Timing case blanking 850

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Onder

Onder

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I wish to blank off the holes in the timing case of my 850 Mk2. How does
the cam bearing on the TS get enough oil (we will leave Earl out of this on this thread) as the
lube has to be flung up to the very top of the case to drain through the little hole.
There is no hole on the crank side.
 
Good idea.

Until you ask where would that pressure be taken from?

At least you’d be able to admire your nice unworn cam bearings whilst replacing the big ends...;)
 
Onder said:
I dunno. I want pressure fed cam bearing...:)
Click to expand...

There is a possibility with the divider wall plugged upward piston motion in the main chamber might draw oil through the T/S bush.
I do not think there is much science to the new lower level drilling as that is about all there is location wise (unless you added some form of riser to it.
It would also have some effect (maybe) on the oil drain from the cylinder head into the T/S.
 
Until you ask where would that pressure be taken from?

uh, Id plug the tiny holes in the con rods.....
 
Onder said:
Until you ask where would that pressure be taken from?

uh, Id plug the tiny holes in the con rods.....
Click to expand...

Good thinking!

But my understanding is that make little to no difference to oil pressure cos what doesn’t go through those tiny holes just makes its way out of the sides anyway...
 
I always thought that the stream was to cool the piston and that, if so, why was the stream outboard rather than inboard?
Seems to me that the inboard side is going to be hotter than the outboard side.
 
The holes appeared when the 3 start oil pump gear changed to 6 start, but it was also around the same time that BSA and Triumph were chasing a high level of timing side piston seizures. This was eventually tracked down to a rogue spark caused by the 4CA points bouncing but until then a lot of work was focused on getting more oil to the timing side piston so maybe Norton were advised by Hepolite what was going on at BSA/Triumph or had their own piston issues and were looking for a cure.

No need to block the holes in the rods, just fit the bottom shells with no holes in the top and the shells with the holes in the bottom. You will then gain the advantage of the full bearing surface area in the highest loaded part of the journal ie from the downward force from combustion.
 
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