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How hard is the newer 3.1 swap? 3.4? 3.8?


aaron7

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At probably near 200k on our 92 LE it's time for a new motor.

 

I can get a ~100k motor for around $250 locally but was wondering, since I'm going through all this work, how hard is the newer-style 3.1 to swap in?

 

What about the 3.4? (not the twin dual cam)

 

And the 3.8? Any specific series that'd be easier, if any?

 

All are cheap and readily available so if it's just the matter of some rewiring I'm down!

 

I'm sure there are threads about this too but after a quick search I couldn't find any :ohdear:

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3.4 is a drop in you just have to rewire 1 or 2 sensors. 3.8 will bolt in but youll need wire harness pcm cv axles heater cores tranny lines radiator hoses and fuel lines and tb cable

At probably near 200k on our 92 LE it's time for a new motor.

 

I can get a ~100k motor for around $250 locally but was wondering, since I'm going through all this work, how hard is the newer-style 3.1 to swap in?

 

What about the 3.4? (not the twin dual cam)

 

And the 3.8? Any specific series that'd be easier, if any?

 

All are cheap and readily available so if it's just the matter of some rewiring I'm down!

 

I'm sure there are threads about this too but after a quick search I couldn't find any :ohdear:

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19cutlass94 would kno more about the swap than me, hes done the swap, mine was swapped when i got it :)

Why would I need a tune if I'm running the factory ECU?

 

I was more curious if the mounts, axles, tranny, etc were the same. Then just rewire the 3.x harness in.

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Why would I need a tune if I'm running the factory ECU?

 

I was more curious if the mounts, axles, tranny, etc were the same. Then just rewire the 3.x harness in.

 

Throughout the years, GM tinkered around with the engines. The 1992 3.1 is not 100% the same as the 2004 3.1 that was in the Malibu, or where ever else you wanna get it from. The most notable differences are the switch from mpfi to sfi, different compression, and of course... the emissions crap they attach to the engine, (or in later years, remove or re-engineer.)

 

Now, you want to swap from a 3.1 mpfi to a 3.4 sfi. Even though the engine is basically the same, at the same time it is vastly different from the 3.1 mpfi. You gotta realize they mess around with the emissions controls and the fuel/air mixture and I think they also mess around with the compression ratio. My point really is that the ECU controls a lot of things and you can't really make a 120hp engine from 92 be a direct drop in for say a 150hp engine from 2002 since the technologies used change, although the block may be literally the same one.

 

Truthfully, asking 19cutlass94 would be a lot of help for you. He used to have a build thread floating around here... don't know what happened to that, but I do remember it isn't a simple thing.

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