roller camshafts

[Joe L.]

Re: roller camshafts

I guess I was looking back to the late 50's and 60's. Believe Isky made one of the early ones with "sraddle" type solid roller lifters, with extensions on the lifter body straddling the cam lobe. This, of course, required machined narrow lobes, and I don't believe the lifter bores were enlarged at all. It probably wasn't too successful.

Stu Fox

Stu-----


For mechanical roller lifters there are several types of anti-rotation devices used, even today. However, for hydraulic roller lifters, all I know of is what's described above. Hydraulic rollers are a fairly recent development (circa the 80's). Mechanical rollers have been around for a very long time.

[Jerry G.]

Re: roller camshafts

I'm just curious. If someone were to run a roller hydralic cam with an over rev kit and use stamped steel rocker with a spring seat pressure of 180 and a full open pressure of 320 what do you think the upper RPM limit might be on this configuration. i like the idea of roller hydralic being easier on the stamped rockers than the solids. Just curious. Jerry

[Clem Z.]

Re: roller camshafts

I'm just curious. If someone were to run a roller hydralic cam with an over rev kit and use stamped steel rocker with a spring seat pressure of 180 and a full open pressure of 320 what do you think the upper RPM limit might be on this configuration. i like the idea of roller hydralic being easier on the stamped rockers than the solids. Just curious. Jerry

to get the RPMs i would go with titanium valves and beehive type valve springs like the new corvette LS engine use and you could get 7500+ RPMs with hyd rollers.

[Joe C.]

Re: roller camshafts

I'm just curious. If someone were to run a roller hydralic cam with an over rev kit and use stamped steel rocker with a spring seat pressure of 180 and a full open pressure of 320 what do you think the upper RPM limit might be on this configuration. i like the idea of roller hydralic being easier on the stamped rockers than the solids. Just curious. Jerry

That's a strange spread between seat pressure and full open pressure. With extreme seat pressures like 180 lbf at say, 1.70, the spring rate would have to be quite compliant at (assuming a 0.600" valve lift) 233.33 lb-in to yield an over the nose force of only 320 pounds.

Why do you need so much seat force?

With stout seat force like 180 pounds, a more typical match would be a spring having a rate in the 500 lb-in range, which would yield 480 over the nose @ 0.600".

[Jerry G.]

Re: roller camshafts

Joe That spring rate would KILL the stamped rockers They shatter at about 390

[Joe C.]

Re: roller camshafts

Joe That spring rate would KILL the stamped rockers They shatter at about 390

Yes, it would.
Did you get the spring force numbers from a particular spring? What's the valve lift that you are talking about?
What I'm saying is that the seat force doesn't seem to match the full open force......unless the valve lift is exceedingly small.