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Timing case leak

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Timing case leak

Posted by George Phillips at March 11. 2016
Sorry that I seem to be hogging this forum but just when I thought everything was generally OK I find oil hissing out from the joint between the back of the timing cover and the Lucas magdyno (up the top at the drive end). My spares book doesn't show any seal there so what stops oil escaping? Could it be that there is no seal and I've got a blocked timing case drain? I don't want to start stripping it all until I know what I'm looking for. Thanks for any help.

Re: Timing case leak

Posted by stuart_munroe at March 11. 2016

Keep asking - cos I'm learning too!

Re: Timing case leak

Posted by jonathan_newton at March 11. 2016

Previously George Phillips wrote:

Sorry that I seem to be hogging this forum but just when I thought everything was generally OK I find oil hissing out from the joint between the back of the timing cover and the Lucas magdyno (up the top at the drive end). My spares book doesn't show any seal there so what stops oil escaping? Could it be that there is no seal and I've got a blocked timing case drain? I don't want to start stripping it all until I know what I'm looking for. Thanks for any help.
 
 Similar joint on mine has a large piece of carpet felt set in there.  dont have it   touching  the  shaft just  a ring of  the stuff.  Though "hissing" out suggests its pressurising.  First off I would check  your breather system  and  the quantity of  oil in  your crankcases....    

Re: Timing case leak

Posted by George Phillips at March 11. 2016
No Jonathan - "hissing" out was a typo - or a euphemism! Whichever you prefer. It meant there was a lot of oily gunge all over the gear box and lower timing case emanating from that joint. If that's how it's done (carpet felt) that means off with the timing cover and timing gears and all the hassle of re-timing it. Bummer!

Re: Timing case leak

Posted by ian_goodhall at March 11. 2016

There isn't a seal but there shouldn't be enough oil in there to leak out. Should only be  a mist of oil to lubricate the timing chain. Should also be a breather at the bottom with a metal pipe that lets any excess oil drain away. I wonder if that breather could be blocked? My '55 ES2 gets virtually no oil in there, to the extent that I occasionally lubricate the timing chain manually.

I like the carpet seal solution but some proper felt would be nicer.

Re: Timing case leak

Posted by john_tickell at March 11. 2016

Hi George. Just been out in the garage and checked mine. There is a gap of at least a 1/16 inch between the mag and the back of the timing cover. Have now completed 750 miles over winter since its rebuild and not a drop has appeared around that area. As I understand it oil mist is meant to pass the inlet cam bush, lube the mag chain then any excess to to vent off from the pipe. I have owned 6 ES2's over 45 years, all have dripped from the vent pipe but none have ever leaked oil from the mag. area. John

Re: Timing case leak

Posted by George Phillips at March 11. 2016
Thanks John and Ian. When I get a minute I'll investigate further. It's a really greasy gunge that's coming out rather than oil mist. Almost like graphite grease. Thanks for your help. G

Re: Timing case leak

Posted by Barry Carson at March 11. 2016

Re: Timing case leak

Posted by George Phillips at March 11. 2016
Thanks John and Ian. When I get a minute I'll investigate further. It's a really greasy gunge that's coming out rather than oil mist. Almost like graphite grease. Thanks for your help. G ps this does not appear to have uploaded so I'll try again. You may get this twice!

Re: Timing case leak

Posted by richard_payne at March 11. 2016

If the drain isn't blocked then there is an excess of oil entering the area via the cam bush.

If it's greasy and gungy then I'd suspect that a previous owner has filled the whole chain area with grease which is not the intention at all.

If you use a long pointy thing to retain them then it is quite possible to remove the timing cover without disturbing the cam wheels and timing...but if the bushes need replacing and reaming then it probably will be necessary to remove everything  as the bushes in the crankcase will be worn too.

My first step would be to remove the chain cover, give everything a clean and reassemble with nothing more than a fingertip of grease along the chain run. It doesn't need a lot - vintage magneto chains ran exposed.

