Oil feed to valve stem

Started by phutton, August 02, 2013, 06:30:34 PM

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phutton

Many thanks for all the replies. My 95 has an adjusting screw on the nearside (left) of the rocker box, but I'm not sure whether to screw it in to increase the flow or to screw it out. From what I've seen so far, it doesn't seem to make much difference!

Another thing: what oil pressure reading should I expect on the gauge?

singleminded

It also appears from the spares list that only some of the right angled  top elbow oil delivery tubes have a ball and spring.My 9A did not have a ball and spring in it , but another 1 I bought has.The spares list indicates different telltale springs for each design.
I used felt from a Vincent wheel bearing grease seal in my rocker box but it still spews oil from the top end.
I'll get it right one day..John

Lawrence Moloney

Hello again - I have just had a read through my limited Model 95 resources and I note that one publication says the needle valve supply to the valves guides on the 95 is "an ADDITIONAL SUPPLY of oil direct to the valve stems" so Paul possibly not all of my previous M9 info applies to your bike - but still possible that remnant felt (if fitted on 95) is blocking the oil ways after the needle valve? Might also be worth checking if the holes in the guides are aligned with the feed holes??

LM

Lawrence Moloney

Hello again - I have just realized that I didn't read the question correctly and also that I have mixed up Vics response with Pauls question! Some further explanation of the way I understand how the system works, may be of use to the reader.

Oil is delivered to the rocker box via the right angle union which contains a small spring a ball and seat and a fine jet.

Oil is delivered to the rocker spindles via the top gallery in to which the aforesaid union is screwed.

Excess oil from the rocker spindles, passes down to a lower gallery, where a felt wad prevents a direct  feed to the valves from occurring,  a direct feed would result in an over supply.

Oil then passes back out in to the rocker box chamber, via the large spring and screwed plug that hold the felt wad in the lower gallery.   Oil then lubricates the push rod ends and from there runs back down the push rod tubes, into the timing case and eventually makes its way out of the motor and  on to  the toe of your right boot!

I have never known what is the correct length of the felt wad - but in practice it must be long enough to cover the passages leading to the valve guide feed tubes and long enough to be in, or near the  oil flow, as it returns from the top gallery, so as to pick up oil, but not so long as to block the return flow completely. Also the wad needs to be engaged or pre- loaded by the retaining spring, when the screwed plug is all the way home in the housing. It would not be desirable to compress the felt too much (with the spring) as its ability to convey oil may be diminished.

It is over 35 years since I have had a fiddle with one of these, so I hope I have got it right for you! Bottom line is the feed to the valve stems should be little more than a wick feed. This is how I have always interpreted it but perhaps check with Les Hobs, he will know  for sure. I do have a diagram I drew up many years ago - I will see if I can find it.

Cheers,


LM

Lawrence Moloney

Hello I would agree with Paul but I have found that the felt is usually one or a number of punched out wads which go in the oil passage ahead of the spring, which then holds them in place. 

I usually punch wads out of a sheet of 5/16 white felt (bearing seal type) and add them in until a reasonable delivery rate is achieved. For anyone who didn't know that these felt wads were incorporated (to my knowledge) in the 33 - 36 rocker boxes, when you can ,  have a dig around deep inside the oil passage where you will probably find the compressed and blackened remains of the old felt. I use a dentists hooked probe for the job.

   Regards to all.

singleminded

I'm watching this with interest as I have the opposite problem and am having trouble STOPPING the oil going to the valve guides..John

VicYouel

Paul,

Is it similar to the 1932/4 model 9's with a jet and spring loaded ball on the other side? These use a bit of felt wound in a spring to set the oil flow..... works on mine but the rocker box integral bored  tubes were totally bolcked before restoration. The oil adjuster added to the racers seems a very sensible modification to me.  Have you got a pressure gauge on the  feed side..... showing over 70 psi?

Vic

phutton

Can anyone advise me how to get the oil feed to the valve stems to work on my 1935 M95? I have tried adjusting the screw on the rocker box, but with no effect, and it does work if I squirt oil into the union. Any ideas?