Timing case leak

A good point - I was just looking at the union for the drain pipe on mine and it was quite mucky, with bits of grit in it.

I'm taking that risk anyway, by returning the oil from the catch bottle to the tank. The chat about modifications to automatically return the escaped oil is really just a thought exercise. I'm just showing an example that has been done on another make of bike.

What I am really hoping for (probably also George) is to work out why some bikes piddle significant quantities of oil from the inlet cam bush. Knowing why might then help us find a fix. So far this thread has not produced an explanation!

ian McD

I think that if it is the correct bush with the grooves stopping before the outer end then it can only be due to the fit between the bush and the spindle - either a badly worn spindle or as you suggest not accurately reamed. For a perfect job the 2 bushes should probably be line reamed. Is there any radial play in the spindle?

Having said that, there shouldn't be much more than oil mist in the timing chest so it's a bit of a mystery why so much liquid oil should come through.

If I was collecting it in a catch bottle I'd probably chuck it away rather than put it back in the tank, and I'm a notorious cheapskate!

Hello. the photo shows an inlet cam out of my 19s .it has a scrolled groove running along the outer shaft where the bush would sit. so you would think it would be a plain bush not a grooved one that would fit over it. unless they change over the years . if the groove in the bush stops short of the end of the shaft. the groove on the cam shaft carries on to the end would it allow oil to pass through the bush when stationary.

Barry

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It may never have needed reaming, George. Once the new bush is in place, offer up the camshaft to check the fit. The camshaft is most probably the original one, 63 years old, and the journal could have a little wear on it which may render reaming unnecessary, if the bush hasn't distorted when being pressed into place.

You will never ream anything accurately whilst holding the piece in one hand and the reamer in the other.

Technically Ian S. is right, they should be line-reamed, but that means changing both bushes, and splitting the crankcases; I don't think you want to go there!

Norman White installed and line-reamed the camshaft bushes on my 650SS engine for me. Of course that set-up is different, in that the camshaft is about 3 times the length of yours, the bushes being in both crankcase halves. You should be ok just doing the one; if it needs it.

Ian C.

If the camshaft rotates the same way as my ES2 (ie anticlockwise looking from outside) that groove would tend to pull oil back into the timing chest rather than feed it out. Maybe the theory is that oil travels along the groove in the bush to the blind end then the scroll on the spindle returns it?

Previously ian_soady wrote:

If the camshaft rotates the same way as my ES2 (ie anticlockwise looking from outside) that groove would tend to pull oil back into the timing chest rather than feed it out. Maybe the theory is that oil travels along the groove in the bush to the blind end then the scroll on the spindle returns it?

I believe that that is the idea. Some oil (more than mist) will always get into the chain cover. A mechanical scroll and the fit of the cam in the bush will never make it 100% oil tight. If it were oil tight the chain would never be lubricated. Having oil in the cover means that it has to go somewhere and rather than it eventually coming from the mag aperture Norton decided to let it drop out of the drain pipe.

The only time my '38 ES2 has never dropped oil from the drain was when I thought I would be clever and lubricate the chain with grease. It blocked the drain pipe! And it has new bushes, line reamed with only a couple of thou end-float.

As an experiment I attached some clear plastic tube to the drain pipe and ran it up by the engine oil pipes leaving the open top at a level just above the camshaft spindle height. I cable tie it to the oil pipes. I now have an "oil gauge" that I could see how much oil was coming out and the height of the oil level in the chain cover. Crankcase pressure never pushed the oil out of the top and it only filled to about to a third of its height after about a 40 mile run. I now leave the pipe connected and when the engine has cooled, drain it into the tray that I leave under the bike when it is parked in the garage (not that it leaks much anyway). Without the pipe it only gave a small drip after a run but it was sufficient to mark the pave drive

George, I think that in the absence of a line reamer your proposal to put the reamer into a drill stand or pillar drill is a viable alternative. At least the bore would be at 90 degrees to the cover. However only do this this turning the drill by hand and remember, reamers should only be turned in a forward direction, never backwards. Also use a good reamer. I bought a set of far eastern adjustable reamers and most of them are only good for cutting dodecagonal shaped holes!

Just to put things in perspective:

From the Franks book:

"With all engine components in good condition, a consumption of 1600 to 2000 mile per gallon should be obtained."

I reckon that, from my measuring gauge, my mag cover drains 0.3 pints per 1000 miles. Peanuts!!

Mr Franks would be referring to burning oil not leaking!

I was just reading an interview with J E Moore regarding the design of the Dominator in which he was asked about the oil pump and whether there was a non- return valve. His answer? "Oil just does not leak past the gears in the Norton pump". Interviewing techniques were clearly more gentlemanly in those days as the journalist accepted this without comment.....

No George your 120cc per 40 miles is not normal. I just found the Franks oil consumption figure and found it outrageous by today's standards!. Try getting that past environmentalists today.

My tests show about 7cc per 40 miles which I feel is OK but still makes mess after a while.

Trying to hand ream a relatively short bush where the diameter is nearly the same as it's length accurately is very difficult without supporting the reamer, either by using a pilot in the other bush or as you suggested, by holding the reamer in a pillar drill to steady it as it opens the bush.

If the PRV is open, or leaking, there will be a lot more than mist in the timing case. I suspect that is where my 19S problems lie, to be investigated over the winter. Flow from my timing bush is around 100ml per 100 miles but I am starting to think it is not directly proportional to distance travelled. Almost sure that a 150 mile run does not produce double the amount of oil of a 75 mile run. Might be temperature related - it takes quite a while to heat up the contents of the oil tank. At higher temperatures might the oil pressure drop and so the PRV more likely to remain closed? I am also thinking that it might be interesting to try a 200 mile run with a lower viscosity oil (less resistance to flow so lower pressure?) and see if that reduces the output. Anyway more interesting things to think about - the Manx beckons!

Ian McD

its funny mine doesn't leak a drop. most of my oils leaks are from the g/box. anyway good luck with it George.

Barry

Aah, but if there is no oil to be pushed through the gap because the PRV stays closed....That should read Manx GP, or Classic TT if you insist.

Ian McD

George, the oil drain pipe is clear i can play a tune on it. i fitted a new timing chain not so long ago. just a thought on your bush. instead of a reamer could you run a fine grade flap wheel through the bush fixed in your stand drill. just to ease it out. used with some form of lubricant.

Barry

yes George probably a bit of over kill . see if you could just hone it out to size with one of those small honeing tools.

Barry

I don't have any experience with the 1938 pattern engines but on the earlier and WD motors, the inlet cam bush in the timing cover is indeed different from the other three and clearly has a scroll which does not extend for the full length.

It is visibly different when in situ but I don't know to what degree the later engine differed.

For 1937, part numbers were 3685 and 3686 and for 1938 8838 & 8839...unfortunately, Norton's decision to completely change the part number system for 1946 (although engines were unchanged) makes it difficult to compare.

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56, 19s outer timing cover inlet cam bush in the photo. where it differs i dont know but similar groove

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That's interesting, Barry. The scroll clearly doesn't extend through but from the thrust face, this later bush could easily be mixed with the exhaust / crankcase bushes.

Interesting that the thrust end of the bush posted by Richard is entirely different and doesn't have the slots in the face to allow oil into the scroll. The grooves in the one posted by Barry don't seem to be of a spiral form but this may just be the photo.

Just a 5 minute job.......

I posted this a little while ago. The extractor worked a treat.

https://www.nortonownersclub.org/noc-chat/technical1-singles-forum/696198693?b_start=0#971787453

There's one on ebay but it's the distributor type. May be worth it to get you out of trouble?

https://www.ebay.co.uk/itm/VINTAGE-NORTON-SINGLE-TIMING-CHEST-DISTRIBUTOR-TYPE-ES2-MODEL-50-ETC/253831895576?hash=item3b198f5a18:g:bZIAAOSw8W1bgdZ2

George. Check your e-mails.

Ian

Previously ian_soady wrote:

There's one on ebay but it's the distributor type. May be worth it to get you out of trouble?

Ian Do you happen to know what the difference is between the cases?

Ian C

I don't actually know but suspect it's just the treatment of the top end of the chaincase where the distributor would be bolted on.

I have looked at old pictures of mag ones and dizzy-equipped models, and they appear the same, but of course, that is without close examination. My guess is that they may differ in the mounting arrangements of the mag and distributor, in which case one would hope a relatively simple mod may do the job.

Yes, of course with the magdyno there is no actual connection between the mag and the chaincase.

We now have pictures of both, showing the differences, for anyone's future reference.

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OK, it only let me load one......

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Don't look too different to me although obviously the hole for the distributor one is bigger.

The dizzy one may work, but he has to win it first. Best George gets his welded up, thread re-cut and he is away.

Anyway there is another thread running on it now.

Ian

Oh bugger! Mine was a pita to get out as well, I totalled the screw but fortunately not the case - Russell motors had the screw and spring in stock, but this was last year.

I don't think high oil pressure would be the culprit as it's (almost) all going to the big end. When the ball lifts. it lubricates the timing gear. It's possible that the lack of this latter may have resulted in excessive bush wear?

True enough......

According to the Norton manual, "the level [in the timing chest] is controlled by a hole drilled in the case, the overflow draining to the base of the crankcase".

No timed breather, just simple overflow, I guess through the hole you mention.

The crankcase breather on the left hand side of the crankcase should take care of that as the passage is bigger than the one into the timing chest. But of course there will be some pressure as you say.

You may be falling into the trap of over-thinking this - one I'm very prone to myself.