• Welcome to the website of the Vincent H.R.D. Owners Club.

    Should you have any questions relating to the Vincent H.R.D. Owners Club, or Vincent H.R.D. motorcycles in general, please contact Graham Smith, Hon. Editor and Webmaster by calling 07977 001 025 or please CLICK HERE.

    You are unrecognised, and therefore, only have VERY restricted access to the many features of this website.

    If you have previously registered to use this forum, you should log in now. CLICK HERE.

    If you have never registered to use this website before, please CLICK HERE.

ET: Engine (Twin) siting of valve collar ET35 on the valve stem


charles d cannon jr

Active Website User
VOC Member
I've recently been working on my cylinder heads and had lapped and assembled the valve assemblies on the rear head, ET 35 "seated" on the valve stems with a rap using a hollow socket and hammer, then attempted to insert an assembled rocker arm/bearing assembly. I'm using the modified rocker arm that is "dished" at the top to accomodate the club modified oil feel bolt. The rocker arm would not fit above ET 35. The rocker arm had some casting richness at the top so I ground that off and smoothed it. My standard of reference is a rocker arm I pulled out of a 1948 head that was polished on top ( it wouldn't fit either). I disassembled the collets, springs etc, and was able to assemble using only the valve, ET 35 and rocker arm/bearing assembly. With the rocker arm in place on top of ET35,and full depression of the arm,which have should have allowed the valve to totally close, the valve was still open a couple of millimeters. I realized that the high position of ET35 on the valve stem was preventing proper assembly/function. The "Instruction sheets" state that "The collar ET35 should be a light drive fit on the stem just above the shoulder of the valve" My Valves have 3 separate stem dimensions, the top, which is about half of the valve length, a mid portion of about 5mm, and the lower part of the stem to where the valve flares. My new assumption is that ET35 needs to go totally down on the midportion???? If so I guess I'll chuck the valve up in the drill press and get out the emery paper again....... Any thoughts or comments are much appreciated!!
 

timetraveller

Well Known and Active Website User
VOC Member
ET 35 needs to go right down to sit on top of the larger, 3/8", lower diameter of the valve stem. I normally use the end of the head of a rubber mallet under the valve head to stop the valve moving downwards and use a suitably sized piece of tube and hammer to knock the ET35 down until you can see it up against the larger diameter.
 

davidd

Well Known and Active Website User
VOC Member
The ET35 has a 45 degree bevel on the bottom that matches the 45 degree bevel on the valve stem. The bevel on the valve stem starts at the 3/8" diameter that is running inside the guide and ends at the 5/16" diameter that runs to the top of the valve with a slight exception. The exception is that there is an extra thou diameter right where the 5/16" diameter starts, but it only goes as high as the thickness of the ET35 (.213" to .230" or so). It is there to hold the ET35 in place during assembly. It can be taken down to 5/16", but it is usually not so different that the ET35 is not seating properly.

Based on your description it sounds like you are not using the G&S stock valve. I would be concerned that the shoulder for the ET35 might not be be the correct height, which is about 2.457" from the bottom of a new G&S valve. Also, if you have not bought the ET35 from a good supplier, they tend to vary in height quite a bit. This would only be a problem if the shoulder is also a little high. You might have a cumulative error creeping in.

I measure the valves with a height gauge.

David
 

charles d cannon jr

Active Website User
VOC Member
Thanks so much. I'll get more physical with it!
The ET35 has a 45 degree bevel on the bottom that matches the 45 degree bevel on the valve stem. The bevel on the valve stem starts at the 3/8" diameter that is running inside the guide and ends at the 5/16" diameter that runs to the top of the valve with a slight exception. The exception is that there is an extra thou diameter right where the 5/16" diameter starts, but it only goes as high as the thickness of the ET35 (.213" to .230" or so). It is there to hold the ET35 in place during assembly. It can be taken down to 5/16", but it is usually not so different that the ET35 is not seating properly.

Based on your description it sounds like you are not using the G&S stock valve. I would be concerned that the shoulder for the ET35 might not be be the correct height, which is about 2.457" from the bottom of a new G&S valve. Also, if you have not bought the ET35 from a good supplier, they tend to vary in height quite a bit. This would only be a problem if the shoulder is also a little high. You might have a cumulative error creeping in.

I measure the valves with a height gauge.

David
Thanks David. I am using club valves. I took down the intermediate area with some emery paper today and was able to proceed. Thanks again for your thoughtful reply.
 

Top