Persistent excessive wet sumping

Tim,

I have 2 x mk 111 bikes, one of which wet sumps (after a couple of weeks ) the other one takes months to do it, so no problem.

Anyway, after going through as much as I could think to do to stop it , I eventually fitted a plumbers gas tap to the feed line, and when the bike is not being used regularly I switch the oil off. I didn't want to fit an anti drain valve (though I have an LPW version on my Trident, which works fine)

Of couse, I know that one lapse in concentration and it's a blown motor, but it hasn't happened since I fitted it, and I do have a reminder stuck on the tacho.

I believe some owners fit the same type of thing but with a micro switch fitted that disables the ignition till the oil is switched on, but to me that's just something else to go wrong.

I realise that this is masking the actual problem, but I'd rather ride the thing without having to drain the sump every time I use the bike.

sam

Hi.

Check that the brass end plate on the pump doesn't protrude beyond the mating face (against the crankcase). This wouldresult inthe symptoms you describe. Put a steel rule across the mating face of the assembled pump and hold it up to the light to check. My Dommi's did!

Regards,

Ian.

Some models of the Mk 111s have an anti-drain valve built into the timing cases. Must be something missing if they still wet-sump!!!

Back to Tim's bike. My money is going on some crankcase distortion in the region of the oil pump. This problem came to light on the 750 Commando in 1971 and consequently the fitting of a paper gasket to the face of the pump became the norm from then on.

However, do check that all the mating parts are seriously flat. I've seen oil pumps, straight from the factory, that had ground faceslooking more like the top of of an old gramophone record. You could trim finger nails on the very poorly ground mating face. Also, check out where the studs go into the crankcase. If these have been overtightened at sometime, then they will pull up a ring of alloy which will hold the pump away from its respective mating surface. A similar problem occurs on the cylinder head with rocker cover studs getting the 'heavy-hand' treatment.

My Mk 3 used to empty its entire oil tank contentsafterabout two weeks ofstanding despite the Norton standard Mk 3 anti-drain valve beingfitted, both before and after a complete rebuild ,so finally fitted a Mick Hemmings anti-drain valve - cured the problem and so far so good.

With the stories of engine blow ups from some who've fitted various types of after market anti-wet sumpingdevices , I just wonder if anyone has had this experience with the Mick Hemmingsvalve ? It's well made and based on the Velocette anti-drain valve which was fitted as standard on their bikes.

Obtusely my '73 Mk 1Ahardly loses a drop from theoil tank afterthree months of standingso doesn't needan anti-drain valve - go figure !

I have just fitted a Mick Hemmings anti drain valve to my 1970 Fastback. Before that it would take about a week to drain half a tank into the crankcases. I was suprised at how much I had to suck on the valve to open it, I was thinking it would have been a lot lighter spring. In addition I thought the bore of the exit pipe would have been a bit bigger as well, as there is scope to have a larger diameter exit tube and still fit 3/8" dia rubber pipe. I know Les Emery will not touch anti drain valves but then I ride my bikes most days.

Hi All. Now that has raised an interesting point. i was today just about to order the MH Anti Drain Valve (TX1474) But after reading all your thoughts i may, for the short term, stick to draining the 1 litre per two weeks from my 72 750 Commando. Its not that its an effort but i do worry about the thread in the crank case.

Mark.

If you fit the sump plug with the built in drain plug you wont have to worry about the threads.

Idont know if my 850 mk2a wet sumps or not as i dont give it chance to.I fitted a valve made by john epp in canada (look on access norton website) it is a manual valve but has a plunger type electrical switch fitted to it. This i have wired from kill switch through the valve switch to work a relay (fused relay operates boyer straight from battery for best voltage) so if oil is not on no sparks. If you forget to turn oil on you soon remember or its you that gets hot an stops turning things over not the engine. In back of some classic bike mags (and I thing the AJS owners club mag maybe) someone advertises an English made valve with the same idea from time to time or you may be able to make something of your own design along those lines. Mine did cost about £100 which is not cheap i admit but is well made neat and easy to use but above all alot cheaper than rebuilding an engine if you forget or if automatic valve fails an stop closed also some say that the auto valve may restrict flow to the pump (depending on type) an so strave engine at high revs when oil flow is needed most.

I know this in your case is not solving the problem but as you say all that is left is the cases of your original motor so fitting such a valve would be easier and cheaper than new cases or a complete different motor. Good luck with it Karl

Obviously, there has to be a reason for Norton wet sumping, the gear oil pump is susceptible and common across the board. But why some worse than others in the standard set up? My 76Mk 3 will empty it'soil tank in about 4 weeks when left standing if I leave it on compression. About a week sooner if I don't.

On the other hand, I have a 1960ES2engine that will empty it's tank in two weeks but a 1959 model 50 enginethat does notwet sump at all, not even whenleft standing for the best part of a year. Why?

