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So I finally got around to pulling the oil pan on my father's 70' cutlass and here's what I found: Peices of a ring and i believe peices of the pistons, probly more in the oil (nothing was magnetic) 1 skirt broken off Another skirt broken off I dont think you are supposed to see the oil ring are you?The cylinder walls looked pretty good from what I can see from the bottom.
anyone have any idea what might have caused this? Also can anyone help identify the pistons? 398665 cast into the inside of the skirt. Appear to have a very small dish thru the spark plug hole.
It was supposedly rebuilt about 10k miles ago, was running with some smoke coming out the breathers, 185-195 on all cylinders except #5 had 50.
Detonation would be my first guess. Stock camshaft? What other build specs? What octane was used for gas?
it was supposedly replaced with a "rv cam" only information I found on it was " 262 cam " on the rebuild receipt.
he would run 87 octane.
its stock 70 cutlass with outside air induction w25, th350, 2.56 rear, 2.5" exhaust, fel-pro head gaskets
Last edited by redbaron442455; Sep 24, 2018 at 07:05 AM.
I agree. Those pics look a lot like what happened to my '70 Supreme 350 back in the early '80s. One day I tanked up with cheap gas (poor college kid), then a couple days later was WOT sideways @5800 RPM and smoke started pouring out of the left side tail pipe. After tearing down the engine, I found a piston with broken top ring, ring land, and piston skirt, just like your pics.
Ok I was thinking they were originals and they just re-ringed it, as far as the detonation goes he always said it runs great on reg 87, hes 75 and probly didn't hear it pinging haha,
thanks for the input, I've been looking at pistons available and this justifies going for the mahle 10cc dish pistons and running 91 octane instead of the stock replacement l2321 5.8cc dish pistons.
Yes, a good plan. The only cam I can find matching a 262 duration, I assume is the 208/208 .445/.445 108 LSA Isky cam. That is a smaller cam and could put cranking compression high. Stock distributor and vacuum advance? Stock timing specs?
Yes, a good plan. The only cam I can find matching a 262 duration, I assume is the 208/208 .445/.445 108 LSA Isky cam. That is a smaller cam and could put cranking compression high. Stock distributor and vacuum advance? Stock timing specs?
It has the pertronix flame thrower distributor and coil. It was timed at stock initial timing I believe, maybe a few degrees advanced.
