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From: Scott Renner
Fromemail: scottrenner@eartlink.net
Category: Technical
Remote Name: 209.178.158.61
Date: 26 Mar 2003
Time: 06:17:17
I took a couple of my cams in to see about getting a little more duration, about the same as the Sparrow 30-70 cam which Edmund refered to in a seperate email. My cam grinder says that he cannot regrind these cams as the tappet is already riding on the shaft surface as it comes off the lobe and down on the heel. He can "plunge" or "undercut" the cam, but then the base circle gets very small and the ramp will be to sharp for the tappet to stay in contact with the cam. MMM,what about roller cams for the Jowett?!?
I had two discussions today regarding making some camshafts. The CNC machinist says about US$250 for the programming work and about 30 mins each on the machine if a small batch (30) is run (US$50). Materia cost is yet to be determined, but could be about US$15 each if we use the steel alloy he thinks would work. This would produce cam blanks which could be ground to any spec. I have to get a firm price from the cam grinder on the cost of grinding and hardening the finished product. At the moment, it looks like the all up cost of a cam would be about US$140
The biggest problem (other than money), is how to increase the lift. The lobesare already at the OD of the bearing. Any increase would mean splitting the block in order to install the cam.
Comments/questions/answers?