2.8/3.1/3.4 interchange info

Hi all, I'm looking at the chance that a 3.1 intake, and MPFI injection set up will fit on my boat anchor 2.8. I can get a 3.1 for free(FWD), and with the newfound 31's on my 2.8, I cannot even get out of it's own way.

I know the 3.1 will not fit, but I'm wondering if the FI setup WILL. I KNOW once I get rid of the 2se carb, this thing will at least be able to move itself at 70.

Only reason I'm going (Trying) this route is because of the freebie factor. IF I wanted to do it and cost was not an option, I'd go TBI from a blazer...But the 3.1 is free, and complete.

Now, The only issue I can see is Distribuitor clearance....BUT I'm wondering if the intake will even MOUNT to the heads.

Anyone have any GM 60* tech floating around?

Go ahead - the anaemic 2.8 can use all the help it can get.

I'd have to check notes (where'd I put that GM Motorsports Power Catalogue, dammit?!) but IIRC, the 2.8/3.1/3.4 are all the same casting, with different bore/stroke combinations - meaning the changed parts are the pistons and crank.

You should be able to bolt the 3.1 PFI right onto your 2.8 block, but you'll have to make sure you get the sensors, harness, and ECM as well for it all to work.

The only real difference between the FWD/RWD versions is the location of the starter motor mounting boss, which changed sides for the RWD version. Apart from that, it's all the same and you can go right ahead and swap over whatever you want.

I still suggest you take this with a grain of salt, simply because I haven't read up on the 2.8 recently - the focus of my attention has been the 199/232/242/258 family.

5-90

sounds good to me

To use the MPFI setup you will also have to swap the heads. The intake port configuration is totally different between the carb and MPFI setup's.

You can find lots of 60* V6 info here:
http://www.60degreev6.com/

This is probably a dumb question. Is th 2.8 in the jeep a 90 degree block? Sorry to interrupt.

Canopener said:

This is probably a dumb question. Is th 2.8 in the jeep a 90 degree block? Sorry to interrupt.

Click to expand...

No...Damnit. IF it was, the 2.8 would have become a 4.3/350 by now.

AMC for ya....Cutting edge design with other makes parts.

also to throw a wrench at you.. I had a 2.8L s-10 and was contemplating a swap with a 2.8L Cavalier. The early models had a MPI set up with a Mass air flow sensor.. from what I could tell, there would be no distributor interferance. I had pulled the whole setup at a junkyard for $40 or so.. but you need a wiring harness and ECM.. and all sensors.. I know in the s-10's the TBI added 40+horsepower over thier carb models... I just picked up a blazer with a carbed 2.8L so I am interested what you find before I do anything short of the V8 swap....

Ludakris said:

also to throw a wrench at you.. I had a 2.8L s-10 and was contemplating a swap with a 2.8L Cavalier. The early models had a MPI set up with a Mass air flow sensor.. from what I could tell, there would be no distributor interferance. I had pulled the whole setup at a junkyard for $40 or so.. but you need a wiring harness and ECM.. and all sensors.. I know in the s-10's the TBI added 40+horsepower over thier carb models... I just picked up a blazer with a carbed 2.8L so I am interested what you find before I do anything short of the V8 swap....

Click to expand...

Discovered one big D"oh.

TB is on the ASS end of the motor...With NO easy way to swap it aside from making a new Plenum....Not a chance. Blazer 2.8 TB might be an option...and I'd prefer the ease of a TBI setup over a Mpfi.

Cheap is good in this case....I"m NOT throwing any large amounts of $$$ at this. Not for a vehicle I paid 200 bones for 3 years ago.

Toolmaker said:

To use the MPFI setup you will also have to swap the heads. The intake port configuration is totally different between the carb and MPFI setup's.

You can find lots of 60* V6 info here:
http://www.60degreev6.com/

Click to expand...

I swapped a 3.4 from a MPI Camaro and the carb'd intake matched. Been running it for 2 yrs with no probs. Don't know about the 3.1 for sure....

i have a 3.1 60 dreg v6 in my z24. i don't know if i would want one in my jeep. i like my 4.0 IL

diabloxj said:

i have a 3.1 60 dreg v6 in my z24. i don't know if i would want one in my jeep. i like my 4.0 IL

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Too bad my AMC XJ came with a V-6.

And FWIW, My old 86 2.8 Mpfi z24 would eat late 80's mustangs off the start.....The 2.8/3.1/3.4 CAN make power.....It's just expensive.

Next step is actually GET the motor here, and see what's up.

you want a lot of info try www.v6z24.com its a z24 site i go to. they have tons of info on the 2.8 3.1 3.4 and 3.6

Storydude said:

Discovered one big D"oh.

TB is on the ASS end of the motor...With NO easy way to swap it aside from making a new Plenum....Not a chance. Blazer 2.8 TB might be an option...and I'd prefer the ease of a TBI setup over a Mpfi.

Cheap is good in this case....I"m NOT throwing any large amounts of $$$ at this. Not for a vehicle I paid 200 bones for 3 years ago.

Click to expand...

Basicly there isn't much diference between the 2.8 and the 3.1 besides stroke
Engine Description (LB6) 2.8L 60 degree V6
Horsepower 130
Torque (ft-lbs) 160
Block Cast Iron
Heads Aluminum
Valves 12
Displacement 2.8L (2800cc, 173ci)
Cylinders 6, V formation, opposed 60 degrees
Bore 89mm (3.503")
Stroke 76mm (2.992")
Compression Ratio 8.9:1

Engine Description (LHO) 3.1L 60 degree V6
Horsepower 140@4800 - 140@4200
Torque (ft-lbs) 180@3600 - 185@3200
Block Cast Iron
Heads Aluminum
Valves 12
Displacement 3.1L (3100cc, 192ci)
Cylinders 6, V formation, opposed 60 degrees
Bore 89mm (3.503")
Stroke 84mm (3.3122")
Compression Ratio 8.9:1

Those figures are for the engines in the z24's....so i guess you would have to weigh the gain of 10 horse and 20 ft-lbs of torque to the time and effort involved in doing the swap.
IMHO if you are dead set on a 3.1 i would be looking for one out of a 3rd gen f-body(camaro, firebird) or a s-10, throttle body will be on the front but it will be a mpfi and you will have to grab the computer and harness.
I don't know if the fwd block has the same motor mount provisions.
I have also been told that if you have a manual trans get a motor out of a car/truck with a manual otherwise the crank won't have the proper diameter hole for the pilot bearing.

I KNOW I"ll get more than 20HP and 20 Ft/Lbs out of the FI conversion....Seeing as my junk Dyno'd at 88 HP@2500 and 100 Ft/Lbs@2000. The 86 Blazer my friend has will roast the tires off the start.....STOCK. I'm not looking to swap engines...just injection.

I'm still looking at allthe options.....But this thing NEEDS some power...Im tired of getting passed by Semi's..........At STOP lights. With the 235's it was not too bad....with 31's, fuggetaboutit.