Planate Cranium

Chrysler 218's have "Lightweight Cast Iron Pistons" according to my Industrial Engines manual. That's what I was expecting to see when I pulled the head off...

Marty, I ran accross your post today while searching for some information on my 230. The engine has been rebuilt prior and I have measured the piston diameter at 3.259", but the pistons do not have any oversize indication on them (i.e. - .030, .040, etc). I bought a set of + .030 rings for a 218, as the cylinder diameters are the same for the 218 and 230, but when I sunk the rings down and measured the gap I got .040"! I believe the oversized 230 aluminum pistons measure different than the oversized 218 cast iron pistons. I was wondering if you had the measurements from your .030 oversized aluminum cam ground pistons so that I could cross reference. Let me know. Thanks.

Thanks for the prompt reply Andy. My cylinder bore average from all 6 is 3.284" which tells me that the original 3.250" bores have been machined .030" and have roughly .002" of wear on each side of the wall. If the cylinders have been bored .030 over then I am assuming that the pistons have to be .030 over as well, but I would think then that the new +.030 rings I bought would work... I can just barely, barely, catch my fingernail on the top of the cylinder occasionally and they are not overly tapered so I do not want to have work done to the block. Thanks again for the reply.

I bought what I was told was a running Chrysler 218 out of a '47 Plymouth Special Deluxe a year and a half ago. I got her down to the block, cleaned everything up, painted all pieces and parts, recently lapped the valves back in, and now I'm ready to begin reassembly. That's when I found out that my '47 Chrysler 218 is really a '57 Dodge 230 and it has been rebuilt before. For all intense and purposes the motors are the same so my gasket set will work, but the .030 oversize rings I purchased for the cast iron pistons of the 218 will not. What I really need to know is what size of oversized pistons I have. The pistons for the 230 are stock cam ground aluminum pistons (CDPD logo on them). 871354 O/S is cast on the inside of the pistons and 954809-x is stamped into the top of them. The piston diameter as measured with my dial calipers is 3.259in. Any and all information will help - thanks.