can i use a van 3.1?

[Firebb15]

I'm replacing the old 2.8 in my 88 4x4 blazer... i'm wondering if the 3.1 used in early 90's chevy/pontiac vans work as a doner engine. I know they HAVE a distributor type ignition, but they are front wheel drive. So basically will that engine bolt to my 60 degree RWD 700r4 trans? And i have read that you should use larger (4.3) injectors for the 2.8-3.4 swap, but since im using a 3.1, will my 2.8 injectors work? Or if i use the 4.3 injectors, will it be too rich? I have also read that i can just bump up the fuel pressure to accomodate the 3.1 with 2.8 injectors? Thanks for any help! Brian

[geoffinbc]

It has the wrong engine mounts so it wont work. The van engine is a FWD motor.

The only easy bolt in motor is a Camaro donor or a Crate motor. A 3.1L could use 2.8L injectors with a bump in pressure but it also depends on your final power output too.

[MATT2007]

what is wrong with the 2.8 you should be able to run a 3.1 crank in your 2.8 I would rebulid the 2.8 with a 3.1 crank mill .040 off the heads and a good camshaft if you are not looking for performance you could just rebulid the 2.8

[Firebb15]

i just bought this 88 blazer with a rod knock for $300, the 2.8 has 203K on it...it had a new bottom end from a rod knock at 100K, and now it has a bad rod knock at 203K, i took it apart to find the oil pick up tube and screen floating around in the bottom of the oil pan with a bunch of metal shavings from the rod bearing...So who knows how much metal the oil pump sucked up, so it's seen 200K so i figure im just going to look for used low mileage 2.8/3.1/3.4 to get it back on the road. I dont think its worth rebuilding for the price of a good low mileage running engine

[geek49203]

motor swap...

The FWD motor into a RWD car swap has been documented here... and it's a real big job.

I'm thinking of using a 2001 FWD motor for a hot rod, so I've explored this topic on my own.

First, the motor mounts can PROBABLY be used from your old engine, and bolted onto your new motor. The blocks are very similar, at least between the 2.8 / 3.1 and the 2800 and 3100. The oil filter fittings are different, so you might need to transfer that part as well.

The starters for MOST FWD blocks is on the wrong side for your vehicle, so you'll need to drill and tap new starter holes in the FWD block. You might get lucky and have one of the very few blocks that were used for both FWD and RWD (I have one in my garage), but for the most part, the starter holes are on the wrong side.

The real improvement in the 60V6 is via the heads. The RWD motors never got the good heads, while the more modern 3100/3400 motors have the "Gen III" aluminum heads that add lots of HP. However, with the new heads goes a new intake, new exhaust, and very different fuel injection.

To retrofit your old motor's heads, intake, etc onto the donor motor might involve custom pushrods and maybe some piston clearance problems. And, it would be like putting old bias ply tires on a new sports car.

On the other hand, you could try to use the ECU from the van, or maybe a Megasquirt, to run your van motor w/ the heads that come with it. This seems to be the nightmare part, since I'm betting that your tranny, speedo, and lots of other things use your vehicle's ECU. Since I'm doing a hot rod, I don't need to worry about cruise control, A/C, etc, but in your case, you do.

In addition, the newer EFI needs a stronger fuel pump -- circa 70 psi -- than the throttle body injection you probably have (maybe 40 psi). A new fuel pump will start at $100 or so, and you're gonna drop the fuel tank.

If you go with the newer heads, then you'll need to re-do your exhaust. There are precious few header options for the 3.1 FWD, so you'll probably need to find someone who'll sell you a nice flange set and fab your own headers.

Either way, unless you really wanna do this project (anything will bolt into anything if you have enough time, money, knowledge, patience, and a big cutting torch), you're gonna be money ahead to simply get a junkyard RWD motor and sell the minivan motor.

