In the process of installing my new Comp 292 cam today, and realized I never checked for piston to valve clearance. (Engine is in car, and yes I know I am a bonehead, still new to hotrodding) My stats are as follows: 414 ci BBC, no decking on block. SP 2383 F60 forged pistons, .110 dome. Stock lenght rods. 290 closed chambers, slightly decked, not sure how much, (intake needed milling to line up.) 2.19 I and 1.88 E valves. Cam has .544 lift at .050, 244/244 at .050. Am I ok, or do I need to go get some light springs and do the 5 degree test thing?

Well, my gut says you'll be OK, But over the years I've become paranoid enough to at least lay a chunk of Playdoh on there and give it a spin!

I prefer the clay method because besides giving you a measurement for P/V "depthwise" it also allows you to see how close the valve comes to the edge of the pocket. I've found that with large cams (usually closer to .600 and 260*@.050) and 2.19 valves, it can get REAL cozy around the outer edges of the pocket. Many replacement type pistons (TRW's) are made thinking more of the original 2.06's. Just doing a spring test won't show you that it is only .005 away from hitting the pocket edge and when the piston rocks it's going to nail it!

So I'd check for sure. BTW....P/V issues are determined more by duration and I/C than lift usually. Also make sure you use a solid lifter to check it with..not a hydraulic. Or you can disassemble the lifter and rearrange partsto check with, but best to just use a solid lifter.

Good luck,


JIM

The chances of being close with that cam are prety slim, I have never seen a rat with a cam that mild be a problem but,,,,as Jim said it is not a place where you would want to be wrong.
If it were mine I would have no problem running it but I'd just as soon not be the one to tell you not to check it :D
Your decision ;)