racerguy180

on sat. i bought a green 79 mazda sundowner i haven't been able to take the engine and tranny out yet but i think i will tomorrow.

i also got a 12a from a 85 rx7 and a 5spd from a 82rx7. the tranny is perfect shifts into all gears and makes no noise when spun. the engine needs to be rebuilt but i haven't taken it all apart yet, i need to get a flywheel stopper or impact gun to take the big nut off.



the truck is in perfect condition (no rust), and it looks like it'll be relativly easy to install the engine and trans.



i'll keep you posted when i take some pics

75 Repu

Nice project.. Then you cango visit mike and race his green repu..

j9fd3s

haha, yeah



mike

racerguy180

yeah it looks like it's gonna be fun

yesterday i took the eng and trans out of the truck. it looks like the 1st gen trans and the truck trans are the same length from the mount to the end of the tail shaft, so i'll be able to keep the stock driveshaft for right now. thats our starting point. with that in mind the eng will sit behind the front axle and since it's a long bed all of the weight will be inside the wheel base. unfortunately it's raining now and is going to rain untill this weekend.



i don't think i'll be able to beat a real repu cuz the rear diff is 3.36 (thats going to change) i want to find like 4.10 or higher that would fit into that diff.

75 Repu

I think Judge ITO said a first gen diff will bolt right up to the rear axle housing on those trucks.. You could try that..

j9fd3s

i know the nupu's use a 1st gen style diff



mike

racerguy180

are you talking about just the carrier or the entire diff?

j9fd3s

i think the carrier might swap.

mazda has 3 basic rwd diffs.

the p type is the big one they use on the mpv, turbo rotaries, and 929/cosmo's. its got an 8" ring gear, all the alxes are the same spline and size (afaik) so any p type diff will fit in any p type case



they have the nupu, na rx7, 94+ miata diff, its smaller than the p type, but basically these are all interchangeable with each other. for instance you can swap miata gears into the early rx7 diffhousing. the 70-83's have smaller alex's but you can swap spider gears to make them adaptable.



they also have the 323awd and 90-93 miata diff, its teeny and doesnt relate with much else



mike

jfaplanet

I'd like to know more about that rearend swap, Let me know how it turns out. I put a 12A in a 84 B2000, which is the same body style as the Sundowner, longbed also. I had a front frame section from a 74 REPU grafted on to my frame so that the 12A bolted right in. I then used a 79-80 transmission, so the shifter would be in the right place. I got a drive shaft from a Ford Courier and had it cut down and used the swing bearing. The frame rails on the Sundowner and Courier are a little narrow for the rotary with the header on it. I wish you better luck than I had fitting it into the stock frame. Keep your Sundowner tranmission. If you can't find a rearend to fit, the gears in the transmission are better in 1st and 2nd and you could build a transmission. Be sure and check out Felix's Car FAQ if you can find it. I used to have it book marked but have lost it. It has some very valuable info on what parts will swap from what years to what years for RX cars and some on the REPU and B2000. If you can't find it email me and I see about making a copy of what I have for you. Good luck, Charles

jfaplanet

Felix's site is http://members.ij.net/mrmazda/cfaqmenu.html#FCF