Blew a headgasket

[Chief915]

I've kinda been waiting on it to happen for the last couple months and it finally did last week. 252,000 miles on the clock, a hot heath chip, 15ish psi max boost, qutie a bit of towing, etc. I remember gettting on it pretty good Wednesday night and it ran geat. Thursday morning I went to breakfast and it started fine, ran great, nothing out of the ordinary. But when I pulled into the parking spot and stopped I noticed a grey/white cloud blow past the front of the truck. After breakfast I kept an eye on the tailpipe while I started it. It spit and sputtered for a few seconds with a nice ploom of whitish/grey smoke, then cleared up and ran good the rest of the way home. When I got home 10 miles later the low coolant light was on, a steady haze from the exhaust, and the upper radiator hose was bigger than normal and was hard as a rock !!

I tore it down Saturday and Monday, the passanger side gasket is the one that went, between the back two cylinders. I did have a little problem, one head bolt on the drivers side broke off when I was breaking it loose. Luckily about 1 inch of it was sticking out of the block once I got the head off, a stud remover got the broken piece out of the block.

I continue to be amazed at how good this engine looks internally for having 252,000 miles on it. It barely has any ridge at the top of the cylinders, and you can still faintly see the cross hatch on the cylinder walls.

I am going to go with a set of studs when I put it back together, hopefully that will keep me from doing this "fun" job again on down the road. I may need some prechambers too while I am in there. I have only looked at one head so far, but 3 of the 4 precups have cracks that are longer than 1/4". I would love to find a good set of diamond precups somewhere.....

 

[Chief915]

The original 1994 engine (599 block) has cracked prechambers (1/4"+ long) and cracks between the valves on each cylinder. Heads are $325ish each, and if I am going to put new heads on it, I might as well rebuild it.....but now we are getting into some cash.

So, I was looking around on craigslist a couple days ago and found a guy selling a military surplus 6.5 engine. After talking to him, he tells me that he has 3 of them still in the shipping containers. He said he didn't know anything about them as far as condition, but they looked complete to him. I took the 3 hour ride to take a look at them and here is what I found. He seemed like a good guy, and a shadetree mechanic. He said he knew the basics about diesels but nothing specific about the 6.2/6.5's....Good news for me!!

After pullig all 3 container lids off....Two were 660 block 6.2's that were complete, but looked to be used. The other was a navistar casting 506 that looked like it had never been used, but had been sitting for a while. I bought the complete 506 engine for $300, and he was happy to get rid of it for that price!!!

I mounted the engine on the stand earlier today and started taking off parts that I am not going to use, manifolds, 24V DB2, v-belt water pump, etc. I pulled the valve covers too and this engine is a fresh rebuild!!! I went ahead and pulled the heads too, to check it out and install studs when it goes back together. Piston tops look great and the cylinders are clean and have a very visable cross hatch. The heads look great, no cracks anywhere, very clean, valves stll have shiny swirl marks on the bottom too. The precups are "squares" and look brand new, no soot or anything on them.

At this point, it suddenly occured to me that it was turning over very easy....too easy actually. I rolled the engine over and took the pan off. Again, everything is super clean, no dirty diesel oil on anything, looks like it had just been assembled and forgotten about. Then I notice the nut that holds the oil pump pickup to the rear main cap is missing......After a little closer look around, one rod cap nut is missing too..... I pulled that rod cap off to see how it looked. The bearing was not spun and looked brand new, no wear or marks on the bearing surface or crank.

Now here is the real funny part..... When I took the nut off the rod bolt, that piston started sliding out and almost fell out on the floor....luckily I caught it before it did!!! No rings on it at all. I went ahead and pulled the other 7 out too.... Everything looks brand new, clean, never ran, etc etc.... but no piston rings on any of the 8 pistons. Every bolt was tight in this engine too, like torqued down tight like you would expect, rod bolts, head bolts, rocker shafts....everything.... just no piston rings in it lol.

What do you think of that? Pics coming soon !!

 

[3500GMC]

Diagnosis: Low crankng compression. :hihi:

Problem: Rings worn COMPLETELY out.

Check your bore sizes and get some rings. Sound like a plan?

 

[matuva]

just no piston rings in it lol.

What do you think of that? Pics coming soon !!

New technology?

Seriously, you may have found a new engine where they just forgot the rings. With a new set of rings, you may have a brand new Navistar for $300 you lucky bastard

 

[Chief915]

Here are some pics of the new engine...... This is exactly how everything looked when I disassembled it, no cleaning of anything.

 

[great white]

Could have been used as a "training aid".

