Author Topic: 30-U rod bolts  (Read 430 times)

Russ T. Fender

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30-U rod bolts
« on: March 17, 2018, 12:32:44 AM »
Looking for a source for rod bolts for my 30-U as mine are stretched beyond use.  There must be something close that is being used on recent rebuilds but I have not been able to find what it is. Thanks.

chetbrz

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Re: 30-U rod bolts
« Reply #1 on: March 17, 2018, 12:59:22 AM »

What is so different about these bolts that make them so hard to find. 

Form, Fit, Function, Thread size ?

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Russ T. Fender

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Re: 30-U rod bolts
« Reply #2 on: March 17, 2018, 04:01:59 AM »
They have a tapered shank above the threads and then a straight shank above that with a groove just under the head. I assume the taper and groove are there for a reason as I doubt they would go to the trouble otherwise.  I was hoping that someone has come up with a modern substitute that works even if it is not exactly the same.  The guys who rebuild these engines professionally must have come up with something that works as I can't believe they are using the old rod bolts on a rebuild. They look like standard 3/8" 24 threads and the overall length is 2-7/16" measured from under the head to the end of the threads.  They have 13/16" of thread and a slight taper over 11/16" of the shank right above the threads and the rest of the shank is not tapered.  There is a 3/32" groove right under the head.



chetbrz

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Re: 30-U rod bolts
« Reply #3 on: March 17, 2018, 04:30:58 AM »
I will email your description to J&M Machine and ask them what they are using on my engine.
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Russ T. Fender

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Re: 30-U rod bolts
« Reply #4 on: March 17, 2018, 12:58:44 PM »
That would be great!  Thanks

chetbrz

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Re: 30-U rod bolts
« Reply #5 on: March 17, 2018, 02:56:44 PM »
We probably wonít hear back until Monday. I donít think they are working this weekend.
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chetbrz

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Re: 30-U rod bolts
« Reply #6 on: March 19, 2018, 11:35:00 PM »
Hi Rusty,

This is what I received back from J&M Machine concerning the rod bolts.

"Chet:
Thanks for the e-mail.
I have been out for several days with the stomach flu so I didnít see your e-mail.
We are trying to find a modern replacement for those bolts as naturally all Nos ones are long gone.
Will let you know what we come up with."

Rusty when I know you'll know.  Sorry I guess this is going to be one of those simple things that turns into a big project.  I would guess that they would have to re-tap a standard rod bolt if one exists.  I hope they don't have to change the connecting rods ?  Now you got me worrying.  $$$

Chet...
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Russ T. Fender

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Re: 30-U rod bolts
« Reply #7 on: March 20, 2018, 12:38:54 AM »
Chet I have been searching for a replacement for several months so I am not surprised.  It really is a problem as it is not good practice to use old stretched bolts.  I had less trouble finding rod bolts for my 1908 Locomobile!  I will keep looking too and let you know if I get anywhere.  This is obviously going to be an issue going forward as more and more tired engines need rebuilding. I believe the same bolt was used on the PA and PB rods so locating a replacement will help them also. Thanks again for the help.

chetbrz

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Re: 30-U rod bolts
« Reply #8 on: March 21, 2018, 07:10:45 PM »
Just in info on the Rod bolts:

Hello Chester:
   Actually replacements are available.
Since we had done a PB engine a few years back I had in my memory we used ARP.

   Tell your friend that the modern replacement is for a 440 Chrysler, of course.
Part number for the bolt is AR312-1 and nut is N503-RE  Heíll need 8 of each.

Thanks
John

Hi Russ,  Please verify before ordering but hopefully this will work,  Chet...
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Russ T. Fender

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Re: 30-U rod bolts
« Reply #9 on: March 22, 2018, 02:28:19 AM »
Thanks Chet!  That's great news.  I will contact ARP tomorrow.

chetbrz

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Re: 30-U rod bolts
« Reply #10 on: April 05, 2018, 07:21:09 PM »
Russ, FYI:


From J&M Machine:

Hello Chester:
    The rod bolts we received for your engine wonít work as he left off one dimension when I ordered them.
The correct one is ARP AR343-1 this bolt is right one fits Studebaker.
John
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chetbrz

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Re: 30-U rod bolts
« Reply #11 on: April 13, 2018, 11:01:16 PM »
Russ, FYI:


From J&M Machine:

Hello Chester:
    The rod bolts we received for your engine wonít work as he left off one dimension when I ordered them.
The correct one is ARP AR343-1 this bolt is right one fits Studebaker.
John

J&M Verified that ARP AR343-1 is the correct rod bolt for our engines.
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