Piston help

I've heard that forged pistons will make noise in a Cleveland until they're warmed up and expanded. Because of that, when I rebuilt my Cleveland years ago I went with Keith Black Hypereutectic pistons (they are silicon impregnated cast pistons). My motor was about 450hp, and I never had a problem with it. I drove it hard for years.

Here's more info on the subject:

http://en.wikipedia.org/wiki/Hypereutectic_piston

Michael

Forged pistons are stronger but use more bore clearance- up to 0.005" while cast pistons of any variety typically use 0.0018-0.0025". This makes forged pistons rattle for about a minute when first starting, but solid lifter (or some fast-bleed hydraulic) cams make about the same noise- only audible at idle. That extra bore clearance for forged pistons can save a block sometimes: you check the bores and if the wear or scratches are only .005 or less, one need not bore the block. Instead, you HONE it 0.004 or 0.005-over, install STANDARD bore forged pistons and std bore moly-rings, and gain a stronger piston, a stronger, thicker cylinder wall and lower rebuild costs. The erosion wear-ring at the very top of a bore need not be complely bored away to adequately rebuild a non-race engine. It's above the travel of the rings and has little influence on a motor's performance, beyond a very slight decrease in compression ratio. I built our last 351-C this way in 1991 and it's still going strong, with no smoke.

Thanks for the info. Boss I understand what your saying about just honing but this 351c has 100,000+ miles. I'll have it out soon to see how the bores look. I could handle the noise of the forged, I am leaning toward a solid cam but concerned about the compression using the 60cc heads. It looks like I need dished top pistons with approx +13.00cc volume to keep the cr around 10.3 : 1.

thanks all and i'll keep you informed..

On one of my Clevelands I was running the TRW forged pop-up piston. It require a minimun of .0055" clearance. Since it was a Boss with solid lifters I never noticed anything except when it was really cold, like 0. Then it would rock like a diesel, but what engine wouldn't?

I have KB hypertutonic in my 347. Those pistons as I recall are set at .0015 and those you hear at cold start up, yup.

It's ok since they fit into the expected character of a high-performance engine. Makes the little Hondas think a little.