Setting Driveline Angle - LS1 Swap with a 21st Century Subframe

[Mkelcy]

I'm in the process of mocking up the LS1 in my 21st Century Street Machine subframe for my project '68 Camaro. The subframe is out of the car on a stand. I'm using AutoKraft LS1 mounts, and the transmission crossmember that came with the frame. With the AutoKraft LS1 mounts swapped (passenger side on driver's side and driver's side on passenger side) my front to rear distance looks pretty good and so far as I can tell with careful measurement/eyeballing I should have the engine about an inch or so away from the firewall.

That said, using the cross-member with a poly transmission mount results in about zero degrees driveline angle and sticks the collectors of the 21st Century headers halfway into the passenger compartment, as well as aiming them directly into the cross-member.
https://www.pro-touring.com/forum/attachment.php?attachmentid=29579&stc=1&d=1239233146

I've determined that a 4 degree downward angle pretty much solves my header to floor issues, leaves the oil pan higher than the front crossmember and allows room for the exhaust to go under the transmission crossmember. I'll have to revise the transmission crossmember by dropping the center section by about 2.375".

So, is 4 degrees too much? When the car's aligned should I set the rear pinion angle to 4 degrees as well, or should I set it to something less so it'll be more nearly 4 degrees under acceleration?

Steve Rupp and Payton King - did you have any cross-member issues with your 21st Century subs? I'm somewhat astonished that I need to make such a dramatic change to the cross-member and would suspect the headers, except that the drivetrain is virtually parallel to the subframe with the unaltered transmission cross member and the poly mount in place. Any thoughts?

[Lance-W]

I believe when I was doing mine the magic number was 3 degrees. I'm using a factory subframe so it's not the same but I just ended up making a custom crossmember after I figured out where it needed to be. If you decide to go that way we can make one fairly easy. Plus from the way your picture looks the cross member is going to be right in the way of the exhaust. If you make a custom one it'll solve that too.

[Mkelcy]

I believe when I was doing mine the magic number was 3 degrees. I'm using a factory subframe so it's not the same but I just ended up making a custom crossmember after I figured out where it needed to be. If you decide to go that way we can make one fairly easy. Plus from the way your picture looks the cross member is going to be right in the way of the exhaust. If you make a custom one it'll solve that too.

Yes, the way it sits right now there's no way to route the exhaust even half way decently. I'm not sure I'd trust my welding skills to do the cross member, but I'd be happy to supply the beer if that was an offer :)

[Lance-W]

Yes, the way it sits right now there's no way to route the exhaust even half way decently. I'm not sure I'd trust my welding skills to do the cross member, but I'd be happy to supply the beer if that was an offer :)

Beer will work :)

[Mkelcy]

Beer will work :)

Cool.

[Payton King]

Snap me some pics of the motor mounts you are using they should be the short style used on a 67. Also what is the clearence of the pan to the rack up front? My oil pan is is paralle with the front cross member and level. Yes the angle is 0 when compared to the sub frame.

Steve ran into some problems, but I did not...of course they installed mine and built the cross member at the shop.

[Mkelcy]

Snap me some pics of the motor mounts you are using they should be the short style used on a 67. Also what is the clearence of the pan to the rack up front? My oil pan is is paralle with the front cross member and level. Yes the angle is 0 when compared to the sub frame.

Steve ran into some problems, but I did not...of course they installed mine and built the cross member at the shop.


Thanks. I'll take some picures.

[Vegas69]

Cross member looks to flat. Take some radius steel and make some notches for exhaust. I'd go with 3 degrees if you have tunnel clearance.

[Payton King]

the clearence from my pan to the rack is 1/8 to 1/4 of an inch. It sits close. The mounting plates on the block for the motor mounts....21st did there's out of 1/4 steel and used the short mounts. I think the depth is 1 11/16 compared to the new mounts that are 2 1/16. Most of the aftermarket block mounts out of aluminum are 1/2 thick. The rear mount for mock up was a stock rubber mount. The stock LS rubber mount is shorter than the one you have. Although mine is at 0 degrees because I am running the same mount you have in the picture, with the correct rear mount you should have about 1 to 1.5 degrees down running front to back.

