nico
Hi. I just pulled my 360 heads apart. I have a question about the valve seals. They sems to be made from hard plastic ore something. How are they hold down in place in the heads. Allmost half of the seals was half way up the valve. I am going to put in new ones , so i just wonder how they are locked down. Parden my english , im just a jeeper from cold norway :-)
tufcj
What you have is OEM "umbrella" style seals. They aren't attached to the head. They sit on the valve stem, they only touch the head when the valve is open. There is only flow past the valve when it's open, so that's when the seal is needed.
If you have the heads off, the upper part of the guide can be machined for a "positive" type seal, which does attach to the head, and allows the valve to slide through it. Most performance valve jobs include positive seals.
Bob
tufcj
AMX69PHATTY
FelPro gasket sets come with 2 types of umbrella seals, black "rubber" and yellowish "plastic". Like Tuf said, they just "float" on the valve stems, although have had stock retainers that allow the umbrella to "snap" to a "lip" on the bottom of the retainers and keeps it attached to the spring retainer. A lotta folks do have the tops of the valve guides machined and fitted with different aftermarket "teflon" valve stem seals, have seen "rubber" ones to, that have a means that allows the seal to be "hand pressed" onto the machined guide top and the seals stay put there on top of the guides. Some use a spring like ring, others a metal friction ban that keeps the seals on the guides. The stock umbrellas seam to do the job ok, they just eventually get hard and brittle and split or fall apart into pieces.
nico
Okey. I thougth mine was broken , but they are loose from factory. Strange solution. Then i just hand press my new ones onto the valves all the way down , and thats it. Thanks folks.
