3.4L to 3.1L Swap Question

[Leckenz34]

I think my motor is on its last leg, 3.4L are quite rare where i live and 3.1L are in abundance, I heard its much easier to put in a 3.1 then another 3.4. How hard is it to do? Are the mounts and wiring basically the same? how long would someone estimate this would take provided i had a full shop with all tools necessary to do?

 

(the 3.1L will be from a first gen z24)

[slick]

It will be much easier to put in another 3.4 than to put in a 3.1. Think about it, the 3.4 is already in there, the new one will be a direct drop in.

 

To swap to a 3.1, you would have to open up the engine harness and move some plugs around, or just get the harness from the donor vehicle.

 

And, since it is coming from a Jbody, you will have to change out all of the mounts, some of the accessories, and a few other odd's and ends.

 

Not going to be worth it, at all. In fact, after the 3.1 swap, you'd probably be so dissapointed to the point of wanting to sell the vehicle. I know I would be.

[z34mightymachine]

I agree with slick. I had a 89 Z24 with a 3.1 and I would take the 3.4L anyday. It would be much easier to put back the 3.4L. Look hard for one. Its worth it.

[meltboy1]

is the 3.4 fixable, or is it more cost effective to replace the motor, why do you say it's on it's last leg?

[digitaloutsider]

Maybe back in 1995 it would have been cost effective to swap to a 3.1, but at this point in time, there's no reason not to get another LQ1. They're cheap, and they're plentiful if you know where to look.

[Breakdown]

I think my motor is on its last leg, 3.4L are quite rare where i live and 3.1L are in abundance, I heard its much easier to put in a 3.1 then another 3.4. How hard is it to do? Are the mounts and wiring basically the same? how long would someone estimate this would take provided i had a full shop with all tools necessary to do?

 

(the 3.1L will be from a first gen z24)

 

Sorry definitely not a fan of the 3.1L V6, the generation III or whatever 3100 series, is a much nicer engine, faster, better on fuel, aside from the LIM gasket issue.

 

Do yourself one favour. Next time you're out in a mall parking lot, find all of the Cutlass Supreme's with the flat dash. Then look real close for an airbag. Chances are they'll have an airbag. Why? Eventhough the airbags were only on the '94s, the 94's were the only ones with the 3100 V6 as well. Most of the 3.1's are off of the road in 1992 & 1993 because people are tired of putting up with their crap.

 

Yeah, disclaimer, if the engine is a 3100 I'm totally sorry disregard everything that I've said, my knowledge on Cavalier's is . . . . not so great, I believe that they only got the 3.1L V6 or first gen.

[Leckenz34]

well I live on Prince Edward Island, Canada there are only like 2 other z34's here besides mine and there both on the road, finding a motor isn't easy. and as for whats wrong with the motor, i got a timing belt idler pulley wobbling quite bad and i there's a knocking sound coming from the engine within the last few days, if anyone knows of any 3.4L for sale on the east side of Canada, let me know

[Breakdown]

well I live on Prince Edward Island, Canada there are only like 2 other z34's here besides mine and there both on the road, finding a motor isn't easy. and as for whats wrong with the motor, i got a timing belt idler pulley wobbling quite bad and i there's a knocking sound coming from the engine within the last few days, if anyone knows of any 3.4L for sale on the east side of Canada, let me know

 

Know what?

 

 

I believe you 100%, and the ones that you might come up with might be an even bigger curse than what's already inside the car now.

 

I'm just saying that I would NOT take the engine out of that Cavalier either, go 1994+.

 

Just my two cents.

[Leckenz34]

what about a swapping the motor out of a 95 Bonneville, its a Series I, 3800 Supercharged

[meltboy1]

well hell, if you are gona go that route why not a series 2, or 3?... lol

Either way you look at it, swapping a non stock motor in the car is going to be a lot of time and trouble.

[Leckenz34]

well the only reason i mentioned it was because i can get that motor for supercheap, but ya i dont really want to go through the trouble of putting a diff motor in my car

[SappySE107]

I don't recall having to do much for wiring when I swapped my 3.1 out for a 3.4 DOHC. Injector harness was it...which is already on a 3.1 or should be. As for the mounts, you can use the 3.4 DOHC engine mounts on a 3.1 if you use the whole unit that bolts to the block. You can use a 93 3.1 chip and keep your stock computer as well and still control your 4T60-E. Just need the dogbone for the front of the motor, which shouldn't be overly difficult to locate.

