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Thread: lsd conversion
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mattraver
Revvin Up
Posts: 95
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posted November 18, 2009 08:39 PM |
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lsd conversion
i purchased the spacer from rex and am having some problems , 1 bolts are too big and are zinc plated (look like grade 3 from home depot ) . 2 what are the origional specs on the diff? lash, pinion preload etc.
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gborch
1st Gear
Posts: 39
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posted November 18, 2009 11:15 PM |
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Torsen
1- I had the same issue. You are going to have to drill out the spacer. Set it up under a drill press or take it to a machine shop.
2- The specs are in one of the manuals. Cant locate mine . . . . reorganizing. I think Sparky has them . . . ((((((((((Sparky????))))))))))
If not I'll find them here for you shortly.
good luck
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MAZDAMARK
Hauling
Posts: 139
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posted November 19, 2009 08:20 AM |
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Are their any #s on the bolt head? Just because their are zinc, doesn't mean they can't be a hardened bolt...
____________
94 RX7
89 RX7 GTUs
85 GSLSE
88 323 GTX
1975 REPU
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mattraver
Revvin Up
Posts: 95
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posted November 19, 2009 10:07 AM |
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the heads of the bolts have been milled off , why ? could"nt tell ya . usually ring bolts are grade 8 or better and are black oxide , also have a shoulder . problem with the bolts in question is they are to big (8mm i need 6mm just for example)
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Brad
Rotorhead
Posts: 1672
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posted November 19, 2009 10:38 AM |
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quote: the heads of the bolts have been milled off , why ? could"nt tell ya . usually ring bolts are grade 8 or better and are black oxide , also have a shoulder . problem with the bolts in question is they are to big (8mm i need 6mm just for example)
I know if the heads are too thick they'll hit the axle housing. Or if it's adjusted far out. I had to grind 2 notches into the housing to clear the bolt heads. Not unheard of, didn't 3rd gens have theirs notched stock?
Do you have a '77 ring and pinion? I know that one uses smaller dia. bolts and there seems to be some smaller bolt ring gears floating around. Max had same prob in his 74.
You can ask Fuzzyeye for smaller bolts.
[URL=http://rides.webshots.com/photo/2959011650033406361ADMjzh][/URL]
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mattraver
Revvin Up
Posts: 95
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posted November 19, 2009 07:42 PM |
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well the plot thickens <found bolts no problem>the spacer ring is not needed on my housing also have a strange gear ratio 3.30 43 tooth ring and 13 tooth pinion . someone have any answers to that , i am in ? ps the smaller ring bolts are 10mmx1.25
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mattraver
Revvin Up
Posts: 95
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posted November 19, 2009 09:42 PM |
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the ring gear has what looks like a c a mazda m logo and the #8788
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repumax
Redlining
Posts: 427
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posted November 20, 2009 08:12 AM |
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I don't think a 330 ratio was an option for a repu. It sounds like you have a ring and pinion from a later
b-series truck which could still work. Do the bolts holes on the spacer line up with your ring gear? What is the width of your spacer? I do know the spacer needs to be .250" for a 77' repu.
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1974 Mazda Repu
1986 Yamaha RZ 500
1988 Yamaha YSR 50
1991 Suzuki RGV 250
1992 Yamaha TZR 250 SP
1996 Aprilia RS 250
2003 Ford F-450 6.0 Diesel
2004 Mazda RX8
2006 Yamaha Banshee
2014 18' Eclipse Toy Hauler
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mattraver
Revvin Up
Posts: 95
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posted November 22, 2009 03:07 PM |
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well no spacer needed , everything fit like a glove and 330 gears with my tire size 205 55 15 makes it about 365 ratio . dont know what the gars are out of but maybe this is a better option than using a spacer .
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MAZDAMARK
Hauling
Posts: 139
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posted November 23, 2009 07:37 AM |
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3.30 gears were only used in the diesel B series, IIRC. That's the tallest R&P Mazda has ever produced I believe. V8 FB Guys would kill for that ratio. You put an ad up on V8RX7forum.com bet you could get a real nice price for those gears... They are VERY rare. IMO 3.30 is way too tall for a rotary...
Actually, I'm surprised you even need an lsd with 3.30 gears... I have 3.91s in my truck and I hate it when towing or carrying a heavy load...
____________
94 RX7
89 RX7 GTUs
85 GSLSE
88 323 GTX
1975 REPU
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MAZDAMARK
Hauling
Posts: 139
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posted November 23, 2009 07:41 AM |
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FYI, I believe the ony 2 ratios offered in the REPU stock were 4.11 and 4.65... Someone please correct me if I'm wrong...
____________
94 RX7
89 RX7 GTUs
85 GSLSE
88 323 GTX
1975 REPU
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sparky
Redlining
Posts: 299
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posted November 23, 2009 08:29 AM |
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I'm not sure but i think my 77 has a 3.90 ratio.
Also, when i installed the torsen i did not shave the tops off the bolts. Used loctite on the bolts and ground down some metal on the carrier bearing support pestals where the bolts could interfere.
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mattraver
Revvin Up
Posts: 95
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posted November 23, 2009 06:24 PM |
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well i dont tow with the truck its just for fun and the 330 gears are great with the tire size . without the lsd iv had the truck up to 145 mph in 4th and it had enough pickup to beat a 350z on the freeway . 5th gear is a great gas saver . the lsd was out of a 3rd gen rx7 from japan , maybe thats why i didnt need that spacer
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sparky
Redlining
Posts: 299
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posted November 24, 2009 08:21 PM |
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How did the truck stay on the road at 145 mph?
I used to have a '74 repu and almost went airborn at 110 mph?
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mattraver
Revvin Up
Posts: 95
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posted November 24, 2009 10:28 PM |
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front end is all new ,all polly lowerwd 2 in. 205 55 15 bfg traction ta tires ,330 gears . stock trucks dont handle that well
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sparky
Redlining
Posts: 299
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posted November 25, 2009 10:01 AM |
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How did you get polyeurathane for the front end. Just replaced everything on mine?
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Mattraver
Revvin Up
Posts: 95
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posted November 25, 2009 10:40 AM |
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I have a laithe and a mill , made the front end parts out of Polly and the leaf spring bushings out of a delron /nylon material . Some of the front end bushings are energy suspenson with a little bit of modification
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