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I know this is asked a lot of times but this is my first flathead so still want your opinions. Only had 272 y-block, 289, 351w and 400 before and used 10w-30 or 15w-40 mineral oil with zink. Even if I live near the arctic circle I dont drive it in low temperatures and if I start it up in winter it's placed in a warm garage. Thanks!!!!!
Mats Nilsson, Sweden
Straight SAE 30 Motor Oil with a Zinc ZDDP Additive is about as close as one can get to what Ford calls for.
Some people use 10W-40 Diesel Oil thinking that its additives are beneficial to the flatheads/older engines, but the zinc additive formulation is usually different than what is used for gasoline engines and not nearly as useful. There is uncertainty out on how these other additive packages/formulations are compatible over time. I think this diesel oil preference gets perpetuated around due to the novelty of the "life hack" or that "I know something you don't" mentality.
If not using the original spec straight SAE 30 Motor Oil coupled with a ZDDP Additive, any modern multi-weight XW-30 Motor (not diesel) with a Zinc ZDDP additive will suffice.
For what it is worth, I run straight SAE 30 oil in my engines coupled with Rislone ZDDP treatment.
ZDDP has additional benefits beyond addressing flat tappets and spring pressures and there are no real drawbacks (unless your flathead is equipped with a catalytic converter ).
I put my trust in the degreed engineers whose only job is to come up with additive packages that provide the needed protection and properties without ZDDP. When you start mucking around with aftermarket additives you run the risk of cancelling some of the original package's effectiveness.
Considering the low quality of original 50's oils compared to what is in modern oils, I don't worry about it. I have had oil analyses done after every kind of use of my engine and the results have all been extremely positive. No wear metals or other concerns. That is with everything from Mobil-1 to Walmart SuperTech 10w30, with no other additives. If you want to add ZDDP, it's your money.
Also depends on your engine. Most newly rebuilt engine owners will use a good detergent oil. Valvoline VR-1 racing oil is considered one of the best choices.
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