Head is off...what to inspect?

[fiverpuller]

I finally got the drivers side head off on the 7.3 engine from my '92. I am looking for a blown head gasket. It was drinking coolant and had a bad miss. Though all my issues may be from cavitation I haven't got that far yet. Would it be obvious where coolant was getting in the cylinder from the head gasket? Wouldn't it be burnt outside the steel ring? It always has been on motorcyles I've rebuilt but I have never had a car/truck engine apart.

What I have seen so far the #2 cylinder has a lot of rust in it...that one I suspect caused the hydrolock. Also suspect coolant intrusion because it was the cleanest...but is also cracked. #8 cyl has some abnormal piston wear...almost like it started melting. Since so much coolant got in the oil there was a lot of "sludge" that was passing through the turbo into the intake manifold. This was coming from the valve cover cdr...and was ran this way for a while before I bought it. From what I have read that sludge would tend to migrate to cylinders 7 and 8.

The middle cylinders look fine. All four are bored .030" over and only say camside and 1809110C1 along with .030 on the pistons. Like I said...never had a truck engine apart...but I would say this one needs another bore if possible. There is a good ridge at the top where the piston stops. I would say it's about .030" which would be .060" too large on the bore. Haven't measured it yet but it sure looks shot. Block has 215K on it and is most likely cavitated as well. Not sure if I want to sleeve all 8 at this point since I have a strong running 6.9 in the limo. I was just going to redo the head gaskets if everything else looked ok. Not sure at this point though. Any thoughts...comments? I will go take some pictures after dinner if I can get some good lighting on it. Thanks, Jason.

 

[Agnem]

You could have made this determination before pulling the heads. You presurize the cooling system, and then test each bore by positioning the piston at TDC, valves closed. If it is a head gasket, the water will still get in the cylinder, and when you take the glow plug out, it will flow out. If no water in that cylinder, then BDC and then if the cylinder fills, it's cavitation. Not sure how you can test the block now that it's opened up, short of figuring out a way to block the water passages and presurize and watch the cylinder walls.

 

[fiverpuller]

I guess I figured a visual inspection would be easier. I have seen some cavitation holes before that only leaked under pressure. But this engine drank 2 gallons of coolant in about an hour...while parked...with radiator cap off...so I figured it would be obvious! The water level dropped to about the top of the cylinders. There must be a big C hole down in there...I don't see how that much coolant could get past the pistons/rings so fast.

Is there even a bore over .030" just in case? If not I will have to sleeve all 8 to save the block. Not sure I want to invest that kinda dough on a "spare" motor at this point. Are there any parts on the 7.3 that would "upgrade" the 6.9? Would the heads have better flow...would they line up with the 6.9 guide pins?

Sure is a good thing I had a running 6.9 laying around when I bought the crew cab.

 

[Agnem]

The 7.3 rocker arms would be highly desired on the 6.9. That's about it.