Junkyard Special Kia 4.77 ring & pinion install
03-06-2007, 11:10 AM
#21
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Those 2 extra steel bearing caps are the Comptech reinforcement.
You may even need to mill the OEM bearing caps while being mounted on the housing with a mounted bearing.
One problem is.. how do you keep that cap fixed if you need to mill it where the bolt is
IIRC Comptech did not make an extra chamber for a sunken head (allen-key) bolt.
(I know for sure the bearing holes are milled with the bearing caps in place and torqued down.)
That extra cap should just touch the OEM cap at the top IMO when its mounted.
Its very, very hard to get 2 planes exactly parallel.
Long time ago at technic school
it was shown that that was a design nono 
to have 2 parallel planes as a mounting surface.If you leave a gap between the 2 caps then the whole idea of strenghtening is wasted.
If the extra cap "dents" the OEM cap youre going to damage your bearing, IOW make it slightly egg-shape.
I'm not saying Comptech was the only one capable of doing this.
With a proper workshop and experience its possible IMO.
You have to be very precise in your milling setup.
I wouldn't use stainless steel or anything, just carbon steel or simular.
And.. IMO you would have to mill the complete shape of the cap (IOW not bend it into shape and then mill the mounting suraces) to avoid stress in the material.
Milling it out of a block is a lot more work but necessarry and you'll end up with a complete stressless cap.
Let us know how you're gettin' on
03-06-2007, 04:15 PM
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SpitfireS, very good info! I spent a small amount of time working in an automotive machine shop and my brother has been working with CNC's and whatnot since he was in high school (he's 30 now). Everything you pointed out makes perfect sense. I have yet to have taken apart the Kia diff (or S2K diff for that matter) and I was hoping that the "caps" were just that and maybe we could make some chromoly or carbon steel caps like aftermarket small block Chevy main caps for example. But now looking deeper into it I see that they are threaded on the end so that may be nearly impossible to tap and have line up properly. I'm going to get this diff apart tomorrow and talk with him and see what we can come up with. I would like to be able to do some sort of cap/bolt combo that a person could just bolt up and not have to mess with a diff exchange. More updates tomorrow...
03-06-2007, 05:45 PM
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Ok so stupid question from a guy who has never installed gears -- say I decide to go buy a set of 4.77 "Kia" gears ... can I just go buy a gear install kit from say, Rick's, and install the gears with that, or will I need to piece out the parts individually?
03-07-2007, 12:45 AM
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300sx Posted on Mar 7 2007, 02:15 AM
The extra caps are just that: extra caps.
I do not recall they were threaded anywhere (apart from the locking screw thread on top)
The EOM bearing caps do not have the mounting surafce to do that.
IMO you have to machine those mounting surfaces on the OEM cap to get the proper "help" from the extra cap.
If there is room between them, then the OEM cap may still flex and thats the start of final drive damage.
Get yourself a S2000 service manual before attempting to work on your S2000 diff.
Please!
I have yet to have taken apart the Kia diff (or S2K diff for that matter) and I was hoping that the "caps" were just that and maybe we could make some chromoly or carbon steel caps like aftermarket small block Chevy main caps for example. But now looking deeper into it I see that they are threaded on the end so that may be nearly impossible to tap and have line up properly.
I do not recall they were threaded anywhere (apart from the locking screw thread on top)
I would like to be able to do some sort of cap/bolt combo that a person could just bolt up and not have to mess with a diff exchange.
IMO you have to machine those mounting surfaces on the OEM cap to get the proper "help" from the extra cap.
If there is room between them, then the OEM cap may still flex and thats the start of final drive damage.
Get yourself a S2000 service manual before attempting to work on your S2000 diff.
Please!
you don't want to end up like me, lol.
