Quote:
Originally Posted by Greg Reid
NOS is fine for some things but suspension parts call for a lot of labor to change. It's the kind of thing you don't want to have to do over in a few months or even a couple of years... That being the case, I'd go with the best new stuff I could find.
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I like Greg's answer from a risk perspective. I'm a metallurgical eng, not a polymer guy, but....
Maybe if you discussed specific NOS parts you could benefit from others' experience with them. I think it will be hard to generalize.
Unfortunately, elastomers degrade just from sitting in air. Even though the material properties when new were well-sorted for the application, it's hard to predict how they might have changed in 50 years. Newer parts use newer materials and while the properties might not duplicate those of original, they are more likely to maintain those properties for the next 20 years than a 50-yr old elastomer.
OTH, newer materials, like thermoplastic elastomers that didn't exist 50 yrs ago, have made it easy to manufacture functional parts for less money but they might not hold up well. They are probably designed to cost less, not last longer.
When engineers make decisions about durability because a company cares about managing warranty costs, statistics typically call for a "life spec" at least 3X longer than the "nominal" requirement.
GM clearly cared about their reputation and their warranty costs so I'm confident they tried to use materials that would maintain mechanical properties well beyond their warranty period or even their "design life".
Modern aftermarket manufacturers, I dunno... but I can guess!
I think we all get it (I don't blame it on "Chinese crap" personally), but your question is a good one. Do you want "old good stuff" or "new sketchy stuff"?
I'm interested to learn how an old rubber-isolated GM suspension part holds up after 50 years on a shelf so I hope you get some comments from others that have used them.
I'm currently putting my front bumper back on and plan to use the original rubber bumper stabilizer cushions. Not as critical as a suspension part, not highly stressed in service, and probably not the same material, but they don't look bad. No cracks and still compliant after 53 years in ozone-rich Colorado air:
Mike