I got the engine and trans out today and pulled the head off. The bolts were all between 85-90lbs, so not very tight. Also there was a fel-pro gasket in there so its been replaced once before. When I got the head off I knoticed oddly clean cylinders and white exhaust valves. There is also some sort of scale on the valves and head. Not sure what it is? I've never seen white scale one a head like this, its pretty even on all cylinders.

What is it and why are the exhaust valves white?

Second, there are some vertical scratches on the cylinder walls. Not much crosshatch to be seen. The motor always ran strong with very little blow-by, and didnt use any oil. Should I be worried about these scratches? Some I can feel slightly when running my hand around the cylinder.

Please advise on these two things so I can get it put back together and running!

 

its my opinion vertical "scratches " are not good .signs of piston to cylinder wear.

when doing the top end i notice the dirtbike gets them when hours get up there. wrist pin wear and its usually on the front side on the "compression" stoke.


and white scale on valves would indicate excessive heat i would think.
kind of like a lean spark plug




thats all i got

 

If you can feel it then It needs to addressed, minimum would be a rehone but maybe more, you will not be able to tell until the pistons get out and you can see how much taper it has and if you can get it honed out enough to get rid of the scratches. I would guess the pistons will need to be replaced also, but once again can't tell until it's all apart.

 

probably better to bore it and replace pistons,especailly if you are going to lean on it when put back together. If low on money and going to be easy on it or getting rid of it you can try a hone and ring job but beware it may use oil.

 

where are the pics????

 

im thinking the same thing

 

Deadliest Catch came on last night so I forgot pics.

 

The head look pretty normal for an engine that gets run hot, real hot from time to time. Some of mine look like that.

The scratching in the cylinders is most likely the top ring getting too hot and the gap closing up. Pop the pistons out and see if it'll clean up with just honing.

 

I was really trying to avoid pulling the engine apart or the pistons out. But I guess for the price of a engine stand its worth the insurance.

 

Make sure it is a good engine stand that thing is heavy lol...

 

I may just hone the cylinders a little and slap it back together. Its never used oil or had much blowby, so it must be sealing good.

 

I agree that with the cylinder scratching you might want to talk to some of the high HP guys about ring end gap. With your max HP, play toy only application might be a good idea to open the top ring up a bit. Gasser race engines run larger ring gaps, don't know if it's true for a diesel application.

 

you should take the pistons out and
hone it.

 

Its the same idea on diesels too. I don't know if anyone does this on an engine this size, but I know some smaller engines that they actually open the bore up around .005" and run std diameter pistons and rings to leave some more room for expansion.

 

I know a guy that had his done at a performance shop and they bored it 20 over and used stock pistons with custom sized rings. I had never heard of that before. You would think the thing would explode.