Author Topic: Monograde oil users - when does summer start?  (Read 1393 times)

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KernowPete

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Re: Monograde oil users - when does summer start?
« Reply #15 on: 03 May, 2024, 19:05:22 »
BSA would have recommended using multigrade because that was the 'flavour of the month' at the time and you didn't need to change fro summer (SAE 40 or 50) to Winter (SAE 20).
However, the multigrades work by suspending the crud/debris etc. until it is filtered out by the oil filter, which is a good idea -if you have a cartridge type paper filter of course. The Monogrades don't and the crud/debris falls to the bottom of the engine and the big bits are caught by the sump gauze filter and the oil tank gauze filter/strainer.
However, apart from the WD B40's and the later B25SS and B50's our BSA's didn't have that luxury when purchased.
So, the answer is, if you have fitted an aftermarket in-line canaster filter then by all means use multigrade, if not then use monograde.

Also, oil technology has significantly improved over the years and all grades are far superior than when our BSA's left Armoury Rd. Plus, compare the mileage you do each year with what a typical owner would have done when new. Do you got to work, the pub, on holiday on your BSA nowadays?
As such, if the grade you use is resulting in greater wear than the alternative, I think most will agree, the likelihood of seeing that in our respective lifetimes is fairly remote!

Thanks

Steve.S

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Re: Monograde oil users - when does summer start?
« Reply #16 on: 19 May, 2024, 15:55:26 »
Change the oil now.
However, it would be helpful to know which models you own. For example, one could be a 1912 Model A and the other a 2024 Gold Star, which may need different oils.

scifi

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Re: Monograde oil users - when does summer start?
« Reply #17 on: 23 May, 2024, 13:19:01 »
I have only used temperature as a guide when Mountain Biking..  Above 15C it was shorts only, below 15C it was shorts and longs.

So if you want figures, then maybe above 18C is Summer grade.   Below 0 C it should be Winter grade.   Hope that helps.

KernowPete

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Re: Monograde oil users - when does summer start?
« Reply #18 on: 27 May, 2024, 07:39:11 »
Thanks people. All done a couple of weeks ago on the B31, including some oil tank repairs. The C15T is without its top end for now so no worries on that one  :)