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Cam Techniques has repaired single lobes for me for not much money.

For other engines I've worked on, both Delta and Web camshafts have welded and reground all the lobes to retain the stock base circle diameter.
 

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I worked with Steve Demos when he was a cam grinder at Reed Cams he does good work and was a funny and wild guy on a motorcycle.
John
 

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What are the advantages to welding up cam lobes vs. grinding the original radius to re-establish lift? You get to keep the same springs, duration not modified? etc. I suppose this isn't always successful. The weld would have to be very good to be permanent.
 

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What are the advantages to welding up cam lobes vs. grinding the original radius to re-establish lift? You get to keep the same springs, duration not modified? etc. I suppose this isn't always successful. The weld would have to be very good to be permanent.
When the base circle gets smaller, a few things happen. For one thing, it's harder for the lifter to follow the smaller diameter lobe. Bigger is better in this case. If the edge of the lifter digs into the lobe, things wear fast. So this restricts just how radical the cam profile can be. A bigger base circle will tend to be easier on the valvetrain.

Also, with a CIH engine, a smaller base circle does the same thing as a longer valve...it causes the rocker arm to tilt relative to its' center pivot. Since the lifter end of the rocker arm has a sliding tip, this reduces the rocker arm ratio, which lessens valve lift and even duration to some extent.

Also if you get too extreme with the base circle diameter, the rocker will sit lower on the rocker stud. Sometimes you run out of threads on the rocker studs for adjustments (bottoms out). So then you need to stack hardened washers below the locking nut to prevent this. You might also have to slot the rocker arms to prevent binding on the studs.
 
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Opelnut
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advance and retard

Is it correct in thinking that cam timing shifts the powerband (adv for up and retard for lower?

How much adv or Retard = how much shift Rpm?

:ugh:
 

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Is it correct in thinking that cam timing shifts the powerband (adv for up and retard for lower?

How much adv or Retard = how much shift Rpm?

:ugh:
Advancing the cam: More low end power, less top end. Usually better throttle response, often at the expense of a rougher idle.

Retarding the cam: More top end power, less bottom end. Throttle response is usually soggier, and idle tends to smooth out.

Every couple of degrees 'supposedly' shifts the powerband by about 400-500 rpms. So if a given camshaft installed 'straight up' has a powerband from 2500-6500, and you advance the cam 2 degrees, the new powerband *should* be 2000-6000 rpms. In theory anyway...



Ya can't have everything! (where would you put it?)
 
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Opeler
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Erson cams

I was in erson cams plant a couple months ago and i had them check out a couple of cams i had from years ago. They made me a racing cam and the owner was a very nice guy and he walked me through the plant and showed me a bend full of opel cam blanks. I told him i would put erson cams on the site but did not get around to it. These people have specs for german racing cams. They are a well known cam company and do cams for a number of nascar teams.
 
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