My new 6.2

[68post]

Well after toasting my 6.2 in the van and selling the 3500HD it's time to install the humvee 6.2 , but there's been a problem. There has been alittle water inside this military "take-out", and metal on top of 1 piston - but dented pistons on all of three pistons. The rest looks "fresh rebuilt" !!

We've bought a couple of sets of military surplus pistons @ $29.99 per set (Ebay), and a set of Perfect Circle moly rings @ $109.00 (Ebay). The cyl's will hone pretty easy ,everything is smooth and rotating just fine right now. I have a hone so the block isn't going to the machine shop - but the crank probably is, just the one journal that I've seen so far has a tiny nick like it was done with the rod bolt on re-assembly. May buy rod bearings @ $24.99 a set (Rock Auto), maybe - but the existing brngs may not warrant being trash-canned ( this one brng looks fine)!

I do have a Fluidampr on the way from Diesel Depot $410.00 delivered.

I'll probably have the crank polished and maybe the balance checked. Any thoughts on this , or anything else so far ?? Suggestions ?

This build will be focused on a reliable engine with the best mileage possible, extra torque will be considered - but fuel mileage is critical.

I will have to build a new exhaust system, it will be 2 1/4" duals with a crossover H-pipe. I've done my own exhaust (musclecars, trucks, race car) since I was 19 yrs old - I'm now 52. It will all be mandrel-bent aluminized pipe and Dynomax large case turbo mufflers connected to the stock dual (drivers side exit) tailpipes.

Should I modify and use the humvee headers ? I always use headers on all other builds, but as far as headers go these are pretty poor looking for any flow improvement.

Thanks, Tim

 

[68post]

Guess I should tell that it's a 1990 engine, I do have to buy a gasket set (Ebay/Felpro 6.2 set $95 ??), and we have to clean the heads alittle (couple rusty intake vavle pockets, slightly crusty water jacket @ the block deck area).
Should a better valve job +/or some porting be considered ? Back cutting the valves ? Should I consider my 95,000 mile '94 turbo 6.5 heads ?? I do have a new set of headbolts to use (Dana/Mahle, ebay $44 shipped).

We will be using the existing military injection pump.

We are going to try to use some CLR in the water jackets to clean the block and heads, does this work ?

Any thoughts at this point are welcomed.

 

[btfarm]

Why not have it hot tanked and get a valve job/head surface check while it's in pieces?

 

[buddy]

I would have the heads/vlaves checked, cleaned while thier off.

Are the Humvee heads going to have any issues with intake or exhaust manifolds? Did it have a centermount turbo with different angle on the surfaces?

An NA 6.2 with dual exhaust sounds like an awesome idea. If you can bend 2.5" pipe I would use slightly larger diameter. Pipe itself causes backpressure as, more and more with length, as well as bends, and mufflers with slightly large I/O would also flow a little easier.

 

[68post]

Why not have it hot tanked and get a valve job/head surface check while it's in pieces?

It just has a little bit of clean-up to do and sludgy waterjackets. I don't want to completely disassemble the whole engine - if so I should have just started with a bare block to rebuild and gone from there. Also this will help keep me within a budget that's affordable.

Maybe I've made it out to sound as if it's in worse shape than it really is !? The heads look very good also - just alittle standing water surface rust in three bowls (I'll take a hard look at the seats) and surface rust on the head above the three cyls that had water ( not severe - but rust has no place in my engine).

It looks as if some issue happened upon start-up and they'd shut it down. Then it took alittle drinkie of water whilst sitting. She wasn't very thirsty tho' !

 

[68post]

I would have the heads/vlaves checked, cleaned while thier off.

Are the Humvee heads going to have any issues with intake or exhaust manifolds? Did it have a centermount turbo with different angle on the surfaces?

An NA 6.2 with dual exhaust sounds like an awesome idea. If you can bend 2.5" pipe I would use slightly larger diameter. Pipe itself causes backpressure as, more and more with length, as well as bends, and mufflers with slightly large I/O would also flow a little easier.

Everything looks to be exactly the same (it's parked next to an '85 6.2 on another engine stand). I don't believe it haS EVER WORN A TURBO ( oops - CAP LOCK).

I don't have a mandrel pipe bender , but with the 2 1/4" pipe being mandrel bent curves and with a crossover it should flow plenty for a 140HP engine , or should I look at its airflow needs in relation to it's torque capacity ? I am a believer that you cannot make your pipes too big, but .. I already have this pipe & mufflers too.

In all honesty it would probably gain torque if I made a good 2 into 1 single exhaust, and I may do that instead. (dual 2 1/4 into a flowmaster Y as quick/short as possible and out w/3"or 3 1/2" - back to the factory dual side by side tailpipes). Of course I have "headers 'n duals" scorched into my brain like most motorheads .. not sure I can help myself.

The "2 into 1" is how we ran our streetstock race car, which is recommended by Brzezinski (racing's cast iron manifold & heads guru). It worked extremely well - dual 2 1/2" into a 3 1/2" with a flowmaster Y, the drivers side pipe was only 9 1/2" from the manifold to the Y.

 

[buddy]

I think true dual exhaust the way you have it envisioned will work best. Diesels work different than gassers, and this engine has no overlapped valve timing for that type of scavenging affect, so no worries about pleasing a PCM with its O2 sensors. The more free it can flow the better. It might look cooler if you dump them out one on each side in the back, pipe pointing straight back would look neat, and less bends the better.