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Piston To Valve Clearance process

How to Degree a Cam

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I have one a question:

Why not measure a new, uncompressed gasket and did not pay attention to the thickness of the old gasket during Piston To Valve Clearance process ?

You certainly could, especially as the old gasket may have been damaged during removal, depending on how close you want to run the clearance - but remember, the old gasket will have been compressed over a considerable period, and through many heat cycles, and will have taken a 'set' that will be thinner than the new gasket.

It may only be a few thousandths, but some run clearances VERY close, even theoretically hitting, and use valve train deflection to give the required operating clearances.

OK thanks

I was read about considerations for Hydraulic Lifters and recommended:

- replacing hydraulic lifters for a mechanical lifters temporarily and set zero lush during degreeing the cam

- make your own check lifter by removing the internal check valve assembly and replacing it with a solid shim or alternatively it can be tack welded solid. (that is a shim, right ? https://images90.fotosik.pl/565/f85b9c102e5b51e3med.jpg

I was reading about "How do I install a new camshaft's summitracing and we recommended a set preload a hydraulic lifter (wihout replace a hydraulic lifter for a mechanical or tack welded solid).


Is this a good method? Can it be used with your 6 step process (for a hydrualic lifters) ?

It seems you're a little confused and mixing up different things, and I'm unsure what you need to know? there are many different valve train arrangements, if you could say what engine(s) in particular you're interested in, I expect there will be some experts in that exact engine that can better advise you.

Yes, they do appear to be shims.

The process you seem to be associating them with is using shims, or spacers, installed inside hydraulic type pivots/lifters/cam followers to remove the variations that the hydraulic' may suffer from. It's fiddly rather than difficult, but usually means the part can be converted back. Sometimes it's easier, where possible, to purchase solid versions just for the checking, sometimes to buy a hydraulic version and carefully weld it so the internals are fixed in place, sometimes one can simply machine dummy parts up from alloy, or whatever.

The SUMMIT article you refer to is, inferring from what it says, for American pushrod engines that use hydraulic lifters - more specifically I expect it's for the Chevrolet (and similar) engines where adjustable stud mounted rockers are used that have an aftermarket poly-lock securing system.

I'm not aware of the "six step process", as I learned many years ago and don't recall reading/watching that.

I think I mixed a different ways of deegring camshaft. It's a many kind of type engines and the Summit racing is primarily for US V8 engines

I have a last question:

What's a rocker gear ?

Is that a rocker gear assembly ? ;)


Yes. It's a generic term used for any valvetrain that uses an intermediate mechanism between the follower/pushrod and valve, that works like a lever, most often associated with pushrod engines. Some single overhead camshaft designs use them with the camshaft operating the rockers directly, with them also acting as the followers. I expect the 'rocker' designation goes right back to steam engines, or even before, because it 'rocks' when the machine is working. It's also used for other engine designs where the pivot may be at one end, the camshaft acting on the middle, and the valve being pushed on the other end - there are other variations, but I don't think they're used on engines.

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