Two blown head gaskets and melted head

I have a old Kohler K321 (14HP) engine that has blown two head gaskets in about 20 min or running. The first head also melted an area near one of the head bolts. The second one did the same but not as bad.

Here is what they look like.



Any idea what could cause this? There was plenty of air blowing over the head so it should have been cooling properly. There was a bit of smoke coming from the breather that covers the access to the valve adjustments.

Thanks for any help.

~Brent

 

Blew the engines after 20 minutes of running, meaning it only has 20 minutes on the engine? It looks like it had a bad/blown head gasket for a long time in that one spot. Maybe it just finally blew through. Has this engine been sitting unused for a long time, or what is the history on it? Looks like the same bolt may have been loose on each side.

 

Yes, the engine had been sitting for a few months before I ran it. I got it running. It was surging a little. I was trying to get the carb adjusted. I managed to get it running smooth enough to run the wood splitter. I ran it for about 10 minutes before I noticed sparks coming from between the head and the block. That was the first head. When I took that head off the bold near where it blew was not as tight as the others. I assumed that was the problem.

I put the second head on and torqued it to the specs. After about 10 minutes of running the same thing happened.

When I put the second head on I had to clean some of the melted head off the top of the block. The only thing I can think of is that I didn't get that surface flat enough and that caused the second one to blow. I hate to keep wasting head gaskets if there is another possible reason though. I mean, is there a chance that even if I have a machine shop resurface the top of the block is there a chance it will do this again?

Thanks,
Brent

 

Clear the old gaskets off completely before putting on a new gasket.
I would also highly recommend replacing the head bolts.

When you replaced the gasket(s), did you put the same bolts back in the same holes?

 

Yes, I was careful to use the same bolts in the same locations. I will try new bolts for the next head I try.

 

Head bolts tend to strech over time (heat and pressure).

I know in the automotive world, we do not reuse headbolts. Not sure if it is a requirement with small engines, but I've always replaced if I putt the head apart.

Was there any marks or major scratches where the blow out happen?

 

I'm thinking you probably won't ever get those heads to seal again. You might clean up the areas and build them up with a weld, then re-surface them. Otherwise they will probably blow again.