All oil is straight 40 with light detergent in the Commando.

As for wet sumping over night, without finding the cause I can only think of two courses of action. First is the tap of one kind or another, the other is to leave the sump plug offwhen left overnight with a container under it. Not much fun if you are away from home though.

Please let us know the cure if you find what was causingthe problem. (Looks like the cases?)

Gentlemen,

I fitted a M / H anti drain valve to my MkIIA three years ago with no issues post installation. Previously, the bike would deposit the contents of the tank in a couple of weeks, despite refurbishing oil pump etc. However, this happening overnight is extreme and suggest another problem. If it was mine and, after the exhaustive diagnoses performed by others, if nothing cane to light, I would fit a manual tap and a "Remove before flight" lanyard and hook is over the bars or somewhere appropriate!

Good luck!

Rgds Steve

Previously robert_tuck wrote:

If you fit the sump plug with the built in drain plug you wont have to worry about the threads.

Hi Robert. I have seen those, but they list for engine numbers before 200000 and after 300000. and mine being a combat engine falls in the middle catagory, but i will ask. Thank you. Mark.

I am not against anti-drain valves asseveral bikes did have them fitted as standard. But I have a huge concern, in the case of Tim's bike, if such a device is fitted without first discovering the root cause of the wet-sumping problem.

If his engine is dumping such a large amount of oil into the sump then it is still likely to do so below any fitted anti-drain valve and therefore leave air in the system. If the main problem is caused by a gap or hole anywhere in the feed plumbing then, when the engine is started, it is going to suck on air possibly to the extent that the AD valve does not release.

This is a problem encountered in the past, by other Norton owners,often as a result of poor fitting of the AD valve. Reusing the oldoil tubing was the most common mistake.This hadgone rigid andno longer madea good seal in the system.

Tim........ another possible way that oil canbypass the pump in such quantities is if there is a fault in the feed tunnel. Perhaps during manufactureof the cases.Check out the attachment.

The GREEN arrow shows the feed in and the RED up from the sump. They would meet at the BLUE star if the drilling of the oilways was done a bit carelessly. Oil from the tank would then bypass the pump and go straight down to the sump. You could check out any problems in this area by removing the grub screw on the outside of the cases (at the base ofthe RED arrow), push inside some tubing (todivert any oil going down to the sump)and seeing if any significant amount of oil drips out.

Hi Tim,

As it dumps the oil so quickly have you considered removing the pump and fitting a bit of tape or similar over the feed holes and then replace the pump. Fill the bike with oil and leave overnight. If any oil has drained into the sump then the problem is before the pump. If none has drained then it is the pump or after.

You may be able to do a similar trick with the exit from the pump where it feeds to the crankshaft.

Break the pronlem down into sections and it may all become clear.

Best of luck.

Tony

I'll second that, process of elimination. Dumping that much oil over night is a real problem and on second thoughts, fitting a tap is not the answer. Please keep us posted.

Please take a look at this website if you are interested in adding some special goodies to your commando.

http://www.hollandnortonworks.eu/?lang=EN&page=10

They have some very nice gear for sale including an anti-drain valve.

However, you might need to donate a leg or sell an organ to pay for the bits.

Previously tim_gostling wrote:

OK chaps, hereâs one for you.

850 MK2a Commando which will empty itâs oil tank into the sump over night, cold engine & 20/50 oil, everything apparently in perfect condition.

Let me give you a little history.

The bike belongs to a friend, heâs owned it for years & has always had this problem. Iâve been involved in a lend a hand/shoulder to cry on capacity & weâve tried/checked all the usual suspects, including fitting new oil pump & all gaskets/seals etc over the years, all to no avail. The engine ran well & was lovely & quiet with no unusual noises, however, the bottom end was taken down for a look but nothing untoward was found, so was put back together with new shells etc. He then decided to fit an anti drain valve from one of the well known suppliers, which did indeed stop the wet sumping. Unfortunately less than 500 miles after fitting, both big ends nipped up, bending the rods & wrecking their journals. The engine is now back together with a replacement crank, new rods, bearings, cam, another new oil pump etc & still empties the contents of itâs oil tank in less than 24 hours. The crank cases & timing cover are the only original major parts left of the bottom end of the engine but look to be in perfect condition with no cracks or damage evident, very lucky considering the above, fortunately when it nipped, he had just ridden into his garage after a ride, heard the death rattle & was just about to kill the engine.

Could there be some porosity in the cases which lets the oil drain? Has anyone come across this before? It may explain why the big ends were starved of oil with the anti drain valve fitted, if the pump was able to suck air through the porosity instead of being supplied oil by gravity?

Not surprisingly, heâs not keen to refit the anti drain valve & has lived with this problem for about 20 years, so will continue to do so if he has to, but it is a pain having to drain the sump every time he wants to go for a ride, so would like to find an answer if there is one.

Any ideas ?

