Thoughts on new camshaft?

[Pete]

Originally Posted by Jim Brierley

An original cam can easily be ground to almost any spec. To do so the cam is mounted in a special machine using the center-line of the cam to hold the cam. (note the small hole in each end of a stock cam) A cam grinding machine is similar to a crank grinding machine but the eccentricity is controlled by a 'master cam'. Most of the grinding is done on the base of the cam, so picture this; you grind off the base (not the nose witch is the fully open part of the lobe), you then adjust the lifter to make it longer and to the proper clearance. Now because the nose has not been ground, the lift is greater by the amount that you extended the lifter. The master lobe usually has greater lift and duration than stock. The only downside is the cam becomes weaker, not a problem in mild cams like touring grinds, in performance cams the racer often adds supports between the original bearings, making it a 5 bearing cam. I have run performance, reground, cams with over 300 degrees of duration and with a lobe lift of .430". A stock A cam has about 240 degrees and .302" of lobe lift. Stock valve spring pressure is 40 lbs., racing cams often have 140 lbs. or more, and when multiplied by the rocker arm ratio on an OHV engine, that is a lot of pressure, but is needed to attain 6,000 or 7,000 RPMs in racing.

Hey, if you want to run lots of lift in a flathead, I have one that has .520 and uses radius lifters. You saw it run at Riverside. That was 168 hp.

[Jim Brierley]

That's a lot of lift, and HP. I've never run a flathead up there, just a 4-port Riley in a street roadster, and my Cook in our 4 4v4r 4 lakester. Both set records.

Originally Posted by Pete

Hey, if you want to run lots of lift in a flathead, I have one that has .520 and uses radius lifters. You saw it run at Riverside. That was 168 hp.

[katy]

Originally Posted by Jim Brierley

Stock valve spring pressure is 40 lbs.

What length would that be at?
TIA, Ken

[Waorani]

A new Burtz camshaft! Fast shipping.

[Gene F]

I have an IB-330 from Stipe Machine. I had a 3/4 Winfield in my car.

[Charlie Stephens]

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Another thing to consider. If the holes in the block that support the cam bearings are worn I believe you can get new cams with oversize journals. Then you need to go back and make the holes in the block round. If you are doing a regrind you can metal spray the journals to the diameter you need.

Charlie Stephens

[Dan McEachern]

Just finished this. Oversize journals on this one.

[Chuck Sea/Tac]

This was line bored and pinto bearings installed. Centers eyebrowed.