English French German Italian Spanish

oil filter draining

Submitted by paul_standeven on Thu, 04/10/2018
Forums
Heavy Twins

My Model 88 is running well, with one issue I need to sort. I fitted a Commando oil filter plate in the scavenge line, behind the gearbox. If left for a few days, it takes ages for oil to start returning to the tank. I think that the oil is draining from the filter into the crank cases, and it takes a while to refill. Meanwhile, the valve gear and cam are not getting lubricated.

While the engine was in pieces, I service the oil pump, by flatting the pressure side cover plate and lapping the body so that there is no end float in the pressure gears. So that when assembled I had light friction in the pump. That works well, as I measured 45 psi at the timing cover with some revs, and 5 psi at idle, on a well-warmed engine on a hot day. I was not able to do the same to the scavenge side, as the drive worm simply refused to come off the pump drive shaft.

Suggestions? I can fit a new oil pump, but need to find a new drive worm for 3-start. Not available new. Or I can delete the filter. Or is there a neat simple -one-way valve I can fit to the scavenge line?

Paul

Submitted by ian_soady on Thu, 04/10/2018

Permalink

I'm slightly surprised that any appreciable amount can get back to the engine as presumably the filter (if fitted like a Commando's) would be near the level of the crankcase hence there would only be a slight head to push the oil back to the engine.

I suppose you could fit one of the available valves (making sure it's the right way round!) between the pump and the filter. The consequences of it failing are much less serious than one fitted in the feed side.

Submitted by paul_standeven on Thu, 04/10/2018

Permalink

Yes, i'm surprised too. The oil filter is horizontal, roughly level with the gearbox mainshaft.

So what valve is on offer which might do the job?

Paul

 


Norton Owners Club Website by 2Toucans