Author Topic: Oil leaking from cam follower guide!  (Read 4776 times)

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Offline Resto-Rob

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Oil leaking from cam follower guide!
« on: 06 Nov 2012 at 12:45 »
Hey Guys,

It turns out the C32 i have bought is more trouble then good!!  It is amazing how the term "in very good running condition" differs from person to person?!
Anyway, i need your help please!

I have finally got my C32 running and it has started pouring oil out from where to lower front valve lifter exits the crankcase.
I know that oil leaks are good in the terms that you know it still has oil in ot and that it is getting as far as the valves but im pretty sure it shouldnt be pouring out.
Can any one please give me an idea as to what could be causing it.

I had the thought that maybe the crankcase is pressurising but then i dont know if the C32 has a relief valve?
I also had the thought that it could be a bung seal but then im not sure they had seals around the lifters in these early bikes?

Please help!
« Last Edit: 07 Nov 2012 at 11:06 by Resto-Rob »

Offline Resto-Rob

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Re: Oil leaking from valve lifer
« Reply #1 on: 06 Nov 2012 at 13:34 »
Ok, so i have found the crankcase breather and it wasnt blocked.... so much for an easy fix?!

Offline Doug

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Re: Oil leaking from valve lifer
« Reply #2 on: 07 Nov 2012 at 04:21 »
Rob,

I assume you mean cam follower guide, and not the exhaust valve lifter.

It sounds like the oil pump is not scavenging the timing chest. Perhaps the pick-up screen is clogged or someone has replaced the hex head fitting in the timing chest cover with a conventional plug bolt that has blocked of the passageway up the timing cover and leading to the pump. There is also a 3/16" diameter hole drilled through the back of the timing chest wall into the crankcase chamber that should set the maximum possible depth of oil in the timing chest to about an inch if the pump were to fail to scavenge. Or, at least there is on an A31 model, and I would have thought the C32 to be likely the same. If that is the case, I would have expected the crankcase to wet sump and the engine to force a lot of oil past the rings. You have checked the return pipe in the oil tank compartment to ensure the oil is returning?

Doug

Offline Resto-Rob

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Re: Oil leaking from valve lifer
« Reply #3 on: 07 Nov 2012 at 05:06 »
Hi Doug,

Thank you, I do mean the cam follower guide.
There is oil retuning to the tank so i assume the scavenging pump is working fine. I havent had the timing chest cover off as i have read that you can do a lot of damage if you remove the lighting generator. something about it becoming de-magnetised? There is no sign of oil on the sparkplugs so it hasnt got passed the rings yet.
Would this leaking be a sign of the oil feed being too fast?

Offline Doug

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Re: Oil leaking from cam follower guide!
« Reply #4 on: 07 Nov 2012 at 23:44 »
Rob,

I still get the feeling that the oil level in the timing chest is abnormally high. Or for some reason that particular guide is exceptionally worn. The lower cam wheel would tend to chuck oil at the front wall of the timing chest where the tappet guide is. But being a dry sump model, there should not be that much oil in the timing chest.

There are no seals on the tappet stems. The tappet guides are tapered on the outside, and fit in tapered sockets. At some point they added a groove around the outside for a felt seal (not sure if the C32 would have it), but this was to seal between the tappet guide and the crankcase and not the tappet in the guide.

If the tappet or guide is exceptionally worn, you should be able to wiggle the end of the tappet up and down.

There is no problem with demagnetizing the dyno by removing the timing cover. The only way that could happen is if you remove the dynamo armature from within the solid magnet field poles. If you take the sheet metal cover off the dynamo, you can remove the two screws that attach it to the timing cover without disturbing the armature. Make a note as to which holes the screws engage and the orientation of the dyno. There are a series, and combinded with the 1/16" eccentricity of the dyno allow one to adjust the gear drive back lash by rotating the dynamo and using alternate screw holes. With the dyno out of the way, you can get to the last timing cover screw (which is a slotted headed screw).

Doug
« Last Edit: 07 Nov 2012 at 23:50 by Doug »

Offline Resto-Rob

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Re: Oil leaking from cam follower guide!
« Reply #5 on: 08 Nov 2012 at 11:04 »
Thanks again Doug.
I have found the problem! The follower guide is heavily worn :(
I take it these would be difficult to replace?


Offline Doug

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Re: Oil leaking from cam follower guide!
« Reply #6 on: 09 Nov 2012 at 12:46 »
Rob,

They are simply held in their tapered socket by the bridge clamp that spans the inlet and exhaust guide. It should be the same guide as any other lightweight model from say 1930 to 1937. Or you could recover yours by re-bushing it.

Doug



[Fix typo.  Doug, 10feb12]
« Last Edit: 11 Nov 2012 at 02:59 by Doug »

Offline Resto-Rob

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Re: Oil leaking from cam follower guide!
« Reply #7 on: 09 Nov 2012 at 17:04 »
Thanks Doug,

The leaking guide has had work on it before as the bridge clamp is a home made one.  You wouldnt happen to have a spare guide laying around would you? :)

Offline Doug

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Re: Oil leaking from cam follower guide!
« Reply #8 on: 11 Nov 2012 at 03:01 »
Rob,

Sorry, they are engaged. 

Doug

Offline Resto-Rob

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Re: Oil leaking from cam follower guide!
« Reply #9 on: 11 Nov 2012 at 09:07 »
Fair enough :)
Would you be able to recommend someone to re-bush my old guides?