Engine swaping 3.1 mpfi to 3.1 sfi or 3.4

[Snafu]

Hi all, New to the forum but not new to cars/trucks/suvs. Been a mechanic for over 20 yrs. Now that dealing with service and repair not Moding and swaping. I owned a 94 olds cutlass supreme sl in 98. Was one of my favs. Family member just gave me a 93 olds cutlass supreme convertible for free. It has the mpfi 3.1 with 150,000mi on it. BAD rod knock. First off, can the engine be pulled out from the top? I'm retired so this will be in a driveway. If it was at a shop I'd just drop the sub frame and deal with it that way. Also, I found a 98 venture van w/3.4 sfi. Now I've done some old carb engines to fuel injected engine swaps ( 350 chevy carb to tbi, 360 dodge carb to tbi) and have run into problems to make it work right. Will the 3.1 mpfi just bolt on a 3.4 sfi? Surely it isn't that easy. And the gm obd1 system, will it feed enough fuel to a 3.4 obd2 system? I mean will the old ecm provide enough to a stock 3.4 to run right? I bought a Iroc long time ago kid blow the 305 so he dropped a 350 crate in it but never swapped the ecm. Hard start, ran hot, too lean. Ran good around town but for get hwy. Sold it to a kid that was going to carb it all, shame. Anyways. Would love to pick a brain. The 93 is in good shape for its age and would like to put it back on the streets in stock or mild form. I know the blocks are some what the same. But from 93 to 98 i'm sure there are some little changes some where.

[Padgett]

My knowledge is mainly 3800s but there are a lot of factors: whether MAF or MAP, fuel maps, injector size, even something so dumb as single vs dual ring crank sensors. Key is that it is more a matter of matching the sensors to the computer and the only way to do that is to instrument it every which way. Or buy a turn key kit.

 

From an engine standpoint, a 350 is just a bored out 305 so under the valve covers they are pretty much the same so there must have been a sensor mismatch somewhere.

 

Similarly the 2.8-3.1-3.4 60 degree V6. I was surprised at how many "old" features (single ring crank, flat tappets) are in the LQ1. If you have a 98 3.4 that should have a dual ring crank sensor and need a computer programmed for it.

 

Have never worked on one of those, that was my 3800 era but when you get down to it a gas/piston engine is an gas/piston engine. You just need to know how to talk to it.

 

ps whether you can pull an engine in the driveway depends on how big an oak tree is growing over it (have done a Buick clutch on an oak root before). Here if it isn't too hot to work in the drive it is raining. "Enough" garage was a goal all of my life & am close.

Edited May 28, 2016 by Padgett

[Nas Escobar]

Yes, you can swap in a 3400 LA1 where an LH0 (your 3.1 MPFI) resides. From my understanding, the 3400 is a bored out version of a 3100 (L82), itself an updated LH0 with SFI and other minor improvements. Your real issue will be that you may have to convert to OBD2 or send your computer out to WOT Tech or Milzy Motorsports to get the computer programmed to run the LA1. That would eliminate the probability of issues with the new engine.

 

What most guys have done here however is swapped out the 60 Degree V6 (the 2.8, 3.1, 3.4, 3100, 3400, 3500 engine family) for a Buick 3800 S2. You could go supercharged or keep it naturally aspirated, however this would be the easiest thing to do as the 1996 Buick Regal and 1998/1999 Chevy Monte Carlo both had a 3800, but in naturally aspirated form. In theory, you could get a donor 96 Regal and convert your 93 to OBD2, and 3800 power it along with the transmission since the 3.1/3100 had the lowest gear ratio of the 3 engines available. The LQ1 had the highest ratio at 3.42 and I think the 3.1 had it at 3.30 or something along those lines.

 

There's a lot of threads of people swapping a 3800 in their 1st gen cars on here.

[Padgett]

There appears to have been one more ratio for the LQ1 with 284: FV0 RATIO, TRANSAXLE FINAL DRIVE 3.67

[Nas Escobar]

There appears to have been one more ratio for the LQ1 with 284: FV0 RATIO, TRANSAXLE FINAL DRIVE 3.67

I didnt know what the 284s fdr was. I know the 4t60s because I was thinking of using one from a 3100 on my LQ1 Cutty

[Padgett]

284 is the Getrag 5 speed trans code M27. Think it was only used with the LQ1. Fiero Getrag was a 282 which is more common.

 

Would probably be using a 4T60E, 4T60 lacks most of the electronics except for the TCC.