Alternative anti sumping valve

[derek]

Reading all of the concern over the anti sumping valve being on the suction side of the oil pump and the possibility of it drawing air with subsequent lubrication failure: Why not fit the spring loaded non-return ball valve on the discharge side of the oil pump? This could be very easily done by fitting it in a modified banjo bolt, the one that passes through the timing cover to the discharge side of the oil filter.
This would then be fool proof as the light spring operated ball would prevent the oil draining into the cranck-case when engine stationary, but would easily open under pressure when the engine is running.

 

[Kevin Fowler]

I have installed my antisumping valve with modified drain tapping. It is undertest as we write. After correctly priming the downstream oil line and allowing an overnight stand to check for oil leaks( the opposite of which is air leaks) A run was undertaken . Constant checking of oil return whilst on the move. This may not be upheld in court , "your honor I was checking the oil " Get the oil warm and return home. Park the bike, use the calibrated 1/4" dowel to check the level in the tank. Note level.mark 7 on the dowel. Recheck in 24 hrs/48 hrs/72 hrs no drop in oil level. So far so good. If the ran stops a decent ride this weekend.

 

[Howard]

I can't help thinking, if anti-sumping valves are such a worry, why fit one? How do you know that after all these tests it won't gum up the day after?

Never had one.
Never had a sumping problem
Don't want one
Don't want anything suspect between oil tank and pump.

H

 

[Kevin Fowler]

Hi Howard, I agree with your view , the correct repair would be to fit a new oil pump, which is how all this started. A broken cranshaft led to a rebuild, the oil pump sleeve was replaced and damaged, creating the oil passage. Prior to the rebuild like you i did not need one, did not want one ,having had a seizure with a Velocette ,caused by air leaking at the banjo, and not pulling the valve open. How ever I do not intend to replace the oil pump at this stage. The Velocette will empty the crank case when started , the Vincent will not start when full.

 

[Howard]

Hi Kevin.

OK I'll go along with your reasoning for this problem. Sometimes I see mods being done to Vins and think WHY?

Have you thought of a manual valve in the feed line? Very simple, you just need a good memory, or one of these memory joggers you get for disc locks.

H

 

[Ken Tidswell]

If you examine the bore of the hole where the oil pump sleeve fits, you will see that far from being a nice clean round hole.
It appears to have been bored with a blunt drill not as smooth or as clean as one would expect. Precision it is not. Even after cleaning out with a1 inch reamer, they are rough. With the coming of lower viscosity oils there must be enough clearance for hot oil to pass , both between the oil pump sleeve and the plunger inside it. Some plungesr are quite tight and some are slack. This causes wear to the worm and plunger. If you examine enough worn pumps you can see where the wear is worst at the crest of one of the teeth, eventually the wear is sufficent to prevent the plunger oscillating and you finish up with a very hot wet sump engine. Ken

 

[Comet Rider]

Hi Kevin.

OK I'll go along with your reasoning for this problem. Sometimes I see mods being done to Vins and think WHY?

Have you thought of a manual valve in the feed line? Very simple, you just need a good memory, or one of these memory joggers you get for disc locks.

H

Hi Howard,
You can get a 1/4 turn ball valve with integrated switch, to either short a magneto to ground, or inhibit a coil ignition system. This can be seen on one of Brain Chapman's machines, who might be able to tell you where he got it

HTH
Neil

 

[Howard]

Hi Neil

Thanks for the info, sounds ideal, but I think it's Kevin and Derek that need this.

H