Changing oil with an anti-wet sump pump valve?

[Howard]

Even though I've no intention of using an anti-sumping valve, Vibrac's comment on my shot-from-the-hip suggestion has made me take a better look.

The anti-sumping valves I've looked at are non-return valves fitted backwards and relying on a weak pump to supply sufficient vacuum to unseat the valve. Furthermore, the valves are fittted as a fix for worn pumps!

This is done because lack of use may cause oil to fill the sump, leading to blue exhaust smoke for a couple of miles, or the removal of the sump plug to drain the sump. Well worth it you may think, but the alternative means that, when standing, oil can drain from between the ASV and the pump, leaving a column of air that can't be seen, and if the engine is run in this condition there is no obvious indicator (blue smoke), the pump can't pump air, and an expensive failure will follow. To prevent this from happening requires pump priming, which takes longer than draining the sump, and isn't an exact science.

The non-return (ASV) needs to be fitted after the pump (on the pressure side) and the answer is “No I don't know where or how it can be done” but that's no excuse for making a pain into a possible disaster. I don't know anyone who's had a failure because they used a standard oil pipe, but I do know people who've lost money and riding time due entirely to bad ASVs.

As far as fitting a manual valve, why not, as long as it's a full bore one and there's a foolproof way of making sure the valve's open when the engine's running. I don't know about the rest of you old codgers, but I can't remember which side the reserve petrol tap is, so there's no way I could risk this without a very safe safety.

Just a few thoughts.

H

 

[ogrilp400]

Dear All,
Given that the oil starts leaking through the pump immediately inside the oil feed banjo, around the pump plunger back into the scroll cavity and around the pump plunger and into the oil filter chamber thence to the big end quill, there is no way of putting an anti drain valve after the pump that would stop the leakage. I hear people say that ADV can cause a wrecked engine through loss of oil. I have seen wrecked engines from taps in the feed lines forgetting to be turned on as well but they seem to still be in proliferation. I'm a great believer in if you don't want excess oil in the sump then ride it.

 

[ogrilp400]

There is a book on Carburettors in the Restoring Motorcycles and in it there is a petrol tap that incorporates a magneto cut out when the tap is turned off. Its a fairly simple arrangement that could easily be manufactured on an oil tap to kill the ignition, magneto or coil, when the tap is turned off.

Phelps.

 

[greg brillus]

Must say I haven't seen too many pumps worn that badly that they leak enough internally to drain the oil tank into the sump. More often it is damage to the pump bore in the cases themselves when the pump sleeve has been removed with burrs and dags catching on the way out and leaving score marks. This is absolutely no different to vertical score marks up the bore of a cylinder, with a loss of compression as a result. Only one realistic way to fix that .......The hard way. The use of any restriction in the delivery line is a risk you the owner must take yourself. It is not something I am in favor of.

 

[vibrac]

Well I dragged the cooking Comet out of Hibernation today (Its the Spares Open day next week) looked in the oil tank and I could see the bar, I connected up the petrol pipes filled her up the dry tank with the rats pee called petrol nowadays, gave her the seasons 20cc anointment of oil via the push rod tubes and started her up, A qiick ride round the test circuit, back home oil still not over bar so no sunping over the winter I certinly did not do any fancy positioning of the engine last autumn so its either good luck or I have a tight oil pump.

 

[Oldhaven]

I did the same drill this last weekend and got about 3/4 quart of oil out of the sump before start up. This after 6 months of sitting still. The engine is a new rebuild, but has its original oil pump and sleeve. I may try the fancy positioning next fall, but I'm not worried about it much.

 

[Howard]

Just had the same trouble changing the oil in a friend's Rap with an ASV. Piece of old petrol pipe siphoned oil out, removed ASV, replaced with pipe and returned ASV to owner in box with other unnecessary bits. Job done.

H

 

[Monkeypants]

The new build 1360 engine with two start Maughans pump had a wet sump problem. The pump flows lots of oil but allows a drip of oil thru to the crankcase about ever twenty seconds when at rest. This fills the sump in about one week. The engine is just at the edge of my ability to kickstart with a dry sump, with a full or half full sump it was impossible. Not wanting to go thru the procedure of removing the pumpand fitting another new one, which would likely still wet sump, I fitted an anti drain valve. The ball and spring type are too risky in my estimation, so I fitted a manual valve with interlock.
The interlock is the ignition key. The ignition key has an alloy fob fitted to it. I whittled the fob out so that it is the handle that turns the oil valve on and off. When the oil is off, the key cannot be removed from the valve. It,s a bit like those shopping carts that hang onto your quarter until you put them properly away.

 

[Monkeypants]

For this to truly be failsafe, there can only be one ignition key. I do have a second key taped to the bike in a hidden location, but that would only come into use in the event that I was out using the bike and lost the main key. In that situation the oil could not be off. I've thought about it quite a lot and haven't been able to come up with a scenario where the engine could be run without oil due to the valve.

Glen

 

[Howard]

I have a problem with "manual failsafe" devices, it's probably just me.

Last year returning home from Spain we stopped at a hotel half way through France. We laughed when we saw the room key had a wooden ball the size of an apple attached to it so we couldn't accidentally take it with us. Guess what I found while we were waiting for the ferry in Calais???? Maybe it's just me.

H