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Racing oil for historic engine
- Thread starter sierra4000
- Start date
BrianPetersen
Mechanical
Anecdotally, the main trouble spots that I've heard of, have been with hot-rodded American push-rod V8 engines with flat-tappet lifters and very high valve spring pressures. And, if your engine is relying on years of sludge build-up to seal its gaskets (!) then modern oil might make them leak. If your engine is so old that it doesn't have a modern full-flow oil filter, maybe that's a problem from the detergent point of view.
Historic two-stroke Detroit Diesel engines seem to want straight-grade oil. No idea why.
I've had no issues using modern oils in vintage motorcycle engines that are DOHC with direct-actuated flat-tappet lifters, but with lighter valve mechanisms and larger contact faces than you would see with the American V8 applications. All have modern full-flow oil filters. Just stick with viscosity somewhere near what was originally recommended. I use the same Motul 7100 10w40 in my 1980s motorcycle that I use in my newer ones.
You can get motor oils designed for historic applications. They won't carry modern compliance markings (e.g. API or ACEA).
Historic two-stroke Detroit Diesel engines seem to want straight-grade oil. No idea why.
I've had no issues using modern oils in vintage motorcycle engines that are DOHC with direct-actuated flat-tappet lifters, but with lighter valve mechanisms and larger contact faces than you would see with the American V8 applications. All have modern full-flow oil filters. Just stick with viscosity somewhere near what was originally recommended. I use the same Motul 7100 10w40 in my 1980s motorcycle that I use in my newer ones.
You can get motor oils designed for historic applications. They won't carry modern compliance markings (e.g. API or ACEA).
Doug Hunter
Automotive
It is safest to follow the original oil spec. Thicker (higher viscosity) oil will work as well for temperatures above freezing, and reduce wear rates, but will cost you some fuel economy and power. 4 bar is plenty of pressure at idle, or even 1500 rpm. The type of racing you are doing can also change your optimum oil type.
TugboatEng
Marine/Ocean
If you don't believe API when they say that current API specs supercede previous specs then you can still get oils with the more classic anti-wear package (zinc) from your motorcycle dealer. For example, Honda GN4 and HP4 still meet the API SJ spec.
If your engine has any value to you, run synthetic oils.
The straight grade oil for Detroit likely comes from Twin Disc. The TD transmissions were wet clutch transmissions and were originally designed to work with the same oil as the engine. Twin Disc made the straight grade recommendation, Detroit never did. I stopped running straight grade in my fleet. I also used high tension oil control rings to reduce oil consumption. Maybe straight grade makes less ash?
Some honda dirt bikes run separate crankcase and transmission oils. They used to recommend a SG/SF oil for the transmission and SJ for the crankcase. SJ was the first energy conserving grade with friction modifiers whatever those are.
If your engine has any value to you, run synthetic oils.
The straight grade oil for Detroit likely comes from Twin Disc. The TD transmissions were wet clutch transmissions and were originally designed to work with the same oil as the engine. Twin Disc made the straight grade recommendation, Detroit never did. I stopped running straight grade in my fleet. I also used high tension oil control rings to reduce oil consumption. Maybe straight grade makes less ash?
Some honda dirt bikes run separate crankcase and transmission oils. They used to recommend a SG/SF oil for the transmission and SJ for the crankcase. SJ was the first energy conserving grade with friction modifiers whatever those are.
dtimberlake
Mechanical
- Oct 31, 2024
- 76
What does your sponsor Castrol recommend?
- Thread starter
- #6
sierra4000
Automotive
Yes, is "flat-tappet lifters and very high valve spring pressures" Ford Cologne V6, 2,8 engine, for circuit racing.
Idea is
www.burtonpower.com
Casrtol is only sticker, sorry.
Idea is
Millers engine oil CSS 20W60 semi-synthetic 5 ltr MIL6254G
A semi-synthetic engine oil - ideal for most classic competi....
www.burtonpower.com
Casrtol is only sticker, sorry.
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