Spintron Demo showing Norton cam & lifter wear

Bernhard · Feb 20, 2020

You could design an engine with over head cam, and use hydraulic cam lifters, and yes it has been done on a bike

Jason Wright · Feb 20, 2020

jseng1 said:
Valves bounce back off the seat at high RPM from inadequate closing ramps. And Spintron tests have shown that the Norton cam flexes enough that it can actually push back on the lifter (after the valve hits the seat) and lift the valve the same as valve bounce. A half moon bronze support under the cam center helps eliminate cam flex.

Someone please help Jason Wright with photo posting options. There should be a link somewhere on this forum.

You certainly have gone into it Jim, it must flex because of forces unknown then not just spinning speeds if it was spun at 4k by its self it wouldn't flex surely? my theory is a spring to hold the BSA lifter to the cam that tests ok at 4k then move onto the valve spring, just an idea and there have been plenty of them over the years

storm42 · Feb 20, 2020

Jason Wright said:
I was wondering if a spring could be used at the follower itself to control it, then spring pressure can be lessened at the valve so its sharing the load

Wouldn't that hold the follower against the cam base circle, would the extra contact time cause increased follower wear?

Jason Wright · Feb 20, 2020

Bernhard said:
You could design an engine with over head cam, and use hydraulic cam lifters, and yes it has been done on a bike

Yes it all has been done before but its all about the Norton twin!

Jason Wright · Feb 20, 2020

storm42 said:
Wouldn't that hold the follower against the cam base circle, would the extra contact time cause increased follower wear?

Yes it would hold it to the base circle so it could wear more

Bernhard · Feb 20, 2020

Jason Wright said:
Yes it all has been done before but its all about the Norton twin!

Yes, but how long can you keep flogging a dead horse ? The engine was designed in the 1950s with many, many attempts to upgrade it! Sooner or later, you are going have to sit down with a clear head and a blank sheet of paper to avoid any recurrence of the original issues.

Jason Wright · Feb 20, 2020

Bernhard said:
Yes, but how long can you keep flogging a dead horse ? The engine was designed in the 1950s with many, many attempts to upgrade it! Sooner or later, you are going have to sit down with a clear head and a blank sheet of paper to avoid any recurrence of the original issues.

But its not dead its living mightier than it ever did! though people not giving up and striving!