Timing case leak

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.

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

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.

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

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.

Could be.......

I have also considered breathing issues in relation to the leak from my 19S camshaft bush. I probably mentioned this before but I have tried the standard breather with ball, a straight through connector with open end, and the same connector with Enfield "Duck Bill". None of them made any noticeable difference to oil flow. This doesn't prove that it is not a breather issue. The purpose of the ball is to expel air from the crankcase on the downstroke and prevent air entering on the upstroke. Ideally this would create a partial vacuum in the cases. Without positive pressure in there oil leakage should become less likely. Other breathing arrangements have been discussed on this forum, including the use of a 2-stroke reed valve and an additional breather from the rocker box tappet cover. If the camshaft bush leak is driven by crankcase pressure these ideas should help, but I haven't yet tried them.

An unlikely possibility but I'll suggest it anyway: could there be any variation in the position or size of the hole that drains the timing case oil back to the crankcase? I guess George's case is still open so if anyone else is able to take a pic of that area a comparison might be useful.

Ian McD

George, I have rummaged and found my spare timing case, being my spare I need to be convinced to let it go! Iâm building a M50 from bits and need some parts, notably the spindles, axle, speedo drive and spacers etc for a full width rear hub and tinware, have you got anything to tempt me?!

Dan

Do you use a photo hosting website? Itâs easier that way.

I use a free program called pixresizer. Very easy to use and works very well.

https://pixresizer.en.softonic.com/

Nice one George. At 102 posts, this thread has run and run ! Luckily the singles sub-forum is a well behaved and friendly place