I am guessing that the motor is too high in the car along with this other stuff.

I would make sure the front mounts are correct and lower the rear cross member. You may check around and see if you can find a shorter rear mount.

I also have about 2.5 inches from motor to firewall.

[silver69camaro]

Motor angle can up to 20* until oiling problems occur. In other words, put it wherever you want and adjust the pinion angle to fit.

[Vegas69]

Motor angle can up to 20* until oiling problems occur. In other words, put it wherever you want and adjust the pinion angle to fit.

Ouch....what about his u joint working angles.

[Mkelcy]

I put the oil pan back on the engine (don't ask) and installed the rack. It looks like I have good clearance for the stock F-body oil pan everywhere but for one of the lines on the rack:
https://www.pro-touring.com/forum/attachment.php?attachmentid=29587&stc=1&d=1239301521

The line isn't pinched, but I don't like the way it's bent. I'll either reroute it away from the pan or try to raise the engine slightly; but I don't think I can go any lower with the engine. I don't think the AutoKraft pan I have will fit with the engine this low, but I'm not sure I need it.

With the engine set at a 3 degree angle, the headers are almost perfectly parallel with the subframe: https://www.pro-touring.com/forum/attachment.php?attachmentid=29588&stc=1&d=1239301732

So it looks I'll be taking Lance up on his offer to help build a new cross member with more drop to accommodate the transmission mount and more arch on both sides for the exhaust.

I'll take some measurements after I've got it mocked up in the body to confirm that the 3 degrees works for the exhaust, etc.

Payton, thanks for your measurements and comments; it's nice to hear from someone who has the same subframe. The rest of the 21st Century piece is so nice, and so well thought out, that I was wondering what I was doing wrong to have the transmission cross-member so far off.

Lance, I'll be talking to you no later than the next Cruise the Crest.

[DEIGuy38]

Have you tried to talk to Steve with Bad Penny. He has the 21st Century sub in his car?

[Lance-W]

Lance, I'll be talking to you no later than the next Cruise the Crest.

No sweat bud. We're outta here for the weekend and riding in the desert. We'll make a plan next week or on the Crest run.

[98ssnova]

I would think that if you left it at zero it would hit the trans tunnel. And 20* seems a little to steep for me what about getting a taller engine mount?

[Payton King]

No need to re-route that line on the rack. Once you bring the rear down it will clear line that you pictured.

The stock LS1 rear mount has 1 stud in the center and the mount you have has two...or you could use bolts...so unless you drill a center hole in the crossmember you cannot use that mount.

You may want to check with Prothane and see if they make a chevy style trans mount that is 1 inch instead of 2. You could always make your own. I would make a new cross member myself, but not until the subrame and motor is installed.

Going back and looking at the pics, the mounting pad on that tricky Viper trans may be slighly different than a stock T56.

On a seperate note, I have been in contact with the same guy that Steve used to valve up his Bilstiens. I should be getting a set soon. What are using for a shock and spring rate?

[Mkelcy]

No need to re-route that line on the rack. Once you bring the rear down it will clear line that you pictured.

The stock LS1 rear mount has 1 stud in the center and the mount you have has two...or you could use bolts...so unless you drill a center hole in the crossmember you cannot use that mount.

You may want to check with Prothane and see if they make a chevy style trans mount that is 1 inch instead of 2. You could always make your own. I would make a new cross member myself, but not until the subrame and motor is installed.

Going back and looking at the pics, the mounting pad on that tricky Viper trans may be slighly different than a stock T56.

On a seperate note, I have been in contact with the same guy that Steve used to valve up his Bilstiens. I should be getting a set soon. What are using for a shock and spring rate?

