the one vacuum port?

I will see if I can borrow a gauge In the meantime.

[Ron Sutton]

thanks Ron, I will have to postpone this for a moment as my vac gauge was destroyed by my 2 year old son. going to order one today.

1 question on the bottom of the carbs there is 2 vacuum ports, 1 is slightly higher then the other, but when hooking the gauge up to do the A/F mixtures, do I need to alternate between hookingit up each carb or can I do all the adjustments from the one vacuum port?

I will see if I can borrow a gauge In the meantime.

On twin carbs, I like to hook the vacuum gauge up under the carb I'm working on ... because every once in a while the vacuum is different if one carb is "off" in it's tune. Of course the manifold vacuum averages in the plenum.

Gotta love the kids. If that's the worst expense he costs you this week ... you are miles ahead of most. LOL

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