LS Swap Questions
Thread Starter
Burning Brakes
Joined: Apr 2009
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From: That one city...you know that one. Idaho
LS Swap Questions
I am swapping an LS based egine into my 93 C4 I have ran into a few snags and would like some advice.
How does the differential bushing affect installing the cbeam?
Has anyone ever seen a cbeam twist?
Would solid mounting the differential cause problems? If so what kind?
The engine was rebuilt, and has not been started. I have not dealt with engine break in, and I am nervous about killing it.
What should I do, and avoid doing here?
With the cbeam I can get 6 bolt holes lined up, but I cant install 2 bolts.
I am not sure what the problem is that is causing this.
How does the differential bushing affect installing the cbeam?
Has anyone ever seen a cbeam twist?
Would solid mounting the differential cause problems? If so what kind?
The engine was rebuilt, and has not been started. I have not dealt with engine break in, and I am nervous about killing it.
What should I do, and avoid doing here?
With the cbeam I can get 6 bolt holes lined up, but I cant install 2 bolts.
I am not sure what the problem is that is causing this.
Team Owner
Joined: Aug 2000
Posts: 40,156
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From: San Pedro CA
The C-beam is a tricky thing... if you are having alignment problems, they are a pain.
Get a pointy metal bar to help align the holes. I do think these get tweeked with age, no question. But they will go in AS LONG AS THE ENGINE is aligned right. IF the motor is cocked left or right, all bets are off.
You cannot hard mount the diff... it already is!
The trans cannot be, because the floor cannot support the torque loading. Remember, this is a back bone architecture, and the body is simply the body...
Get a pointy metal bar to help align the holes. I do think these get tweeked with age, no question. But they will go in AS LONG AS THE ENGINE is aligned right. IF the motor is cocked left or right, all bets are off.
You cannot hard mount the diff... it already is!
The trans cannot be, because the floor cannot support the torque loading. Remember, this is a back bone architecture, and the body is simply the body...
Team Owner
Joined: Aug 2004
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From: Park City Utah
You CAN "hard mount" the diff to the frame. The detriment would be an increase in NVH into the cabin of the car, and added weight.
There is no meaningful "torque loading" from the trans, into a crossmember on any modern car that I am aware of, and certainly not on a C4 w/a cross member added. Engine/trans torque is introduced to the "body" (frame actually) through the motor mounts.
The Corvette does not use a "backbone architecture". That is LORE that has been passed on from early misprints of how the car is made and it still persists. Bogus, I'd recommend THIS READING for you, if you have some time. The C4 is a perimeter frame car, the only thing "special" about it is that the body panels are adhered directly to the frame, rather than bolted on top of it...and the C-beam, which simply eliminates the need for a cross member and heavy beams to support the diff. You can use a trans cross member in a C4 (383vet is proof of that), but again, it will add weight and also lower ground clearance.
OP: I'd do what ever I have to do, to get the C-beam to fit and work.
As for engine break in, there isn't much required in modern engines with roller cams, etc. Just make sure the oil pump is charged, start it, and drive it normally for the first bit.
The trans cannot be, because the floor cannot support the torque loading. Remember, this is a back bone architecture, and the body is simply the body...
The Corvette does not use a "backbone architecture". That is LORE that has been passed on from early misprints of how the car is made and it still persists. Bogus, I'd recommend THIS READING for you, if you have some time. The C4 is a perimeter frame car, the only thing "special" about it is that the body panels are adhered directly to the frame, rather than bolted on top of it...and the C-beam, which simply eliminates the need for a cross member and heavy beams to support the diff. You can use a trans cross member in a C4 (383vet is proof of that), but again, it will add weight and also lower ground clearance.
OP: I'd do what ever I have to do, to get the C-beam to fit and work.
As for engine break in, there isn't much required in modern engines with roller cams, etc. Just make sure the oil pump is charged, start it, and drive it normally for the first bit.
Last edited by Tom400CFI; Aug 19, 2014 at 07:38 PM.
Thread Starter
Burning Brakes
Joined: Apr 2009
Posts: 1,228
Likes: 10
From: That one city...you know that one. Idaho
I am unsure how solid mounting the differential would add weight. Could you explain that?
I have noticed that it is always the same 6 bolt holes that line up, and no matter what I try I cant get the 2 bolt holes on top of the differential lined up. The 2 bushings? that mount the differential to the frame need replacing.
I ended up getting a D36 cbeam because my D44 cbeam seems too short. Other then being too long it would work.
PS
I think I need to thoroughly inspect the rear suspension for damage. What points shout I look at the closest? I'm asking because the car has coil-over shocks, and either the RR or RL shock had issues. I was hoping that I could just replace the shock, but now I think I need to look at everything closer. The shock is a QA1 DS502. I am not sure how to explain what happened.
I have noticed that it is always the same 6 bolt holes that line up, and no matter what I try I cant get the 2 bolt holes on top of the differential lined up. The 2 bushings? that mount the differential to the frame need replacing.
I ended up getting a D36 cbeam because my D44 cbeam seems too short. Other then being too long it would work.
PS
I think I need to thoroughly inspect the rear suspension for damage. What points shout I look at the closest? I'm asking because the car has coil-over shocks, and either the RR or RL shock had issues. I was hoping that I could just replace the shock, but now I think I need to look at everything closer. The shock is a QA1 DS502. I am not sure how to explain what happened.
Last edited by aDigitalPhantom; Aug 19, 2014 at 08:01 PM.
Team Owner
Joined: Aug 2004
Posts: 21,543
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From: Park City Utah
Can you re-drill the C beam?
Last edited by Tom400CFI; Aug 19, 2014 at 11:48 PM.
Thread Starter
Burning Brakes
Joined: Apr 2009
Posts: 1,228
Likes: 10
From: That one city...you know that one. Idaho
I could re-drill the D36 cbeam to work, but I don't have the tools I need for that.
With the D44 cbeam the new holes would just hit the outside edge, and I doubt there would be enough material for that to work correctly.
The engine is not stock but I am unsure how much power it will make.
With the D44 cbeam the new holes would just hit the outside edge, and I doubt there would be enough material for that to work correctly.
The engine is not stock but I am unsure how much power it will make.
Team Owner
Joined: Sep 2003
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You have incorrect engine mount adapters for the LS install in an LT suspension member. You either modify the adapters you have or you replace your suspension cross-member with a '90 or '91 L98 suspension member so you can use your adapters BUT you would need to buy the earlier style mounts and discard the LT type mount you're attempting to use. The alternative would be to purchase adapters for an LS install using LT type mounts in a C4. I didn't look.
In your other thread I suggested you start a thread:
"ANYONE INSTALLED AN LS IN A '92+ LT1 CHASSIS WITH ZF".
There's threads where newer C5/6 brackets to engine were used and either manufactured "solids" or mounts other than something OE. I also think your Novak release is going to be an issue but it's not my build so I didn't look any further.
This is an 11 page read that maybe you could learn from.
http://forums.corvetteforum.com/c4-t...arts-list.html
In your other thread I suggested you start a thread:
"ANYONE INSTALLED AN LS IN A '92+ LT1 CHASSIS WITH ZF".
There's threads where newer C5/6 brackets to engine were used and either manufactured "solids" or mounts other than something OE. I also think your Novak release is going to be an issue but it's not my build so I didn't look any further.
This is an 11 page read that maybe you could learn from.
http://forums.corvetteforum.com/c4-t...arts-list.html
