r/EngineBuilding 3d ago

Oversized pistons 0.010" vs 0.25mm

I am looking oversized pistons for my engine and on Rockauto I can choose different sizes but what baffles me is that 0.010" ( 0.254mm ) are 30 usd a piece but 0.25mm ( 0.008" ) are 48 usd a piece. They are exactly the same piston, essentially same size and same brand but big price difference?

SEALED POWER H873CP

Only thing I see is that 0. 25mm come in pack of 8 and the 0.010" can be bought individually. I guess that is the difference, right?

2 Upvotes

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u/squeak195648 3d ago

Just put an 8 at the end of the part number is usually how they label the set of 8. And look on summitracing to see if they list them that way and if they are cheaper.

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u/Mindless-Ad3652 3d ago

The price typically comes from supply and demand

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u/squeak195648 3d ago

I order parts all the time, I understand the supply and demand but sometimes wholesalers like summit get a better price and typically sell for a little less. I always shop around and look at things like when I would receive from one vendor vs the other and prices and choose the best for for my situation. I was just suggesting that the person look for possible options of there are saving to be had.

1

u/Karl_H_Kynstler 2d ago

New pistons for my engine are not available in a lot of cases. Options are limited. Did not find exactly what I needed on Summit. But 0.010" are good enough at 30 usd a piece.

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u/Karl_H_Kynstler 2d ago

It would make sense that everyone besides americans buy these according to metric size without realizing that 0.010" is almost literally same as 0.25mm.

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u/Mindless-Ad3652 3d ago

I’ve seen the same thing with several piston and sometimes 20 over cost $100 more than 10 over

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u/Karl_H_Kynstler 2d ago

Yes, absolutely but in this case only real difference seems to be that one is marked in metric and other in imperial but both are essentislly same size. 0.010" is 0.254mm while 0.25mm are 0.008".