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Norton Model 16H - engine oil leak

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Hi everyone,

I know this is not unusual to have oil leaking from the engine for a 1943 16H, but is it usual for the whole oil tank to drain into the engine and onto the garage floor, (missing my oil tray of course!) over a week?

I have not long finished the rebuild and was getting ready for the first true at starting her.

I have read Rob van den Brink web site where he has fitted a tap to seal off the oil on the inlet to the engine side to stop this happening to his 16h.

I am wondering if I missing something? as the original manuals are very vague. Is it just the oil pump that stops the gravity fed and if so would that mean it is so warn that a replacement is recommended (god knows where I would get one!) or should I put a tap on it like Rob, as his just keep going, as long as he remember to turn it on, lol....

Any advise would be gratefully received 

Thanks 

Nigel

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To me a week seems a bit more than usual on a 16H. Not sure though. Would not be a problem if it's your daily ride. A tap is a quite common addition. But it's too easy to forget opening it. I've done it twice on different bikes. Luckily enough found out after a short ride. Both engines seems to have survived.Both times on bikes with roller bearings. The 16H also have a roller big end bearing which don't need much oil supply. Using a multigrade oil makes pump leakage worse.Stick to a straight 50 weight oil.

There are some threads on this and other forums on different ways how to remember to open the tap. Long cords to the handlebar, like people use for disk brake locks. Extended tap levers that is in the way for the kick start lever. Automatic valves like the Velocette has. Taps with a kill switch so that you can't start it with a closed tap.

Make a starting routine including fuel and oil taps open. When started, check the oil pressure indicator on the engine (a good thing Norton have fitted on the 16H). Check return flow into the oil tank. After a while the return flow is intermittent when the crankcase is cleared and the return pump starts to suck air. Now the return flow is equal to the oil supplied to the engine.

When the 16H was redesigned for 1931, introducing the dry sump double gear pump, the previous oil tap for the total loss system was omitted. Norton declared that oil did not leak past the gears!

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It's not unusual for oil from the tank to drain into the sump over time, but as Mikael says, a week is quite quick. You say that it ended up on the floor though which is more unusual and might indicate some assembly problem as well as a leaky oil pump. Is the sump plug leaking? Crankcase faces sealing? If the bike hasn't run the leak is presumably caused by gravity rather than oil pressure. Good luck.

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It might be worth checking out the components in the timing case oil passages. Unfortunately that means removing the timing case and then re-timing the magneto. 1 Is the pump outlet to timing case seal (usually a fibre washer) present and of sufficient thickness to seal the joint? 2 Are the crankshaft oil jet and spring present? 3 Is the pressure relief valve ball seating properly? 4 Is the rear mating face of the pump flat? Check with a straight edge. It is not unknown for the alloy body to bow. My apologies if you have already checked those items on assembly but poor sealing at any of those places could make it easier for oil to flow back to the crankcase.

If the pump really is too badly worn then new ones are available (at a price) from Andover, Norvil or RGM. A bigger drip tray might be cheaper!

Ian McD

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Thanks for the great advice.

Hi Mikael,

The oil I use is a 50 weight oil and thank for the ideas. do you know where I can get a oil tap or have them made? Just incase, after doing out all the recommended check it is still leaking?

Hi John,

Yes it is gravity and the oil seems to have worked its way to the sump and come out on the left side over flow tube, the one that points to the rear drive chain as far as I can tell? as it then went down the casing into the sump guard before spreading the oil out all over the place! The sump plug was not leaking.

Hi Ian,

 Looks like I will have to take the timing case off and check (1, 4) the oil pump washer and and mating faces. All the other (2, 3) are present and correct, but will check again. hope I don't have to buy a new one.

Many thank for your help

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Hi Nigel

According to PL Garratt "The thickness of the oil pump washer should be such as to prevent the joint faces of the panel and timing chest meeting by 1/64 inch. This ensures that when the panel screws are tightened, the washer is compressed to make an oil tight joint." I may have seen another figure (1/32"?) quoted elsewhere but the point is that you need enough compression to obtain a seal on the washer but not so much that the timing cover is overstressed by tightening the screws. If the pump is bowed it may be possible to correct that by grinding the mating face against plate glass covered in grinding paste. Best done with the pump dismantled and make sure it is completely clean before reassembly.

Let us know the outcome

Ian McD

hi my names paul my 16h would leak a tank of oil in a week so I had engine rebuilt the engine oil pump so I knew that was ok i fitted an oil tap in the supply line didn't like doing this for obvious reasons I was checking the timing so had timing cover off when I turned on the tap I found a leak from behind the oil pump face traced to the gasket I replaced the gasket was poor quality made a new one problem fixed .

 


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