Claying Heads

[Henry/Kokomo]

I'm familiar with the general concept of "claying" heads to determine piston-to-head and valve-to-head clearance. However, I've never had the occassion to actually do this - until now. Can anyone supply specifics of both materials and proceedures as well as potential problems which can occur. Any info would be appreciated. Thanks in advance.

 

[Don W/Norfolk]

Instead of "claying" you might substitute small balls of aluminum foil. Place them at the locations where you want to determine the clearance, install the head (without a gasket), snug down a few head bolts and rotate the crank through at least one full rotation. Remove the head, and after carefully removing the foil balls, measure them with a micrometer. Their thickness will be the clearance you have at their respective locations. Works for me.
dw

 

[Joe AZ]

There is an earlier thread "resurfacing heads" that covered this topic pretty well. Joe

 

[37fatfender]

This works for me and gives a pretty accurate mold that can be measured. First lightly grease or oil both the head and piston, then mix up a small amount of Bondo body filler. Place it on top of your piston and rotate you engive to TDC. Wait a half hour and you have a perfect casting. I do this with and without the head gasket. Note, I do not torque the head. I then cut the disk in half and measure at the thinnest part of the Bondo. I do this for the valves also.

 

[Joe AZ]

Great idea.......much easier to measure than clay. I'm sure the tinfoil method works good as well. Joe

 

[55 dude]

like this? these pictures were taken yesterday and looks like clay works well. this head has been milled, how much i don't know but it looks like valves are clearing.

 

[andyg]

be very careful when using the advice above to "not use a gasket". if you hit, it doesn't take very much force to cause damage. most people us "2 head gaskets" and take one off their measurement. that way you know your not going to make contact. let us know how it turns out. also you need to make 2 full revolutions.