I have a high mileage comp G. I am gathering parts for engine replacement after christmas season. I have just found a 99 LeSabre with under 80k miles, single adult owner, will not pass inspection due to rust. $500. I plan on using the engine and do top swap. Can I also use the transmission? My car has the tap shift. My current trans has no issues just a lot of miles. Also does the comp G have a unique torque converter? Thanks Tom
Transmission question
- Thread starter Tom0247
- Start date
Fivefingerdeathpunch
New member
Comp G needs Comp G trans for it to be a direct swap.
You can't use anything older than 2004.
And why are you going to replace the motor, is it really dead???
Seems like you'll just be opening a can of worms trying to top swap an on a high compression engine.
You can't use anything older than 2004.
And why are you going to replace the motor, is it really dead???
Seems like you'll just be opening a can of worms trying to top swap an on a high compression engine.
BillBoost37
New member
You would have to replace the channel plate, valve body, wiring harness and the range selector if you wanted to use that trans.
Fivefingerdeathpunch low compression in # 3 cylinder and mileage over 2ook. It does appear a lot of info on www about doing top swap, besides 3.8 are a dime a dozen, every supercharged 3.8 I have found is high miles. I have plenty of low mileage n/a motors in my area. Im not looking for a performer here, I have a well set up Grand national and a corvette. I drive over an hour each way to work thru the mountains seems this car would be economical and a fun drive to work. As the builder of this 10 sec buick I understand how compression relates to detonation. Previously I was told a tune would make this work. As looking at some kits available and reading a few stories here plenty people have done this swap. I have not purchased a donor car and will not start this project until after christmas. So I may still find a s/c 3.8 to use. I work for a auto wholesaler part time and still await finding a wreck. I dont need this car to drive and have time on my side.
Thank you both for transmission information. Im still gathering info before doing this swap.I will keep reading. Seems the Bonneville forum has some knowledgeable members also.
Thanks for your input.
Tom
Thank you both for transmission information. Im still gathering info before doing this swap.I will keep reading. Seems the Bonneville forum has some knowledgeable members also.
Thanks for your input.
Tom
You need to confirm that your heads are still good first before you can say you're going to top swap.
Low compression can be a dead valve as a result of taking a hit from a chip of your piston.
The stock tune on your car is way too aggressive in regards to WOT timing for even the factory bottom end, let alone the NA bottom end.
At the very least, a tune and a larger pulley. Unless by some magical chance your engine runs knock free on the 3.8 pulley with the NA bottom end. If not, the NA bottom end won't last as long as the SC one did. The ring landing is closer to the top of the piston, making it weaker and more prone to breakage due to detonation.
Low compression can be a dead valve as a result of taking a hit from a chip of your piston.
The stock tune on your car is way too aggressive in regards to WOT timing for even the factory bottom end, let alone the NA bottom end.
At the very least, a tune and a larger pulley. Unless by some magical chance your engine runs knock free on the 3.8 pulley with the NA bottom end. If not, the NA bottom end won't last as long as the SC one did. The ring landing is closer to the top of the piston, making it weaker and more prone to breakage due to detonation.