twas_brillig
Jedi Knight

Offline
[h=3][/h][h=3] For more detail and discussions, ensure that you read "Very interesting very long blog posting - racing oil and zinc" on this Forum.
And I don't want to steal anything from that thread, but figured adding the following both to the original thread plus starting a new one with a more easily referenced Title might be appropriate. Doug
***********************
I've written a couple of lubricant manufacturers regards their recommendations for 'our' engines (I identified 1959 to 1962 Sprites and a 3000). Here is a reply from Shell (I'd written Quaker State, owned by Shell), and from Castrol:
Castrol:
"Classic cars with flat tappet cam engines represent a special case in regards to engine oil lubrication. These engines have valve train configurations that require elevated levels of zddp (zinc dialkyl dithiophosphate) anti-wear for proper protection of the flat tappet camshaft and its lifters. Insufficient concentration of zddp will lead to premature wear and failure of the camshaft and lifters. Current GF-4 and GF-5 fuel economy grade engine oils are designed for extended life of the catalytic convertors in modern passenger cars and have industry mandated limitations on the amount of sulfur and phosphorus within the oil.
Castrol EDGE SAE 5W-50 has been recently reformulated to have a boosted level of ZDDP (1250 ppm) to help protect flat tappet cam engines in classic cars. This engine oil is a full synthetic, has excellent cold temperature properties, and has a high temperature viscosity (SAE 50) that is suitable for use in many classic car applications."
Quaker State/Shell:
"For your Austin-Healeys Model, it is recommended for those years model to consider an oil with API SF. In addition to that, your flat tappet engine required an oil with a reasonable amount of Zinc that will create the needed sacrificial layer for this area of your engine. My recommendation will be to consider using Shell Rotella T4 TP 15W-40 which contains in average 1200 ppm of zinc."
[/h]
And I don't want to steal anything from that thread, but figured adding the following both to the original thread plus starting a new one with a more easily referenced Title might be appropriate. Doug
***********************
I've written a couple of lubricant manufacturers regards their recommendations for 'our' engines (I identified 1959 to 1962 Sprites and a 3000). Here is a reply from Shell (I'd written Quaker State, owned by Shell), and from Castrol:
Castrol:
"Classic cars with flat tappet cam engines represent a special case in regards to engine oil lubrication. These engines have valve train configurations that require elevated levels of zddp (zinc dialkyl dithiophosphate) anti-wear for proper protection of the flat tappet camshaft and its lifters. Insufficient concentration of zddp will lead to premature wear and failure of the camshaft and lifters. Current GF-4 and GF-5 fuel economy grade engine oils are designed for extended life of the catalytic convertors in modern passenger cars and have industry mandated limitations on the amount of sulfur and phosphorus within the oil.
Castrol EDGE SAE 5W-50 has been recently reformulated to have a boosted level of ZDDP (1250 ppm) to help protect flat tappet cam engines in classic cars. This engine oil is a full synthetic, has excellent cold temperature properties, and has a high temperature viscosity (SAE 50) that is suitable for use in many classic car applications."
Quaker State/Shell:
"For your Austin-Healeys Model, it is recommended for those years model to consider an oil with API SF. In addition to that, your flat tappet engine required an oil with a reasonable amount of Zinc that will create the needed sacrificial layer for this area of your engine. My recommendation will be to consider using Shell Rotella T4 TP 15W-40 which contains in average 1200 ppm of zinc."
[/h]