Bennoz wrote:
Sorry to dig up an old topic, but I've just been bitten by this. I built this motor many many years ago & it's just sat there. I had completely forgotten all about this problem.
Recently fired it up & this is the result after approx 5000kms.



Good lord that looks terrible!
I have to say, my personal experiences with Kent Cams have been less than fantastic as well. I don't like to say it because they have such a good reputation, I've noticed the same sorts of things. A cam I had a few years ago was hardened but not core refined, and during grinding you could see where the hard layer was cracking off the core. Also had issues with lobes being out by miles.
Just touching quickly on comments about heat treating camshafts, it is a NIGHTMARE trying to find anyone that knows how to quench harden thin shafts without bending them. It doesn't surprise me at all to hear stories of them coming back bent or twisted.
Problems occur when the shaft is just dropped in water or oil. One side quenches before the other and bends it up. You need to swirl the water or oil and get a whirl pool happening, then stick the shaft in the centre and allow the vortex to collapse on the shaft instantly quenching it from all sides at the same time. Yes it will still move a bit, but not nearly as badly as it would other wise. Next part is making sure its actually tempered properly so that the hard outside layer bonds to the soft core properly (the part I've seen ****ed up on kent cams in the past). Cast iron shafts are a bit different because the lobes and journals are chilled during casting.
I know that Tighe Cams heat treat their cams, as did Wade, as do Clive. Its not uncommon practice, and it does benefit wear.
Where I'm working at the moment, we hardness test Camshafts, Crank Shafts, Gudgeon Pins, rocker shafts and other parts before assembly. And I know that Jim Donahue has a hardness tester and checks his parts too (as well as a Cam Doctor), as does even Windsor Engines (though they send theirs out for hardness testing, I don't think they do theirs in house), as did wade and Tighe test theirs too. Any quality, performance engine shop will do it, it's cheap assurance that parts aren't going to fail on you (especially when you're dealing with Diesels that are worth more than most houses in Sydney

).
Always interesting to see how these parts are wearing after a few hours of use. And good points raised by GR about having even brand new followers checked and corrected as needed.
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