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Discussion Starter #1
In a gasket set I got 16 o-ring style seals and 8 umbrella seals.
What gives?
Pontiac 350 1969 LeMans.
 

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After searching the other forums I found this, is it correct?
Do the guides need to be machined to accept the umbrella-style seals? They were not there when I disassembled the heads.

The umbrella seals you speak of are actually positive seals that go on the intake valve guides. the o-rings go on the exhaust valves. You have to compress the spring and install the o-rings on the second groove and then the locks. They are designed to be used with the stock componets including the shields that go in between the retainers and springs. There are usually 16 o-rings and go on the intakes as well.......so from the factory there are 2 types of seals on the intake valves.
 

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The stock seals are the O-ring type valve stem seals that go in the second groove on the valve stem. In addition to the stem seals, Pontiac always used a steel spring splash shield over the valve springs to reduce direct oil splash onto the valve stems: A lot of people delete these splash shields during assembly, and see increased oil consumption when using only the upper o-ring stem seals.

The "umbrella" seals that come in the kits are pretty cheap and cheesy - don't use those. Rather, if you want to go with a "PC" (Positive Control) oil seal, use one of the good sets of PC seals with the metal compression bands. Yes, the valve guides need to be machined to accept the PC seals - a common operation for any good machine shop.
 
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