Hey, I am planning to buy these flattop 946P8 cast pistons for my 350. I think they may have been made by Ertel but are no longer around. How hard will it be to find rings for these or are all std 350 rings the same dimensions? View attachment 3027532 View attachment 3027533
stock cast replacement pistons, should take stock replacement rings. The racing pistons sometimes use thinner rings, but the stockers are pretty much all the same. measure the ring groove width, just to be sure.
The compression rings you get should have no more than about 0.002" side clearance in the groove. The ring should go fully into the groove, enough so none protrudes above the piston ring land surface. The clearances, and values are shown on the last page here. https://www.jepistons.com/PDFs/TechCorner/SCPDrawings/piston_instrc4032.pdf
Ertel and Dyna gear, Ohio, are the same, all are gone. usually a Hastings 139 ring, available in iron or moly. 5/64-5/64-3/16" ring sizes. Do not use the JE catalog clearances as those are for forged pistons. Yours are cast and use no more than .0015-.002" for normal use. Do not use rings for GM pistons. The ring thickness and depth vary from year to year..
yes, the crate motor lost a rod at under a year, its good to go, I'm going to ball hone it to refreshen the hatch but that's it.
You have to love it when a plan comes together! Not many would be able to take advantage of Stock Bore pistons. Good Luck with it and keep us posted on the results.
Since the early seventies. GM (Chevy) has used "shallow" oil ring grooves, also narrow top "shallow" rings. Several different "metric" top ring groove widths and depths.. One reason that you need the VIN numbers on post eighty engines if you use GM stuff.. Aftermkt pretty much stayed with the 5/64 and 1/16 compression and 3/16 oil ring. into the nineties.
I have a set of new in the box Hastings rings. If you need them send me your address and I can put them in the mail.
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