426 wedge piston id

[Jim914]

Trying to find the compression ratio of these 416 wedge pistons. They are standard 4.25 5 look original and 3 look aftermarket. Would they be max wedge style?

 

[33 IMP]

Well, the info i have from an old trw catalog shows only a .033 over L2185F, and since yours show standard.....??
My book shows 800 gram piston weight, 225gr pin weight, pressed pin, 2.049 ch, and effective piston dome volume of 26cc.
I dont know for sure, but the trw look most like maxwedge pistons to me. The others look like they have more dome volume, and look like an arias aftermarket piston.
Is there anything, any brand marking under the head of the #4 piston?

 

[33 IMP]

Making a BUNCH of assumptions regarding cylinder heads, head gaskets, and deck heights......the trws should be around 11 1/2 with 906 style open chamber heads, and approaching 12 to one with original closed chamber 426 wedge heads.
The "arias (?)" I cant even make an educated guess.

 

[Jim914]

No other markings on them. Think they maybe too be much for the street

 

[33 IMP]

Okay, well first, if your trws are like my 2295 (supposed 11 1/2 trws for 440) they are solid dome, which means you can mill off part, or all, of the dome to get the compression ratio you want.
Also, as i said, i had to make lots of assumptions to calculate compression ratio. Actual measurements are REQUIRED to get actual results. For instance, my "11 1/2 trw's are really around 10 1/2 because of deck heights, gasket thickness, and cylinder head volume. Yours might be too. The difference between .034 deck (calculated using trw piston info, and blueprint deck height) and the .060 you might have, then adding in a thicker head gasket than the stock steel shim, can easily mean a full point change in c.r.
But, in my humble opinion,..... i dont think either of those pistons would be happy on the street with 91 octane gas, as is.

 

[33 IMP]

According to my trw catalog, your 426 pistons have twice the dome volume as my "11 1/2" 2295 pistons, 26 to 13. Your pistons were likely intended to run on 102 Sunoco, not 91 union 76.

 

[Jim914]

Thanks for your time giving me the info!!
Would make cool looking wall art

 

[33 IMP]

We all try to help around here, when we can. You're welcome.

 

[62 Dart Convertible]

From what I've seen, the TRW L2185 is a stock replacement for '63-'64 Max Wedge 425HP HC piston (and TRW L2184 is for 415HP LC)

 

[Nate S]

Just sold a set of these. 425hp max wedge. With 88cc heads you’ll be around 13.5:1. You’ll need those really thick copper gaskets to get compression out of the stratoshpere. If I remember right the .093” ones will get you just under 11.

As for milling the top, be careful. These are stock weight, they didn’t just thicken the top and make them heavier. The forging inside follows the contour of the dome. Lop that off and you’ll go right through or be paper thin.

 

[Jim914]

Thanks guys. Never messed with one of these. Like all the info.
Thanks again