changing oil on matchless 3gl

[milbike]

i am replacing the black sludge in my matchless 3gl with some morris's 50w ,i have drained oil tank and cleaned oil tank filter and drained any oil left in crankcase,any suggestions on priming the oil pump,i am concerned that there may be air in the feed /return lines , or do i simply fill tank and run engine

thanks

[retriever]

I always just start up let it idle and watch for oil returning to tank before topping up. If you did not drain the pump it should have enough oil in the pipes and pump to get it all moving.

[Tony B]

If it is any help. On the Land Rover 101 there is the same problem when oil is drained and filter changed. Oil pump won't prime itself. The method there is to remove front plate of pump and pack Petroleum Jelly into the gap bettween the cog wheels. Then add oil and start. You could also fill the filter with fresh oil before fitting, provided it won't pour out.

[Ron]

I agree with Retriever. Just let it idle till the oil returns to the tank........ After a full engine rebuild it can be a nail biting few minutes before the oil returns.

 

Retriever, is your Douglas a WD bike? Picture please!

 

Ron

[retriever]

Yes the bike is wd. from 1917 douglas only built for the army until the end of the war. see picture in my gallery page

[Ron]

OK. But you will have to give me a clue about the gallery page?

 

Ron

[wdbikemad]

Don't worry about priming or air in the system.......these old lubrication systems are very primitive, and robust...........

 

As mentioned, it can take a while for the oil to work it's way through the pipework and if paranoid you can always put a small cup-full down the cylinder bore but it's not strictly necessary......

 

The only advice I'd add would be cleanliness........check all ball valves are seating properly, minimise leaks where possible and check all joints for tightness.......

[griff66]

if the old oil was that bad and u can afford it fill with new oil run bike get it nice and warm drain oil and refill should get rid of most of that remaining sludge

[Tony B]

Out of intrest would you use a modern flushing agent on an engine that old? I be concerned that take to much muck out and the seals would leack.

[Ron]

Yes definitely not a good idea to use flushing oil or modern detergent oil in an old engine that has been running for a long time on mono grade non detergent oil. Ron