Finished 1 axle! hopefully I'll do the other tonight:


WD-40 straws for both boots to help vent them:


First autocross of the season (the practice event) was on Sunday, so I spent some time on Saturday getting the corolla up and running again.
- Vacuumed out the mouse nest (yay)
- fabricated a new battery tie down because I lost the old one some how...
- put a new battery in it, all my motorcycle AGM batteries don't hold a charge, so I ordered one of these:

480 CCA and 3.75 lbs.. It worked amazing in the corolla. So good in fact, I've decided it's too good for the corolla and it'll be going into the RX-7 to replace the 26 lb Optima Yellow top that's in it now. (and it has more CCA to boot). We'll see how well that works.

Video of the Corolla on Sunday, 2nd in SMF on 5 year old street tires, lost by 0.4s to a Neon ACR on slicks... I could have beat him pretty easily, I left a lot of time out there, pretty rusty.

 

Amazon.com: Battery Tender BTL35A480C Lithium Iron Phosphate Battery: Automotive Amazon.com: Battery Tender BTL35A480C Lithium Iron Phosphate Battery: Automotive

480 CCA and 3.75 lbs.. It worked amazing in the corolla. So good in fact, I've decided it's too good for the corolla and it'll be going into the RX-7 to replace the 26 lb Optima Yellow top that's in it now. (and it has more CCA to boot). We'll see how well that works.


Nice find! Much cheaper than the Shorai LiFePO4 I used in the FD and posts on both sides with just a hair less CCA.

This technology is getting cheaper fast! Pretty soon I will be able to afford my dream EV race car.

 

That battery is mighty impressive

 

I had no idea these existed!! I must buy, but holy cow they are pricey. I have had seen people utilize an aftermarket integra endlink to get same results. I no idea the auto trans starter bolted up, I got one of those laying around here now which does me no good because I have the rx8 trans but my S1 starter is poop (and its a 2kw motor too) time to source an S2.

 

You can just buy a single pair and it gets a bit cheaper:
FC Camber Links - Complete Pair

 

Both axles built and ready to go:

 

I did find those afterwards, stock ones from mazda motorsports for the pair are about 100-110 buck, not a bad deal from ronnin!

Also a friend of mine would be interested in your t2 axles if you don't plan on keeping them.

 

Good looking out on the CV vents. That fixed my outer boot grease ejection issue that happened a couple times.

 

good news and bad news....

good news: drive shaft finally arrived!

and it's decently light

with 2 u-joints, but without yokes its 6 lbs. when you factory in u-joints are a little over 1lb each, that's pretty impressive.

I thew the driveshaft and the 2 yokes on the scale:


9.4 lbs (I round down )

4.5 lbs lighter than the stock shaft, and 1.4 lbs lighter than mazdatrix's aluminum shaft and this is 6" longer for the diff swap.


I then went and tried to assemble it which is where the issues came up...

first, the spicer 7260->1310 conversion u-joint for the front yoke doesn't fit in the yoke...


This is pretty surprising since it's the same yoke mazdatrix sells and their replacement u-joint for their driveshafts is listed as 5-788x (the spicer part number). So I'm going to try to get in contact with them to see what's up.

Denny's driveshaft shop also had a warning which I promptly ignored:
Dana Spicer 5-788X 7260 series Mopar to 1310 series combination u-joint. Non greaseable maintenance free
yeah... so I ordered a neapco u-joint (2-3100, which denny's also sells and doesn't have that warning on).

So then I tried to take one of the u-joints out of the driveshaft.... and there isn't enough clearance for it to come out:


when comparing it to my rear flange yoke, it looks like the issue is post-snap ring has the same ID as pre-snap ring so it's stuck there instead of just sliding out...
So this is the part where I dremel my brand new drive shaft to get the ID slightly more open post-circlip so once I'm at this point the u-joint cap can slide out. *sigh*

in other news, the uprights came for the new wing too , but that will have to wait...

