My noise valve train Options

[904svo]

While running my engine on the test stand the engine made a funny sound at which point I pull the heads and found this.


It always sounded like the engine needed the valves adjusted. I then turn the engine over by hand with the pistons and cylinders removed. Ever now a then the engine would be real hard to turn over then it would be easy, with help from John Jentz he notice that the case had shinny spots on the lifter bore after putting the cam back in the half case with a piece of paper between the case and cam there was no clearance and by pulling the paper out the cam would rotate! I then check all the loop clearances, dam they all had the problem. The cam that was installed was a SCAT C35 high lift cam. So beware if you install a high lift cam made sure you have clearance between the cam and the case.

[Jake Raby]

That happened because of the base circle of the cam... The Scat C35 isn't high lift, by definition. If the thrust bearing is worn it may be because someone didn't properly set the cam end play when the engine is assembled.

What you should be more concerned about is that magnesium cam gear thats installed.. I noted that before everything else..

[bobhasissues]

That happened because of the base circle of the cam... The Scat C35 isn't high lift, by definition. If the thrust bearing is worn it may be because someone didn't properly set the cam end play when the engine is assembled.

What you should be more concerned about is that magnesium cam gear thats installed.. I noted that before everything else..

What is the proper cam end play, and how is it set? Have never seen this discussed before.

[Jake Raby]

That happened because of the base circle of the cam... The Scat C35 isn't high lift, by definition. If the thrust bearing is worn it may be because someone didn't properly set the cam end play when the engine is assembled.

What you should be more concerned about is that magnesium cam gear thats installed.. I noted that before everything else..

What is the proper cam end play, and how is it set? Have never seen this discussed before.

I go over cam end play in my engine assembly video.

My spec for it .002 measured after the cam is "set" fore and aft in the case. Material removal to attain target clearance is accomplished with light sandpaper on a totally flat surface.

The proper tool for measurement is a dial indicator with measurements taken longitudinally with the cam installed in 1/2 of the crankcase and all bearings in place and lubricated.

Larry,
Ensuring that interference issues like this don't occur is just part of building the engine.. Don't blame the cam,(its just a generic component anyway) its an area where attention to detail can't be great enough.