Quote:
Originally Posted by tekuhn
A bit more information on my SR block. Each cylinder is stamped with an S, P, or U. I assume it was to let the person fitting the pistons know something about the bore size. Standard, Undersize, P??. Also the deck machining is pretty coarse. All the machine marks are oriented in the same direction as expected, but then there are lines made by a hand grinder that are in a different direction. The hand grinding is not very well done and feel low if you rub your fingers across them. I assume that a standard thickness and composition head gasket will still seal though. No wonder they put Bars Leak in them from the factory.
|
MIKES ANSWER:
I would Shave the top of the Block to Deck the grooves out before you rebuild that Block. From what I read the Factory had to match certain Pistons to Bore size quick and to do those 3 pistons that fits all, in your case. "S","P","U", assuming they only had to mark the Bores that were different from normal for that particular Engine the letters may depict the Rings size. Next step is to lap the rings without lapping them on the assembly line so they take out the lap clearances by using different letter correspondence per Ring Clearence.
Same Bore size, same Piston size and 3 different lapped Rings to fit all the Pistons. Someone would have to measure the diameter in 3 places to find which letter Ring corresponds to that cylinder first. Then stamp that cylinder. Normal Piston with Ring won't be stamped. I watched Modern Rings being installed on today's production rebuilds to share this info. and assuming that is the way it was done in the past.
They do have a special Ring insertion tool also to make the job quicker. I think the rings are about 30 degrees away from each other. Thus, never lining up there grooves as not to lose compression.