I should have clarified what the picture shows. I took the transmission mount out, so the rear of the transmission has been dropped about 1.75" (the thickness of the transmission mount) and is sitting directly on the crossmember. The picture of the rack and oil pan is with 3 degrees of down angle on the engine/transmission.

I'll put the subframe on the car, see where everything falls and decide on leaving the mounts where they are and re-routing the line on the rack, or getting mounting plates that raise the engine. I kind of like the idea of the engine being as low as practical, so it's going to be, as they say, a "game time decision."

As for shocks and springs, my car's still a way from being on the road. That said, I'll start with some single adjustable QA1's and 550lb springs I had sitting around on the front and 225-250's on the rear with some double adjustable M2's I ordered from AFCO. I gave the shock guru at AFCO the details on the car and they custom valved a set for me. (I was (and am) too ignorant of what I need to give them any direction.) Both sets of shocks are rebuildable and revalvable (if needed), so maybe I can get the Pozzi's to thrash the car once I get it on the road and get some good suspension input.

I don't know how directly the rear end setup of Steve's car is going to relate to ours, because (as I understand it) his upper cross-member is lower than stock because of prior modifications to the car. If that's correct, the angle at which the suspension is working is likely going to be different from his car to ours and the spring and shock valving rates may be affected.

[CarlC]

LS eh? Nice.

[Mkelcy]

LS eh? Nice.

Don't tell anyone, but I found a pretty decent deal on a NIB 376/480 LS3 with the ECU, wiring harness, etc. kit. The engine in the picture will be up on Craig's List once I get done with my mockup.

[Payton King]

of the way my pan sits in relation to the front cross member so you can see if the motor is indeed to low. I would not want my oil pan lower than the front cross member just from a damage standpoint on that cast pan.

I am guess that you will need to raise your tunnel a bit to get it to clear the transmission.

I started out with an AFCO street rod shock and 350 lbs springs. I have DSE leafs and koni's in the back. Rode like a Caddy, but a little to floaty. Went to a 450 lbs up front and it feels great. With the new Bilstiens I may be running 500 lbs. Eventually I will be changing the leafs out...but admittedly, they are working pretty darn good.

Looking forward watching yours come together.

If you need to get a power steering pump, get it from Turn One and tell them you are running a Mustang II rack. If you already have a pump, call them and get a flow reducer. It takes about 2 minutes to pull the old one out and put the new one in. Makes all the difference in the world on the way your steering feels. Best $35 I have spent.

[Mkelcy]

of the way my pan sits in relation to the front cross member so you can see if the motor is indeed to low. I would not want my oil pan lower than the front cross member just from a damage standpoint on that cast pan.

I am guess that you will need to raise your tunnel a bit to get it to clear the transmission.

I started out with an AFCO street rod shock and 350 lbs springs. I have DSE leafs and koni's in the back. Rode like a Caddy, but a little to floaty. Went to a 450 lbs up front and it feels great. With the new Bilstiens I may be running 500 lbs. Eventually I will be changing the leafs out...but admittedly, they are working pretty darn good.

Looking forward watching yours come together.

If you need to get a power steering pump, get it from Turn One and tell them you are running a Mustang II rack. If you already have a pump, call them and get a flow reducer. It takes about 2 minutes to pull the old one out and put the new one in. Makes all the difference in the world on the way your steering feels. Best $35 I have spent.

I've been following Steve's development of Penny because I've got both the 21st Century subframe and the LD 3 link in my car. For some reason I thought you also had the LD 3 link in your car, hence my comments on how the rear suspension in Steve's car is going to be different because of the cross-member location.

I'd appreciate the picture; that's the best way to do the comparison. The stock F-body oil pan is completely above the front cross-member, however my bellhousing may get scraped from time-to-time:

https://www.pro-touring.com/forum/attachment.php?attachmentid=29602&stc=1&d=1239373664

Thanks for the tip on the power steering pump. I don't have the front accessories yet - I was thinking about going with the GMPP setup.

