924Board.org

[jasespace]

I am rebuilding my NA '77 924. I have a collection of cam followers which are all second hand. Some seem better than others. I have had my cam reground to its original profile. I have read that you should not use second hand lifters with a new cam. But replacing all new lifters is not within my budget. How do I assess which lifters are useable? What is the trick to maintaining this part of the engine in good condition? I know I should make sure the oil feed tube is clean and working with a new plastic elbow. I imagine using good oil and upper cylinder head lubricant will help.
Also, are there any tricks to setting the clearance? Turning those screws while the cam is bolted down seems harsh to me. Doesn't that damage the valve caps? I was thinking it would be better to measure all clearances, unbolt the cam, make adjustments, bolt it down again and recheck.
Thanks in advance, Jase

[safe]

If you see wear on them, they need replacing.
If you can feel wear with you fingertips, you might need replacing, your fingers can feel very small imperfections.
If you have worn followers, I can't afford to replace them just chuck in an old camshaft and not your new.

[daniel]

Technically yes you should always use new cam followers, however as you have mentioned this is not always practical. Have a look at the follower and try to determine how it has worn. If there is any evidence that the hardening has been worn through, toss it away. Next is to see if the follower is concave or convex. If the follower is concave you 'shouldn't' use it, although it is possible to use - ill explain later. If the surface is flat or better still convex and the surface is free from damage, go for it. Most cam grinding shops will take followers like this and re polish them so they are 100% but you MAY get away with using how they are.

Back to convex followers, everyone will tell you no good but I have experience to suggest otherwise. Back when I was building FVee motors we had a control cam and had a maximum valve lift. I built several motors with badly worn convex lifters and never had an issue. The idea is that as the cam lobe hits the lifter and drops away into the followers 'dip', provided you could still achieve the max valve lift through rocker geometry, you could increase the effective duration, i.e. from when the valve opens you can lift the valve list curve up so the valve opens more rapidly and stays at peak lift for longer.
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Over the top of skyline, total brake failure.... hit the wall at over 200 kp/h at the dipper, so anyone who has to brake for the esses is a pussy.
1977.5 Race Car, CAMS Group S Spec
1989 944 Cabriolet