How wet is wet (in sumping terms)?

How long is a piece of string?!! In the 50?s I owned a Dominator 88, it never wet sumped enough to pump oil outof the breather. However my riding habits were different then. The bike was ridden nearly every day, and never stood idle for more than a few weeks. Also, because the bike was ridden hard, I used Castrol Grand Prix 50 grade oil, which, was less likely to seep through the oil pump. I now ride a very similar 54 Dominator, using 20/50 oil. This will pump out oil, if left more than a week. If my riding habits were the same, this would probably not occur. When I go on the week long Colombres Rally, there is no oil blown out when starting. My solution is to place a clean container under the breather pipe, and pour the oil back into the tank when it stops dripping.

On my SS-engined Wideline I have a black plastic pot, much bigger than the one you use George, wedged down in the rear engine plates between the oil tank and tool box. The breather pipe, which is from the back of the timing chest, goes in that, with another going from there to the back mudguard. Provided the ends of both pipes always remain higher than any oil which may be in the tank, it works well. It rarely needs emptying. I also have a small breather pipe going from the inlet rocker cover into the catch tank.

The bike gets used quite regularly, but if I was to lay it up for any length of time I would drain the oil tank, just in case.

In answer to the OP's question, I don't know how much it wet sumps!

In all my years as an ES2 rider, two off, I have never had any oil out of the breather pipe, If left for a week, or two then the entire contents of the oil tank may empty into the crank case but soon gets pumped up into the tank with no ill effects what so ever. I do however get some out of the left side main bearing as there is no seal there.The type of oil used has sod all affect on the drainage neither does the fact it is TDC or BDC.

I recently read an article in a bike magazine from the 1930's and they were asking the same questions back then. The idiots at the factory only solved the problem on the Mkiii Commando. Not bad really as it only took them seventy odd years to sort the problem!!!!!!

There was a recent article in Roadholder about reconditioning your oil pump to prevent wet-sumping. I don't remember which issue. The gist of it is that if your pump has end-float, or any debris damage, oil will flow through the pump into the sump. You have to lap the pump body so that there is almost no end-float at all, but not a high-friction pump.

Doing this will reduce the problem to a small level. Another approach is to accept the sump-filling, and fit a long breather pipe. When you are about to start the motor, remove the long pipe from your oil collection bottle, and place it in the neck of your oil tank. That way, the crank-case pressure will drive the oil out via the breather pipe, straight into your oil tank. Once it stops, your motor will have warmed up somewhat, and you and the bike will be ready to set off.

You like?

Paul

The idea of piping the breather, to a catch bottle, may be "eco friendly", but defeats the original intention of lubricating the rear chain. I refer to the early twins, which did not have the breather piped to the oil tank.

Previously John Shorter wrote:

The idea of piping the breather, to a catch bottle, may be "eco friendly", but defeats the original intention of lubricating the rear chain. I refer to the early twins, which did not have the breather piped to the oil tank.

Not so, John. The breather pipe from the oil tank lightly lubricates the rear chain. The breather to catch tank is from the engine.

Sorry, you are wrong. The later Dominators may have the system you describe, but, up to, and including, the?54 model, the crankcase breather was a copper tube exiting above the gearbox sprocket.

Les, if you want to know what level of drain-down is possible 'at best' then my advice would be to fit a new Andover Norton oil pump. They are better than the originals and certainly better than any sixty-year old reconditioned pump.

My experience on a Commando and a friend's on a 16H has been that losses are minimal over a period of weeks and only noticeable over months.

Crankcase venting into the oil tank is a bit horrible really. It results in products of combustion and condensation being delivered to the oil tank with the further problem that if the oil tank has been overfilled, a venturi effect will blow the lot out of the back...

Les, I've been down the lapping route and to be honest, I wouldn't bother anymore if I didn't have to do it. Prior to the AN pump I used a Nourish pump on the Commando. They were said to be CNC machined and higher spec but it drained down worse than the old standard type.

There were a lot of pattern pumps around in the early 1980s. I think they were Wassell ? They weren't bad and there was nothing else at the time but they were clearly made down to a price and I don't think that the aspect of draining down was a major priority.

I've never seen a Norton pump so bad that it failed to deliver and scavenge but this aspect of static leakage is a blasted nuisance.

