Using Used Pistons, Yes or No?

[MrSony]

I bought a set of rods for my 350, and they already have sealed power .030 pistons on them. The jackass didn't package them in anything other that what looks like butcher paper, so a few of them have some nicks and scrapes on them. I've removed a few of them with some very light sanding and filing, so they can be fixed. The question is, should I reuse them? The only reason I'm asking is Buick pistons are quite pricey, anywhere from 2-300 dollars for even stock type cast pistons. Of course I'd install new rings and whatnot and make sure there are no burrs and whatnot, but should I?

 

[L67ss]

Do you have a micrometer and cylinder hone along with factory specs for those pistons?

 

[MrSony]

Nope. But I am going to get a brush hone regardless of what I do piston wise. The engine they're going into has been bored .030 over 5500 miles ago (it had 5600 on it when it spun bearings and thus is the reason I bought new rods) but should still be cleaned up, if just to give it the best surface posible for the new rings to seal against. I'd assume the piston is just .030 bigger than the factory piston size. I can't find any specs for stock pistons regarding the diameter of the piston itself. They definitely are Buick pistons, that's for sure.

 

[L67ss]

Whay you have to remember is no two 0.030 pistons are alike. They have to be fitted to the cylinder. Its quite possible you'll install them and theyll seize in the block when warm or result in excessive blow by. Or they could fit. Thats why you need the micrometer and piston specs

 

[Bar50]

Pretty sure Buick 350 is 3.80 Bore and a 3.850 stroke. With calipers measure about and inch down from the wrist pin centerline (90° from the wrist pin bore) and measure the pistons.

Ideally they would seem to be 3.80 + 0.030 to equal 3.830. Most often, the piston will be undersize the amount of piston to cylinder wall clearance, say 0.0025 or 0.003, in that case the pistonswill measure 3.827

There is nothing wrong with using used pistons, the trick on pistons that are pressed onto rods, is that most of the time, the pistons get damaged when the rods are pressed off/free.

Buick pioneered the use of hypereutectic pistons (uses a higher silicone content than normal cast pistons) that use closer piston to cylinder wall clearance than other motors of the era.

Please excuse my ignorance, but, did your motor only suffer rod bearing failure, not involving the main bearings?

What year model is your block? Has the oil pick up galley been drilled to 5/8" diameter?

 

[Matthew Goeke]

did you buy them from ebay? if you complain likey you will get your money back and keep it, or he might create a packaging slip.

 

[MrSony]

did you buy them from ebay? if you complain likey you will get your money back and keep it, or he might create a packaging slip.

It's not worth all the trouble to me. I was really just after the rods, which albeit dirty seem to be in good usable shape.

 

[MrSony]

Pretty sure Buick 350 is 3.80 Bore and a 3.850 stroke. With calipers measure about and inch down from the wrist pin centerline (90° from the wrist pin bore) and measure the pistons.

Ideally they would seem to be 3.80 + 0.030 to equal 3.830. Most often, the piston will be undersize the amount of piston to cylinder wall clearance, say 0.0025 or 0.003, in that case the pistonswill measure 3.827

There is nothing wrong with using used pistons, the trick on pistons that are pressed onto rods, is that most of the time, the pistons get damaged when the rods are pressed off/free.

Buick pioneered the use of hypereutectic pistons (uses a higher silicone content than normal cast pistons) that use closer piston to cylinder wall clearance than other motors of the era.

Please excuse my ignorance, but, did your motor only suffer rod bearing failure, not involving the main bearings?

What year model is your block? Has the oil pick up galley been drilled to 5/8" diameter?

Yep. Smallest bore and longest stroke of the GM 350s. Great torque, even stock. What happened to my motor, was the front cam bearing failed due to low oil pressure upon break in, but I didn't know it at the time. it took 5500 miles of hard driving for it to take out the rest of the bearings. Crank was kind of scratched up everywhere, but the only thing that did any real damage was #7 rod which spun. Oh, and the engine was bone stock 1976 350 Buick. All I did to it was new bearings, .030 over, new pistons of course, rings, gaskets, cam, and swapped to a 4 barrel. Oh, and rebuild the oil pump with new gears, thrust/wear plate, and adjustable pressure regulator.

 

[565bbchevy]

Oh, and the engine was bone stock 1976 350 Buick. All I did to it was new bearings, .030 over, new pistons of course, rings, gaskets, cam, and swapped to a 4 barrel. Oh, and rebuild the oil pump with new gears, thrust/wear plate, and adjustable pressure regulator.

I thought you spent like $5,000 on that engine and trans in there.

 

[MrSony]

I thought you spent like $5,000 on that engine and trans in there.

I did. sh*t was expensive. I'm sure theres some stuff I'm forgetting to list, but it was damn near 5,000.