oil feed to rocker cover seal - Part number 148-40

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stevewhitt
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oil feed to rocker cover seal - Part number 148-40

Post by stevewhitt »

Hi
I fired up my W/NG today having done quite a lot of work since November. One problem is an oil leak on the upper banjo on the rocker oil feed pipe, (the right hand side one with 2 pipes). The other banjo on the left side has 2 washers which sit either side of the banjo. They are not fibre washers, not sure of the material, but they are quite stiff and very thin; this side does not leak. On the side that does, I only have one of the very thin washers (on the inside) and a fibre washer on the outside. Its definitely leaking on that joint, and I think its on the fibre washer side.

Is there anything special about the washers that are used on those joints? I see I can buy fibre washers for part number 148-40, but I just want to check fibre is the correct material.
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simon.holyfield
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Re: oil feed to rocker cover seal - Part number 148-40

Post by simon.holyfield »

I've battled this one for ages. The secret is in the tightening sequence.

Following wisdom from other members, I now remove the rocker shaft cover (with the big screw head) from the drive side revealing the slot in the end of the rocker shaft. With a special screwdriver in the rocker shaft I then tighten the acorn nut against the banjo. You can then put the shaft cover back (which has a special fibre washer) with the same wide screwdriver.

IMG_20221023_163246.jpg

I have fibre washers, by the way. I've used ally and copper but went back to fibre.
cheers

Simes

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'30 Model A
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Simon.Gardiner
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Re: oil feed to rocker cover seal - Part number 148-40

Post by Simon.Gardiner »

Get rid of the washers under the acorn nuts - make sure there are no burrs (or muck) around the banjos or the nuts.
The steel nut should make its own sealing seat on the softer metal of the banjo as it's tightened.
My VH has been running like this for over 10 years and doesn't leak oil (not from the banjos, anyway!)
I've been told the banjos shouldn't need a washer against the rocker box either but I will admit to having a fibre washer there - although I don't think I've ever renewed the first ones that were fitted.
Other folks might suggest a Dowty washer (steel with a rubber or plastic insert against the shaft, that gets compressed as things get tightened against the outer steel washer) - I'm pretty sure there a refs to those on the Forum.

HTH

SG
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'55 Huntmaster, '56 VH, ' 51 VH, '62 Arrow, '80 R100RT, '00 Sprint ST (now with a new Arrow project, and just now those 4-stroke Ariel parts can't even make one running bike...)
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Re: oil feed to rocker cover seal - Part number 148-40

Post by paul.jameson »

I have had a persistent minor leak from the left exhaust rocker of my KH for some time now. After several failed attempts to solve the problem when the petrol tank has been off, I now think that the "acorn" nut (which on the KH has to have a flat top) is too shallow and is therefore not nipping up on the washers and banjo. Instead, it is running out of thread and space inside the nut. Next time the petrol tank is off, I shall be fitting an extra copper washer to see if that cures the problem.
Paul Jameson
35 LG (project), 37 RH500, 52 ex ISDT KHA, 54 KH(A), 75 Healey 1000/4.
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist (but not Machine Registrar), Gauges and Clocks Spares Organiser.
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