Quote:
Originally Posted by Forddan
Duke36, ZDDP will not be a problem to the transmission gears ?
If I use a mixture of 600W oil and STP, the ZDDP will not be a problem ? Also for any yellow metal I could have there ? Mine is a January 29 Tudor and I do not have idea how much is still original in the transmission.
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Search other threads. Lot's of discussion about motor oils and gear lubes.
The Porsche club of America did some tests where 356 engines were broken down and measured for valve train components wear with and without zinc rich oils. The zinc rich oils did help some.
Some of the "600 w" oils form the vendors look and feel like today's SAE 140 gear oil and are not always equivalent to the heavy molasses consistency of the 1930' s versions. Penrite and Lubriplate SPO 299 (which I use) offer SAE 250 wt. which I believe is closer to the original and is yellow metal friendly. It takes longer to warm up in the tranny but doesn't foam as much. I prefer no ZDDP or STP in the classics we work on except sometimes some small amounts of zinc added in the motor oil