In my ongoing search to find an engine for my GT, I have found an 1990 3.1 V6 from a minivan. Does this engine have the same Hight Output heads as on our 2.8 V6? I was going to go the 3.4 route but I talked to Ed Parks and it doesn't seem to be as simple as just tapping a new starter hole; there are a lot of other bits and mods a guy has to do as well to get it to work. I just wanted to check to make sure that this is the right engine. I heard that there is one version of the 3.1 that uses low compression pistons and makes no power at all. What is the HP and torque difference between the 3.1 and 2.8? Once again, thanks for all of your help.

As I recall, all the FWD motors, car or minivan, should fit. The only ones you have to mess with the starter on are the inline RWD motors. You didn't say which van it is, but I thought all GM mini's where FWD.

I'm not sure what else GM would have done to the motor. Usually truck motors make more power. In V8's they often have 4 bolt mains, but I don't think GM did that with the V6 for truck.

I could be wrong here?? But think I read where the heads on the 3.1 are not the same as the Fiero 2.8??? That if you went with the 3.1 you would want to use the 2.8 heads?
Also the difference in displacement between a 2.8 and a 3.1 is not worth the work & $$$??? Depending on what you can get the 3.1 for??
Just My thoughts???

Don't forget that even though the 3.1 only has 0.3L more displacement, it has a longer stroke, hence more low end torque.
Displacement isn't the only factor in power.

In the days that the Fiero was being produced there were no dedicated FWD engines. They were all derived from RWD turn sideways. Such is true for the 2.8 which was used in a wide variety of both FWD and RWD applications as well as the 2.5. The 3.1 block is part of the new generation of dedicated FWD blocks. They take even more tinkering with than the 3.4 iron headed block. The current 3.1 and 3.4 engines are very different from the same displacement engines of the mid 80s and mid 90s. The 3.4 of choice for Fieros is the 3.4 iron head V6 that was used for the 92- 95 f-bodies and chevy S-10.

The money difference from a 2.8 to a 3.1 to a 3.4 is that for the same money it would be easier to go straight to the 3.4 rather than a 3.1. Kinda like putting a 5.0 liter v8 intstead of 5.7. Same money for less.

The 3.4 has a lot of very satisfied owners on the streets right now. Aside from the starter relocation an the AC bracket, what other bits are you talking about?

Thanks for the info. The 1990 3.1 has the cast heads, not the aluminum ones so I thought it should drop right in. For the 3.4 conversion, I was told I would get new injectors and a new fuel pressure regulator. The add up to about an extra $500 Canadian. Also, it would take the shop 5 hours to tap the new starter. If I was all done school, I would certainly go this route. But unfortunately, the funds are pretty low right now while at university. I am just looking for something affordable with a bit more jam than my old 2.8 engine.

FIVE HOURS TO TAP THE STARTER HOLES!!!!

ARE THEY MEDITATING BEFORE LUNCH BEFORE THEY START???

Okay, okay, perhaps they would'nt have the tool to do the job correctly but that seems to be a hell of a long time....

The injectors for the 3.4 are needed but we still have not seen any reason for an adjustable regulator. If you are getting a crate engine there is no other choice but to anty up. The other alternative is to get a low miler 3.4 out of the salvage yard.

Oh, one more option(Shameless Plug: I work there occasionally) is to get a prepared 3.4 long block from Fiero Motorsports (I think Ed Parks does that too, not sure.) We have shipped several of them out. Give a call for prices and shipping. 714 639-9005 after 11 AM.

[This message has been edited by WKDFIRO (edited 01-25-2000).]

Loafer, that 3.1 minivan engine with cast iron heads should be a direct swap. The heads will probably be the standard ones with smaller valves, not the HO heads like the Fieros. I think the cam might be milder too.

Ogre, wasn't the Chevy Astro minivan a rear wheel drive?

On the question of larger injectors and adjustable fuel pressure regulator I think you need one or the other, not both. The larger injectors will get proper fuel flow at the standard fuel pressure. The original injectors need a higher fuel pressure to pass the higher volume of fuel. With the adjustable fuel pressure regulator you can raise the pressure accordingly.

I just found a 3.4 form a 95 s-10 w/ 6000 miles on it for $300, from a boneyard. so , do i need to use my 2.8 heads for more power or the 3.4 heads that are on it???

From what I've read, you'll want to use your heads.a Actually, the only thing you'll use from the 3.4 the short block, oil pan optional) and injectors. Everything else is from the 2.8. One of the real attractions to this conversion is that it looks just like the original motor configuration when completed. Makes a reather "stealthy" set-up! Ed Parks offers all the details you'll need if you visit his site.

I would be very interested to see if that 3.1 conversion works out. Unless GM was playing with other heads as well the 3.4 and the Fiero 2.8 should be identical.

87 Steve... If the S-10 has a 3.4, it's not factory. The only V-6s that ever came in an S-10 were the 2.8, and the 4.3. The 4.3 is a 90 degree V-6. Essentially 3/4 of a 350. Won't bolt into a Fiero without a lot of "massaging".

All you need to make a 2.8 a 3.1 is a 3.1 crank (I used one for a '89 Pontiac 6000 for @$120),3.1 pistons for a iron head 3.1(I used stock '92 firebird ones for @$15 each), and a a flywheel without any counter weight (I.E. any 3.1. I got mine from the junkyard for @$25). There isnt a big compression difference(if any) between cast iron and aluminum head engines but there is a huge difference in combustion chamber volume so you've got to use the right pistons unless you want 14:1 or 4:1 compression.

Think of the boost pressure we could run at 4:1 compression!. Do I hear 50 PSI?

Ok, I'm kidding, no flames please.

I just heard that Pontiac made a few 89-90 Grand Prix 3.1 turbo cars. Was this an ultra rare option or are there a few of those engines floating around out in salvage land?

Squid.. have you done this conversion?
It sounds a lot cheaper than what I've heard in the past... I'd like to hear more about this!

It's the same 2.8 to 3.1 conversion that's been discussed many times, just Squid poked around the salvage yard and got some bargain parts to begin with. This is a great way to reduce the overall cost of the project. Used internal engine parts (like the crank) should be checked out thoroughly and magnafluxed by a machine shop.

I got a 3.1 out of a 93 Chevy Lumina APV and it is the cast iron head version of the 3.1

The valves are the same size as the Fiero's and the heads "look" exactly the same.

I don't know about the cam being "weaker" (i.e. less HP output) so to insure more power "grunt", I will exchange it for something a little more bumpier.

There is one thing that Ed Parks warned me about on these 3.1 engines. They DO NOT USE ALL THE BOLT HOLES in the timing chain/water pump housing!!! One needs to be either welded up or siliconed up to keep coolant from leaking!! Which one ... I don't know, yet. Went I get to it, I will take a picture of it and post it in my Photopoint collection.

Paul

[This message has been edited by pherder (edited 01-29-2000).]

Batboy -- The Turbo conversion was done by Mclaren/ASC, starting in 1989. It consisted of the turbo V-6,special 4-speed auto trans, special suspension and wheels with 245/50R16 Goodyear Gatorbacks,and extensive aero body cladding. All of them were red and it was produced in very limited numbers. It was the same in 1990, and dropped in 1991 to be replaced with the GTP. I've heard only around 2000 were produced. got the info from Classical Pontiac

[This message has been edited by Standard (edited 01-29-2000).]