Need a wise mechanic to help with noob question [Archive] - Forum


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01-24-2011, 03:11 PM
I watched a friend's 2001 GAGT motor go. I think he said the bill for a new crate engine from GM and installation at a garage was either $3200 or $4000. Not very much anyway. The motors are cheaper than I thought. It occurs to me that his car was a year older than mine with 50,000 km less on the engine at 172,000 km. This has me kind of nervous over my engine.

Anyways, knowing that it doesn't cost very much to replace the engine if it goes, the body and frame are in excellent shape, how much more complicated would it be to install the 3.8L engine from a Grand Prix instead of the 3.4L?

Now before I get laughed at, understand that I have very limited knowledge of mechanics but am a very curious person. I'm just wondering how many sensors would have to be changed, a new BCM from a Grand Prix or maybe just reprogram the one that's already in the car, possible problems with the transmission? Or is the motor just too incompatible? Too big maybe? Is it something I can consider doing when the time comes? Could a no name garage actually do it or would a dealership be required? And if it can be done by a no name garage, would it have to be a very wise mechanic?

01-24-2011, 04:20 PM
No reason your engine should go yet if it's been reliably maintained. But if you did end up having to replace it, I'd just put another 3400 in there or step up to a 3500. All the research has been done and the parts are available to make the 3500 work already.

I would never consider putting a 3800 in there. First off it's a heavier motor and an older less efficient design. A stock NA 3800 only makes 15-20 more HP and a few ft/lbs more than a 3400. Not very good for an engine with nearly a half liter more displacement.

Also they are from totally different engine families. They share a common bolt pattern for transmission housings, but other than that they are totally different. There would be a LOT more custom work involved to make a 3800 work. A couple people have done supercharged 3800 swaps with the 4T65 transmissions, and the results where less than impressive for the money spent. It also ended up requiring running TWO computers to make it all work and retain the factory gauge cluster. Totally not worth it.

01-24-2011, 07:26 PM
That was an excellent reply. So it's not a good idea. Stepping up to a 3500 isn't much work then I take it? So some no name garage could do that?

If I did have to get a new motor, I was thinking of shopping around for a well qualified garage and maybe get a half decent turbo. I wouldn't trust one with a motor with as many km on it as mine. I've read some threads on here and some of the modifications don't seem to difficult, and by difficult I mean costly in labor and such.

Well know I now.

01-24-2011, 09:19 PM
check out this thread. We were just talking about swapping a 3500.

It's not that hard, but a normal mechanics shop may have trouble with it depending on how good they are and how well they know your engine. It's a fairly simple swap, but there are certain parts that have to be used. Pretty much everything you need to know is in the thread link for I posted in the other thread.

If you have questions about this though, I definitely wouldn't start thinking about a turbo. Waaaaaaay more complicated once you add boost to one of these. You need to know what you are doing, and you need to know how to tune your own car. It's not as simple as just throwing a turbo on there, and taking it to an inexperienced shop would be a waste of money because you'd probably just end up with a blown engine and a junked turbo.