Cracked Head

The head cracked on my L motor. I haven't even started it yet. I had just put water in the radiator to check for leaks, and it turned out the head has a crack in it. The crack goes from somewhere in the sparkplug dent to the outside corner of the head. What causes a crack like this? Is it a common failure?

 

probly was overheated i dont think it would freeze crack that high. head is no good if the crack goes into the plug threads,i think you should remove the head and inspect for cracks betwen the cylinders and from the exhaust valve seat to the cylinder wall.if that is the only crack it could be repaired if it does not go thru the plug threads.a head should be ez to find if you need a replacement.XX

 

Yeah, you have to suspect other damage if you see a crack like that.

For a replacement, post up a WTB on the Willystech parts forum.

 

I've got two spare heads already. I'm just hoping to avoid whatever caused that crack. The next head I'm going to try has ribs between the headbolt holes.

 

Everytime I ever saw a crack in the spark plug threads, the engine had been overheated and run hot for sometome.

 

When you put on the replacement head, I would try to find a set of matching head bolts. Yours appear to run from grade 2 up through at least a couple of real ones. All the different grades will have different stretch lengths which could contribute to the problem. Freezing can indeed crack the head, but when it does, the block will usually have more than a few problems also.

 

you should be using studs anyway

 

NCS, You should replace your head bolts. Those miss mached ones might be the cause of the crack, they maybe caused the head to warp causing the gasses in the combustion chamber to escape, letting the water out causing an overheating problem....

Some of these engines used studs, some used bolts, but most used a combonation of studs and bolts! Just use the ones that will be strong enough. Ron Fitzpatric at G503.com has them as will most of the "normal" suppliers. Waleks, Willysworks, etc etc.

Be sure to look for other damage while you have the head off. Good luck, Matt W.

 

This just isn't working out well. I got a new head, new gasket, and it's leaking water again, but at the head gasket this time. I checked all the fittings and hoses and they were fine. The only thing that seems odd is the head gasket.

The head gasket is from a new Omix gasket kit. It's the right shape and everything, but . . . it's solid silver. Both sides of the gasket are covered in what appears to be the same metal the fire rings are made out of. Is that what it's supposed to look like?

 

Next time you take the head off,, check the surface of the block,, It might need to be machined to make it flat..

 

What did you do for your bolt/stud situation and did you coat the gasket with anything or install it dry?