Recently there was some discussion about quieting ramps on Vincent cams. A few days ago I put one genuine Andrews Mk 2 cam on my test rig for camshafts for checking it about any quieting ramps. When you know how to look at them you can detect them by eye but actually there is not a lot on them. I´d say about 0,20mm on the camshaft which is a bit more via levers on the valve as my jig got no lever follower for getting lifts. I had a plain follower on the Sony encoder that is why the diagram looks a bit weird with the non-symmetric shape. But this is exactly what it HAS to be when a lever is in the business. Any obscure camshaft that looks symmetric will be WRONG in a Vinecnt engine as it will not fit a lever follower, no matter if plain or radiused. Just a cam for a radius follower appears a bit more symmetric and rounded.
This test was NOT to show valve lift curves, just for checking for quieting ramps. And when it comes to this it is essential to keep zero valve clearance in cold all alu engine and steel pushrods. Unfortunately I expect with steel pushrods you will get a bit too much valve clearance with a hot engine and the modest quieting ramps will be pushed out of business then and some more valve clatter and additional valve gear loads will act on all components in there.
This was one of several reasons why I went for 10x2 mm alu tubes for pushrods like I have on most engines in my garage - and a lot longer than the Vincent sizes. So then I will see if zero clearance is suitable or I set some small clearance when cold - by listening to valve ticker when hot.
Anyway, when chasing for new cams I´d like to point to Andrews/ Megacycle cams as I believe they will be the best bet and I would not have any faith in reground cams from unknown origine - could turn out to an expensive learning later.
I got all Libre Office numbers from my test jig but would not know how to post them here, unless I do a number of screen shots, on demand certainly.
Vic
Max lift in the diagram is 8.45 mm, so a Mk 2 type:
A failed Horex "sports" cam:
This test was NOT to show valve lift curves, just for checking for quieting ramps. And when it comes to this it is essential to keep zero valve clearance in cold all alu engine and steel pushrods. Unfortunately I expect with steel pushrods you will get a bit too much valve clearance with a hot engine and the modest quieting ramps will be pushed out of business then and some more valve clatter and additional valve gear loads will act on all components in there.
This was one of several reasons why I went for 10x2 mm alu tubes for pushrods like I have on most engines in my garage - and a lot longer than the Vincent sizes. So then I will see if zero clearance is suitable or I set some small clearance when cold - by listening to valve ticker when hot.
Anyway, when chasing for new cams I´d like to point to Andrews/ Megacycle cams as I believe they will be the best bet and I would not have any faith in reground cams from unknown origine - could turn out to an expensive learning later.
I got all Libre Office numbers from my test jig but would not know how to post them here, unless I do a number of screen shots, on demand certainly.
Vic
Max lift in the diagram is 8.45 mm, so a Mk 2 type:
A failed Horex "sports" cam: