Another rod bolt/nut question
 

I did not want to hijack the other thread.

Most of my motors all have rods with cap bolts-so no bolts with bolt and nuts. I picked up a set of used billet Crower rods with through bolts. 3 of them I can hand screw the nuts all the way down. The other 5 have 1 nut that gets tight like there is a "crimp" , other nut hand tighten. It is the nut not the bolts. No galling. Which is normal?

Called Crower no specific comment other than probably nuts not bolts-which or back ordered. He said to order ARP nuts. Got some new ARPs and all are tight even on a new 7/16 lug nut stud I have.

I would work with ARP and get the proper nuts (that are not tight) and get a refund from
them on the ones you return. Should not damage the nuts in any way to return nuts that
will not properly thread onto your bolts.

Tom V.

Tom the ARPs thread on until that last thread. Which is what the Crower nuts do also.

I have never used a rod nut that screwed on as if it was crimped or acted like a lock nut. That includes the old Crower through bolt rods. I'm thinking you can get a new set of nuts from ARP and have a good set of rods.

If your using the stretch method then why would it matter ?

Paul the new ARP nuts are doing the same thing right out of the package even on a good free wheel stud, that is why I was wondering if that is how they are supposed to be. I know the old stock rods I have taken apart do not do that.
Steve I guess using stretch method not as big a deal, just was not sure if they were engineered to have that, but it definitely would add more torque resistance.

SD-ROD 7/16 nuts spin free until seated. Just saying.

Skip is this the same situation "3 of them I can hand screw the nuts all the way down. The other 5 have 1 nut that gets tight like there is a "crimp" with the new ARP nuts?

Paul I just tried the ARP nuts on a couple of the rods and they were tight on all of the bolts I tried them on.

I guess like Steve I wonder if using stretch would it make a difference. Even the Crower nuts I can bug down with a shortie 3/8 ratchet.

ARP says nor crimp-normal nut so I'll try a few more and get a new grade 8 bolt to spin them on!

I think that it might a be a case of the black anodizing they put on them being a few thousands thicker in the threads.
It’s not a easy process to control from what I understand.

So me and a buddy jacked with them today. Weird deal ALL the ones that were tight spin right down perfect upside down! Spin right down on my thread chaser but those are a little loose anyways. Some are a little snug on a new 7/16 Grade 8 bolt some are not. ARP nuts spin fine on the new Grade 8 bolt but are even worse on the rod bolts. ARP nuts look a hair larger OD on the shoulder and not sure there is much extra room o the rods.

Mixing and matching the nuts we got most that are pretty good. No "dimple" for rod stretch gauge.

It looks like maybe previous off and on dinged the nuts a little and when the big ends got a little grinding the end threads on the bolts got just barely touched. I think it is mainly really tight tolerances on the threads and slight dings adding up-why swapping them around worked better!

Man these Crower rods are heavy 907 gms! Plan is to go in an extra parts 455 anyway-for dyno testing soem different dual quad intakes M/T, Warrior and the new Bathtub.