Mk3 Timing cover on a Mk2 engine, anything to pay attention to?

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laurentdom said:
Salut Bruno and All,

A few posts above, Jim mentioned the larger flange to use with a MK3 oil seal and you said it wasn't clear for you. You can see that larger flange protruding a little bit out of aand behind the seal in the first picture posted by Gortnipper. It shows what it is and how it must be located.

Hope this helps.

Laurent
Click to expand...

Thank you Laurent,
Yes, pretty sure I have the good one, as I ordered one with the new pump to be sure and they are identical.
Merci!
 
The pores that leaked were only visible from the inside of the crankcase.
I only found them with the cases split.
Of course if the oil in the tank drained into the crankcase without appearing in the timing chest then you would know there was a problem.
 
Well, no question for now to split the crankcases. I can only hope the cause to my problem lies elsewhere, fingers crossed. I didn't go to Yves' shed today, he didn't work for very long but he did plug the treaded hole in the crankcase.
We will try to explore the possibility that oil creeps back into the engine from the scavenge pipe. The oil filter on that scavenge line is located between the converta plates, just in front of the gearbox, with its top about an inch below the bottom of the cylinder block which shouldn't be of concern, the oil lines in and out from the filters are kept as short as possible.
 
comnoz said:
.
Of course if the oil in the tank drained into the crankcase without appearing in the timing chest then you would know there was a problem.
Click to expand...

Well, I am not sure how we could find out if the oil is leaking directly in the crankcases or in the timing chest first...any easy way to do so with the engine in the frame?
Thank you again for your input, I really appreciate!
 
Is your oil filter mounted horizontally (or worse, pointing upwards)?

If yes, and it is above the pump, then surely it will empty back through the pump and into the case?
 
Fast Eddie said:
Is your oil filter mounted horizontally (or worse, pointing upwards)?

If yes, and it is above the pump, then surely it will empty back through the pump and into the case?
Click to expand...
i always thought the oil filter had a built in one way valve?
 
Hi Eddie, I think Lab was talking about the anti drain in the timing cover not the oil filter, and even if the oil filter is above the the pump level , isn(t the oil tank too? I am scratching my head ........!
 
Yes the oil tank is above the pump, but the return pipe should exit above the oil level. That’s what Jim was asking about earlier, he was clearly thinking that an incorrectly made tank could be a way of the oil tank emptying itself into the engine via the return line.

My thoughts on the filter were just an extension of that theory really. On a Commando, the filter hangs down, so it can’t empty itself back into the engine with, or without, a none return valve.

I’m clutching at straws I know, but this one is a strange one!
 
Exactly, the filter is indeed slightly above the pump, but installed the correct way (ie. Hanging down) and the scavenge line inside the tank is a small pipe that goes all the way to the top where the oil gets back into the tank itself trough a few holes very close to the Monza cap.
In other words, everything seems completely normal on that front.

And still no conclusive cause for the overnight wetsumping...grrrr.
 
L.A.B. said:
It doesn't, it's horizontal, but as the return port is higher than the level in the oil tank the oil can't drain back through the filter.
Click to expand...

Of course it does! Mine doesn’t have one, and thought wrongly for some reason!
 
Jagbruno said:
Exactly, the filter is indeed slightly above the pump, but installed the correct way (ie. Hanging down) and the scavenge line inside the tank is a small pipe that goes all the way to the top where the oil gets back into the tank itself trough a few holes very close to the Monza cap.
In other words, everything seems completely normal on that front.

And still no conclusive cause for the overnight wetsumping...grrrr.
Click to expand...

Oh dear. Back to the drawing board...
 
Jagbruno said:
Well, I am not sure how we could find out if the oil is leaking directly in the crankcases or in the timing chest first...any easy way to do so with the engine in the frame?
Thank you again for your input, I really appreciate!
Click to expand...

Yes, You would just remove the timing cover, plug the oil pump outlet hole and remove the engine crankcase drain plug. Then you would fill the oil tank and see if the oil drips from the crankcase drain. Jim
 
Well, it turns out that although I couldn't go to the shed today, Yves already put back the timing cover, so we'll have to be a bit more imaginative. Actually, we will check the return tube into the tank simply by putting the normal quantity of oil in it and then simply unplug the return oil line. If we do that before starting the engine, there shouldn't be anything coming out of it.

Then, we plan on starting the engine to strobe the ignition and leave it rest until we check the the sump on Monday.
Cross fingers.
 
Today's update:

The new oil pump is in, we checked the oil tank return pipe to be in good condition, ie. no leak under the top oil level in the tank, ignition adjusted 28°@4000rpm, the bike started first kick.
I rode home from Yves' shed (25km) without any issue, everything oil tight and running like clockwork.

I'll let the bike alone untill tomorrow before checking the wetsump...fingers crossed.

And Yves is already busy installing a thinner (0,6mm) copper head gasket on his gorgeous 920cc Seeley...he never stops!!
 
Jagbruno said:
Well, no question for now to split the crankcases. I can only hope the cause to my problem lies elsewhere, fingers crossed. I didn't go to Yves' shed today, he didn't work for very long but he did plug the treaded hole in the crankcase.
We will try to explore the possibility that oil creeps back into the engine from the scavenge pipe. The oil filter on that scavenge line is located between the converta plates, just in front of the gearbox, with its top about an inch below the bottom of the cylinder block which shouldn't be of concern, the oil lines in and out from the filters are kept as short as possible.
Click to expand...

If the return oil pipe in the oil tank is holed/broken the, Yes the oil will drain back down.
 
Bernhard said:
If the return oil pipe in the oil tank is holed/broken the, Yes the oil will drain back down.
Click to expand...

Bernhard, as I wrote just above, this morning we have actually unplugged the return line from the oil tank with the oil at top level and it was as dry as a rattlesnake skin in the Mojave sun. So all is ok on the scavenge front.
Once we started the engine and the oil fiter had filled up, we had a VERY healthy oil return flow.
 
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YESSS!

Complete success, this morning there was virtually nothing (less than 20ml) in the sump and the bike happily started first kick after a cold night outside, it purrs like a (very angry) kitten!

So, all along it must have been the worn oil pump and perhaps a problem with the over pressure valve, but in any case it now works as it should.
Thank you all for the advices or comments and to Yves of course for his help.

Now a quick lunch before going out for a nice ride in the sunny Belgian springtime...
 
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