How deep can the machinist cut the heads for the hardened seats without hitting the water jacket on a set of #6 cylinder heads?

I got the .219 Manley hardened seats that are compatible with the stock exhaust valves (which I am using).

I just want to make sure that the machinist knows not to go to far thinking he is working with Chevy heads which are thicker (so I am told).

d1

 

My machine shop used to cut the hole .200" deep, and just trim off the top .020 with a cutter to keep as much material as possible in the head. They say that .220" is ok, but if there was core shift of any sort, or a casting issue with that pour it could lead to issues later on. Better to be safe, I like that train of thought.

Did you ever get any valves?
I have not had a chance to look, I am sure I have some around the garage, at least in another set of heads.

Jim

 

Could you please post a picture of the original seats that were bad ,. I have always wanted to see what they would look like. thanks tony

 

That seems like sound advice. I talked with the machinist today and he related that he cuts shallow as a rule. So, hopefully he took my concerns to heart.

I did get valves, but thanks for asking.


Tony, I don't believe my seats were bad. I would take a picture for you but I never thought to do it before I took the heads to the machinist. I am having the hardened seats installed for more "peace of mind" than anything else. I know this is a debatable topic, but I think it is a good investment as this motor will be in a daily driver.


d1

 

Excuse the thread jump --am in fact trying to add to the info.I have a set of BBO B heads that I was contemplating doing the same --ie installing hardened seats .Any ideas on the depth of cut here to "be safe"
thanks mike