Re: Timing case leak

Posted by Dan Field at March 11. 2016

I think I'm right in saying that the oil pressure relief valve lets oil into the timing case, and from there into the mag chain case if it is blowing. Although this should drain out of the pipe at the bottom, so shouldn't cause your problem so long as the pipe isn't blocked.    It might be worth you investigating this although it will require removal of the timing case, which in turn will require the mag chain coming off......... . Perhaps do the other simple checks first!

Re: Timing case leak

Posted by George Phillips at March 11. 2016
Thanks guys, Richard - there certainly was a lot of black grease in there when I got the bike. I've scooped a load out but I'll now clean it out properly and check the drain. John - that's interesting about the gap. I assumed there was a seal there.Thanks to all for your input. G

Re: Timing case leak

Posted by Hans Eberlein at March 11. 2016

Hi George,

Have you checked the inlet camshaft bush? In my c ase, I have to turned a new one, because it had too much side play.

Unlike the exhaust camshaft, the inlet camshaft drives the magdyno chain, which sometimes could have been set too tight.

The exhaust cam bush has a spiral groove for lubrication along the entirely lenght, while the inlet camshaft bush reaches only half way from the inner side, thus avoiding any excess of oil reaching the magdyno chain area.

Hope this help.

Hans from Chile.

P.S. Attached a photograph of the new inlet camshaft bush. (on the right).

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Re: Timing case leak

Posted by George Phillips at March 11. 2016
Thanks Hans.Something else for me to check! Thanks also for the pic.

Re: Timing case leak

Posted by George Phillips at March 12. 2016
One for Dan - I removed the timing cover and cleaned out the greasy gunge with paraffin. removed and cleared the drain pipe. Reassembled and took it for a run. Nothing hairy but enough to show a prob. So far all clear. If it has not worked I'll be back, have no fear! Thanks for all your help.

Re: Timing case leak

Posted by George Phillips at August 18. 2018

I've resurrected this thread rather than start a new one. The leak at the dynamo end was sorted. A new inlet cam bush has been fitted (some months ago, now) but oil now runs out of the timing ccase drain at the end of a run. A 40 mile jaunt more that fills the 100ml yogourt pot that I fitted as a catch pot. When I remove the pot to pour it back nto the oil tank the oil drain drips to the point of almost running out. There is a mass of oil getting in there. Surely it can only enter via the inlet camshaft bush? Maybe I was over zealous in my reaming? Could I solder the grooves on the inner side of the bush. Any bright ideas?

Cheers

 

George

Re: Timing case leak

Posted by ian_soady at August 19. 2018

There isn't a huge amount of oil inside the timing cover so there shouldn't be too much getting through the inlet bush. As you say, this is the only way oil can get in. I wonder whether you have slight wet sumping, and also whether your crankcase breather is working properly. If the crankcase is getting pressurised this may force oil out through the bush especially if you have been a bit over enthusiastic in reaming it.

Did you make sure the slot in the inner end of the bush was correctly orientated?

Re: Timing case leak

Posted by George Phillips at August 19. 2018

Thanks Ian, I'm fairly certain the c/case vent (on the drive side) is clear. I recall removing the ball bearing some while ago and checking the tube for throughput.

Just remind me what "correct orientation" means?

G

Re: Timing case leak

Posted by ian_soady at August 19. 2018

I thought I had a diagram somewhere but can't lay my hands on it. The bushes have slots in their inner ends which need to be at a 45 degree angle but I can't remember which way round they go!

My diagram is probably if EM Franks's book which I only have in grubby hard copy.

Re: Timing case leak

Posted by George Phillips at August 19. 2018

Why have they got to be at 45deg? Just out of interest. I'll do a bit of research as well.

George

Re: Timing case leak

Posted by ian_soady at August 20. 2018

As I thought it was Edgar Frank's book, although he doesn't actually show the inlet bush in the timing cover. I would guess that the groove needs to be at right angles to the one in the timing chest however (not 45 degrees as I had thought). But someone will know better.....

 

Note what he says about the oilway being blocked off in the inlet bush.

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Re: Timing case leak

Posted by George Phillips at August 20. 2018

Very helpful, Ian. If I'm interpreting it correctly the groove in the cover bush should end up at right angles to the groove in the crankcase? What would happen of they inadvertently lined up? I'm guessing oil would run down the upper groove and straight out the bottom groove? I'm trying to figure of this can be the cause of my excessive oil transfer to the timing case. If the oilway were not blocked off I can see that that would allow more oil transfer.

