Hi, I have a question about the valve seals that have a spring seat included(I believe some call them hat type). I have these on my 1972 350 heads currently (about 10,000 since rebuild) and have a very good reason to believe they are worn out. The question I have is that I have a new set of umbrella type seals from Mondello and was told to remove what is currently on the car and just install these, will removing the seals with the seats change the valve spring setup? Any other suggestions on what type of seals to run ,keep in mind that the engine is together and I do not want to pull the heads. I am not sure as to the state of the guides ,ie: if they are machined at the seal area , Won't know that till I pull one of the old ones off.

 

Your terminology is off which makes it hard to follow. The factory used umbrella type seals which did not seal the guide very well but acted like an umbrella or shield to keep oil drips from going down the guide. The other type were known as teflon seals and at first required the top of the guide to be machined down to accept the seal. These had a spring ring on them to hold them stationary to the top of the guide. The umbrella type rode up and down with the valve. There are now the improved type seals that dont require machining of the guide. To do the replacement you must use something to keep the valve from dropping into the cylinder. This is usually compressed air.

 

I know what the factory used , but the guy that did the heads used the hat type perfect circle seals(what many guys used to call pc seals).

 

sorry if I seem a little confused, the guy that did the heads has retired and left the area so I have no way of exactly knowing what was done for seals other than a visual observation.

 

Changing valve stem seals will not change anything with springs, retainers or valve stem height if they are correct for your engine.

 

ok , thanks for the info. I was unsure if did not install the hat type again if the setup for the spring would change due to removing the thickness of the seal that the spring sits on. I would like to go with a Viton type positive seal , is there anything I should be aware of that would present a problem down the road ? Would it be ok to use the umbrella stem seals also?

 

The valve spring sits on the cast iron head. The valve seals only sit on top of the guide and the springs dont even touch the valve stem seal. Any type you prefer will do but as said the stock type seals dont really seal very well. The stock guides have a sort of knurling in them which helps oil control a little.