JRP944

Okay Folks-

I have a question about pistons. I've done some searching and think I have the answer, but the inconsistent markings on my pistons compared to the FSM make me curious.

This is what my dirty pistons currently look like:



Might be a little hard to see in the picture, but I have a "+" between the two valve relief cuts and a "1" off to the side. I'm pretty sure this means group 1 pistons, but I'm curious what the "+" means?

Looking in the FSM, it shows the piston markings should be like this:



So not only is my "1" in the wrong spot, but it shows a "I" (that's a slash or hash mark) where my "+" is currently located. Looking some more in the FSM, it appears this "slash" is for oversized pistons, so I guess that means the image in the FSM is just a generic image, which is perfectly fine.

What confuses me still more though is that the tolerance groups in the FSM are listed as 0, 2, 3 for standard sized pistons and 0, 1, 2 (with slashes) for oversized pistons.



This is inconsistent with what is posted in this thread on 944online:
http://www.944online.com/cgi-bin/yab...num=1294677422

So I guess I have two questions:

1. Do I have group 1 standard pistons?
2. Does the FSM simply have a typo when stating the standard tolerance groups as 0, 2, 3?

Thanks for the help!

Justin

odonnell

All the NA pistons I've seen have that + on them, I believe it's normal.

968workaholic

Group size 1 are your pistons, which are about 95% of all 944 motors. Yes that appears to be one of the many typos in the 944 wsm

JRP944

Cool, thanks for the replies.