Regards, Tim

My 1971 Fastback also wet sumps if left for more than 2 weeks between rides. Norton always claimed that their engines didn't do this, but my engine was rebuilt by Norvil with a new pump and all new bearings etc. It still does it even using straight 50 as recommended by Norvil, and leaving it on compression. There are no other symptoms, the engine runs well andoil returns to oil tank fine. I am not in favour of fitting anything in the oil supply line which restricts the flow in any way. I have fitted the sump plug with the central drain, and use this if the bike has been left standing. I would suggest the "problem" arises mainly through lack of use, if my bike is used regularly, it doesn't do it.

Hi

I have the same problem of wet sumping on my Domi have read about most of the comments that have been mentioned here before but have not read that it could be the seal from the pump to the timing cover as this is hard to determine. Has anyone been down this path ? I think I will go for the tap with a switch as a safe option. As I bought my domi with a blown engine from the tap being turned off!! As a now old codger do not trust my memory.

Nick

Previously nick_fowler wrote:

As a now old codger do not trust my memory.

Nick

Ditto. I have three wet-sumping Nortons, in all of which I have installed taps in the oill feed lines. On one the tap also switches the electrickery on/off, on another (which has an ignition key) the key resides in the hollowed-out underside of the tap until needed for its primary function and on the third, a magneto-powered specimen, a dayglo disc lock reminder cable loops round the kickstart lever and the off-position tap. Works for me.

Well All Norton twins lubrication is to the main bearing journals , and low presser feed to the rocker arms every thing Else in a Norton twin motor is splash feed So fitting a tap or other devices will only mask the real problem the old pump, if you have renewed the oil pump We can rule this one out, so the best way of finding a crack or porous alloy ,Is to empty the oil tank, and remove sump plug drain every thing off, clean the sump plug ,replace the sump plug , them mix up some Engineers Blue with spirit and clean engine oil now fill the tank to one 1/4 and leave over night then drain it all off , take off the timing cover and you see the blue stain were the oil mix has been this is how we did things on the Ships, hope this helps yours Anna J

Anna is 100% correct regarding a tap or valve in the oil feed line masking the real cause of wet-sumping. In Tim's case, I believe he has an issue behind the oil pump on his bike. ie porous metal or a crack.

As a rule of thumb, in all the yearsI have been helping to sort out wet-sumping problems, theroot cause has often turned out to be a worn or damagedoil pump. This is the first line of defence against the contents of the oil tankheading for the sump.

The next weakness in the system is the oil seal in the timing cover. Like the main crankshaft oil seal, this is often re-used time and time again with scant regard to its condition. Careless refitting of the cover or any debrisfrom oil tank will quickly kill off thesealing effectiveness of this item. Commando owners will tell you that if extreme care is not taken with the points oil seal, on their bikes, then they get an instant pressure feed to the points. There have been some cheap versions of these seals on the market, for a few years, and they are absolute rubbish. They distort in use and really should be replaced each time the cover is disturbed. Stick to a big name supplier.

Logically, if the oil is escaping, at great speed,from the system when the engine is not running then it is likely to do so even faster when the motor is being used. In which case....how long will those big-ends last???

Hi all , My 750 Fastback wet sumps over about two weeks . I fitted an anti drain valve ,( BRI TIE ) but to ensure i could monitor its performance i also fitted an oil gauge which i mounted in an aluminium pod between the Tacho /Speedo . I have run this way for over ten years and had no problems.! On starting the bike i can see the oil pressure build up and know the valve has opened . I also was supprised at the strength of the valve spring when testing it prior to fitting . I recently purchased another valve for my Moto Guzzi Lodola which i have yet to fit . Its an aluminium assembly machined from bar stock , and can be stripped for cleaning . The spring in this is much lighter than the Commando one ,but the seller assured me it is highly effective in use and can be mounted in any position .vis vertical or horrizontal. I have yet to try it . Any one interested , its currently on FleeBay, from a chap in Northallerton , North Yorkshire At £19.95. + £2.5 post.

More lateral thinking..................On most standard Dominators, the return feed, from the pump,goes into the bottom of the oil tank.Oil then has to passthrough some internaltubing to the top of the tankbefore adding to the contents. A split in this tubing would giveoil from the tank a quick route back to the sump via the return gears of the pump, which always wear more than the feed side.

On my Commando the return pipe goes, externally, straight to the top of the oil tank. Does yours???

I've just come back to this thread and before I got to the bottom/last post from Phil, I was thinking that the return pipe through the oil tank must be cracked or perforated to allow the oil from the tank back into the cases. If you were to connect a pipe to the bottom of the oil tank return and blow on it after blocking the outlet with your finger, you should not expect to see any bubbles.

Tim, don't be shy, please tell us which well known supplier we have to avoid when buying our non return valves. Then others will benefit from your bad experience.

Be careful paying too much attention to AJD's opinion as according to her post , the main bearings are pressure fed.