I finally got around to checking my piston to valve clearance. It was spectacular and never got close to spec(.08 I believe is minimum). Problem I have is that the piston is just barely hitting the hump for he spark plug. Luckily I noticed it as I was starting to clean the heads one final time before installing them. I saw this nick in all 4 cylinders .


I went ahead and confirmed with clay that they were new and fresh marks. Sure enough they are. There is a large knot for the spark plug threads and I think I should be OK to grind some away but wanted to see what others had for ideas. Biggest thing is will be I OK to use these heads.

Here is where it is contacting on the piston.




I didn't have a head gasket so that is another .051 of clearance but if I am lucky that currently gets the piston to not touch the head I still need some clearance for safety!

Here is the head with clay on it.

 

Why are you checking ptv clearance without a gasket?

 

why are you asking why?!?

 

Are you using bubble gum...

 

Lmao.

 

What do you mean?

 

considering his other ideas this is a relatively good one!

and PS - make sure you get that dowel pin pulled out of the head!

 

I must be missing something.

 

Man... I don't know what to tell you. Honestly I'd try it with a head gasket and see if you still have contact/check your clearance. Get a cheapy graphite gasket or throw a used one in there. I'm assuming you're going to be using ARP studs or bolts, so go ahead and torque them down, and see where you stand.

I don't know about taking some material out of the head, but it would be something to look into if you really want to use those heads. G'luck

 

I am not using a gasket because I don't have an old one and Kinda foolish to mess up the new $45 gasket when I can just add .051 to my measurements. Maybe I am wrong but sees pretty simple to me.

Does anyone know what kind of clearance I should have? I know PTV is preferred to be .081 but does that apply to piston to head too? Like I said I think the gasket will get me so they no longer touch but I want some more room them flush!

Guys on LS1 said take it out of the piston if anything. I don't like that idea at all.

I think I am going to shave a tiny bit off the head and call it good. A quick hand filing of the head should clear out plenty of material so there are at least a few thousands of clearance. Shouldn't be enough to effect the integrity of the spark plug boss and gain me the clearance I need.