soo...think I found my problem

[achris]

Re: soo...think I found my problem

its is a 1994 mercruiser 454, Mark V block. It didn't overheat.

I'm assuming it was timing, however, when examining the head it really appears like an issue with the casting.

I wouldn't have thought that a casting flaw would take 18 years to manifest... I would suspect something else is going on. My experience is that there usually isn't just one thing wrong, it's usually a combination of little things that add up to a big problem, like a burnt head. I would also be checking the block deck in that area extremely closely. For that much damage on the head to occur means it was doing it for quite a while. For the block to be completely undamaged.... not very likely (you have better odds at winning a lottery).

Chris.......

 

[PowerAddict]

Re: soo...think I found my problem

the engine was just re-built very recently by the previous owner, and then they never used it. So anything is up for grabs as far as the culprit, no idea if those are the original heads either. But, for instance, it appears they used the wrong head gaskets. Which could have caused a hot spot in the center of the head. That added to the timing issue, who knows.

(the head gaskets that were used are for a mark IV block, and While I am still verifying, it appears to be a mark V block...not good.)

 

[Tail_Gunner]

Re: soo...think I found my problem

Hard to visualize a 454 w/ iron block and iron heads having that much head damage and nothing on the block. Hopefully it is just a flaw in the head casting, leaving the block intact. Still would get a straight edge and check that block real good before giving a clean bill of health.

It would be a miracle is the block was not damaged...the block material would have to something other than the head...unless the gasket insultated it thourgh a act of god..

 

[Howard Sterndrive]

Re: soo...think I found my problem

It is called fire slotting, from the head gasket being blown between the cylinders and fire blowing through the slot.

we used to call it "guttering" - same thing.

there was nothing wrong with the head - any cast iron can be slotted with a cutting torch... heat it up white and pull the trigger and the molten iron flies.... same thing as a the combustion in the adjacent cylinders crossing back and forth