posted November 11, 2003 03:45 PM
I just took apart my heads and found that the #2 cylinder that was bending a valve have very tight clearance. Its so bad that you can see the ridges where the valve was trying to spin. Can I just drill this out to lossen the clearance or do I have to take it to a machine shop. All other valve move very freely within the guide.

I dont have any numbers or specs on clearances, but i do have a set of fresh heads that i assembled a little while back. The valves would all slide up and down freely in the guide and if turned over would fall out. At the same time, i was able to put my finger over the valve guide and tried to pull the valve out and it pulled vacuum.

Daniel

We run between .0008 & .0012 intake & .0015-.002 exhaust with bronze guides or bronze liners, .0015 min intake & .002 min ex. with cast guides
You should not just ream the guide out & you should definitly not "drill" it out.
Anytime a guide is reamed or honed the seat should be touched up as it disturbs the valve centerline.

If you are using positive seals, keep your stem clearance on the high side of the recommended spec. Otherwise you will gall the stems.