E: Engine Camshaft

[Deleted member 3831]

Bruce, your reference to constant accelleration should have been answered in my previous post. Attached is a graphic to illustrate four traces, lift, velocity, accelleration and jerk. This clearly shows a fairly long duration where accelleration is constant, and because accelleration is constant, so is jerk.
The data is design data, not measured, and John Andrews original design data would have been similarly smooth

 

[bmetcalf]

My remark was inspired by TT’s sentence at the end of the next to last paragraph in post #22.

 

[roy the mechanic]

Reading Mat Biberman's book about the vincati, Big Sid ran Andrews mk2 originally. They gave more power than he wanted. Reverted to mk 1 for a more user friendly motor.

 

[greg brillus]

I've just pulled some cams out of a Vincent powered road racing sidecar, 1200 cc done the old way with original heads, the cams have about 0.380" lift at the inlet valve and have the numbers 596 etched into them, anyone know what or who made them............ Cheers.............

 

[mercurycrest]

If anyone would care to send me one of these Andrews cams, I will measure it and then return it with a data file in S96 format, which can be opened in Notepad or Wordpad to view the data, or in an additional R file, which contains full manufacturing data.

Mine still have a lot of the original coating left, so they should be fairly accurate. PM me your details.

 

[erik]

is it an easy Job to press the camshafts in and out ?

 

[BigEd]

............
If anyone would care to send me one of these Andrews cams, I will measure it and then return it with a data file in S96 format, which can be opened in Notepad or Wordpad to view the data, or in an additional R file, which contains full manufacturing data.

That is a most generous offer that I hope will get a good response from people with good cams to be measured. The data should be useful for everyone and should be part of the club data archive for future reference.

 

[Deleted member 3831]

Mine still have a lot of the original coating left, so they should be fairly accurate. PM me your details.

PM sent

 

[timetraveller]

I could also send some cams to Grey One but do not want to overburden him following his generous offer. However, one needs to have a jig, or a spare Vincent engine, to ensure that the cam to follower geometry, and the rocker geometry are faithfully reproduced.

Eight decimal places! That is one hundredth of one millionth of an inch. When I was a young astronomer one of my jobs was to measure the positions of star images on glass photographic plates. In those days we were measuring to one micron and the mechanical measuring machines were state of the art. This is long before the advent of Moiré fringe digitisers, which is what I assume Grey One has access to. I remember visiting the metrology lab of an engineering company years ago. I was given an interesting demo. In this temperature controlled environment the chap set up a 'depth' gauge on top of a piece of steel and then put a finger on each side of the piece of steel. You could see the gauge move almost at once and then continuously as the heat from his fingers caused the steel to expand. Its a wonderful world if one has the right gadgets and the knowledge to use them properly.

 

[Peter Holmes]

I thought I had drifted onto the wrong forum for a minute, maybe NASA if they have a forum, we are normally discussing motorcycles manufactured in pre and post war Britain on antiquated and clapped out machinery, I would have thought working to a tenth of a thou would have prompted a degree of back slapping, eight decimal places, I doubt that even Maughan and Son could manage that.