Valve Cage Leaks
Leaking valve cages can hurt performance in many old cars, and are difficult to detect. The valves may be tight, and the top edge can be sealed, and yet they can still leak into the manifolds.
A tip from Howard,
- lap in the bottom edge of the seat, just like you would seat a valve, this will give a good seal at the bottom.
- Then place a small bead of Copper Ultra Seal (available at nearly every auto supply) on the bottom sealing edge of the cage,
- reinstall and tighten cage.
Presto, no leaks!
The Copper Ultra Seal and the lapped seat should also help prevent valve cage turning in makes, like Buick, that are susceptible to this problem.
I wasn’t aware of how much leakage could occur around the base of the cage until Howard suggested putting air in the cylinders and listen around the manifold ports, sure enough some leakage on my Buick.
Followed Howard’s suggestions, and no leakage. Thanks Howard!.