Camshaft Base Circle - how low can you go?
 

Is there a suggested lower limit for camshaft base circle diameter?

I have read about the problems with valve adjusters when the base circle becomes too small, but when does that actually come into play?

The reason I ask is because there is a local (and reputable) shop that can regrind cams for a whole lot less than I would spend at webcam for a new or hardwelded set.

Contact "camgrinder"

I've been burned a few times with the 'local shops' with simple stuff like wheel alignments & mounting tires..... just saying.....

It's alot easier to ship the cams to the expert than fix any problems later.

Bump

base circle
 

A rule of thumb when I set up custom valve lengths, adjust the valve lash and remove the rocker without changing the adjuster and look to see what you have for threads exposed, I shoot for 1/2 to 1 thread exposed on the backside of the rocker and that will apply to base circle size as well

Mike Bruns

Don't fall for MM's contention they can grind an S cam profile on a T camshaft - there's not enough meat. The base circle will be too small and the valve/rocker geometry will be incorrect.

(in case you're conversing with them)
Sherwood

GTC,

Not knowing the "local shop" I will share this from Speed Talk:

Re: cam lobe design for radius pad rockers

New postby CamKing » Fri Oct 21, 2011 11:50 am
We've done plenty of these, and you can't use any lobe that was designed for a lifter the rides in a bore.
When you have a rocker riding directly on the cam, you have to design the valve lift curve, and then work back thru the geometry of the rocker follower, to generate the lobe profile.
With a cam that has a lifter riding in a bore, the lifter moves in a straight line, and you just need to design for the radius of the tappet face(or roller).
With your type, you not only have the radius of the follower pad, but the arc of the centerline of that radius also.

http://www.audietech.com/images/stor..._wo_lifter.gif
Mike Jones
Jones Cam Designs

The cams in a lifter type motor is nothing like the Porsche OHC.


Denver, NC
jonescams@bellsouth.net
camwave