quote:Originally posted by Bosswrench:quote:Also I got a question about CJ spec clevelands. I had heard that along with dropping the compresion ratio a whole ton, they also retarded the cam by four degrees to pass smog tests. Wouldn't just taking the cam out and turning it back four degrees without doing nothing else make you engine livelier??
Maybe- depending on the combination of parts inside your engine. What Ford did in late '72 was to retard the camshaft 4 or so degrees by changing the silent-chain crank sprocket's keyway location. Changing cam advance only shifts the powerband up or down the rev-range; it normally doesn't increase it. All aftermarket roller cam chains recommended for 351Cs have multiple keyway slots for those who want to tune their engines. Decades ago, builders used the 4 degree advance key-slot to compensate for expected chain stretch after 500 miles, but nowadays with modern cams and better quality cam chains, 'some' extra advance is already built in by the cam grinder. So I don't advocate blindly cranking in more cam advance without first checking as to what the effect will be on power, or valve-to-piston clearances. Dyno-tuning an engine pays many dividends.
Thank you Mr. Bosswrench. I bought the engine back in 2005 and it was a remanufactured CJ spec engine, and just like you said, at 500 miles the timing suddenly got real retarded so I had to twist the ditributor. Now I have close to 1000 miles on it and I am kind of missing the previous euro-spec engine it had in it, but since that one went to heaven, I can't just put it back. But I did save the old closed chamber heads, so I was thinking of sticking those on my CJ spec engine instead of the no compression wide open chamber boat anchors that are on there now, and while I was at it, maybe tweak the cam a little, like maybe four teeth or whatever and just see if it ran better when I put it all back together again. I am sure Dynos are real good to have around, but I doubt I will ever get around to owning something like that. Heck I am lucky to have the right size wrench most the time, let alone any fancy tools like that.