 

3.1 gets better gas mileage than the 3100 from my experience. Never heard of a 3100 getting 40mpg highway without high compression. If you just want the car to drive and not race, then screw the 3.4 DOHC. It's a performance motor with higher maintenance. If you can't fix the timing belt yourself, you need a different motor.

 

 

[xtremerevolution]

well hell, if you are gona go that route why not a series 2, or 3?... lol

Either way you look at it, swapping a non stock motor in the car is going to be a lot of time and trouble.

 

Because with a series 2 or 3, you have to swap over to OBD2, which is even more work. The question is whether or not that additional work will be worth the trouble for him.

 

I have a 1995 Series 1 3800, and I think just about everyone knows what I think of the motor, but to sum it up:

A lot faster than a 3.1 and without a LIM failure.

More reliable, cheaper to maintain, easier to work on than a 3.4.

More torque than either the 3.1 or 3.4.

Cheap as dirt in junkyards and really easy to find.

 

The only downfall: no aftermarket (aside from intake, exhaust, and roller rockers). Then again, there isn't much of one for the 3.1 or 3.4 either.

 

Oh yeah, and they're cheap as dirt in a J/Y.

 

Ask anyone around here; a Series 1 3.8 will outlast any car it was originally put into, and hey, they don't catch fire like the Series 2 3.8's do

[Breakdown]

well hell, if you are gona go that route why not a series 2, or 3?... lol

Either way you look at it, swapping a non stock motor in the car is going to be a lot of time and trouble.

 

Because with a series 2 or 3, you have to swap over to OBD2, which is even more work. The question is whether or not that additional work will be worth the trouble for him.

 

I have a 1995 Series 1 3800, and I think just about everyone knows what I think of the motor, but to sum it up:

A lot faster than a 3.1 and without a LIM failure.

More reliable, cheaper to maintain, easier to work on than a 3.4.

More torque than either the 3.1 or 3.4.

Cheap as dirt in junkyards and really easy to find.

 

The only downfall: no aftermarket (aside from intake, exhaust, and roller rockers). Then again, there isn't much of one for the 3.1 or 3.4 either.

 

Oh yeah, and they're cheap as dirt in a J/Y.

 

Ask anyone around here; a Series 1 3.8 will outlast any car it was originally put into, and hey, they don't catch fire like the Series 2 3.8's do

 

I agree with everything you just said except for the 3.1L vs. 3100 fuel economy, from personal full-time use AND stats that I've seen, the 3100 is the winner for fuel enconomy maybe 5% better.

[SappySE107]

Yeah, you can't find anything for a 3.1... When did I slip back to 1996?

[xtremerevolution]

 

I agree with everything you just said except for the 3.1L vs. 3100 fuel economy, from personal full-time use AND stats that I've seen, the 3100 is the winner for fuel enconomy maybe 5% better.

 

Yeah that's one thing you're right about. I forgot to mention fuel economy. The 3.1L does get better fuel economy than the 3800 Series 1. You're also about right with the margin. My 3800 with 181,000 miles averages 22.3 miles per gallon city/highway with plenty of stop and go traffic.

 

Then again, I've also taken especially good care of that car since I bought it.

[Breakdown]

Leckenz34,

 

 

I don't really think that you have that bad an idea it's just that I don't recommend using an engine as old as you are considering, also I just don't like that engine.

 

Just go through the posts, these things aren't idling right, they're stalling and they are costing a fortune:

 

MadPSI, BuckFifty, myself, I can't even recall just how many members who are at their wits end replacing things within the engine and are getting frustrated.

 

They don't die a spectacular death, with head gasket problems, cracked block, any of those things, it's slow and painful and $250 here, and another $350 there . . . . . .

 

My fuel economy ladder (I know someone's going to disagree):

 

3.8L < 3.1L < 3800 = 3100, I haven't "experienced" the L67 so I'm not going to comment.

 

Again, I like your idea, I'd just wait for a 3100 that's from a car with a toasted tranny or something.

[ManicMechanic]

the 94's were the only ones with the 3100 V6 as well.

