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con rod balancing Q #2872171
01/10/21 04:55 PM
01/10/21 04:55 PM
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Lincoln Nebraska
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RapidRobert Offline OP
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I saw a utube vid & in one of the Mopar books that you (1) grind on the big end till all the weighed big ends are equal then (2) lay the whole rod on the scale & weigh it & grind on the small end till the whole rod weights are all equal (within 1/2-1 gram) & you are set. then I see another vid from a speed shop & they equalize the big end weights then they equalize the small end weights & you are set. what is right here? thank you for your time.


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Re: con rod balancing Q [Re: RapidRobert] #2872190
01/10/21 05:56 PM
01/10/21 05:56 PM
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okla.
sam64 Offline
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I can't answer your question but on 2 sets of LY rods that I had balanced only signs of grinding was on the big end.

Re: con rod balancing Q [Re: sam64] #2872194
01/10/21 06:05 PM
01/10/21 06:05 PM
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St. Paul , Mn.
tubtar Offline
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I learned by equalizing the weight of the weight of the big end , then the small end.

Re: con rod balancing Q [Re: RapidRobert] #2872200
01/10/21 06:23 PM
01/10/21 06:23 PM
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New York
polyspheric Offline
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When balancing ends, the subject end must be on the scale, a line through both pin and journal centers must be horizontal, and the opposite end suspended (weightless).
Unless the same process is used on both ends, the exact point where metal is removed may add an error.


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Re: con rod balancing Q [Re: polyspheric] #2872224
01/10/21 07:31 PM
01/10/21 07:31 PM
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Bend,OR USA
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Originally Posted by polyspheric
When balancing ends, the subject end must be on the scale, a line through both pin and journal centers must be horizontal, and the opposite end suspended (weightless).
Unless the same process is used on both ends, the exact point where metal is removed may add an error.
iagree
That is the only way I've seen good balancing shops balance rods scope
It seems to me that they also tried to have the rod halfway between scale and the suspending tool both times weighing each end work scope


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: con rod balancing Q [Re: Cab_Burge] #2872263
01/10/21 09:11 PM
01/10/21 09:11 PM
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Lincoln Nebraska
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RapidRobert Offline OP
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the 1st vid & the book had it: big end on the scale, horizontle of course,other end suspended & grind on the big ends till the big ends are equal (1/2-1 gram) on all of em then lay the whole rod on the scale & grind on the small end till the whole rod on the scale weights are equal (1/2-1 gram) DONE. then I saw that vid from a speed shop out west & the equalized all the big ends (within 1/2-1 gram I would assume) then equalized all the small ends (within 1/2-1 gram I would assume) DONE. that's as far as I could grasp.


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Re: con rod balancing Q [Re: polyspheric] #2872266
01/10/21 09:13 PM
01/10/21 09:13 PM
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fredericksburg,va
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cudaman1969 Offline
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Kinda hard to do on a stock Hemi rod or say an Eagle rod with the rounded top.

Re: con rod balancing Q [Re: cudaman1969] #2872268
01/10/21 09:14 PM
01/10/21 09:14 PM
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RapidRobert Offline OP
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^^^ I would think


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Re: con rod balancing Q [Re: RapidRobert] #2872321
01/10/21 11:05 PM
01/10/21 11:05 PM
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Temperance, MI
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68 HEMI GTS Offline
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I always balanced the big end on a fixture, then you know to equalize the rod the rest needs to come off the small end. It’s not like your gonna grind on the beam. So yes, balance the big end on fixture and then you can weigh the whole rod to balance the small end. I only did hundreds of engines that way though so.... Internet experts are king


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Re: con rod balancing Q [Re: cudaman1969] #2872325
01/10/21 11:18 PM
01/10/21 11:18 PM
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Mooresburg, Tn
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'72CudaRacer Offline
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Originally Posted by cudaman1969
Kinda hard to do on a stock Hemi rod or say an Eagle rod with the rounded top.


Actually, it's quite easy to remove material from the rounded small end. It's not like you 're gonna grind a lot off of it. If it's that far off, something is BAD wrong.

Brian

Re: con rod balancing Q [Re: 68 HEMI GTS] #2872377
01/11/21 03:53 AM
01/11/21 03:53 AM
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Bend,OR USA
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Did you use a shadow graph to hold the ends up off the scale when switching them around to weigh each end?


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: con rod balancing Q [Re: Cab_Burge] #2872408
01/11/21 08:26 AM
01/11/21 08:26 AM
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Brisvegas, Australia
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Alchemi Offline
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When I did mine, I found enough difference in the pistons & pins to even all the reciprocating ends out to within .5 of a gram with some swapping, the rods small ends were not far off overall, only had to grind some big ends a little

K1 rods n source pistons

Re: con rod balancing Q [Re: Cab_Burge] #2872891
01/11/21 10:19 PM
01/11/21 10:19 PM
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Scully Offline
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Originally Posted by Cab_Burge
Did you use a shadow graph to hold the ends up off the scale when switching them around to weigh each end?

I use my shadow graph for setting up the bob weights, the rods are easier to do on a small digital scale.







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