Reply to "Valve lash"

I can tell you this. I am using a Compcams, solid lifter 294s series cam. It has .605 lift, 110 centers, 248 duration @ .050, 74 degrees of overlap. I'm running A3 Ford aluminum heads, iron block and Weber carbs.

It idles at 850rpm, gives me 13 inches at idle. Lifter specs are .022.

Compcams told me to adjust them cold (70 F air temp). Because of the aluminum heads, set them at .016. Their comment was "we guaranty they will be right on spec at running temperature".

I have been told by some that they are too quiet for solids. These are all Chevy guys so you need to take that into consideration because in their case, a solid lifter Chevy generally sounds like a broken typewriter at idle and to boot, won't hold the adjustment for more then 500 miles.

 

Does mine rev like a dynamo? I never though of it that way but I'd have to say yes. Of course there is other engine noise involved back there with the 180s and the Webers but kinda' sounds like a Formula One car when you rev it.

 

You can usually play with solid lifters with a plus or minus .002" safely. The looser they get, the nosier they get and the more stress they will put on the valve train components generally resulting in faster wear. The biggest concern of failure is going to be on aluminum roller rocker arms , the push rods and the rocker arm studs. They are only safe up to a certain valve spring load. They will snap. I use the Compcams chrome molly steel rocker arms and ARP studs.

I would think that a shaft rocker arm like Jessels or the equivalent would be safer with a full comp cam, as far as long term dependability is concerned? I have heard that they wear out quickly with roller cams though.

 

 

Now to your answer. For you to have only 7 to 8 inches at idle, you most likely have a camshaft with 80 to 82 degrees of overlap and it may also be a 108 ground center. In my view, that's a full competition cam. Power is going to be in the 8,000 to 8,500 rpm range and gives away lots of torque under 2,500 to 3,000 rpm.

I'm not the Pied Piper of cams. If you like yours, fine. Leave it alone but 7 inches is probably correct for it's timing events.

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