(Boy, I look at these prictures and realize I REALLY need to clean the dump my shop has become.)

[silver69camaro]

Ouch....what about his u joint working angles.

I was noting when "serious" problems occur. He didn't know if 4* was too much...if the motor and headers clears, he's way within the limits. There is no "optimum" angle. Just set it and be done with it.

[CarlC]

Your secret is safe with me.

We can talk pumps next week Mike. I'll have some track time on mine by the time you need one so you will hopefully have several options.

What engine are you mocking up/selling?

[Mkelcy]

Your secret is safe with me.

We can talk pumps next week Mike. I'll have some track time on mine by the time you need one so you will hopefully have several options.

What engine are you mocking up/selling?

An LS1 I purchased several years ago and have been storing since. The wife was not pleased to hear that we'd been storing that big box in the garage for over two years now, and it's just going to be sold off. I've been warned I'd better refill the space or I'll lose it. Unfortunately, that will be easy to do.

[Payton King]

along with one shot from under the car. My pan does not hang below the cross member.

Have you put the frame in the car yet?

[Mkelcy]

Have you put the frame in the car yet?

I spent a nice Easter Sunday getting it in the car, along with the LD rear. I need to make the car a roller for the final body work and paint.

The passenger side head is about 1-3/8" from the fire wall. I think I need to drop the rear of the transmission about another 1/2" from where it sits now. That should be enough to eliminate some interference between the header collector flanges and the floor, aim the headers down a bit from the top of the crossmember for better exhaust routing and eliminate some minor interference between the T56 and the transmission tunnel. I'll confirm the needed amount when I pull the engine and tranny before sending it back to paint.

https://www.pro-touring.com/forum/attachment.php?attachmentid=29659&stc=1&d=1239648503

The header collector flanges are hitting the floor, but I was able to get the driver's side in with the frame in the car, so I think the 1/2" drop might do it.

https://www.pro-touring.com/forum/attachment.php?attachmentid=29662&stc=1&d=1239648642

The oil pan is nicely tucked up behind the front crossmember:

https://www.pro-touring.com/forum/attachment.php?attachmentid=29660&stc=1&d=1239648503

I'm installing the front running gear now and hope to get it back to the body shop this week.

[Payton King]

Went back over the entire thread. The line that you are on at the rack is a balance tube so to speak. Since the boots fit so tight when one compresses the air goes to the other boot that is expanding. Just rotate the boots towards the front of the car and the the line will not be under the pan.

My headers were close on my as well. You have way more room than I did in my tunnel from the back. I am not running the reverse lock out. Does not bother me except when I let someone else drive my car and they are grinding reverse instead of hitting 5th. I agree about another 1/2 drop and you will be golden.

With the front cap off, now would be a great time to mock up your acc drive. Depending on which system you are running and if you are running ac you may have some issues.

[Mkelcy]

Went back over the entire thread. The line that you are on at the rack is a balance tube so to speak. Since the boots fit so tight when one compresses the air goes to the other boot that is expanding. Just rotate the boots towards the front of the car and the the line will not be under the pan.

My headers were close on my as well. You have way more room than I did in my tunnel from the back. I am not running the reverse lock out. Does not bother me except when I let someone else drive my car and they are grinding reverse instead of hitting 5th. I agree about another 1/2 drop and you will be golden.

With the front cap off, now would be a great time to mock up your acc drive. Depending on which system you are running and if you are running ac you may have some issues.

I wondered what the line hitting the pan was. I'll try rotating it. Thanks for the tip.

I'm pretty pleased with the way it's going together. I'll have to decide how much to mod the transmission cross member - just drop the center, or try to arc the sides for more exhaust clearance. I'm going to run a 3" exhaust (at least from the headers to the X crossover) so more room is better.

I'm thinking about running this GMPP kit http://paceperformance.com/index.asp?PageAction=VIEWPROD&ProdID=248708 and then getting this AC compressor bracket http://www.kwikperf.com/lsx_ac.html. Not particularly pretty, but inexpensive and should be as reliable as a rock.

