Good day.

Yes today is a very good day for me, after 3 years of colecting and buying parts, working in my garage (with the help of my father) for my M20 after 50 years today was the big day. V. Frankestein would say "it lives" :) yes we manage to start the engine today I was so exceitet that I forgot to record "the awakening".


But here are some questions:
- what oil schould I have in the engine (for starting it was given a 15-40W)
- what oil schould I have in the gearbox (in both cases I mus say that I will drive the bike in the temperatures between 5 to 35 degress).

- I have took out the oil filter to see if the oil is comming back to the oil tank and it commes back smoothly. The question is the engine geting enough oil for lubrication. Tomorrow I will mount a manometer, how much presure it schould have. I have read somewhere that with 7 psi (0,5 bar) the spring opens (presure valve) and the oil gets to the big end. But how much presure schould the engine have is 30 psi (2 bars) allright?

BR, Mitja

email (option): mitja.peterka@siol.net

Hi Mitja...You should run the engine on an SAE 30 grade in the winter and an SAE 40 grade in the summer...If it's a very hot summer put in an SAE 50...

The gearbox and primary chaincase also use an SAE 40...Do not use hypoid gearbox oils in the gearbox, these can damage the gearbox..Engine oil only..

If you cannot obtain single grade oils use a 20/50 multigrade as a substitute...

The oil system is not a pressurised system like that used by an engine with white metal big end shells...As such oil pressure is not really the thing to think about. Oil volume is more important.

I do have some oil pump volume figures for the M20 but setting up such a test can be problematical as you have to determine the engine revs and then to calculate the oil pump revs to work it out..It is actually easier to test the pumps performance off the bike...

However, I have to say lack of oil supply is very very rarely a problem with the BSA engines...I have never encountered it in over 40 years...

I am confident that as long as everything is correctly assembled and the oil is returning to the tank you will be OK in that regard....Ian

email (option): ian@wright52.plus.com

One tip I do know is..do not use any modern oil with a detergent in it. Any gunge or baked on oil deposits that have tucked themselves away in the engine for the past 70 years (and not doing any harm) will get lifted and deposit themselves where you dont want them.
Drop that modern oil you have in her asap and stick with a classic oil such as millers 30 or 40.
Rich

Thanks Ian I will put SAE 40 in the gearbox and the engine. What oil do you use?

Yes I read some articles about the presure for the engine and its hard to test if the oil is circulating the whole engine.

I hope everything is OK because it is realy working like a swis clock :) and I hope it stays so.

So Ian if the oil is coming back to the oil tank everything schould be OK with the lubrication of the engine if I am understanding right.

I am 100 % sure the engine was compound correct.

BR, Mitja

email (option): mitja.peterka@siol.net

So this is the oil

http://classicoils.absolutewebhosting2.co.uk/Product-152/Oils-by-Manufacturer-Brand/Millers/Millers-Classic-Millerol-M40

or

http://www.wipperhausen.de/Rektol-Oldtimer-Motoroel-SB-40

BR, Mitja

email (option): mitja.peterka@siol.net