rod nuts

[Bill Romano]

502.03.114 or 912.502.031.14 rod nuts

OK a Porsche part is dear ... but $5.69 for a nut?

Please, would someone tell me what's so special about these nuts that they're that costly and can't be reused?

I have a bag of used ones that look absolutely lovely!

[Dan Epperly]

I live dangerously and reuse mine.
Unless they were NOS I'm not sure I would trust new ones given the crap quality of many reproduction new parts.

[David Jones]

Before ARP nuts became available for VW engines I would not use new Brazilian rod bolts because of the apparent propensity for failure and always used original VW bolts. Never had one fail. I still re-use Porsche nuts but I did add 2 ft/lb of torque and green loctite.

[Don Gale]

502.03.114 or 912.502.031.14 rod nuts

OK a Porsche part is dear ... but $5.69 for a nut?

Please, would someone tell me what's so special about these nuts that they're that costly and can't be reused?

I have a bag of used ones that look absolutely lovely!

They are single use because the threads deflect at the torque spec. close to their yield stress, which makes them self-locking. $5.69 x 8 is down in the noise compared to overall rebuild expense. That said, if it was a VW engine, I'd reuse them, but in a 356/912, I'd prefer not to roll the dice.

[Dick Weiss]

I've reused them as long as they're installed the same way when removed and I use red Loctite.
Never had a problem during the "old days" when they were hard to get from various suppliers.

[Vic Skirmants]

Before ARP nuts became available for VW engines I would not use new Brazilian rod bolts because of the apparent propensity for failure and always used original VW bolts. Never had one fail. I still re-use Porsche nuts but I did add 2 ft/lb of torque and green loctite.

+1, but with Blue Loctite.

[Dennis Vogel]

They are single use because the threads deflect at the torque spec. close to their yield stress, which makes them self-locking.

Thanks for that insight. I was following the Pellow recommendation on only using new ones, but did not know the real reason behind it.

[Steve Hatfield]

Curious if anyone has witnessed or is aware of any experience involving a rod nut that either failed or unspun that did not result in catastrophic bottom-end grenading which rendered an accurate post-mortum impossible.

[Don Gale]

Curious if anyone has witnessed or is aware of any experience involving a rod nut that either failed or unspun that did not result in catastrophic bottom-end grenading which rendered an accurate post-mortum impossible.

Maybe someone with a used rod & nuts could torque them to spec, then increase the torque in 2 ft-lb increments until one strips, then post the results to see what margin is there. My guess is the softer nut will strip before the hardened rod stud fails.

For most conventional properly designed bolted connections, if the bolt or nut does not fail by torquing to spec, it won't fail in service, excluding those which were compremised in previous torque-to-yield apps.

[Al Zim]

If you are not going to rebuild the rods (usually a hundred dollars or so per rod) why worry about new rod nuts. What the hell if the big end of the rod is a little large! You can still get by with flat cam followers also. If you do the above does that qualify as a rebuild? al zim I was incorrect about the price of rebuilding the connecting rods please see my next post. al

[Steve Hatfield]

I can’t find any reference here to question the rebuilding of rods. And a hundred a rod is quite reasonable if that buys a competent inspection including mag and correction to specs. Is that Zim’s rate, Al?

[Al Zim]

Restoring connecting rods. Over the millions of RPM'S the big end of the rod stretches. More so at higher RPM'S. the fist thing is to resize the big end of the rod. this is done by cutting a small amount of material off the top end of the rod the bolting the rod together and honing the big end till it meet factory specifications. The second step is being sure that all the rods are the same length. With a mandrel you can offset the pin bushing to correct the rod length for only a short distance. Sometimes pin bushings will have to be made offset to adjust the rod length. Finally the rod needs to be balanced end for end to eliminate vibration. Zim's offers a complete rod restoration including new piston pin bushings and rod nuts shipped to you (in the continental US) for $595.00. The usual turn around can be up to three weeks. Each connecting rod is numbered so that you can keep track of your parts. Ship the parts to us at 1804 Reliance Parkway, Bedford Texas 76021 INSURED Attn. AARON be sure to include your name and phone number. Oversize big end of the rods cause lower oil pressure and premature rod bearing wear. al zim 800.356.2964