g741.org

I am hoping to take my truck's head in for milling Friday. I am at 8000' elevation, and any more compression would help. I have the head off now, and I am wondering how you can tell how much you can take off. Is there a standard head thickness that will let you know if it has been previously milled? Do I need to take a caliper to each valve and see how high the maximum lift is? Any advice would be helpful.

I was surprised that the head was dead flat across the top of the piston. I expected some dome there.

What is a good method for cleaning carbon off of the top of the pistons, valves and block? Everything is in place now as I have only pulled the head investigating moisture in the crank case

I measured the valve heights with a depth mic and then checked the clearance on the head the same way. I would suggest consulting with your engine builder because there are several other variables that you need to keep in mind.

Bert

T. Highway, there is no engine builder, just me. All I have is a digital caliper for measuring. I also do not know how much to account for gasket thickness. I might go with the minimum the machine shop recommends if I don't get any solid numbers here. The last thing I need is ruined valves and more. I don't have the time and experience to really tear into an engine right now

I know that my engine had what I believe was one government rebuild.
I to was not sure how much to figure for gasket compression but figured it at 50% but only saw about 20% after it was torqued down. I used the Best brand of head gasket with copper on two sides. http://www.bestgasket.com/pop_up_pictur ... umber=510C
I was told by my engine builder and a guy that races flatheads that .120" was the bare minimum clearance for the valves to the head.
After I measured everything, including how far the sparkplugs stuck thru the head (Just in case one of them was lower than the others) I shaved .080" off the head. My math data showed that I could of taken .130" off but I was not sure how this would work with my custom ground cam.

As for cleaning carbon off the valves & pistons you my want to leave them alone. If you get debris loosen and it falls down to the rings I would be afraid of locking up a ring and creating a much bigger problem.

I hope this helps but please don't assume that my numbers will work in your engine without double checking clearances.

Bert

T. Highway, thanks for the replies. At this point I am eager to get my truck running, and I will probably go with the minimum the machinist recommends, since I do not have numbers to base a major milling off of. The truck was running well before, and I can always try it again over a winter when I have more time and I am not driving the truck. They salt the roads here and I don't want to rust the old girl out.