We sacrifice some operational equipment for training purposes in the military. The experienced gained by younger techs is well worth it.

Suggestion:

Take it all apart and verify it's all there and installed correctly.

Then build it back up and enjoy what may very well be a "zero hour" GEP engine.

300 bucks.....sheesh, some guys have all the luck....

 

[Chief915]

Diagnosis: Low crankng compression. :hihi:

Problem: Rings worn COMPLETELY out.

Yea.... I can just picture when they tried to test run it.....

WTF.....this thing doesn't have any compression.....

Check your bore sizes and get some rings. Sound like a plan?

Oh yea, that's the plan.

 

[Chief915]

Could have been used as a "training aid".

We sacrifice some operational equipment for training purposes in the military. The experienced gained by younger techs is well worth it.

I kinda doubt it was a training aid.... I have seen those too.

This one had gaskets everywhere it was suppose to and none of the bolt heads were "worn" like they had been loosened and tightened many times.

I am an Army maintenance tech..... that's the way our training aids are.

I am not really sure what happened here..... I can't imagine that someone building this engine for uncle sam put it together without rings and didn't notice that when he slid the pistons into the cylinder.....

Suggestion:

Take it all apart and verify it's all there and installed correctly.

Then build it back up and enjoy what may very well be a "zero hour" GEP engine....

That's the plan..... A set of rings, gaskets, and I have a fresh GEP...... I must be living right !!

 

[WarWagon]

Get some gapless rings - night and day with clean oil. How did the 'old engine' look on the bottom end?
You make me want to start poking around used military places for one of these better blocks...

Any marks on the tops of the pistons to indicate if it was bored oversize? I would double check piston size and bore size just in case you have a .10 over and std pistons...

 

[Crankme69]

Nice find & thanks for posting the pics, looks great.

 

[NVW]

Nice find, Matuva said it best.

 

[Michaeljp86]

The way uncle same is they probably rebuild them and it it doesnt run it gets junked. Someone forgot the rings so they just send it on its way.

In the CG the dont sell anything, it only goes to a landfill. One guy at the school I went to said they would take multimillion dollar all aluminum boats and cut them and and throw them in a dumpster. They couldnt be scrapped because that would be selling it. He said to sell just one item was like 6 years of paperwork.

 

[Chief915]

Get some gapless rings - night and day with clean oil.

Any marks on the tops of the pistons to indicate if it was bored oversize? I would double check piston size and bore size just in case you have a .10 over and std pistons...

Where is the best place to get the gapless rings?

The new engine is STD bore.... it measures 4.055"

How did the 'old engine' look on the bottom end?

I don't know yet, it's still in the truck. It will probably come out sometime this coming weekend.

 

[JiFaire]

Great score, Chief! Thanks for sharing; please keep up with the pics on the rebuild!

Jim

 

[Guster]

http://www.totalseal.com is the place

 

[Chief915]

How did the 'old engine' look on the bottom end?

UPDATE: Got the old engine out and mounted to the stand Saturday night. Sunday I tore the oil pan off, and since WarWagon asked, here are some pics of the internals of the old engine......252,000 miles on it.

 

[3500GMC]

#5 was 'pre steam cleaned' for you..:hihi: (a curious lack of OIL) or maybe you shot some solvent down in there?

Quarter million mile bearings are pretty good, considering..

 

[Chief915]

#5 was 'pre steam cleaned' for you..:hihi: (a curious lack of OIL) or maybe you shot some solvent down in there?

Quarter million mile bearings are pretty good, considering..

I cleaned the web areas with brake clean lookng for signs of cracks. The bearings looked better than I expected them to as well.

The only thing odd to me was the spots on the top piston ring in the picture. It isn't carbon, it's pits in the ring or small flakes of material missing. Not sure why or how that would happen. Bad coating on the ring maybe?

 

[Mike K3500]

While you're that far into your "new" Optimizer.... I would recommend getting new clevite main / rod bearings for a 2000 6.5 ( they have the holes in them for the piston squirters ) and a a new oil pump / pick up for a 2000 6.5 ( it will have the 3 piece body indicating hv / hp ). That will get your bottom end up to "turbo" spec.

There was somebody in the classified section that had Diamond cups for sale... If not I still have a set of "T" cups that might be good. I would at least get the cups up to "turbo" spec as well.

By the way, Great find and congrats !!

Mike

 

[3500GMC]

....... It isn't carbon, it's pits in the ring or small flakes of material missing. Not sure why or how that would happen. Bad coating on the ring maybe?

The rings in my 213k '93 6.5 looked the same way. I suspect it is the coating giving up.