Cylinder pressures??? GRADY Hissin?

What are your cylinder pressures? When I got my engine redone my pressures were at 190+ and my car dynoed 330 - 357, it has not felt as strong for the last few months, Ran a comp. test all of my cylinders are at 173+ this is doing a wet and dry test. The car is using NO oil, everything else is the same. Went a step further and took it into my tuner for a few dyno pulls, my numbers came back horrible. I had a few rocker studs break on me, and I replaced all of them with new ARP studs, readjusted my rockers and even put in new pushrods just in case I had bent one. My car idles fine, runs fine, no bent valves, but my numbers came back waaaaayyyyyy lower. I got a print out this time for ya grady. My A/F is good..... I'm at a loss. No vaccuume leaks, no exhaust leaks, timing is set right at 14* car pulls fine, but only to 6k rpm's before dropping, before they started to drop right about 6300 rpm. This is starting to wear thin on my nerves.

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Ohh yeah and now I have a vibration until 2k rpm's, not a bad one but an annoying one; after 2k it's smooth as silk.

I checked the timing, it right on. I always do my comp. checks on a cold engine throttle closed. The rocker studs were a bad batch from AFR, they are the old studs. Thanks for the info, i'll check out that website.

svt2785 said:

If your cam was properly degreed in when you built this motor and you used a new chain it is likely that it has stretched somewhat during break in. I have seen double rollers lose 4 degrees + of cam timing before they take a set position. This would retard your cam making the intake close later. (the piston will be further up the bore, heading for TDC before it closes and you will lose some compression. This could account for some of your power loss.
As mentioned by another responder compression test results can vary anyway. Engine temp. air density, throttle position can impact all impact it. Also if your rocker geometry is correct you shouldn't be breaking studs. (try finding Jim Miller Engineering on the web for the best information on valve train geometry that I have found).

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