Posted by WOJ on October 27, 1999 at 20:41:53:
In Reply to: Need info:Gas Additives,original shop manuals, exhaust manifold posted by Mark Davis on October 25, 1999 at 18:02:07:
All Chrysler flat head 6's have hardened valve seats so NO lead additive is needed. The Chrysler V8 are another story and DO NOT have hardened valve seats. Tetraethyl lead was added as an anti-knock additives but had a side effect of coting the EXHAUST valve seat with a microscopict layer of lead acetate, which helped to cushion the valve face upon contact with the seat. This was a n American gas additive. When Chrysler sent these PW's and other equipment over-seas, they did not have TEL in their gas, so instead of overhauling Europes refinery system, Chrysler just put in HARDENED valve seats.
On SODIUM FILLED VALVES. This valve was used not for lead problems , but for heat problems developed by industrial engines being used at their peak output, like in a generator application, running for a long time. The sodium was in the stem as the stem would lenghten upon being heated and then streched by the valve spring. An exhust valve will run normally red hot.