Forum

[Pat]

Hi there,

I have a 1995 enfield and recently I bought a triumph speed twin 1957, as per triumph manual/lubrication chart the gearbox, primary chaincase and engine oil tank an S.A.E 20, S.A.E 50 and S.A.E 20 should be used respectively.

Can someone advice how these specifications translate in today’s word, i.e. does S.A.E 20 corresponds with 20W-40? Any ideas on what types of oil should I use for the above 3 parts?
Many thanks

Patrick

[Dennis C]

Gearbox and engine 20w50 primary chaincase automatic transmission fluid. Although you can still get the original grades if you really want to.

[jefrs]

The SAE20, SAE50 are "straight" oils and for example the SAE50 has exactly the /same/ viscosity as 20W-50 or 10W-50 at 100°C, which is assumed to be the operating temperature of an engine. The "W" oils are "winter" grades, the testing measurement is different - if an oil behaves (cranking properties etc) like a SAE10 oil at low temperature it is classed as a 10W. therefore the important number for an oil at engine operating temperature is the larger, second one. The first number, the "W" is not strictly speaking a viscosity but a performance factor, whereas the SAE number is a viscosity measurement, the lower the number, the thinner it is. SAE20 does not correspond to 20W-40 but SAE50 would correspond to 20W-50. Straight SAE20 and SAE30 are easy enough to find but SAE50 less so. If you use an oil around a wet-plate clutch (primary chaincase) it is very important to use a waterless oil e.g. JASO MA/MB type motorcycle oil (otherwise the friction plates can come unglued) - not all oils have this but ATF does. Oils have moved on, a lot, since 1957

[Dennis C]

More muddy waters being stirred up.20w50 put simply is multigrade, when cold it is as thin as 20 grade and when hot will retain the protection of 50 grade. Use it in your Triumph with confidence I have used it in all mine for as long as I can remember, simple and plain answer.

[jefrs]

Not quite DennisC, the first part of the number is the "winter" properties and has more to do with cranking and sealing when cold, the "20W" is not a true viscosity measurement - the oil behaves like a hot SAE20 oil when it is cold (they have charts showing varying viscosities over a range of temperatures), when hot at 100°C then 20W-50 has the same viscosity as SAE50 oil, the second "hot" number is a viscosity measurement. It you have to use a multi-grade oil as a substitute then use the second number i.e. 0W-20 or 10W-20 for SAE20 and 20W-50 for SAE 50.

[Dennis C]

For goodness sake Jeff the guy asked a simple question which deserved a simple answer why complicate matters with gobbledygook?.

[Beezabryan]

A simple answer to a simple question is all that is required.

[2cvandy]

Just remember, not Everything you read on a Forum will be Right, or even Sensible,,,,,,,,,

[Dennis C]

Andy I think people on this forum have had that point made very clear on many occasions ;-}

[Rattlebattle]

Pat: I have a 1954 Tiger 100. In the engine I use either 20W/50 or monograde 50 (Not "straight"' 50 - there's a difference. I doubt anybody makes straight oil, ie without additives, these days though plenty do supply monograde oils). In the gearbox I use monograde 50, but this is an oil designed for use in gearboxes in which there are plain bearings that are susceptible to being attacked by hypoid 90 grade oils. In the primary chaincase I use monograde 20. You could use ATF but as the chaincase leaks it wouldn't look period oozing red stuff....
I get all my oil from Morris; they provide an efficient and quick service and supply in 25 litre drums too - handy for engine oil. I hope that answers your question. Enjoy your Speed Twin; I'm sure you will....