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Balance Shaft Bearing nightmare

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97gsxIA

10+ Year Contributor
419
45
Apr 22, 2011
Des Moines, Iowa
Ok so as I'm popping the piston and rods out of the 6bolt I have laying around, I notice yet ANOTHER issue with whoever built this block...

The BSE was performed, but instead of turning the bearing and popping them back in, "they" just left them out. No wonder they sold this block.. probably didnt have squat for oil pressure on start up. Making me scramble to check crank journals for premature wear (all good wheeew)

So here's my two concerns:
1. The had already plugged the opening where the balance shaft sprocket was (and JB welded it)
2. The only balance shaft bearings I have are the ones off of an old 7 bolt I have or the ones in my 6bolt that's in my car now. I know the two bearing are different from each other, but are they different from 6bolt-7bolt?

for #1 I'm assuming I could disassemble my front case components and take it off to access, but I have everything in place now including a Kiggly CPS and I dont really want to take it all apart for the third time unless I have to. Is there any alternatives? I was thinking about sticking the bearings in the freezer, and then tap them into place from the inside since the internals will be out while I swap rings.

#2 Anyone know the difference in BS bearings? or have alternatives?

Thanks,
Cam
 
Yes the BS bearings are the same for 6 and 7 bolts.

Doubtful freezing the bearing will work, the press fit is about .0035-.005

I would pull the front case and knock them in proper.
 
Most likely that's what I'll end up doing...

But... now I want to do some math for shits and giggles.

What type of alloy are the BS bearings?
I'm sure there's a thermal expansion formula laying around here somewhere....

if the Bearing journal was heated up to say 250* F
and the bearing was frozen to 15*F

What are the thermal expansion properties of iron in comparison to the alloy of the bearing material?
What temperature difference would be needed to get that .0035-.005 to widen up?

UPDATE:

Linear Temperature Expansion Coefficient

Metal Type (10^-6 in/in *F)
----------------------------------------------------
Cast Iron 5.9

Aluminum 12.3

Steel 7.3

Any takers? :D
 
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