Cummins pistons

SVcummins · Oct 25, 2021

Do the oem cummins pistons come from the factory with bore size on the head ?

the tractor vet · Oct 25, 2021

Those are just casting numbers

SVcummins · Oct 26, 2021

I know I forgot to take a picture of the top of the piston. Doh i get the dummy award

Geo-TH,In · Oct 26, 2021

I like pic of bottom, MADE IN THE USA!!!

Steve@Advance · Oct 26, 2021

Numbers like that can mean a lot of things, mostly internal to the production process.

Can be casting numbers, inspection numbers, shift, date, weight, size, as in matching the piston to the bore or sleeve to get the proper clearance.

Usually an over bore size will be on top, but the only way to truly know is to measure.

rustred · Oct 26, 2021

no bore sizes are stamped on any pistons that i know of. those are the casting numbers.

wore out · Oct 26, 2021

(quoted from post at 08:08:44 10/26/21) no bore sizes are stamped on any pistons that i know of. those are the casting numbers.

LOTS of pistons are STAMPED "STD" or the "oversize" measurement on the top.

The characters in SV's photo were put in place by the mold when the piston was cast or the "die" when the piston was forged, LONG before the piston was machined to it's finished size.

In some engines the pistons and sleeves are "graded" as to which side of the manufacturing tolerance they measure at and a code stamped on them so they can be matched to each other to end up with a "nominal" fit tolerance.

Destroked 450 · Oct 26, 2021

The pistons I put Im my 5.9 12 valve Cummins were made by Mahle who is a oem supplier
There were part numbers and other markings on the tops of the pistons but they were not marked std for their size

This post was edited by Destroked 450 on 10/26/2021 at 12:05 pm.

Destroked 450 · Oct 26, 2021

The pistons I put Im my 5.9 12 valve Cummins were made by Mahle how is a pen supplier
There were part numbers and other markings on the tops of the pistons but they were not marked std for their size

SVcummins · Oct 26, 2021

I mean are the pistons cummins puts In at the factory are they marked ? I just pulled an engine apart with 600,000 miles on it and the pistons were marked with the bore size

SVcummins · Oct 26, 2021

The pistons I just put in are marked .020 oversized

Cummins pistons

SVcummins

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the tractor vet

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SVcummins

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Geo-TH,In

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Steve@Advance

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rustred

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wore out

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Destroked 450

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Destroked 450

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SVcummins

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SVcummins

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