Pistons: NOS vs. new production OEM Type

[patentgeek]

I need to buy 256-type pistons for a 1970 XS1 and I'm trying to figure out the pros and cons of NOS vs. new production OEM type pistons.

New production pistons like those sold by Heiden Tuning are described as having the "latest modern thin piston rings." What specific benefits does that offer?

Do you think there have been any significant metallurgy improvements over the past 45+ years that would make new production OEM type pistons better?

Thanks in advance for the help.

 

[650Skull]

have a read through this as an option for Aftermarket sales.
http://www.xs650.com/threads/cheap-piston-sets-on-ebay.26971/


As for your question on Metallurgy...............i think it depends on the manufacturer and the components used.............

 

[gggGary]

It's certainly possible to machine production parts to a much closer tolerance than it was 40 years ago. As far as I've seen, heard on here the crusin image parts are top notch.

 

[TwoManyXS1Bs]

With 45 year-old NOS pistons, consider that they may have been banging around in some box, possibly unsealed, turned gray. That gray color is aluminum oxide, same stuff that makes grindstones.

The original 256 ring thicknesses were 1.5mm, 1.5mm, 2.8mm
Kinda hard to find.

Later 447 ring thicknesses are 1.2mm, 1.5mm, 2.8mm
Much easier to find.

A 256 piston with 447 rings would make future ring searches easier.
Don't know about the Heiden rings.

OEM pistons were cast.
NEW production would be cast, or forged, or billet.
Lighter pistons mean less vibration.

Some piston info and weights in here:

http://www.xs650.com/threads/power.289/

Ring info:

http://www.xs650.com/threads/xs-rings.133/

 

[patentgeek]

Thanks for the responses.

I had previously read through the thread on aftermarket piston offerings, but the aftermarket offerings discussed in that thread didn't seem to include 256-type pistons, and I couldn't find any input on the potential pros/cons of the thinner rings used on the more modern OEM type offerings.

Agreed that it's easier/cheaper to machine parts to closer tolerances now than 40 years ago, but we're talking about tolerance ranges that weren't too difficult to maintain back in the day.

I would prefer forged or billet pistons, but OEM quality cast pistons will be perfectly fine for my use case. All of the new production 256-type, 650cc pistons in the original (8.1:1 to 8.7:1) compression range seem to be cast. Hoos Racing offers offers 256-type, 700cc JE (forged) pistons which can be adapted to achieve ~8.5:1 CR, so that is a good option. I don't consider the cost differences between NOS, new production OEM-type, and the Hoos Racing JE pistons to be a significant factor.