Tech Support - April 2008

A. The D16Z6 with P29/PM7 piston combination has been done successfully (with various camshafts). As we've never tried this exact build ourselves and don't know details, we asked the experts at Skunk2. Their stoic answer was, "It is up to the engine builder to check for proper clearance during the build." We agree with this statement, as there are too many variables involved with engine building to simply answer with a "yes" or "no." Things like cam timing adjustment, piston to deck height measurements, milling of the head or valve train modifications can all affect clearance. The clay test has to be done to ensure proper clearance between the pistons and valves. At some point, you just have to try it and make adjustments as needed (head gasket thickness or modifying the pistons). On your last question (11.66:1 w/cam vs. 12:1 on stock cam), you would need to run both set-ups on a dyno to get your answer. Building power goes beyond raising compression and adding a cam. Variables such as head flow characteristics, cam profile, intake design, header/exhaust design, fuel mixture, octane rating, and ignition timing all have to be synchronized together. Given a proper tune, our money would be on the 11.66:1 with a Skunk2 cam.

By Gary Narusawa

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