George

Re: Timing case leak

Posted by ian_soady at August 20. 2018

I don't really know and there's nothing in the book to tell us. It's the only place I've seen that information - the official Norton book doesn't mention the bushes other than to say your dealer should fit them, and the Haycraft Pitman book, although generally helpful is equally silent.

Re: Timing case leak

Posted by Barry Carson at August 20. 2018

hello, i dont expect a reply. but heres a photo of my 56 19s crank case showing oil holes in tops of the bushes

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Re: Timing case leak

Posted by Ian MacDougall at August 20. 2018

Hi George, I'm following this with interest - as you know I have the same problem with my 19S. Sorry to hear that the new bush did not solve the problem (but spares me a job!). The bush orientation highlighted by Ian sounds promising.

Some years ago Mike Pemberton overhauled the bottom end of my engine. Because of the oil loss from the inlet camshaft I asked him to check the condition of the bushes. He reported that they were in good condition and did not need to be changed. He reset the pressure relief valve as he said it was screwed in tight and would not have operated as intended, resulting in high oil pressure. After this work the rate of oil loss past the camshaft bush actually increased significantly. When the relief valve opens the excess oil is delivered to the camshaft gears so I wonder if part of the problem comes from an over supply of oil to this area.

Ian has also mentioned crankcase pressure as a possible contributing factor. I am not ruling that out but I have tried running with the standard one way ball valve, with an open breather, and with an Enfield "duck bill" tube on the breather pipe. I didn't notice any significant difference to how quickly the catch bottle filled. It might however be worth trying more sophisticated breathing arrangements involving reed valves that have been suggested in other threads on this site.

Ian McD

Re: Timing case leak

Posted by ian_soady at August 20. 2018

I'm suspecting that the oil groove(s) in your inlet cam bush actually extends all the way to the end, which would allow the oil to pass straight into the mag drive. I'm interpreting Franks's comment to mean that the spiral groove should stop short of the end of the bush.

You can see from Barry's photo that the grooves in the crankshaft bushes go all the way through. If the inlet one in the timing cover is like this it will allow loads of oil through - and you may even be able to feel crankshaft pressure pulses on the end of the little drain pipe.

Re: Timing case leak

Posted by George Phillips at August 20. 2018

I think we're homing in guys! So , when I get into the garage, I'll check the oil prv setting. Tighten it fully then back off 1.5 turns. If it set too high less oil will bypass and be squirted onto the timing gears and leaks may appear round the top end (on mine); if set too low, less will be bypassed and less  leakage up top. I could try re-setting the prv to a slightly higher pressure (less bypassed onto gears) and see what happens. I guess I'll just get more leakage somewhere else!

Thanks for all your inputs. It's all very interesting.

BTW is it possible to solder a blockage into the bush groove?

George

 

Re: Timing case leak

Posted by George Phillips at August 20. 2018

Oops. Fingers Phillips again! 2nd line should read "If set too low, MORE oil will be bypassed.."

George

Re: Timing case leak

Posted by Ian MacDougall at August 20. 2018

It should be possible to fill the grooves with solder. You will need to clean off all traces of oil first. Easier with an uninstalled bush. You may have to apply the reamer again, to clean off any overspill.

Don't forget that the top end is fed with oil from the return side of the pump, so pressure adjustments on the feed side unlikely to affect the quantity reaching the top end.

I have also wondered if leaks from the pump, either from the pump/crankcase surface or from where the pump outlet spigot meets the outer case (fibre washer) could result in too much oil reaching the timing gears. Do you know if yours has a paper gasket behind the pump (none on mine)?

Ian McD

Re: Timing case leak

Posted by Ian MacDougall at August 20. 2018

Another thought - it might be tricky to fill both grooves. The solder in the first one will probably run out when you heat the second one. Part full may be the best you can achieve. Might epoxy or JB Weld be easier? But you don't want anything that might debond in use.

Ian McD

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