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Old 01-07-2007, 05:00 PM   #1
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Default RX-7 LSD Question

Hey guys, if any of you have your RX-7 LSD out of your car, i was wondering if you could measure something for me. I need the thickness of the outer part of the shell for the end that does not have the ring gear attached to it(the left side). In this picture:

I'm talking about the thickness of the left lip of the two halves. The reason I ask is because I bought 2 units (one from an automatic RX7, one from a manual) and the difference between them is visibly noticeable, measured around .060". I'm wondering if one of them had been machined down in substitution of shimming or perhaps it was just a casting difference (there are differences in the castings, probably from different years).

Another funny thing I noticed between the two, looking from the outside in one of the side openings where you can see the plates, what looks to be the friction plates (they have small grooves on one side of them), on one, the grooves of two visible plates are facing the same way, where as on the other one, 2 plates grooves are facing each other, as if someone may have opened the differential at one point (this is the one with the smaller lip).

I realize my questions could probably be answered by opening up the differentials themselves, but I was hoping someone could help me before I do that. Thanks!!
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Old 01-29-2008, 02:10 AM   #2
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bringing it up from the dead because i was wondering the same thing. Anyone know of any difference how it is flipped around? (probably wont make sense if youve never seen it before). Also if there is any advantage to either shim stack order:
84-85 is plate-clutch-plate-clutch
86-88 is plate-clutch-clutch-plate
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Old 03-22-2008, 11:32 PM   #3
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ok... 3rd question in this thread that probably won't be answered...

"*note: The 85-85 LSD will fit, however, the housing is not compatible....unless you want to convert to a solid rear axle "

Does this mean that the LSD will fit in the stock 1.8L housing, but you can't use the RX7 housing (i know the rx7 is solid axle)? The wording is a bit confusing, I'm an engineer so the whole written language thing is baffling me.
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Old 03-23-2008, 06:28 PM   #4
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Quote:
Originally Posted by akaryrye View Post
bringing it up from the dead because i was wondering the same thing. Anyone know of any difference how it is flipped around? (probably wont make sense if youve never seen it before). Also if there is any advantage to either shim stack order:
84-85 is plate-clutch-plate-clutch
86-88 is plate-clutch-clutch-plate
How what is flipped?

I went with disc-plate--disc-plate as most af diffs are this way whether that makes it lock up better or not I do not know.(mine is an 87 btw)

Your plate looks fucked also and I wouldnt reuse it.
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Old 03-23-2008, 06:31 PM   #5
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Quote:
Originally Posted by Arkmage View Post
ok... 3rd question in this thread that probably won't be answered...

"*note: The 85-85 LSD will fit, however, the housing is not compatible....unless you want to convert to a solid rear axle "

Does this mean that the LSD will fit in the stock 1.8L housing, but you can't use the RX7 housing (i know the rx7 is solid axle)? The wording is a bit confusing, I'm an engineer so the whole written language thing is baffling me.
Housing as in the rear housing, so you cant use the housing like the later rx7 ones (like I did) and bolt on the front third member. Got her?
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Old 03-23-2008, 11:37 PM   #6
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but it will slid into a 1.8L front/rear housing?
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Old 03-24-2008, 04:07 PM   #7
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but it will slid into a 1.8L front/rear housing?
Yes the lsd unit from the early rx7 will fit in the miata housing
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Old 03-24-2008, 04:12 PM   #8
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I meant the aluminum winged section...

the 84-85 has a solid rear axle...so while you can use the internals, you cant use the aluminum carrier.

on a 86-88, you can use the aluminum carrier if you put miata bushings in it, like what i did...

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Old 03-24-2008, 04:18 PM   #9
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Quote:
Originally Posted by akaryrye View Post
bringing it up from the dead because i was wondering the same thing. Anyone know of any difference how it is flipped around? (probably wont make sense if youve never seen it before). Also if there is any advantage to either shim stack order:
84-85 is plate-clutch-plate-clutch
86-88 is plate-clutch-clutch-plate
In the Cusco Type RS, the high lockup setting (100%) is plate-clutch-plate-clutch-etc..... Minimum lockup (60%) is plate-plate-clutch-clutch-plate-plate-etc... So it's safe to assume that the more plate/clutch surfaces that touch, the higher the lockup.
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Old 03-25-2008, 01:35 PM   #10
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Your plate looks fucked also and I wouldnt reuse it.
why is that? oh well its not even my plate anyway, i just ganked that picture off of clubrx7.com
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