Do You Prefer NOS Engine Parts?

SportFury70

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Hi folks,

As some of you may know my other interest besides Mopars is tractors and I am currently restoring one. The engine on the tractor has not run in 15 years or more and is going to need to get rebuilt; which I will attempt to do myself with my stepdads help as I never rebuilt a small engine and he has.

There is a tractor show the first weekend of May (or Mother's Day weekend) that you can drive your tractor around at, and I would like to possibly if I can to get the engine running so I can drive the tractor around as is.

I REALLY like and MUCH prefer NOS parts and would like to use some in my engine such as rubbery piston rings, gaskets etc BUT i also know that these parts are 50+ years old. My 2 questions to all you folks is....

1) do or did you use rubbery NOS parts in your engines, and

2) do you advise me to?? I'm pretty sure I could if I seal everything correctly and rebuild the engine the right way and not half ass, BUT my stepdad seems to think that 50+ year old NOS rubbery parts like piston rings, gaskets etc is NOT a good idea because technically it would be like starting at square one before I rebuilt the engine.

I would really like to know your thoughts, opinions, and advice

Thanks in advance!
 

CBODY67

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Other than the age-related degrading of parts . . . even on humans . . . the technology on gaskets has improved greatly since the engines were first designed. So, in that respect, newer is better. Piston rings don't get "rubbery" with age, only from use, but newer OEM-type designs can be better than anything we had back then. BUT for any of these newer parts to work as they should, they need to be installed with a high degree of execution than not, by observation.

But, on the other hand, the OEM parts were usually designed to last well past 75K miles, with appropriate maintenance, with all due respect. So it can get to be what one wants to pay for. Yet paying $$$ for NOS or NORS parts, when compared to what the newer, fresher replacement parts might cost, can get to be a judgment call. ONE thing is that the newer parts will carry a manufacturer's warranty that the older ones will not, IF that might matter.

Consider, too, that "age" starts when the orig part was produced, packed, and sent out for distribution. Just as current-production parts do.

DO your own research to see what actually came in the engines when new. Then position that against what is currently available on the particular manufacturer's replacement parts websites (not only on what might be found at places like RockAuto, for example). You might well find that as good or allegedly desirable as the orig stuff might have been back then, it might not even be "on scale" with currently-available items.

Just some thoughts,
CBODY67
 

Big_John

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Rubber isn't like fine wine. It doesn't get better with age. Just sitting on a shelf, the natural oxidation will eventually destroy it and if it's not in a box, light makes it worse. New, even if it's offshore, is pretty much always going to be better, although it may not last as long as the OE did.

Piston rings? Yea, I'd use NOS in a heartbeat.

I've said before, NOS can be meaningless because it's often just the box and the vendor's word. It's a crap shoot and you always need to buy from good, established NOS parts dealers.

I don't know if you buy anything from Ag Kits. A friend started that as a side business for his machine shop and his son took over and ran with it. Long story short, they were bought out and everyone lived happily ever after.
 

Big_John

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Those aren't rubber.

Usual configuration is top rings are cast iron with the oil ring being 2 piece steel with an expander. Of course, that's the automotive version. Variations include hard chroming and moly coating the upper ring.

With a smaller motor, there are some differences, like only a top ring and an oil ring or the oil ring may be one piece with or without an expander.
 

Snotty

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When my Son and I rebuilt the 401 we dropped into his Gremlin, everything was new. I wanted it reliable, not original.
 

volksworld

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ok thats a .010 oversize ring set...which would require you to bore the cylinder .010 oversize and install a .010 oversize piston...when you're talking one cylinder Tecumseh i assume this is a lawn mower you're restoring, not a farm tractor ?....no you dont want old rubber parts...metal stuff, if its not rusted or corroded is fine...i put army surplus 1945 bearings in a hercules engine a couple years ago...they were wrapped in so much wax, cloth and cosmoline it took over 20 minutes just to get them out of the packaging and they probably could have been stored underwater...needless to say they were fine...but a cardboard box in a damp shop or left out in the rain at a swap meet a couple seasons is another story so just cause its nos doesnt mean its good
 

SportFury70

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when you're talking one cylinder Tecumseh i assume this is a lawn mower you're restoring, not a farm tractor ?....
It is a lawn tractor unfortunately not a farm tractor no, this exact one here is the one I'm restoring.....

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Fireflite56

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I would generally support new rubber components in all instances, however make sure they are a quality product - as in US-made if possible or a part someone has had on their car for some time without deterioration. I have seen new rubber that has cracked and deteriorated within a year of gentle use and in those cases, the 60-year-old rubber would have been better.

On my engines, I always use NOS or NORS tune-up parts. I have heard bad things about some newer parts, especially condensers and ballast resistors that fail regularly. NORS parts are still usually pretty plentiful and economical.
 
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