So was given these pistons- TRW L3012F and are 30 over, googled them as you do, did not find much?

That sounds like a Mopar 318 piston part number.
Measure across the head, it should be close to 4 inches. (3.938)
Were there 8 pistons in the set?
DD

Good to see you on here doc. Hopefully the fires are not by your house.


Greg

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Hey everbody, six pistons in the box, inside was a data chart, L-3012F is listed as 3.400" which is what i got, took somes pics, but need to find out how to link off google drive.

My bad, the TRW 318 piston is L3013F
As for the CA fires, those are 60 & 100 miles North of us at the moment.
DD

you may want to mike the pistons to verify
but 3.400 is the OE stock size bore,
slants needing a rebuild typically need a .020 or .030 or more overbore
and over sized pistons/rings to match
you will need to find a NOS block or have a used block sleeved to use those pistons.
if they are not OS,,
don't trash em,,some folks like having old stuff around, or make bookends or trophies from them....

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Doo Ron Ron and the Duke of Earl are friends of mine.....
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Cool.

60 miles is still too close for those fires. Best wishes that they get those contained soon.

Now back to piston talk.


Greg

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You know i was just waiting for someone to reply with this, pistons are 30 over, but yes you are correct if they were L-3012F , but they are L-3012F-30.

Hey just out of interest, does the "F" stand for forged? Had a look on the net, some say yes and some say no?

In this case...…...No

I found my old TRW catalog

Pistons:

L prefix Alloy piston

100-400 series powergroove
500-1900 cast aluminum
2000 series with F suffix power forged
2000 series with CF suffix cast aluminum
3000 series with F suffix cast aluminum decompressed

F suffix pin fitted
CF suffix cast aluminum pin fitted
KF suffix piston and rings pin fitted
HF suffix hyperteutectic alloy pin fitted

_________________
Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

.030 over pistons would be useable, I would still have them checked for diameter so
you know exactly what you have


I know that the molten aluminum used to cast pistons is degassed,
I have never heard the term 'decompressed' used with cast aluminum pistons.
Is there any additional info in the TRW catalog concerning the 'cast aluminum decompressed'?

_________________
Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8