I was planning on sending the car to paint then blowing it apart again for final finish of all the undercarriage stuff. I've painted the subframe, but might have it powder coated; the rear and the links need to be painted or powder coated, etc., etc. I hate overspray, and I trust myself not to scratch my painted car more than I trust the painter not to mess up finished undercarriage parts.

[andrewb70]

You can use V-band collector flanges to give you some more clearance.

Andrew

[Mkelcy]

:)
You can use V-band collector flanges to give you some more clearance.

Andrew

If the 1/2" additional drop doesn't eliminate the interference, I'll look into it. I need to add the O2 bungs to the headers anyway, so a little more welding wouldn't be a big deal, right Lance? :)

[Chad-1stGen]

Looking good Mike!

Either that is one tall lift or you have a steep slope just ouside your garage :)

[Mkelcy]

Looking good Mike!

Either that is one tall lift or you have a steep slope just ouside your garage :)

When we did our remodel, I wasn't able to negotiate a large enough or tall enough shop to have the lift inside, so the lift sits at the end of the pad outside the shop. Just beyond the lift, the yard is terraced steeply down about 6-7 feet and from that point the street runs down hill.

[Lance-W]

:)

If the 1/2" additional drop doesn't eliminate the interference, I'll look into it. I need to add the O2 bungs to the headers anyway, so a little more welding wouldn't be a big deal, right Lance? :)

No problem. The headers are stainless or carbon steel? Either one is fine stainless just takes a different gas.

As far as the 1/2" drop have you thought about just taking that big thick flange on the crossmember end out and using something thinner? I have the V-bands on my 3" exhaust. They're awesome but pricey. Zero gaskets and zero leaks!

I'm jealous of your lift!

On second thought if you just take that big thick flange out you'll still have exhaust clearance problems the problem will just be lower.

[Payton King]

I bought just the LS1 power steering pump and it was $300.

Since you are running AC you may look at Street & Performance. They make a bracket for running the Sanden compressor low on the passenger side and back where it runs off of the factory grove in the the back of the harmonic balancer. I know the vette balancer does not stick out as far as the ls1 version, but you should still have enough room. This is what I am running. I will get you a pic tonight

[Payton King]

S&P makes it with one idler pulley or 2. I have the it with only one. I also have the belt off at this time as well.

[Mkelcy]

Payton: That tucks in there nicely. If I did that, I'd have to get some accesories that actually looked decent.

Do you have a part number for the steering pump flow restrictor? Are you running a hydroboost or vacuum or manual brakes?

Lance: The headers are showing just a touch of surface rust, so I'm assuming carbon steel.

[Payton King]

I called and spoke to the tech line about it. The site address is
www.turnone-steering.com (http://www.turnone-steering.com) I think it is about $30-$40 shipped. It reduces the flow not the pressure. They can explain it all to you. Made a huge difference in the feel of the steering. I know Rupp has one of their pumps in his car and it has the same flow reducer on it.

The bracket is really not fancy at all and it mount so low in the car you have to look for the compressor. The other bonus is it runs on its own belt so you can still use the Vette acc drive. I am running a stock LS pump in the stock F body location, Street and Performance high alternator mount and tensioner. I eliminated an idler pulley that comes with the kit...actually Ron came up with the idea at RTTH 4 when I was having trouble.

You can run the stock F body stuff like Rupp has done, but there is a little fitting remaking to get it to work. The low alernator position puts it on one of the rack fittings.

I had Jim Pettigres make up a custom twin master deal. They are manual and use the stock pedals.

[LSX1STGEN]

That Is a beautiful car. I saw it at the Canton GA Cruise In. Please tell me, does the S&P A/C mount use the stock camaro or corvette compressor carriage?

Thanks,

Clay


S&P makes it with one idler pulley or 2. I have the it with only one. I also have the belt off at this time as well.