Initial timing SBC 38 deg+

[matheny00]

Ok here it is SBC 383 stroker had built by a shop 7 years ago (long story) anyway just got to the point of firing it up about 2 months ago did all the pre work prime pump and such so... I did not like the gear drive it had so I took it off and put a dbl roller on. Cam gear 6:00 crank at 12:00 put it together and installed balancer spot on zero Deg. So got it fired back up and decided to start fine tuning everything so grabbed a timing light up till now it was done by ear, Starts easily and runs nice sounds great. Here is the problem checking the timing I am at 38+ deg vac advanced disconnected and nipple on carb plugged @ 750 rpm. And yes the timing clamp for the light is on number 1 cylinder wire driver side front.

What I have done taken dist out 3 times shifted each way one tooth and no go so it is back to the original spot.
I did install it right after the timing chain was installed so technically number 6 comp but I do not think that is the issue...
The dizzy is a dual point that was converted using a Pertronix electronic unit.

Engine specs:
600 Edelbrook carb
Edelbrook pro performer heads 64cc
Cam Lunati

Cam Style

Hydraulic flat tappet


Basic Operating RPM Range

2,000-6,000


Intake Duration at 050 inch Lift

230


Exhaust Duration at 050 inch Lift

230


Duration at 050 inch Lift

230 int./230 exh.


Advertised Intake Duration

292


Advertised Exhaust Duration

292


Advertised Duration

292 int./292 exh.


Intake Valve Lift with Factory Rocker Arm Ratio

0.480 in.


Exhaust Valve Lift with Factory Rocker Arm Ratio

0.480 in.


Valve Lift with Factory Rocker Arm Ratio

0.480 int./0.480 exh.


Lobe Separation (degrees)




109





Crank / Rods Scat stoker setup
Pistons Keith black here is the issue I do not know the compression if I am remembering as I had 2 engines done at that time mine are 10:1 I am almost positive.

I am using a sears timing light with advance timing dial.

No matter what I have done I can not seem to get it lower the last comment someone told me was maybe the weights are stuck or to light of spring or the Pertronix electronic unit could be bad and to toss in a HEI Dizzy but I am tight on room.

[MrQuick]

Sounds like you have the wrong dampner/timing tab combo.

[regal454]

I would start by finding the true TDC of the motor. Do you have a degree wheel and piston stop? You can make a cheap piston stop out of an old spark plug.

[Johnny Blaze]

Sounds like the distributer has the timing locked.

[matheny00]

Mr. Quick Sounds like you have the wrong dampner/timing tab combo.:
I do not think that is possible when I put it all togeather a tdc the tab and mark on balancer lined up

John Regal
That is one of the next things I am going to do

Mr. Quick
I have heard this term before unfamiliar with it the dist is a Mallory dual point that has been converted to a Pertronix module.

Here is another thought just not sure if I am so frustrated I am grasping at straws...

When I put the dbl roller chain assembly on I lined it up crack at 12:00 cam at 6:00 as always so #6 cylinder would be TDC can a car run at 180 off and advanced like crazy? Again I am grasping.

Thanks

[MrQuick]

then that leaves the distributor.

[David Pozzi]

Is the pickup lead attached near the spark plug? The distributor end can often pick up pulses from other nearby wires.
If I'm understanding you right, you are turning the distributor clockwise to retard it and it doesn't change? Or does it retard a little but the distributor is hitting & won't turn more?
What is the timing light dial set at?

[matheny00]

Dave thanks,
Pick up lead right next to the plug... I have full movement of dizzy nothing is hitting it was dying when I retarded it to much.... The timing light dial on 0 would put the mark about 12:00 so if at 35 it would be what I think is TDC but need to check still for true TDC

Here is the latest I took the cap and rotor off to check the weights and they are very easy moved and sloppy so I put it back together what I did notice also a lot of up and down movement 1/8 - 1/4" of play not sure if this is normal. But I started looking everything over and I noticed also the idle mixture screw was not even engaged to the plate, the truck was running off no idle adj what so ever. I brought the idle screw in till it touched the tab and maybe a half turn fired up the truck upon more adjustments I got it to about 12 deg seems a little rich smell the gas at exhaust. I need to find true top dead center now. I did take the rpms up to around 3500 max checked the timing it was right about 20 Deg which sounds way low.

After it idled for about 10 minutes drove it up the block and back pulled in the driveway shout it off and a short diesel happened.


So here are the questions:

Am i to advanced or retarded?
Do I need to shim the dizzy?

[MrQuick]

Sounds like you need an old fashion carb and distri tune.

Are you getting vacuum to your advance can at idle?
What port are you hooking up to for vacuum advance? Should be on ported.
If you are getting vacuum at idle at the ported circuit the throttle blade is open too much or you have an internal leak.

Are you unable to lower you idle?
How much idle circuit are getting at the secondary bores?

Dieseling is usually caused by a high idle, throttle plates are past transfer slots.

Set your idle with a mix between mixture screws and throttle plate adjusting. Set your timing with vac can disconnected. If your timing advances when you hook the hose then you need to figure out why you have vac at that circuit. You may have little and an adjustable vac can can fix that. Set your initial 8-15 degrees then use mechanical to get your total. 32-38 is safe, your engine may enjoy more.
Then you move on to jets and power valve tuning.

[Spitfire100]

Just a guess, but I am having a similar problem. Some years ago I was an avid Drag Racer, and in high rpm situations saw not only harmonic balancers slip, but completely come apart. Most balancers are two pieces of metal separated by a piece of rubber that are bonded together. I am suspecting after many years the rubber deteriorates which leads to failure. I am going to start with finding true TDC and go from there. If I were you I would do the same, when a balancer fails it can be ugly. Just a guess but you might want to check. Also when I find out I will let you know.

Dale

[matheny00]

Mr. Quick

I agree I am now at a point of being close so what I am going to do is....

Find True TDC once that is done then I can truly figure out what is next. I do not have the stuff I need so ordered it on summit along with a shim kit and curve kit for this dizzy. So I will up date everyone in about a week as I am working for the next 10 days straight.

In the mean time thank you for all your advise.

Spitfire the balancer has not shifted one it is brand new and two when I put the chain on it lined up fine

[joeelutz]

After it idled for about 10 minutes drove it up the block and back pulled in the driveway shout it off and a short diesel happened.


So here are the questions:

Am i to advanced or retarded?
Do I need to shim the dizzy?

I would guess retarded, but I have seen too much advance cause dieseling also. Have you held the light on the damper while you rev the engine to see if it is advancing?

[matheny00]

Joe I have done that not much advance so I figure back to square one find True TDC and then go forward from there.

Thanks All

[matheny00]

Ok here is the update tonight I will officially find TDC and then after that is accomplished I will work on the dizzy to remove the slope once that is finished I will put it all back together and then update it will most likely be Saturday that I update.

Again thank you all for your help