As someone stated, I'd simply put a 3.1 crank kit into it. While I've got it on the stand, I'd change the oil pump, seals and gaskets, and maybe rings. The heads can pick up a lot of HP if you port and polish them. And, for grins, there are some nice aftermarket intake manifolds that would allow you to use a Holly carb.

[Firebb15]

thanks for that info...i think thats what im going to do is buy a junkyard/ebay rwd engine and just bolt my manifolds on it and drop it in... I'm looking at a 3.1 from a 91 firebird right now. So the only thing i would have to do to this engine after i bolt all my manifolds on it is just bump up the fuel pressure slightly to accomodate the 3.1 instead of the old 2.8. Sounds easy enough

[ForcedFirebird]

Or just use the 3.1 injectors that are on the Firebird, that way you're not putting a "band-aid" on your 200k+ mile injectors.

[Guest]

Or just use the 3.1 injectors that are on the Firebird, that way you're not putting a "band-aid" on your 200k+ mile injectors.

S-dimes never came with multi-port. So there is no transfer of injector here.

BUT!!!!

You can use the injectors and maybe TB from the Lumina APV 3.1.

I'm not really sure they are any different, it really wouldn't surprise me if they were the same injector.

[ForcedFirebird]

OOPS! I forget that this site has so many vehicles.
As mentioned earlier, to use the MPFI you would have to change the pump.

[Firebb15]

i actually dont have a 3.1 from a van, but i was looking at one from a local junkyard. I now have found a 3.1 from a 91 firebird i will most likely use. But i will check out the injectors on the van and see if they are the same. I will probably just use my 2.8 injectors on the 3.1 as soon as i find out how to raise the fuel pressure. Is the fuel regulator in the throttle body of the blazer? Do i need an adjustable one? Thanks, Brian

[Guest]

i actually dont have a 3.1 from a van, but i was looking at one from a local junkyard. I now have found a 3.1 from a 91 firebird i will most likely use. But i will check out the injectors on the van and see if they are the same. I will probably just use my 2.8 injectors on the 3.1 as soon as i find out how to raise the fuel pressure. Is the fuel regulator in the throttle body of the blazer? Do i need an adjustable one? Thanks, Brian

Yes the regulator is built into the TB.

What I was getting at is you really don't need to fuck with the injectors or fuel pressure to swap this engine. There are guys that run 2.8 injectors on 3.4s with only a slight lean condition at higher RPM and WOT with high load.

Check to see if there is a difference in injector, I would not be surprised if they were the same injector.

[ForcedFirebird]

Lots of people have swaped 3.4's from 2.8's only using the short block.

[Ed_Mc.]

This info should help regarding fuel pressure adjustment:

http://www.aces.edu/~gparmer/efi/tbi_adjust.htm

I did adjustment "#5" to an '89 Trooper's stock 2.8 TBI fuel pressure regulator after I turned the motor into a "3.2" (3.1 crank with overbore and Sealed Power teflon-coated 3.1 pistons).

Before the adjustment it was lean-surging when cold and jacking the fuel pressure up fixed that nicely.

Note this was another Trooper I built as a 'torquer' for my folks; if you're looking for more snap on the upper end you'll want to bore out your intake and install a larger TBI.

My '90 LS with a hopped-up 3.4 undoubtedly runs a lot harder, although the 3.1 is still a worthy upgrade from a 2.8.

If you were to build a "3.1" with an HT 3.4 Crate Motor cam/springs/retainers, did the intake mods and had a free-flowing exhaust, it'd run pretty strong.

[geoffinbc]

3.1L TBI engines did use the same TBI unit and injecors and also the same fuel pressure as the 2.8L TBI engines. The only difference was in the ECM programming.

[Firebb15]

Thanks...that's a lot of good info for me. I was looking forward to just getting 3.1 TBI injectors from a van to put in a camaro 3.1 with my 2.8 throttle body from my blazer. I didn't know for sure if the injectors were the same. Looks like it's not as easy as i thought. Does anyone know a good place to go to reprogram the ECM?