Not a good day

Did you put in used big end shells or new ones that looked iffy?

Many of us use the Mick Hemmings anti-wet sump valve , including myself on a Mk 3 850. Mine also gets long layoffs and I'm always careful to run engine stationary for several minutes on first start after several weeks layoff checking oil is returning to tank before setting off. Never had a problem - so far. Curious to hear others' experiences with this anti-drain valve.

i have often wondered why we don't have an oil pressure warning light, does not have to be a capilory type (bit risky) the 12v type fitted to cars would be good. Is there a small sensor that could be fitted to the pressure release or inside the timing cover?.

None of my bikes wet sump badly because I have always taken effective measures to prevent this from happpening. Consequently, I have never fitted an anti-sumping device. Not that I would anyway..........you too often hear of problems with them. eg. sticking open, sticking closed, manual versions that need to be switched on and haven't been.

Generally, the cause of wet sumping can be narrowed down to 1) a worn oil pump..............Because they are double-speeded from the original design specification, they need to be serviced at around 50,000 miles. 2) worn timing cover seals (crank and pump) 3) leakage from behind the pump.

The big twins have huge rotating cranks that flex the metal behind the oil pump. The warming and cooling of the engine also causes some distortion, plus you will also come across badly machined pump faces guaranteed to allow the Black Gold to escape directly to the sump. Adding to this, overtightening of the pump nuts will cause the threaded shoulder to hump and hold the pump off its mounting. Sort out 1 to 3 first and you should not need any anti-drain or anti-wet sump device. All my bikes can sit for a month before the oil level drops to half-way.

There have been so many reports of anti drain valves leading to loss of lubrication with the inevitable results, I do wonder why they are still offered for sale. If you have a wet sumping issue, find & rectify the cause, don't try to mask it with an after-market mod of dubious reputation.

James, on a mk3 Commando you should have a built in anti drain valve on the pressure side of the pump, (in the timing cover, the only sensible place to have it.) You really should not have to even consider the fitting of a second anti drain valve in the feed line, much less do it.

I have an anti wet sump valve fitted for 20 years, always prime the pipe when it is disturbed, always check for good oil return after a layup and never had a problem.

i had a similar problem 40 years ago with a Venom. Started it up after lying up all Winter, observed oil return to tank, seized 5 miles later. At the time I reckoned the ball in the valve had stuck. The Velo forum had a lot of debate last week on same problem. The consensus was the steel ball can let by, but the more modern Nitrile type ball can be very prone to sticking [some of the most experienced members being caught out] Anyway,these days, if the bike has sat for any time I always hit the valve a sharp tap as a precaution.

Previously tim_gostling wrote:

James, on a mk3 Commando you should have a built in anti drain valve on the pressure side of the pump, (in the timing cover, the only sensible place to have it.) You really should not have to even consider the fitting of a second anti drain valve in the feed line, much less do it.

Indeed , but I found this standard Mk3 anti-drain valve in the timing coveronly slowed down the seepage rate , not stopped it. I tried changing it for a new one butno improvement.Over a three month layoffmuch of the oil tank contentstill ended up in the crankcase. The fact that Norton took the trouble to design inan anti-drain valve on the Mk 3 would point to an intrinsic foible of the commando engine they recognised.When Irode the bike more regularly -at least once every 2 or 3 weeks -most of the oil remained in the tank between start ups but current lifestyle has meant less frequent usage , sometimes laid up for 3 months.

While conventional wisdommightred flag after market anti-drain valves,the Mick Hemmingsone iswell made and quality(based on the standard Velocette item)and I'm of the"several minute oil-return check on start up" and the "re-prime after oil changes" school of thought.So far troublefreethree years after installation.

Previously david_evans wrote:

I'll let you know what I find, but guess what bit isn't going to be featuring in the next rebuild?

Dave, Sorry to hearwhats happened but if I guess right, can I have it?

Regards, Alan

Yes Dave, I'll be there. In fact I'm just trying to book my ferry. See you there, Cheers, Alan

Previously david_evans wrote:

It's yours Alan, brave man. will you be at Wicklow?

Previously Alan Throssell wrote:

Previously david_evans wrote:

I'll let you know what I find, but guess what bit isn't going to be featuring in the next rebuild?

Dave, Sorry to hear whats happened but if I guess right, can I have it?

Regards, Alan

just bought one of these gadgets, getting a bit windy over whether to fit it now

do you want mine as well alan !!!!

The important bit is to look at the return in the tank long enough to be sure the oil you see has made it past the valve after a layup. For the first start up of the spring this has to be a few minutes, this can be lower for more regular riding until next spring. My valve has a steel ball and a rubber lined seat, I also reduced the spring length, you are only holding up 2 ft of oil so it should open with a light blow of the lungs.

Previously paul_hignett wrote:

just bought one of these gadgets, getting a bit windy over whether to fit it now

do you want mine as well alan !!!!

Hi Paul, When I see you at the camping weekend at Easter we can discuss the subject of wet sumping over a pint, but at the end of the day the choice is yours. See you Good Friday.

Kind regards, Alan

Hi,

Can I add a little. I have a 650 dommi and the oil pump needs some work however I control the oil with a car brake pipe clamp on the rubber hose. This clampis so big thatit almost fouls the kickstart so I never forget to remove it. I do forget to put it back so it isn't fool proof. In the 70s my brother and I used to use laboratory tubing gate clamps but they were small enough to forget, not a good idea when you are 45 years older.Started my Velo up last week after the winter layup - the oil returned fine. It is fitted with the VOC nitrile ball.

Good luck guys.

Peter B

A thankyou to this site, I have used a Hemmings valve for years with no trouble but thought I should check the return after starting up for the Spring - no return! It turned out to be a loose gland nut allowing air to enter the oil line so major trouble averted. Club membership worth every penny and a lesson to go over the bike with a spanner regularly.

Interesting bit in the latest Fishtail regarding anti-sumping valves, which Velocette have as standard. On the post-war singles, the oil feed line runs under the gearbox to the anti-sumping valve. This keeps it low and eliminates the tendency for oil to drain from it to the sump. What you shouldn't do is have the anti-sumping valve in a direct line between the oil tank and the oil pump (which is where they go on Nortons) as oil can drain down leading to an air gap and anon-opening anti-sumping valve with consequences so graphically stated above.