3.4L heads on 2.8L block

[Canyonero]

I'm not looking for any preformance gains persay, but just to limp an engine along on-the-cheap.

I have some iron heads from a 3.4L, and a good 2.8L bottom end in the rig. Can I make a working engine? What would be the downside (or what would I gain)?

The heads would be from the engine with the broken motor mount that I posted about earlier.

[ForcedFirebird]

Iron heads are iron heads. Thay all are almost identical except for a few of the earlier carbed models. (maybe should have said all FI iron heads are FI iron heads).

[Canyonero]

Nice! I thought it might be just stupid enough to work.

I have some questions about your 3.1L BTW, but I haven't the time right now to articulate them.

[ForcedFirebird]

Nice! I thought it might be just stupid enough to work.

I have some questions about your 3.1L BTW, but I haven't the time right now to articulate them.

The 3.1 is gone at the moment. Next time it's running, it will be a 3.1/3400 hybrid with a pair of to4e turbos.

The current motor is almost finished...

http://60degreev6.com/forum/showthread.php?t=37808&page=2

[Canyonero]

Yeah, I've been watching your hybrid thread too. That might be the basis for my next engine.

Anyway, I was looking at your photobucket album and noting some differences in the 3.1 and 3.4 intakes. I was tipped off that the 3.1L intake would probably fit my application better. I think I answered some of my questions already.

You should sell me your 3.1 intake and accessory brackets if you aren't going to use them.

[Canyonero]

Semi-related question:

So I have this 3.4L block that is junk but the rest is fine. Can I make a 3.1L with my original 2.8L block using the 3.4L crank, etc?

[IsaacHayes]

Yup. 2.8-3.1 was stroked, 3.1-3.4 was bored.

As long as you have the rods/pistons required yup you can put a 3.4 crank in the 2.8 block. 2.8/3.1 blocks are the same as far as bore (probably exactly the same). And the 3.1/3.4 cranks are the same too. In the FWD applications if you take apart a 3400 the crank says 3.1.

[Canyonero]

Do I have the rods/pistons required? I have the two complete engines, just the 3.4L has that damned broken motor mount.

So, 2.8L block and pistons + 3.4L crank and rods = 3.1L engine?

I might make lemonade out of this after all.

[IsaacHayes]

3.4L crank and rods in a 2.8 block. Check.

Not sure on the pistons, if you can use the 2.8 ones. You might need 3.1l pistons. Not sure if there is a difference between the two.

[Superdave]

yes, pin height changed

[Ed_Mc.]

You can use the 3.4 crank and rods in a 2.8 to build a 'stroker' motor of 3.1L displacement but you need to used pistons from a RWD, cast-iron-headed 3.1 motor. Only those pistons have the correct wrist pin height to match the block/crank combination.

These pistons were used in early-mid 90's GM FWD minivans with cast-iron-headed, TBI'd 3.1's.

Also used in 3.1 Camaros; 3.1 4WD Isuzu Rodeos; and 3.1 4WD Isuzu Pickups.

I built up an 89 Trooper for my folks a few years ago and used some Federal Mogul "Sealed Power" pistons which are teflon-coated on the skirts. A very well-machined piston with tight clearances and the teflon coating helps prevent the Dreaded 3.1 Piston Slap. Not so much slapping found on RWD motors, but pretty bad from what I understand on the FWD'rs.

Part # for these pistons is H562CP, the "CP" stands for "coated piston" I assume.

Anyway, a nice upgrade for a 2.8. If you use the HT 3.4 Crate Motor cam, valve springs & retainers, and a set of 1.6:1 roller-tipped rocker arms, she'll run real strong.

HTH..........ed

[Canyonero]

Good info, thanks!

[geoffinbc]

Yea Ed has pretty much described my plan. But now that I got my Trooper to stop leaking it runs like a dream and doesn't loose any fluids or burn them. So now my only excuse for removing the engine is more power. But I just bought a house so that has to come first.

But don;t worry I have been modding

My Clucth fan ate its bearings and spit the cage out and jammed it up solid. So I put in an E-Fan.

My Valve covers were leaking because the last owner didn't use gaskets, only RTV. So I put in Fiero Covers.

The oil cooler lines were leaking so I removed them and put in a remote filter system.

The power steering return hose was leaking and I did not like the stock cooler. So I put in a second gen S-10 cooler.


That all the major stuff for now. Next project will be the engine.

[Canyonero]

Congrats on the house!

My 3.4L Trooper doesn't have an oil cooler. There is one at the salvage yard here that does, I might try to poach the parts. Well, he sawed though the cooler when cutting off the front end, but I could still get the filter base and lines. Both my friend's troopers have them.

Those GT valve covers do look nice. I'll try to find some someday.

I was thinking of using the Comp Cams High Energy 252H Cam.

HYDRAULIC: Good power for 2 or 4 wheel drive S-10, S-15 or blazer. Works well in mild towing applications. Smooth idle.

Specs: http://www.compcams.com/Technical/Se...umber=16-232-4

[geoffinbc]

Don't bother with the stock oil cooler, I have seen power steering coolers larger than that thing. Plus the lines are a whore to source and none of the fittings are used in North America. If you decide you need one make a remote filter setup with an after market cooler.

The COMP 252 is a good choice. It has some nice low end grunt.