97 grand prix engine swap

**biscuit** · 03-06-2011

I have a 97 3.8L grand prix, will an engine out of a 99 fit and is there anything that I need to get off of the 99 to make it work in my 97? Thanks ahead of time for any information

**Bio248** · 03-06-2011

same motor. the throttle body is different, but they are interchangeable.

**curtcamaro** · 03-12-2011

Hey biscuit I'm doing the exact same thing...only my 97 GPGT car is getting a 99 regal motor, also the same, but post any useful info that you come up with it when you do it. Otherwise I'll do the same when I do.

**indyal** · 03-13-2011

Make sure you have the alternator from the 99 97 mounts different

**biscuit** · 03-14-2011

I just ran out to my shop to look, and dang it you were right! What do you think was the only thing that did not come with the motor...... the alternator. It looks like I can switch the bracket over. Do you know if that is possible?

**biscuit** · 03-14-2011

You got it, I let you know any snags I have. I pulled the old engine out last night and like the post below states the only difference is the alternator bracket.

**BillBoost37** · 03-15-2011

The base motors are identical in all the 3800's 97+. Swap a few accessories/brackets, rear exhaust manifold and flex plate. Those are about he only things to consider.

Reason I say flex is the H/C/G bodies had a 258mm converter not the 245mm.

**biscuit** · 03-16-2011

I mounted the transmission on the 99 motor last night and everything bolted up fine. What do you mean by 258 mm and 245mm, will I have shifting problems?

**BillBoost37** · 03-16-2011

No...the bolt pattern between the flex plate and the torque converter. If things don't line up, you'll know.

In your case, you had two of the same motor with the same flex, your all set.

**BillBoost37** · 03-16-2011

Grabbed pics to explain it better. The flex on an H/C/G body car has a larger bolt pattern for a larger torque converter. The 04+ cars came with dual drilled flex plates to solve this issue. Meanwhile the pattern on a W body is 245mm and the pattern on these others is 258mm. All this means is the bolts won't line up if you mix them.

258mm flex with 245mm torque converter looks like this.

Here's when i pulled it apart and put the right flex on it. See where the bolts are, that's the spacing.

This customer didn't mention he was supplying an H/C/G motor and 245mm TC. I noted it.

Here is how it looks when it lines up.

**biscuit** · 03-16-2011

thanks for the info, very helpful

**biscuit** · 03-20-2011

The only things that I switched over from the 99 motor to the 97 motor was the coil mount (because it is integrated into my top engine mount), alternator bracket (because my new engine didnt come with an alternator and they 97 wont fit on the 99 bracket), and the throttle body. I just finished last night and drove it about 10 minutes ago and it is running like a champ. Feel free to ask any questions and I will do my best to help out in anyway I can.

**curtcamaro** · 03-20-2011

I'm starting this week so I'll make sure to ask if I come across any problems

**Tea Time** · 03-28-2011

biscuit.....u do the swap into a 97 gt or gtp?

**curtcamaro** · 03-29-2011

I don't know if I really post into this or create my own, well if anyone cares, say something.

I started yesterday afternoon and got everything disassembled and the bell housing seperated, just waiting on the cherry picker rental to pull the old motor out. (grr only one place in town has one and they know it,) anyone in Pella/DesMoines area wanna loan one out for a couple days to a week?

Everything looks good, I'm obsessively bagging and labeling all bolts and keeping everything in a tub. i feel stupid and overwhelmed this is my first serious and solo project on any car so its nerveracking but all is well so far.

So far guys, i'm scared but having fun, its a weird mix of emotions.

**BillBoost37** · 03-29-2011

Read what was written please. Take your alternator bracket off and put it on the new motor. It's 3 bolts and very easy.

**biscuit** · 03-30-2011

I put the engine n a GT

**curtcamaro** · 03-31-2011

How the hell do you get to that one bolt on the bell housing that that is facing the opposite direction as the rest?

I have the passenger wheel off, car jacked up and power steering pump up and out. I have to wait to go get a new elbow socket after i broke my one impact rated one (go figure) to get the exhaust the rest of the way off.

But my main problem is I can't even see it! i have 3ft worth of extensions to reach it, but I can't see it to line up on it

**Tea Time** · 03-31-2011

Theres a black metal bracket on the end of the transmission closest to the pass side wheel, i think its only 4 bolts holding it on, once u remove that bracket, u should be able to see right in there to that bolt unless ur engine (and cradle) are considerably lower on the driver side than the pass side. just look straight in from the pass side but have the engine / tranny level.

**Tea Time** · 03-31-2011

http://www.grandprixforums.net/how-r...ion-35485.html

This how - to will show u where the bolt u need to get to is...and the bracket u need to remove.