Usage:
All 3208 Engines
Reference: Truck Engine News; February 15, 1984; Page 7; "Parts Service Information For Pistons " for All 3208 Engines. Disregard this article. Make reference to a new article with the same title in this issue.
Since the reference article, several new pistons have been released for emissions purposes. The typical crater volume is changed to alter the compression ratio. However, in order to meet emission regulations, the height from the pin bore to the crown of the piston has been increased. The distance from the crown of the piston to the top ring groove has been adjusted accordingly from the standard location.
For emission reasons, new pistons are not available in oversizes. To repair a damaged cylinder, a 9N6275 Cylinder Sleeve must be installed. See Special Instruction SMHS7638 "Installation Of The 9N6275 Cylinder Sleeve". All remanufactured engines and short blocks are sleeved back to standard size.
In the past, several different piston designs have been used in 3208 Engines. As improved pistons have been used, some of the former pistons have been canceled. Some applications use pistons with straight sides on the pin bore boss. These pistons are no longer used in production. However, they are available for parts service. Neither the pistons with the straight sides nor those with tapered sides are direct replacements for each other. All the pistons shown for the separate applications are direct replacements if they have the same pin boss design and are the same size. The charts show the new and former pistons. The charts also show the compression ratio, piston height, and ring groove locations.
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USING A DIFFERENT PISTON IN AN EPA-REGULATED ENGINE VIOLATES THE CERTIFICATION OF THE ENGINE. USE ONLY THE PISTON SPECIFIED IN THE ENGINE ARRANGEMENT. Installing a piston in a used block with the top ring groove located closer to the crown may result in broken top rings. Do NOT use tapered connecting rods with straight-sided pistons. This combination of parts could cause the piston and rod assembly to be unbalanced. Refer to the engine arrangement for the correct piston to use for your engine.
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NOTE: All of the pistons in Chart A have standard piston height and standard ring groove location. Chart B contains updated piston information.