Fair point, John, (rear chain lube) but must admit my original idea was for the timing side drain. If I leave my ES2 for a week or so I get clouds of white smoke on initial start up. Presumably oil in the sump?

John, as you mentioned a catch bottle, which is what I said I have, I then explained that I too have rear chain lube courtesy of the oil tank breather. Mine is a 650SS motor, so clearly not an early twin, as you mentioned. I am not suggesting Les does the same with his, it would spoil the originality.

No Ian, you said the chain was lubricated from the oil tank breather, not from the crankcase. Not so, for the early twins, the crankcase breather blew onto the rear chain. Les?s engine is almost identical with an early 88, but his breather apparently does not extend to the gearbox sprocket.After over 60 years, who knows if it has been modified, or not.

I was talking about my bike John, not Les's. Mine has the catch tank, ffs. You have got hold of the wrong end of the stick. Let it go.

Modern chains still benefit from regular oiling, hence Scott oilers!

Since the oil mist must go somewhere, why not direct it to where it was originally intended, i.e. the rear chain? PC, and eco friendly, enthusiasts may be horrified, but, how many bikes over 60 years old are ridden regularly for long distances?

It's better to have an oily chain than a dry one, even in dusty conditions. JG Churchward, a well known engineer in his day, ran trials which involved feeding sand into axleboxes. The dry ones failed very rapidly, the lubricated ones survived. A good enough comparison for me. One drawback withkeeping the back of the bike free of oil is corrosion of the mudguard. One of my bikes has a fully enclosed chaincase so no oil fling and it's rear mudguard has rusted through... One of the reasons classic bikes have survived is the anti-corrosion properties of oil leaks. My Land Rover chassis has survived 60+ years thanks to light oil misting. The odd drip on the shed floor isn't always a bad thing.

No one has mentioned the anti drain valve. Mic Hemmings told me the other day he has sold 2000 of them so they must work.

Looking back at your initial post Les, you say that the bike is newly restored. I wonder if the rubber seal that fits over the nose of the oil pump has been omitted or dislodged when fitting. this would allow oil to drain quickly through the pump and into the timing cover and on into the crankcase.

I have a Mick Hemmings anti drain valve for sale in the classified ads of this site if you are interested

If the seal is split or dislodged then there is hope, your pump will still pump oil and the flow will swamp the opening to the gallery in the crank. The centripetal forces will drive the oil out to the big ends and the space it leaves will be replaced by more oil, so you will still have flow to the big ends, pressure will be well down though. As long as you have the 6 start worm and pressure feed to the rockers, if you crack open the feed to head at the rocker box then the emerging flow will tell you if there is pressure or not and give an idea if the seal is missing or split.

Les I left school many years ago and have no more exams to take, what something is called is of no consequence as long as it works in an engine .

You say that the pump controls the rate of drainage when idle, a further plug in the bath is the seepage past the big end shells. If your crankshaft nose seal is missing or split then the big end shells will be out-drained by the missing seal. (Some people try and leave the crank in the TDC position when idle to reduce the weepage past the big end. Unless your big end journals were higher than the oil tank, I don't think this is a game changer)

The attachment shows 2 timing cover gaskets. The light brown one is for a 650 twin and the other mottled grey for a 750 Commando. Both will fit the full range of Heavy twins from 1948 up to the first 850 engines. The big difference, which many people ignore, is the thickness. The Dommi gasket is only 8 thou thick whereas the Commando version is 34 thou. Fit the Commando gasket to a Model 7 engine and you can immediately lose up to 24 thou of pressure on the conical oil pump seal. Though these seals were, at one time, available in two thicknesses.

With regard to wet-sumping, the suggestion of leaving the crankshaft positioned at TDC helps as a temporary fix, but is not a good idea for long term storage. That statement should get this thread lively!!!

Adding a little more to the wet-sumping comments, a good many owners of 961s (but not all) have had anti-drain valves fitted in their plumbing in order to solve a similar disappearing oil issue. Is this a quality control problem???

The Commando gasket will be a lot thinner by the time it is clamped up though Phil. Being some sort of rubber, the oil pump seal should cope with varying degrees of pressure, one would have thought. It shouldn't take too much to seal it.

