OILY TIMING SIDE

Previously anthony_leedal wrote:

A friend has a 49 ES2 which has excessive oili in the timing cover. Oil is leaking badly from the mag chain cover vent pipe and top of the case round the mag drive. I removed the mag chain cover and it was completly fullof oil, the timing cover also seems to have too much oil inside. I have checked the pressure relief valve in the timing cover, seems ok, spring present and undamaged no debris on the seat and the ball undamaged. Theoil pump fibre washer is present and undamaged. also the mainshaft feed quill is ok. How does oil from here return to the crank case sump, is it just via main bearing, there are no visble drain holes between timing case and crankcase. Could oil be escaping round the pump fibre washer and would an O ring give abetter seal here? The engine has had the breather checked and the rings are good and the compression fine so I dont think there is a crank case compression issue here, just an excess of oil in the timing cover. My friends mod 50 is as dry a a bone here, as is my similar ES2 and my 500t so any help would be most welcome please

Thanks Tony

Tony,.. It could be the bush in the timing cover that supports the inlet cam. I had a over oiling problem some time ago .i removed the timing cover and pressed in a new bush.i didn't,t have nothing to ream the bush out so jut re,assembled it and has been OK for ages.the bush has a scroll in it for oil to lub the cam chain but when worn allows more oil through. People who know better than me say if you have a small drop of oil from the vent pipe it's ok. I got the bush from Russell motors about£10... Tony.

Theoil level in the cam box will stay constant due to the two drain holes you see. I had the same problem after making a new inlet cam outer bush, hand cutting the scroll oil grooves the same as the sample. I fixed the excess oil dripping from the mag chain cover drain by soldering up most of the oil grooves I had cut, particularly the two collector grooves that run against the camwheel leaving only a very small trace of the groove. Tapping the bush inwards to minimise the end float coupled with a close boreclearance to cam spindle fixed the problem. A subsequent check of the chain showed it to be oily, but not wet. Also, there is supposed to be a felt dust washer held between the magneto end cover and the cam chain cover rear.

Have to disagree with your last statement. I don't think there ever was a felt seal between the two parts. John

Your correct John, there is nothing shown in the parts book, I think in hindsightI should have said 'it's advisable' to fit a felt dustwasher ....

Thanks Paul, that sheds new light on the long term incontinence of my 19S. I had been thinking in terms of excess pressure in the timing chest pushing the oil out past the bush but the drain holes make that very unlikely. When I rebuilt the engine many years ago I left out the leather washers that had been fitted by a previous owner behind the mag sprocket...doh! As a "temporary" fix I have run the breather pipe into a catch bottle which then has to be emptied at the end of every run. To the casual observer I have a dry Norton! Come winter I will take a close look at the camshaft bushes and replace/modify as required. Just a thought; I wonder if there is any variation in the position of the drain holes - if so it might explain why some engines remain dry while others leak profusely (although wear in the bushes might be more significant).

Ian McD

Hi all

had identical over oiling problem with my '49 ES2 and likewise, my model 50 is quite dry at the mag chain. On the ES2, I took the crankcase drive side breather out to clean and discovered it had no contents, literally just a hole straight through. Obtained a breather union with the one way valve, problem cured, no more blowing oil from timing side breather, no oil accumulating. Your breather has been checked but I recall the thread, I think, enables the breather Union to be attached either way. If the wrong way, I would think that would have the same effect as a straight through hole, plus no pressure release. Run the engine and put a finger over the crankcase breather pipe or union, should feel and indeed hear, pressure escaping. I am not an engineer however, but it worked for me.Both my '37 model 50 and my '35 Inter mag chains run, or would run, quite oil free if I left them to it

Dave