Author Topic: Timing side oil leak  (Read 989 times)

Online chaterlea25

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Re: Timing side oil leak
« Reply #30 on: 30.08. 2020 00:44 »
Hi Richard,
The cork seal goes between the pulley and the case not on the inside.
The scroll in the bush does not come all the way to the outside of it, if it did crankcase pressure/ vacuum would leak out into the dynamo drive compartment
Some (most suppliers) send out the wrong bush (badly made to boot)
This is the correct outer bush
https://www.draganfly.co.uk/index.php/component/hikashop/product/14168-

But   If you buy one measure the outside diameter carefully as the last one I bought was a couple of thou too big and split the inner timing case when I hurriedly pressed it in,  in spite of heating the case  *angry* *angry* *angry*

John

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Online Minto

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Re: Timing side oil leak
« Reply #31 on: 30.08. 2020 23:39 »
Could that hole have been drilled to get access to the pin that holds the dynamo fixing strap without taking off the inner case ??

When I stripped my engine I found that there was a hole there that had been tapped and plugged, I assumed that's why it had been drilled as it was exactly in front of the strap pin.
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Offline TT John

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Re: Timing side oil leak
« Reply #32 on: 01.09. 2020 22:44 »
Good point Chaterlea mentioned about using a G clamp to hold the dynamo in place and bring it close in to the case, I do the same but I use the flat mole grips to hold it in.

Cheers TTJohn
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Online Ratchet Richard

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Re: Timing side oil leak
« Reply #33 on: 03.09. 2020 09:06 »
Just a quick update,  haven’t had much chance to make progress as other family things  have needed sorting.  I have read all the replies and feel I have a far better idea for a plan of action. I am going to work on the bases of “do no harm” and have put the outer case back on.  I have started the engine and ridden around 10 miles.  No leak just yet but need to do some more miles.  When the leak returns, which I am sure it will, I can look to see if it is coming from the small hole.  Once I have identified for certain where it is coming from I can then work on fixing it.  I have gaskets and a idler gear bush on order from Dragonfly just in case I need them. 
I will update as and when I make progress or need further assistance.
Thanks all
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Online Ratchet Richard

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Re: Timing side oil leak
« Reply #34 on: 15.09. 2020 11:42 »
Back at trying to sort the oil leak.  Have worked out that the oil is definitely coming from the cork dynamo gasket.  After I have refitting the out chain case I can ride the bike for about 20 miles before enough oil has found its way into the dynamo drive compartment to start leaking.  It is not leaking from the small hole as the oil level does not get that high before it leaks from the cork gasket.  Someone suggested that I should drill a small hole below the dynamo drive pulls to let the oil drain back into the crankcase.  Any thoughts on that would be helpful, would it interfere with the crank case breather? 
Thank
Richard
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Online JulianS

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Re: Timing side oil leak
« Reply #35 on: 15.09. 2020 11:58 »
Maybe the cause is excess crankcase pressure? Piston blowby?
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Offline Swarfcut

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Re: Timing side oil leak
« Reply #36 on: 15.09. 2020 12:15 »
Richard, on the face of it, this seems a good idea, oil comes in, oil goes out. BUT... this will subject the dynamo compartment to the varying suck and blow crankcase pressure as the pistons rise and fall, and the leak could be substantially worse. It's never a good thing to go drilling holes in old genuine parts.

 As mentioned the condition and direction of the scroll in the outer bush is our best shot. I've dug out a couple of inner timing covers and both are identical. The bush is plain from the top hat to the oil hole, from where the scroll starts and this is cut anti clockwise to the outer edge of the bush. From the outside of the cover the scroll goes anti clockwise towards the crankcase. The scroll needs to be clean and unblocked, likewise the idler gear spindle needs to be a reasonable, not sloppy, fit in the bush. Wear on the bush will reduce the depth of the scroll and its oil carrying capacity. The bush is fitted so the top hat faces the idler gear.

 Julian suggests crankcase pressure, a good call, as a start check that the breather sleeve actually uncovers the duct hole fully, and that the duct has unobstructed flow to atmosphere.

 Swarfy.
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Online bsa-bill

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Re: Timing side oil leak
« Reply #37 on: 15.09. 2020 12:17 »
Quote
drill a small hole below the dynamo drive pulls to let the oil drain back into the crankcase.

