Oil feed valve

If John Holmes might forgive me, I'd draw attention to this brief thread: http://www.nortonownersclub.org/noc-chat/technical4-commando-forum/417983147

Have had a Mick Hemmings anti-drain valve fitted on my Mk 3 850 for the last few years without any problem although alwayscheck oil is returning to tank after starting. Important to prime valve on initialfitting and againafter each oil change.

Colin no problem

I have been using an inline valve in the feedline for 20 odd years with no issues. However the issue of it not opening and killing your big ends is a potential issue. I minimise this risk by the following.

1. I used my own valve which is dismantable, I dropped a version with a steel ball and steel seat early on as it leaked and wet sumped. I then changed to a steel ball sealing onto a rubber seat, that does seal. I also adjusted the spring until it was only just strong enough to hold a column of oil just higher than the top of the oil tank.

2. When fitting or when the pipes are disturbed you must prime the pipes with oil so the pump will pull the ball off the seat, air in the pipe will stopthat from happening.

3. On the first start up of the day remove the seat and check the oil return is good and do this for long enough to confirm its fresh oil that is being returned not just what was in the sump.

Now the longer term fix is the AMR mod, but I will say that even that is not 100% as the only time I have had an issue with a stuck non return valve was on a C15 where that is like the AMR after the pump. Theory says that a gear pump will increase the pressure to inifinity when the outlet is blocked but there is always a clearance for the pressure to escape as it did on my C15. Luckily I was running a clear feed pipe and saw the oil at first feed normally before reversing and then fill with air.

The only way to be certain the non return valve is working regardless of its location is a oil pressure gauge or warning light.

It's your call personally I leave the pistons on TDC which doesn't stop the oil migrating to the sump but definitely slows down the process and the excess oil pumps back up to the oil tank a lot quicker than it would to split the crankcase to replace the mains should something go wrong. I would be pulling the oil pump and either reconditioning or replacing it as if it's worn a one way valve could put more strain on it and as the oil pump is the heart of any engine the last thing is to treat the symptoms instead of the cause another way is to ride the bike regularly as that was what was in mind when they were designed so the problem won't be occurring.... all food for thought but as I said it's your bike so it's your call

David

I looked at various solutions for this but was concerned about any one-way valve failing and anything I viewed as too complex, e.g. electrical switches and timing case mods.

Of the one-way valves on the market the one from Holland Norton Works looked to be the best, e.g. lowest spring pressure.

In the end I went for a simple ball valve in the feed line. I attach a disc brake lock 'reminder' cord when the switch is turned-off. I also fitted an oil pressure sensor switch wired to a warning light in the headlamp shell as an additional check. This just acts in the same way as those fitted to BSAs and Triumphs in the 60s and 70s.

I also have an oil pressure gauge - I'm a 'belt and braces' type'!

Just my two penn'orth.

Message me if you need any details.

Andy

I had a Mick Hemmings valve fitted to my Commando for many years with no problems. But as John says, it is absolutely vital that the pipe downstream of the valve is full of oil otherwise any air will stop the valve from opening.

I do not believe there is a fundamental problem with this type of valve as Velos had them fitted to all sprung frame singles and I have never heard of an issue with them. The point about ensuring the oil line is full is however stressed in the Velo Red Book.

I have read quite a lot about various owners experiences with oil draining into the crankcase and have always thought it strange, because when I had my first Mk3 Interstate, it was unheard of (by me anyway). I used the bike for several years for weekend travel, first between Norfolk and London, then Leicestershire and London, plus local use, depending on weather/shifts, etc. I guess I was averaging 250 miles a week. In all that time, I never had any issues with oil drainage. However, the normal maximum for the bike to be unused was probably 5 days - it was my only transport, so was used all year.

So maybe just regular use is the key; not necessarily long trips, but long enough to re-establish the correct oil levels. If there is planned downtime for the bike, e.g. winter hibernation, then draining the oil from the tank and replenishing after the lay-up would prevent the issue. Or just start the bike and warm it thoroughly every couple of weeks or so. In other words, an anti-det ground run.......might mean something to some?

The above would avoid the need for a valve and consequent concerns about reliability, flow impedance, etc.

Andy

The MK3 has the AMR type valve in the timing cover, what it lacks is the O rings inside the oil pump to stop the oil getting through the shafts and bypassing the valve. Bit of a lottery whether the MK3 one works, its a piston not a ball so can hang up in the gallery and not seal.

David

Suggest you look for a 'full flow' or 'full bore' mini ball valve and get the correct size barbs.

I have tried to find details of the one I have in use but cannot find the receipt at present - these sometimes 'go missing' in the interest of matromonial harmony!

From memory the oil pipe size is 3/8" ID - but do check. The type of valve is shown on page 2 of this document - bottom right in photo. If 3/8" ID then size G3/8 would be the one.

http://www.farnell.com/datasheets/308609.pdf

If I find further details I'll post them.

Andy

David

Looks like I got the valve and barbs on ebay:

all valve http://www.ebay.co.uk/itm/Brass-Chrome-Mini-Ball-Valve-Female-x-Female-1-2-bsp-/132325274258Barbs 2x http://www.ebay.co.uk/itm/Hose-Adaptor-1-4-3-8-1-2-BSP-6-to-13mm-PCL-Hose-Air-Tool-Fitting-Connector-End-/151037629763?var=&hash=item232a8b5543

Select 1/2 BSP to 9.5mm (3/8") (HC6908)

PTFE tape on barb threads.

Hope this helps

Andy

David

I too have a wet sumping 1970 Commando. I run strait 50 weight. It drains in about a day and a half when its hot out.

After reading all the blogs about one way valves, I put a brass Plumbing ball cock valve with a big red handle and wrote a reminder at the key switch (OIL!). I Have developed muscle memory that when the key goes in the valve is opened. when the bike is shut down the valve is closed. I wrote a reminder at the handlebar in the center (OIL?).

So far so good.

Bob McInnes

This is always a contentious issue - I fitted a microbore gas tap (Screwfix supply the item as: MINI BALL VALVE 8 X 8MM (26184) @ £6.29). A short length of copper microbore 'stub' connected to the compression coupling on both sides of the tap are ideal for fitting the oil pipe. The tap itself is approved for gas/water etc. thus will be OK for oil. I fitted mine circa 15 years ago together with an electrical cut-off that isolates the bike electrics if the tap isn't turned on. It has worked perfectly ... .

Not much to go wrong (unless it isn't turned on!!!!).

For me keeping things simple is a virtue although I can understand the appeal of clever fixes.

A simple fix for wet sumping is to siphon the oil from the tank when the machine is going to be idle. The key gets tied to the oil container to make it less likely the machine will be started before the oil is returned to the tank.

Hi David.

I'm afraid I can't see how the oil beneath the valve can "piddle away" as unless there is an air leak there is no way air can get in to replace the missing oil. If air can't get in then the oil can't go anywhere as there would be a vacuum above it - which, as we all know, nature abhors.

As I mentioned I have never heard of a Velo having trouble with the valve which is fitted as standard (although I accept as they have all roller bearing engines they're less sensitive than a Commando with shell big ends). The only issues with the Velo valve are when people try to seat it by whacking the ball onto the seat with a hammer which destroys the seat which must be a knife edge.

If you did see wet sumped oil returning for any significant period of time then it indicates the valve wasn't actually stopping the oil from filling the sump. What I would get with my Commando fitted with a valve was full flow on return for the first few seconds as it cleared whatever had drained down to the crankcase from the head etc, then the familiar bubbly intermittent flow as it returned oil and air. That would apply whether te bike had been left overnight or for several weeks.