Is my cylinder head ruined?

[quicksandfarmer]

I recently took the cylinder head off on my Jinma 354 (Y485 engine) to replace the head gasket. On the number two and four cylinders the part of the head that forms the top of the combustion chamber is severely pitted. I assume this is from coolant leaking in (which is why I'm replacing the gasket in the first place). The valves seem to be fine based on visual examination and the gasket mating surface seems to be fine.

My inclination is to put it back together and see how it works. I don't see any reason why this would make a difference as long as the head isn't actually leaking. I guess it increases the volume of the cylinder, but microscopically. But I thought I'd pose the question to those more knowledgeable than I.

Thoughts?

Thanks.

 

[RonMar]

It should be fine, as long as it seals as you stated. The amount of volume change from pitting would be IMO mostly insignificant.

 

[Ken]

Before replacing the head gasket have the head checked for warping. Something changed to allow the gasket to leak.
Do it your self with a square or piece of metal use a light to back light and see if the area where can see under the metal should be flat.
machine shops can make it proper.
kenj

 

[jonyyuma]

Defintely have it check for trueness on the sealing side...You should check the valves too, while you have the head off. a simple test is to stand it on edge and pour some fluid down the intake side{kerosene or diesel will work} and look for leaks.. Might need to set a day. then clean it and stand on the other edge and add fluid.. the leak will be at the seats..Personally if i had a doubt, i would have it checked for cracks too. It is money in the bank to do some research on it now, or you will be doing it again soon...I like to use Coppercoat Spray gasket sealer on barehead gaskets.

 

[quicksandfarmer]

Just to close the loop here -- since everyone seemed to think it wasn't a problem I went ahead and put the engine back together. It started on the first turn -- which it didn't do when it was new. I mowed for about five hours yesterday and everything was strong, and oil and coolant were fine afterwards. So it seems to be working fine.

 

[Rich Waugh]

Thanks for the update! It seems like you dodged the bullet on this one - that's great.

 

[KBle]

Maybe you should re torqe the cyl head after a few house running and keep checking for air bubles in the radiater

 

[quicksandfarmer]

I'm at 35 hours since the new head gasket and I plan to retorque it at 50. I don't want to jinx anything but it has been running so well since it got the new head gasket and oil pump, I swear it's better than new.

 

[Mace Canute]

A little FYI...if you are going to retorque the head bolts, you don't put the torque wrench on each bolt and apply force. Because you want to have just sliding friction, not static friction to over come, you have to back each individual bolt off about a quarter turn or so so that when you do torque it, you are always moving until you hit the recommended value. You do one bolt at a time, in the proper order, loosening it, and then in one single smooth pulling motion, go to the max recommended torque.