BOP possibilities

stevieray
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BOP possibilities

Postby stevieray » Sun Feb 07, 2016 7:12 pm

I have a BOP 8.2 inch with 2.93 gear. I have determined that is has 27 spline yoke and 7/16 LH thread on gear. This unit has obviously never been touched. I would like to change over to a 3.08 or 3.23 to put a 1969 Grand Prix back to original (this car came with 3.23 but currently sports a 7.5 inch from a 81 Monte Carlo with a really high gear, guessing a 2.29???). I am having no luck finding a 3.23 gear set or even a 3.08. So, my question is: Can I use a Chevy 8.2 gear set in this differential. And if I can, what would be required to make the change.
Thanks,
Steve

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monzaz
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Re: BOP possibilities

Postby monzaz » Mon Feb 08, 2016 12:57 am

You can not NORMALLY swap gears from different size rears. WE can retro fit 3.08 chevy gears into the BOP 8.2 rear it will require some trick parts... Need a 8.2 CHEVY yoke... then we have a custom steel bushing made for increasing the yokes seal diameter to match the BOP seal ID lip . You will also need a totally different carrier series than the 2.93 one. So as you can see it is just not as easy as bolting it right in.

10 bolt 7.5 can only use 7.5 / 7.6 gears from 1978-2004 s-10 Camaro, fire bird, g-body, nova etc.
8.2 you need BOP 8.2 gears
8.2 Chevy you need 8.2 Chevy and so on.
You can not just pop gears in and out of different housing that are the same size either...You need to reset them up properly again. Once they are removed from a different housing to a another it requires and complete re setting and meshing again...

People have bolted in gears form one 10 bolt 8.2 BOP to another and used all the same parts and been successful...But they are lucky. and the set is probably slightly off some but not too noticeable and will only affect the longevity of the gear by years.... sometimes they are way off and the parts will just whine very bad or just plain grenade on the first run...

Jim
The are hard gears to find for the 8.2 BOP rear 3.08 3.23... they will be inthe 100-200 range for good used.

7.5 rear should be easy as there are NEW gears for that rear. 3.08 we have good used.
J D Race

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Re: BOP possibilities

Postby stevieray » Mon Feb 08, 2016 10:15 am

Thanks!

I have no intention of just plopping the Chevy gear in there. My intention is to fully rebuild and properly set up the unit what ever gear set I use. Just wanting to know if this can be done. It is my understanding that the BOP carrier breaks are 2.76/2.93 and 3.23/3.31, so I thought I did have the correct 3 series carrier. Would I need a different carrier because of the difference in bolt sizes, 3/8 vs. 7/16? Of course I would prefer the 3.23. Can I be put on a waiting list or something.

Oh, I have no intention of using anything from the 7.5....just want to get rid of it and put the correct rear end back. The 2.29 does not do justice to my 428!

Thanks,
Steve

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monzaz
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Re: BOP possibilities

Postby monzaz » Mon Feb 08, 2016 10:34 pm

Ok well it was kind of confusing the way it read... like you wanted to try and put a 7.5 gear in a 8.2 rear or something like that? Is that not what you were asking? If not sorry got that wrong...

Carrier breaks for the 8.2 is correct you listed. Long wait as we have not had one in years... 45 year old rears are getting tough to find with good used gears.
WE do look all the time.... just getting thin in the mid eastern states with the government giving yards incentives to junk anything old. Then the china metal rush did not help either back a few years ago...

7/16 carreir ring gear holed carrier with a 3/8 " right hand thread bolt conversion we can do. We have small bushing to go into the 7/16 holes to use the 3/8 bolts through the center of each hole. That do cost again...But yes we can solve that problem.

I will call around so guys in the biz and see what I can dig up for you. They all know they are worth money too. Will see if we can find anything first then see how extreme their prices are, Jim
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stevieray
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Re: BOP possibilities

Postby stevieray » Tue Feb 09, 2016 6:14 am

Many Thanks!!!

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monzaz
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Re: BOP possibilities

Postby monzaz » Tue Feb 09, 2016 2:59 pm

PM me a email I might have found a set of 3.23...God can not believe that... lol. He will send pictures over soon I will pass them on to you. Jim
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Re: BOP possibilities

Postby stevieray » Mon Mar 07, 2016 6:15 am

Jim,

I need some advise on the gear lash.
DSCN2986.JPG
DSCN2987.JPG

I'm not getting the nice well defined contact pattern that I see in other posts. Also, is the pattern I am getting acceptable?

Thanks,
Steve

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Re: BOP possibilities

Postby monzaz » Mon Mar 07, 2016 12:13 pm

Your doing good... A good used pattern will be light like that .... YOUR good just a bit too deep. keep the backlash .008-.010 on used gears.

What is your shim thickness for the pictures just given? looks like a few thousand shallower will do it. take out .002 - .003

That pattern should feel pretty good too as you spin the gear - Jim
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Re: BOP possibilities

Postby stevieray » Mon Mar 07, 2016 4:32 pm

For the first attempt at the shim, I just left the original bearing and shim in place. I haven't pulled the old bearing off yet to see what the shim thickness is. It took several attempts to get the back lash where it currently is at 0.009. It spins nicely:-)
Steve

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Re: BOP possibilities

Postby monzaz » Tue Mar 08, 2016 12:54 am

Throw some oil on that gear and see what it looks like again before removing it. Jim
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stevieray
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Re: BOP possibilities

Postby stevieray » Wed Mar 09, 2016 3:21 pm

After oiling pics follow:
after oil 2.jpg
after oil 3.jpg

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monzaz
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Re: BOP possibilities

Postby monzaz » Wed Mar 09, 2016 9:21 pm

Coast side seems spot on. Maybe run it and see how it goes. Only thing I worry about is the bearing is old and may have lost some depth meaning if you put on the NEW bearing it may make the pattern go deeper.

Sometimes the installer needs to make the call. If it feels smooth pattern looks good...backlash is good. Run it. Jim
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Re: BOP possibilities

Postby stevieray » Thu Mar 10, 2016 6:16 am

I'll put the new bearing in and check it one more time...like you said, this is a process. It will be easier to fix now than later!

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Re: BOP possibilities

Postby monzaz » Thu Mar 10, 2016 9:37 am

I AGREE... Will see what it looks like. usually couple thousands would be required to clean it up .001 .002 Jim
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stevieray
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Re: BOP possibilities

Postby stevieray » Thu Mar 10, 2016 6:05 pm

Any thoughts on bushings....rubber or poly?


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