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kellcats521 kellcats521 is offline
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Join Date: Feb 2005
Location: Atlanta Metro
Posts: 219
FYI on using 91 P&C on pre 91 3.3

As part of my rebuild, I purchased a set of the 91-92 fully finned P&C kits that were on ebay (the seller is local to me so I picked them up).

First, the engine tin needed to be trimmed a bit in order to fit as close to the cylinders as it did on the stock cylinders. Even though it may fit w/o trimming, Id expect that they were designed to work at a specific distance from the cylinder, so I trimmed them to maintain this distance.

But, the REAL problem surfaced when I was completing final assembly - I turned the motor over by hand a few revolutions to make sure all was OK, and I started to pat myself on the back as Inoticed how smooth and easy it turned over. I quickly realized that even 7:1 will have noticable compression, and I had a big problem.
The 91 cylinders have a 2.5mm lip on the top that seats in the head. Unfortunately, the 87 heads have a corresponding 3mm deep seat - the stock 87 cylinders have a 3mm lip. 0.5mm of 'open space' doesn't do well for maintaining compression, so the motor is back apart for the ~$7 0.5mm sealing rings on the 91-92 motor.

I did ask questions about using these and this never came up, but it's still phooey on me for not measuring things. A search of several lists' archieves resulted in one post from 2004 or so with a similar issue, but again for some reason the searches I did before I assembled the motor didn't reveal this issue.

Hopefully any others who bought these will not do the double assembly I'm into now......

Pat K
87 930
Old 05-21-2007, 03:41 AM
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