As for the 961 wet-sumping, who now says it is not a proper Norton?

I have been able to quantify the wet sumping on my 650SS. Due to a broken exhaust pushrod needing to be replaced, I have had my timing cover off for retiming. Due to other work, I have only just refitted the timing cover after one month. In this time only 85mL of oil drained through the pump into the collection container below the pump. So my engine wet sumps less than 4mL of oil per day. Oil used is Penrite HPR 50 (SAE 40 - 70 multigrade)

Hope this helps.

Just as a point of interest my ES2 sometimes wet sumps more badly than others, on one occasion after about a month of siting idle, the oil tank was almost empty, I started it and let it tick over, all the oil returned to the tank and not a drop came out of a breather.

If I knew that my bike was going to pump oil out of the breather all over the floor after standing for a while, I would do one of two things; either drain the lion's share of the oil out of the sump drain plug before starting; or if I knew it was going to be laid up for a while, drain the oil tank after the last run. Either would probably take less time than mopping the mess up off the garage floor/drive/road, not to mention the unsightly stains which are left, incurring the wrath of swmbo....

I got fed up with the mess and fitted my 99 with a 3/8th pipe up to the tank and enlarged the tank breather pipe to the rear chain , easy to do using small bore gas copper fittings and plumbers solder,also easy to hide on a DL . I now have to oil the rear chain as little oil gets to it.Before this oil from the breather was lubing the rear tyre.I use 40 oil .If left for a month or so I drain the sump.I do get condensation in the tank so am working on raising the tank temperature in winter with a little tank insulation. I will fit a tap in the feed line.

Pretty obviously, gear pumps aren't going to be oil-tight but with everyday use the oil shouldn't get much chance to drain through in any significant quantity - assuming the pump isn't badly worn. Some wet-sumping is inevitable so if you don't use the bike every day, fit a sump plug with a drain screw, borrow a Pyrex measuring jug from the kitchen and, before each start-up, measure the amount oil drained off. Dispose of that and fill to the same measure with fresh oil before starting. If you keep a log of mileage and amounts of oil replaced you could ascertain whether any regular oil changes are actually needed! You might well be replacing an oil tankful every 5,000 miles or less.

If you ARE sumping a significant amount of oil then you must check the tank level before starting up. Pump maintenance is pretty limited - grind the outer plate flat so that all the groove marks are removed and check the gear clearance to the body face by using a straight edge and feeler gauges. I don't know what the clearance should be but I would prefer something less than 5 thou - probably 2 to 3 thou. I will check my Jag workshop manual later as I used to overhaul their pumps - oil is oil!

Cheers, Lionel

I'm surprised that this thread has gone on for so long, but thought I'd just add something to the brew.

3 bikes. 99, 77, and Commando. All hopelessly different oil-wise.

I had to fit a tap to the 99 itleakedpast the pump so badly. I could leave it for two weeks and it would smoke as if it was on naval manoeuvres. The 77 leaks abouthalf a tank in 6 weeks; I tend to drain the sump before starting, and the Commando doesn't leak much at all, though I do use it quite often. Went out on Tuesday for 50 miles. Stupidly cold, frozen stiff.

4years ago I fitted a new pump to the Commandowhen I found out that the oil was only getting back to the tankbecause of the pressure in the crank case.

Warning! Don't fit a tap. You will forget it, and its not because of your age!

I also have a Jubilee, but don't want to talk about oil in relation to that. Its a total loss system!!!!

Thereason formy diatribe is this. The oil pump is the heart of your Norton. If it leaks to a great extent, it is probably worn and the pressurewhen running could well be low. If Ifound that I hadlow blood pressure I would worry and probably at least have to change my underwear. In the interest of your Norton'sengine, if the pump worries you,don't dicker about with taps and valves, change the pump. It isn't a difficult job and it will give you piece of mind.It really is money well spent.

Only 33 years and we will be able to wish each other happy 20/50. Meanwhile, have a happy 2017.

Here is a question to consider:

On two bikes with equal milage and wear, one being a twin and the other being a single, which bike would be more prone to wet-sump?

I am thinking that there will be more drainage thru the roller bearing main on a single than past the plain bearings on a twin.

Yea or nay?

Mike