How do you tell if a car has a solid lifter cam

[92646]

I know this sounds like a dumb one but how can you tell if a car has a solid or hydraulic cam. I know listen for the solids rattling but I am thinking the lifters could be so far out of adjustment that they are going to make noise no matter. I was thinking of pulling the valve covers and push on some push rods that have the valves open after the motor has been sitting a couple of days. I thought the lifters would bleed off if they were hydraulic. Any other ideas?
Mark Sheppard

[Chevy454]

You could probably just check the clearance with a feeler guage, as solids should have considerably more clearance (IIRC, hydraulics go to zero clearance + 1/4 turn or so, while your solids are probably gonna be in the .020"-.030" range). The few hydraulic lifter troubles I've had have had a different sound than a comparable solid lifter, but that doesn't mean I could pick them out of a line-up with my eyes closed, either! LOL!!