Looking at some heads today and wondering how much can be planed off a head to clean it up. The one I wwas looking at has some deep rust at the rear mounting surface and laying a straight edge across it you can see daylight quite well. I believe it is junk. Just sorting parts and took a look at it.
I run one on my '26 with .090" planed off and know of a few that have taken it down .125". Depending on what you want to do, you can have it just cleaned up or go to the dimensions I mentioned. I try to mark mine with the amount removed so down the line someone will have some indication of what's been done.
Marking the head in such a manner is a great idea! Thanks. I am thinking about having one of my heads cleaned up as it has a weep spot right in front.
MarkG and Nellybell
Dennis & Mark: I plane every head I put on an engine. And every head is stamped on the edge of the planed surface with the amount taken off. If the head is not cracked you should have it planed before you declare it junk. Many that are pitted or warped will clean up with suprisingly little removed. I have rebuilt over 250 engines and learned the hard way that every head must be cleaned up before installation if you want it to seal and not leak water or compression. This also applies to the block surface as well.
Jack Putnam, builder of the T-100 engines.
Dennis -- I had .125 taken off a stock low head. I don't know whether it had been surfaced before or not. Used on an engine that also has domed pistons, it runs great!
That is a lot of engines!! That is why I came to the conclusion that I would get my two projects to someone that has your kind of experience rather than try to reinvent the process myself.
But at least I came to that conclusion on my own after lots of study!
How much will removing .125 raise the compression?