39 Head torque

Valve relief ! Great idea! I am sure there is a lot of meat in the heads for a little relief. I sure would like to salvage this project without breaking the bank. All this help is very much appreciated!
 
SuperDave said:
Bad news... Got the head back from the 'shene shop.. They cut it .012. I didn't like what I saw. The head was bowed with the center raised. Making the end chambers slightly smaller.Couldn't find my magnetic mount for my dial indicator. (probably loaned out!).I should have stopped but being an optimist... I put the head on without a head gasket. Cranked engine over by hand and nothing touched (that I could feel). Checked the thickness of the gasket I took off, "Best". Found the compressed gasket measured .058". I figured there should be enough clearance if the new "Best" gasket compresses the same. I would bet that the deck was cut at some time since it is a .040 over bore. It certainly had a major rebuild along the way.. Every thing was great up to the third torqueing after two runs and cooling. Third torqueing went OK but when I started it up.. knocking! Removed the head and found the front and back exhaust valve just barely touching the head. So Now it looks like we are looking for new heads. If it was my car I would opt for stock iron and dress it up with chrome nut covers but the owner likes the Bling of the finned heads. I keep telling myself that this is a fun hobby.. It sure as heck isn't a profitable one! Anyone have a set of uncut finned heads?
Click to expand...
Obviously they had to be touching when you tried it without a gasket! A little grinding and you will be just fine. I would use the aluminum foils balls to check clearance before you finish the job. An ounce of prevention is worth a pound of cure.
 
I don't know how I missed the clearance problem.. Maybe a senior moment.. But you were right! I added a little more space in the valve pockets and problem solved. :)Now to get another head gasket. That is the good news. The bad news is I broke the temp gauge bulb..:mad:
 
Unfortunately, these heads are not very thick. However when clearencing for valve relief. You should do this at a 5 degree angle, that way you don't have to take off much material. I realize saving money is important, but you have to know the pit falls of doing it wrong. Might cost you more than you planned. An easy way to check all this is to lay the head on the block located by a few bolts, with out a gasket. Spinn the motor, if nothing hit's your golden. But actually measuring the volume and clearances can actually make things work better. Plus you'll know what the CR is.
 
Thanks for our sage advise Ron. Valve shrouding is certainly an issue with these old heads once they have been cut so much. I could have CC'd the head if I still had my setup that I gave away a few years ago when I stopped oval track racing, At this point I just want this thing to run, not overheat and leave my shop!
 
You must log in or register to reply here.
Back
Top