Yanmar 1500 head gasket

[Dr M]

my 1500 blew a head gasket and put some water in the crankcase. i think i caught it before any damage was done, but here's my question.
the old gasket was damaged in 2 seperate places, so i didn't look any further for a problem. i put a new head gasket on, ran it approx 30min. all looked good. the oil looked clean, no trouble. the next day i ran it again about 20 min. and it poured water in the crankcase. i pulled the head again, looked closer to the head and top of the block. i noticed that when at TDC the piston sleeve is about .006 above the top of the block. it that normal?? when the piston is at TDC it is another .006 above the piston sleeve.
i took the head to the mach shop, it was warped and they are milling it.
anything else i should look for???

Help.
Dave

 

[kenmac]

Depending on how much he takes off the head ,It may change compression & valve to piston clearence. Is this a 2 cylinder engine .If so, do both sleeves & pistons the come out of the block the same ? If 1 isn't out of the block & 1 is ,I would say something is wrong.

 

[Dr M]

Yes. it is a 2 cyl.
and yes both sleeves look the same. approx .006 above the top of the block

 

[HoyeTractor]

I went back and looked at one of our 1500 blocks that had the head removed. They also had the liners slightly above the top of the block. I did not have time to really get technical and use a feeler gauge. 0.006" is only about 2 sheets of paper thick so it is really hard to tell but it did stick up very slightly.

Aaron
Parts@HoyeTractor.com
(940)592-0181

 

[spyder2]

It is always a good idea to check for warpage of the cylinder head if an engine has blown a headgasket before fitting a new one.

Do you know what the cause was for it blowing the head gasket? Did it overheat or did the head gasket simply erode away where it started leaking or did the metal rust away slightly? Reason for all these questions is that you may have another problem causing the gasket to blow such as overheating or using the tractor for a long time without sufficent coolant/Anti-freeze etc. It may save you some time/money/trouble in future by just attending to a couple of small things. I have worked on a number of engines where the sleeves are slightly proud of the engine block. (I do not know about your engine specifically though)

I hope your problem is sorted now.

 

[HGM]

Food for thought.... I'm pretty sure the head bolts are not torque to yeild on this engine, but could they be stretched? This wouldnt allow you to tighten the head properly... Aaron or some of the other guys may be able to tell you for sure if its even possible on this engine, but I've seen it on trucks so I thought I'd bring it up.. Good luck..

 

[spyder2]

Food for thought.... I'm pretty sure the head bolts are not torque to yeild on this engine, but could they be stretched?QUOTE]

Good point. I forgot to mention that. Unfortunatley I do not know these engines well enough yet.

 

[Dr M]

i will check.


Thanks for the help.

 

[Dr M]

i think it was from over heating. i added a coolant recovery bottle and a new rad cap, which solved that problem. i agree with you, i think the sleeves are ok. i should get the head back on tuesday and i will set the head on top of the block first and give it a visual to see how it sits before putting the gasket on.

thanks for the help.

Dave

 

[Dr M]

Thanks Aaron,

i will get back to you after i hear from the mach shop.

Dave