I know this has been discussed, but I was wondering if anyone has a definitive swap list to get the tallest gears possible in the rx-7 rear. I don't want to waste money on a crap shoot. I've got the 85 GSL with 3.91.
I have the '83 GSL with LSD and the same gear ratio.
So far I've read that the 82-84 B2000 Gas MT and Diesel MT (front) will swap in, but cannot find anything locally or online but a bunch of 3.6:1 and 3.38:1 for between $35 and $75, ring and pinion only. Not sure if these will bolt up to the lsd.
The 3.6 sounds like it is from the MX-626. I think the "3.38" is really a 3.308. The stick shift B2k has the 3.308. The prices sound good.
Anyone have these specs for the mystery Mazda?
front or rear (ring & pinion)
I'll send you a few files of everything I've been able to find out so far. One file lists the year/gear ratio/teeth counts/ and a lot of commentary that I've pasted it from various sites/forums.
Basically a 1982 to 1984 Mazda B2000 with standard shift transmission has a 3.308:1 r/p that will fit into the 1st generation Rx7 rear ends.
I just bought a complete 1984 Mazda B2000 stick shift carrier for $130 delivered from a Fla junk yard upstate.
10/22/07 I finally took my RX7 differential apart and the B2k gears WILL NOT FIT! The gas engined B2k has 7-1/2" gears not the 7" that the RX-7 uses. Sorry for the misinformation but I was quoting information I found on several sites on the web.
They have another one and I know of another yard that has the same carrier.
will get you to the start of the search for the carrier. "A-1-A auto parts" and "Langston's used auto parts" are the two yards I know of. Shipping will be expen$ive though. The thing weighs 60+ lbs. [The standard "I'm not affiliated.........." applies.]
The B2k carrier itself will not bolt up to the RX7 housing since the number of bolts that hold carrier to the housing is different between the RX7 and the B2K. Also the B2k carrier housing is larger in diameter. But the r/p gears are supposed to fit onto the RX7 carrier from every thing I've been able to determine. Other parts in the carrier will also fit, spiders, bearings etc. so you'll have "spare parts".
I haven't taken my RX7 carrier off the car yet. I'm still measuring the B2k one and putting off changing things since it's so hot down here. But I'll start soon. I'm making a 7" micrometer right now to set the pre-load. When I get through with my change over I'll add the info to my website.
Something I just found the other day that is very
interesting. Some '94+ 1.8L Miatas have a rubber "dampener" flange
that goes on the pinion. The dampener is used on the rear ends that have LSD. NO, not -that- LSD!!!
That r/p will also fit into the RX7 housing. Unfortunately the ratios are all numerically high and won't help us. BUT the r/p gears are the same as the RX7 gears, so that means the flange should also fit the B2K. I'm not sure of the u-joint bolt pattern though. Once I get my RX7 flange off I'll go over the the local Mazda dealer and see if it's something usable.
Right now my shifts can be pretty harsh with no cushioning in the drive train similar to what the motorcycles have. Hopefully the dampener can cure that.[/b]