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Wed Sep 14, 2011 12:20 am

Oh, I donno, do you really NEED to know?
A lot of this stuff is a process, reconditioning a rod is the same way.

Chances are the heat shrunk it, a guy could simply torque it up and hone it out again, but that's not the right way. Still a lot of stress in it

But if the proper steps are followed in the right order, checking as you go, it makes a better job.

If you don't have a rod vice and a cap grinder and a shot peener and a rod hone....... then the knowledge won't be much use :wink:

I too would rather have at least a 2" journal. The small journal crank is kinda neat, but I spose there is a reason they fell out of favor

Wed Sep 14, 2011 5:28 am

bartman360 wrote: I am thinking of going to a 84mm with some 2 inch journals and get away from the 88mm and the tiny journals. I think that's a wise decision.

RC

Wed Sep 14, 2011 6:02 pm

[quote="modok"]Oh, I donno, do you really NEED to know?
A lot of this stuff is a process, reconditioning a rod is the same way.

Just checking to see if you knew some tricks that I didn't already know. I am always open to listening to someones thoughts or processes.
I am really on the fence here because this is a wedgemated crank and from what I can see the rods for this thing are very expensive compared to the average forged H beam rods. It seems like such a waste to set aside such a pretty crank. Oh well..........Anyone got a 84 or 86mm crank and rods for sale??? Thanks for all your guys time. I know it is not easy to come by these days, as I own a small shop of my own and time is $$.
Thanks.

Wed Sep 14, 2011 7:22 pm

Bartman,
when a rod is damaged or colored due to bearing failure it is almost always collapsed at the split / parting line, meaning narrowed if measured across the bolt holes or alignment sleeves, I've seen more than -.020" error in some rods. This problem can usually be found by comparing the exact measurement against an undamaged part in the same set. To repair it correctly this must be brought back to it's original dimension prior to any attempt at resizing. Physically spreading, often by carefully pressing the two halves over specific sized or shaped mandrels is necessary to gain the correct measurement. the rod can then stress relieved and sized, new bolts are also part of the deal. There is experienced method involved in doing this type of work and delivering a trouble free, usable part.. problem is very few repair shops know it.

Wed Sep 14, 2011 7:43 pm

For most rods it's cheaper to buy a new one. For antique or one off stuff that could be quite different.

Wed Sep 14, 2011 9:18 pm

1432 wrote: Bartman,
when a rod is damaged or colored due to bearing failure it is almost always collapsed at the split / parting line, meaning narrowed if measured across the bolt holes or alignment sleeves, I've seen more than -.020" error in some rods. This problem can usually be found by comparing the exact measurement against an undamaged part in the same set. To repair it correctly this must be brought back to it's original dimension prior to any attempt at resizing. Physically spreading, often by carefully pressing the two halves over specific sized or shaped mandrels is necessary to gain the correct measurement. the rod can then stress relieved and sized, new bolts are also part of the deal. There is experienced method involved in doing this type of work and delivering a trouble free, usable part.. problem is very few repair shops know it.

exactly
The first step is to inspect and measure and see where it's at, and then decide what needs to be done, and things need to be done in an order.
If the rod is too far out of shape, just like 1432 described, that needs to be corrected first, before cutting the cap and rod parting surfaces.

also, a lot of things you do, like honing it or shot peening it or grinding on it, will change it some, so you don't go to finish size all in one step. First it needs to be roughed to round and near size, then everything else is done, and then torqued up again and finished to final size as the very last step.

Thu Sep 15, 2011 6:46 am

RockCrusher wrote: For most rods it's cheaper to buy a new one. For antique or one off stuff that could be quite different.
RC,
yes it likely would be cheaper but even in low end offshore rods finding one to integrate into a set is not always as easy as you may think. matching dimensions to weight as well as finding a supplier willing to break a set of 4 (or x) often forces the rebuild option into play.

modoc,
I'd bet you're the goto guy in your area.

Thu Sep 15, 2011 8:43 am

wonder how the 2000+ hp motors seem to hold up with small journels? that just dont fly.
check and make sure the oil hole isant pluged with weld,that 2387 burgerman had 2 that were almost compleatly closed up about 3/8" down in the hole.

Thu Sep 15, 2011 9:08 am

Bartman,
What you are describing on the cylinder walls sounds like a wristpin button or the piston cocking in the the cylinder because of the crank flex.
Going to a shorter stroke like an 84mm and if you are using it at higher RPM look into going to the typeIV center main journal as it has more overlap between it and the rod journals for less crank flex.
There is a modified BMW bearing to use for the center main that adapts the typeIV main to the typeI case.

Wed Dec 28, 2011 1:08 am

jsturtlebuggy wrote: Bartman,
What you are describing on the cylinder walls sounds like a wristpin button or the piston cocking in the the cylinder because of the crank flex.
Going to a shorter stroke like an 84mm and if you are using it at higher RPM look into going to the typeIV center main journal as it has more overlap between it and the rod journals for less crank flex.
There is a modified BMW bearing to use for the center main that adapts the typeIV main to the typeI case.

Does anyone have a pic of the two different center mains for comparison views?
Further inestigation on this engine (bought it used) finds that Rimco did the machine work last time around and looks like one of the Berg boys modified the semi-hemi combustion chambers of the CB heads. Still can not ID the 4415 stamped 88mm crank.
Bret

Fri Jun 14, 2013 12:38 am

Sounds like a @" Chevy Journal? I Have an 86 VW/Chevy Journal and will measure just to see what it is by width and diameter. G(Ya, I know this is old, but still incomplete!) Had Mance Crank turn a 1-Piece counter weighted crank from 69 to 73.7mm for Rabbit rods, just went to Rimco when they were in Santa Ana, CA and bought a set with bearings, fit and ran killer! I never got to drive it, sold it b-4 it was even built! 9.0to1 CR and a pair of 40 dcnfs. Dude kept breaking diff.gears, asked him to buy damn Beef-a-diff, but KIDS! OH, and the Rimco 20866 = 20 over case, .866= std. Thrust, G-Man
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