6.5 Diesel engine build

[DieselSJ]

This one isn't going into my R30, but it is very close to what I will be building for that.

Back story - in the early 2000's I decided to do a diesel swap into my 87 Jeep Grand Wagoneer. After measuring and researching, I came up with a 6.5/700R4 combo. Engine was sold to me from a diesel engine shop as a "factory low mileage take-out with 20K miles". LOL...yeah, got screwed. More on that later. Other than some issues with the engine itself, it has been an excellent combo. Got it running in 2007, and put 60K miles on it in 3 years then the injection pump went out in 2010, right around the time I was going through a divorce. Project sat for almost 8 years and now I'm getting back into making it run again.

Initial plan was to have the pump rebuilt, but knowing the issues with the engine I decided to tear into the engine and figure our the noise and the oil control issues.

Finding what I found, I sourced a Navistar "diamond" block and am building a new 18:1 engine around it. Now on to the story...

[DieselSJ]

Engine was supposed to be a low-mileage take-out. Yeah, right. From day 1 it had oil control issues. Went through a quart in about 500 miles. Also had a lot of blow-by. And it was noisy. Mechanically noisy. Lifter/rocker/valve noisy.

Pulled the pump and sent it out for rebuild, then started opening it up to do some diagnosis. First thing I found were about a half dozen bent pushrods. Not a good place to start. So one of the heads came off while it was still in the car.

Hmmm... 5 out of 8 looked like this.




So, out it came.




Oldest daughter tearing down while my dad gives encouragement.




Needs a good pressure wash.

[DieselSJ]

I needed the crank and rods for the new build, so teardown continued...




Parts for the machine shop.




Parts for the scrap heap.




Looks like a gasser...lol

[DieselSJ]

Diagnosis of issues -

Engine was not a low-mileage take-out. It had been rebuilt and was .040 over. Additionally I found stampings on the back of the deck that indicated that .007 had been taken off the decks. That would have been fine had they used the 010 thicker head gaskets, but they used stock thickness which resulted in the piston/valve contact. Valve guides in the heads were shot, as were the seals which is where a lot of my oil consumption had been. Ring end gaps were huge, and cylinder/piston clearance was 008-010. I don't know how this thing went 60K miles.

New stuff.

Military surplus Navistar block. Navistar started casting the blocks around 2000-ish when GM moved away from the 6.5. They increased deck thickness as well as web thickness and changed the formulation in the metal. New block weighs about 60lbs more than the old block.




Bought a torque plate.




18:1 compression pistons with ceramic tops and microslick on the skirts.




Everything was dropped at machine shop last week. More pictures as things progress.

[weq92f]

There's your problem ( noise )!

Nice work!

-klb

[Tom]

This is cool.

[kipps]

These 6.5's have intrigued me, but I know very little about them.

You mention that Navistar(formerly International Harvester) began casting the blocks in 2000 for the military after GM quit using the engine. Are these post-2000 blocks the famed p400, or is that a different beast altogether? Is the p400 the same as a civilian 6.5 except for the block, or are other major components different?

How does the best of the 6.5's stack up against the duramax? Can one be built to rival the duramax on power, economy, and longevity?

[DieselSJ]

Originally Posted by kipps

These 6.5's have intrigued me, but I know very little about them.

You mention that Navistar(formerly International Harvester) began casting the blocks in 2000 for the military after GM quit using the engine. Are these post-2000 blocks the famed p400, or is that a different beast altogether? Is the p400 the same as a civilian 6.5 except for the block, or are other major components different?

How does the best of the 6.5's stack up against the duramax? Can one be built to rival the duramax on power, economy, and longevity?

The Navistar "diamond" block is not the same as the famed P400. The P400 has a different lower section and these blocks won't fit truck applications without modifying the truck or the pan. While both are cast by Navistar, the diamond block was designed to be a direct replacement for the GM 6.5 block and the P400 is a redesign. P400 also has a forged crank vs the cast crank in all other 6.2/6.5 engines. P400 heads are redesigned in the water ports, however they interchange directly with 6.5 truck heads.

Article covering the differences - http://www.thedieselpage.com/features/AMGsnew65.htm

What year Dmax? A lot of development has gone into 6.5 upgrades and there is a wealth of information out there on them. There are a couple builds that are putting out 550ft/lbs and 350hp at the rear wheels and they are still going at 150K+ miles and they are used hard for towing. Are you going to ever get one to make the power of a 2018 Dmax? No. Can you make the power of a 2006 Dmax reliably? Absolutely. I'm shooting for torque right around 550 (flywheel) on this build. When I build the engine for my dually, I'll be looking for more.

[68is4me]

Following, my brother is big into the 6.5's.

Looks like a great build

[GASoline71]

Curious why you're not reusing the main caps? Using stronger aftermarket caps?

Gary

[DieselSJ]

Originally Posted by GASoline71

Curious why you're not reusing the main caps? Using stronger aftermarket caps?

Gary

Not reusing the entire block. I acquired a Navistar block for the new build. Old block was already 040 over with 007 off the decks. Also found a crack in one of the main webs and what appears to be the start of a crack in #8 cylinder.

I have another Navistar block that I'm going to build for my dually. That one will get aftermarket splayed main caps. That one will be built for much higher power levels.

[68is4me]

What are you doing for crankshafts? I have heard that is one of the major weak spots.

[Bigdav160]

Man-o-man did I make a lot of money working on those 6.5l in the 1990's.

Actually they were not bad to work on. I always wanted a diesel 4x4 Suburban but never found a deal on one.

[DieselSJ]

Originally Posted by 68is4me

What are you doing for crankshafts? I have heard that is one of the major weak spots.

Stock cranks are fine. Scat makes a good replacement, or I can spend stupid money and get a forged unit from a P400. For the power levels I'm looking at and the 3600rpm limit, stock will be fine.

[DieselSJ]

Slight setback. Got a call from the machine shop that both heads had been cracked and welded around one of the center head bolt holes. A very strange place for those to crack. I could probably live with that, but both have also been machined past minimum thickness, one being .028 past minimum, so they are now a set of paperweights.

Researched some of the aftermarket stuff and most is Chinese garbage and have issues with casting shift and weak material on the pre-cups. $1800 for a new set of AMG heads isn't in the budget. Found a couple good used heads with 6 month warranty and guaranteed not cracked on Ebay for under $200 each. Going to have the machine shop work those for me.

[DieselSJ]

Update...

Used heads came in, got them disassembled and cleaned and they look to be good for a rebuild.

One of my Navistar blocks was cracked. Seems no one has ever seen a cracked one before. Main web. Block is junk.

Machine shop called back today and told me that 2 of the rods are cracked. Really, only 2? Because with the way everything else is going I would have expected issues with all of them. So got some used rods on the way so they can be rebuilt with the 6 good ones.

Current carnage list heading for the scrap heap -
GM 506 block
Navistar 506 block
2 heads
2 full sets of rocker arms with shafts
2 rods

Told the shop if they find cracks on the crank then I'm scrapping the engine project and dumping in a 4bt.

[DieselSJ]

Add to the carnage list another set of heads. The set that came in last week looked good until they were cleaned and checked for cracks and 7 of the 8 chambers are cracked between the valve seats. Guy I bought from is honoring his warranty though and sending another set.

[DieselSJ]

Finally some progress. The correct size sleeve finally came in, so machine work is underway.

Final bore for the Sleeve -



Bored hole ready for sleeve -


Sleeve in -


Bore/hone in process -