I picked up a 228 GMC earlier this week and am contemplating rebuild. I have low compression.
From my books the 228 has the same bore as a 235. I was wondering if the pistons were interchangeable since 235 pistons are cheaper just about everywhere I can find them than 228 pistons.
I am not sure the pin height will be the same between the chevy and gmc engines. I am guessing not. The combustion chambers are also a bit different, so I believe it is safe to say you need to use 228 pistons in a 228. It may be possible to use those 235 pistons, but the modifications necessary to make the work will be a lot more pricy than buying the right pistons from the get go.
I disassembled the entire engine and the pistons are definitely different. Everything is different. They have 4 rings in them and they have full floating pins. They also have a flat top dome in the center of the piston. Good thing is that I don't think that I will need to bore the block since there is no taper in the bore.
I will re-ring and hone and put new bearings, cam, and a re-conditioned head.
I realize this is a very old thread, but if 54monster is still monitoring this site, I'd like to end a pic of flat top domed pistons that I have in my 1946 GMC 1/2 top, with a 228 ci engine, and ask if these are the same as the ones he found in his engine. Thx.
54Monster has not logged onto the site in 10 years.
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Hank: This picture is of the original #2 piston in my 1952 228 when I pulled the head for a valve job almost 10 years ago. All 6 original pistons are still installed and running well 40,000 miles later. These pistons are flat at the manifold side for a little less than 1/2 the diameter, then slop up into a flat dome across the rest of the piston top. Don't know if this is what you are looking for, but the GMC Master Parts Book says the same pistons were used from 1939 through 52.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
54 Monster described his pistons as having " flat domed center" I've heard of pistons being either flat topped or domed, but never flat domed center. I was wondering if 54Monster's engine had the same pistons as I have.