Doing that would subject the dynamo drive compartment of the timing case to crankcase pressure - would make the oil leak worse.
 There should be no oil in the dynamo drive compartment to leak out, oil in there will leak out of the small hole when it gets full enough to reach it but it should not be there, suggest you look again at the bushes for the idler pinion as this is probably the only way oil can get in there.
The cork gasket is there to keep the outside world from getting into the dynamo drive compartment, the small hole would be better plugged somehow but it's not going to let much in other than water which probably would be better avoided

Basically agreeing with swarfy
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All the best - Bill
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1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Online Ratchet Richard

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Re: Timing side oil leak
« Reply #38 on: 15.09. 2020 16:29 »
Thanks guys
Some progress this afternoon also some bad news.  We took the inner casing off to check the  idler pinion bush,  the worming in the bush was indeed the wrong way pushing oil into the Dynamo drive compartment.  The worming is also the full length of the bush. New bush going in tomorrow (obtained from dragonfly with the correct part number as per the older parts manual).  We shall see if that works.  I agree with all the feed back re drilling holes and that there should be no oil in the compartment anyway.  Any one guessed what the bad news might be!  When we had the casing off thought it was a good idea to check crankshaft end float.  It’s about 16 thou, I believe it should be under 5 thou.  So looks like an engine out complete strip down is on the cards. The term Bo****k comes to mind. 
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Online bsa-bill

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Re: Timing side oil leak
« Reply #39 on: 15.09. 2020 16:40 »
Yes the clearance to aim for when putting the crank back in is 3 thou, however this will grow as the engine is used I don't know what the recommended clearance is that warrants correction, I'm sure someone will be forthcoming
 
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All the best - Bill
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1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline Swarfcut

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Re: Timing side oil leak
« Reply #40 on: 15.09. 2020 20:38 »
 Richard    OK, here comes a big stone thrown into the millpond of life.

  In an ideal world the crank needs enough cold float to stop it binding when hot, but just enough under running conditions to prevent it moving from side to side. Depending on source, anything from 2-5 thou cold is the figure to aim for.

  Now if we consider the crank and sideways force, reaction against the oilpump worm and spindle gear is trying to push the crank towards the drive side roller bearing, which is designed to cater for this axial force. If the crank  slops towards the timing side there is a nice flanged bush to catch it.

  Here in the real world, my bike came with float of about 1/16" and ran perfectly fine. So in my experience, its not panic stations, just  another minor irritant to  keep in mind until something more critical comes along.  Attending to other mechanical mishaps that need attention is a good opportunity to sort the float and clean the sludge trap in the crank, but I would be inclined to fit the new bush, get a runner, change the oil and treat the bike gently and get some use until the weather changes and you can budget and plan a major overhaul. This will not be cheap, and unless you can see any other real problem, use the bike as is for the time being.

   The bad news expected was 16 thou lift on the timing bush. The good news is that you have found something that is definitely amiss.

 Swarfy

 Additional. Just viewed the Youtube viddys and well impressed with the machine. Even with that pesky crank float it runs fine and does not sound any different from the rest. Thanks to mugwump who set  the way to solving the problem.

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Online Bsareg

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Re: Timing side oil leak
« Reply #41 on: 15.09. 2020 20:43 »
Paul Henshaw on YouTube has just solved a similar problem. Turned out the scroll on the timing cover bush was wrong direction, throwing oil out instead of back to crankcase.
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Online Ratchet Richard

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Re: Timing side oil leak
« Reply #42 on: 15.09. 2020 21:06 »
That would be my bike that Paul has just done, it was Paul who diagnosed the crankshaft end float.
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Online chaterlea25

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Re: Timing side oil leak
« Reply #43 on: 15.09. 2020 22:08 »
Hi Richard,
I posted a link to the correct bush earlier,  The parts book is incorrect as far as I know
The early engines have a different bush/ or part number

Again a reminder to measure the outer diameter of the new Bush  *eek*

John
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Re: Timing side oil leak
« Reply #44 on: 15.09. 2020 23:20 »
ratchet Richard it sounds to me that your bike has a gas leak somewhere , check exhaust ports and cylinder head.
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