 

Incorrect. You could have a 1993 with a 3100, but not in Canada from what I gather.

[Addicted To Boost]

3.8L < 3.1L < 3800 = 3100, I haven't "experienced" the L67 so I'm not going to comment.

I'm gonna have to disagree with you here.

 

In my experience, 3.1s get excellent gas mileage. My Turbo 3.1 pulled off 31 MPG on the original plugs, wires, and sensors last year, and I also had an 89 2.8 that could pull off 35+ MPG easily. My dad has a 98 regal with a 3800 that struggles to get over 22 MPG with all highway driving.

 

3.1s are excellent motors, but if you are looking for performance out of your Z, find another 3.4.

[Breakdown]

the 94's were the only ones with the 3100 V6 as well.

 

Incorrect. You could have a 1993 with a 3100, but not in Canada from what I gather.

 

Actually I just read that on wikipedia just after posting. I don't think that we had them or they were late year additions I haven't found one, but when and if I do I'll pass along the VIN#.

[Night Fury]

3.1's suck ass, 3100's are WAYYY better.

 

I NEVER had a problem with my 3100, and it got 36 mpg fairly easily on the highway.

 

I can't STOP having problems with my 3.1. And the best mpg it has got was about 15. Yes, that was pure highway.

 

I will never own a 3.1 as long as I live.

 

Flame this all you want, But I blame it all on the heat of the engines. Hell, I could drive my Ciera to hell and back and almost keep my hand on the plenum without getting burned. If I drove around the block in the 3.1 though, fuck if I should try to even open the hood without getting burned!

 

Heat takes a huge toll to everything under a hood over time... even the transmissions apparently.

[GP1138]

3.1's suck ass, 3100's are WAYYY better.

 

I NEVER had a problem with my 3100, and it got 36 mpg fairly easily on the highway.

 

I can't STOP having problems with my 3.1. And the best mpg it has got was about 15. Yes, that was pure highway.

 

I will never own a 3.1 as long as I live.

 

Flame this all you want, But I blame it all on the heat of the engines. Hell, I could drive my Ciera to hell and back and almost keep my hand on the plenum without getting burned. If I drove around the block in the 3.1 though, fuck if I should try to even open the hood without getting burned!

 

Heat takes a huge toll to everything under a hood over time... even the transmissions apparently.

 

I think you have problems.. my 3.1's were slow, but reliable. Plenty of low-end torque, as well. Jack shit up high, but could spin the tires just fine.

 

I'd still rather have a 3.4L or 3100, but I would take a 3.1L Cavalier any day.

[ManicMechanic]

the 94's were the only ones with the 3100 V6 as well.

 

Incorrect. You could have a 1993 with a 3100, but not in Canada from what I gather.

 

Actually I just read that on wikipedia just after posting. I don't think that we had them or they were late year additions I haven't found one, but when and if I do I'll pass along the VIN#.

 

I have yet to find a WH11M or WH51M car...Or even a WT34M or WT31M car. The 3100 became available around Jan. 1st 1993...and the CS was the only car to get it, I believe.

[ManicMechanic]

The 2.8/3.1 was the 283/327 of the V6s...

[Night Fury]

3.1's suck ass, 3100's are WAYYY better.

 

I NEVER had a problem with my 3100, and it got 36 mpg fairly easily on the highway.

 

I can't STOP having problems with my 3.1. And the best mpg it has got was about 15. Yes, that was pure highway.

 

I will never own a 3.1 as long as I live.

 

Flame this all you want, But I blame it all on the heat of the engines. Hell, I could drive my Ciera to hell and back and almost keep my hand on the plenum without getting burned. If I drove around the block in the 3.1 though, fuck if I should try to even open the hood without getting burned!

 

Heat takes a huge toll to everything under a hood over time... even the transmissions apparently.

 

I think you have problems.. my 3.1's were slow, but reliable. Plenty of low-end torque, as well. Jack shit up high, but could spin the tires just fine.

 

I'd still rather have a 3.4L or 3100, but I would take a 3.1L Cavalier any day.

 

 

It was fine when I got it, but being a DD after sitting for a year+ wasn't the best of it's life. I would still rather have a 3100. Unless I was guaranteed NEVER to have problems with a 3.1.