External Oil filter question

[Beeza]

I’m trying to clarify an opinion. If you run an in-line type oil filter,(large spin-on type) is there any need for the sludge trap centrifuge sediment trap tube thingy, and needing to run mineral oils only.
Also, as an aside question, would he then be able to then run a full synthetic type oil?
Asking for a friend..

[Triton Thrasher]

The requirement for mineral oil is something of a superstition.

The sludge trap may still do some good, because it traps out particles of carbon black which are too small to be stopped by a paper filter.

[morris]

Agree with TT
Regarding synthetic oils, they're made for modern tight tolerance engines and usually rather low in viscosity so personally I wouldn't recommend them for our engines.
There's plenty choice in good quality "classic oils", so why go for a (usually) more expensive synthetic?

[edboy]

hi , i run castrol synthetic 10 / 40 in my bsa a10 [ after running in ] and i believe the advertising  science as the engines quieter especially around cam and followers. [ less wear i think ] . longer between oil changes also.

[Beeza]

Thanks for the replies, I was of the understanding that with the mineral oils that suspended particles have the ability to be trapped in the centrifuge, however with the synthetic oils (or even detergent oils) that the particles have the ability to remain suspended in the oil. I have a very vague memory of reading this, or it may all be a dream, I can’t recall.
Ed boy, are you running an external oil filter?

[RoyC]

I have an external oil filter and use synthetic oils.
When our bikes were new, the oils that BSA recommended were the best oils available at the time.
In the last sixty years oil technology has advanced a lot and the oil available today is light years ahead of the oil available in the 50s.

[Triton Thrasher]

Regarding synthetic oils, they're made for modern tight tolerance engines and usually rather low in viscosity so personally I wouldn't recommend them for our engines.

I’m sure none of us would recommend an oil that was too thin.

There's plenty choice in good quality "classic oils", so why go for a (usually) more expensive synthetic?

Less wear, probably.

[RDfella]

Use the oil that the engine was designed around. A modern oil is detergent, ie it keeps contaminants in suspension for the oil filter to remove. With no filter (as with our A10's) the stuff just keeps circulating like grinding paste. Seen several engines destroyed by putting modern oils in old engines.

[edboy]

all the bsa handbooks mention esso extra 20/30 and 20/40 as the old esso brand was a lovely oil. sadly no longer made. i use a norton cartridge filter but without one then i would use a monograde oil. i was unsure of fully synthetic until i tried it and also noticed less smoking that some cheap mineral oils seem to produce.