Checking used camshafts for wear.

[CooperTune]

I build a lot of engines and some customers want to supply their own cam. I have no problem with that but any time installing a used cam I like to run a few checks. Due to the material our cams are made of they don't pit like cams found in US V8s. At the same time they do wear and being surface hardened this is a problem. I mike the lobes at the highest point the four intakes should be the same height and the exhaust same as each other. If one lobe is shorter than it's brothers I discard the cam. I have a customer who purchased a cam from someone on this board and I found one lobe .015 shorter than the other three. I do not expect a A+ generation cam to very lobe to lobe. Any thoughts? Steve (CTR)

[Speedwell Sprint]

I thought size was measured from the lobe center vs. the overall diameter?

[CooperTune]

OK, I can see that and it should tell you what the lift is. I guess my questions is would all lobes be the same height as each other on a new or used std production cam? Intakes and exhaust may be different depending on spec. When the nose is flat it's not hard to tell it's is due to wear. When only .015 is missing it's not so clear. Thanks Steve (CTR)

[Spider]

I have found the quality of the cams that did come from the factory to be very good and highly consistent, in terms of lift and profile.

If you're measuring 0.015" difference, does sound like wear.

[mk1]

I agree, 15 thou is wear & std cams are usually very good. I have mapped a couple of cams in my time on V blocks with a larger circ protractor & dial gauge. The ones I did were pretty consistent, both through the centre line & base circle to lobe tip.

Personally I would never use a s/h cam from an unknown source, regardless if it was a mate. A cam is such an important part of an engine it's just not worth the aggro in my opinion.

M