 

You need to then go back the other way with the spider and push the other cap out like the first.

 

Keep up the good fight.
Justice and the American Way are at stake.

 

So neither Mazdatrix or Quartermaster was very helpful.

I did contact PTI, who made the front yoke:
Mazdatrix's response was basically "sucks to be you":
When I told them what PTI said:
Thanks for nothing...


So I ordered a new joint, a Neapco 2-3100 and it fits just fine, yay.

You can see the difference in the dimensions of the 7260 side of the joint:


I also decided against the dremel on my brand new driveshaft.... I went at it a bit harder with a pipe wrench and was able to twist the u-joint cap out. (I'm not using that u-joint anyway)


slowly getting there....

 

It's done!

pressing in the new neapco 7260/1310 hybrid joint:


inner clips on the 7260 joint:


pressing in the rear small pattern ford flange (used the quartermaster 1310 joint the DS came with)


1310 joint outer clips:


it's a driveshaft!


9.3 lbs!

 

Made a thread detailing how to make your own driveshaft:
https://www.rx7club.com/2nd-generati...shaft-1081644/

 

Too legit!

 

Differential is in!


I'm not going to lie, that was one of the most tedious things I've done to the car in a while... There are just so many small things you need to take care of / think about.

still not quite running. I still need to:
- fill the diff with oil (the car isn't currently level)
- put a breather on the diff
- grease the u-joints (should have done that earlier...)
- check the pinion angle


when I was installing it I also installed the new ronin stage 1 camber links (you can see them in the above picture) and swapped my 450# rear springs for 600# rear springs.

Here is my current vent (90* 1/8" NPT to 3/8" barb):


in retrospec I probably should have just gotten something like this:
http://www.summitracing.com/parts/cur-ce-9028

I was going to plumb a 3/8" hope to a stud mount filter I have... but there really isn't any where good to mount it. So I'll probably just get a 3/8" clamp on hose run run that right off the diff. We'll see if it leaks at all.

 

I also installed the new automatic (2 kW) starter, it turns out the previous owner's SAE bolt "fix" was slightly smaller OD than it actually should have been so the threads in the transmission were still usable. I found a random M10x1.25 bolt and it torqued right up, no problem, so that was a relief.

No pictures, at this point in the night I was properly filthy and didn't want to touch my phone It looks like a starter installed in a car

 

Nice work! Another rotary guy will be going to this same setup soon.. He blew up his Turbo II diff at the track yesterday.

 

Thanks!

and in case anyone is curious why the diff looks like that, the rear cover was painted black when I got it, I attempted to wire brush it off, but the wire brush I had wasn't up to the task (I couldn't find my radial wire brush, I just had one like this)

I just decided to clean off all the tips of the fins and call it a day... I don't mind it.

 

I finished up everything last night.

So... I tried to drive the car to work today and it didn't go to well...

a ton of vibration combined with a grinding noise. I got about a 1/4 mile down the road and just turned around.

the vibration is hopefully just my pinion angle (which I didn't bother to check :-) ). I think I have my subframe link adjusted pretty short (for having solid subframe mounts) so hopefully that'll fix it....

I have no idea about the grinding. It could be something in the brakes. or maybe driveshaft flanges too close to the subframe I didn't have time to check it this morning + it was raining. hopefully it's not the freshly rebuilt diff....

sad panda...

 

I fixed it!

After actually setting the pinion angle it completely cured the vibration. (not surprisingly)

since the front flange is entirely not accessible with the driveshaft in (it's above the subframe) and you have to drop the diff to get the driveshaft out... I thought about it for a while and tried several things, and ended up just measuring the angle of the rear mounting flange. I'm not 100% sure if this is exactly identical to the front pinion flange, but it's close enough for it to fix my vibrations.

so the car is up and running, and I drove it to work today

but there is still a ton of gear noise....

I called the shop that built it, and he said he did it exactly to the spec and the gear pattern looked great. The owner of the shop even oversaw it because they were 5.14s...

so I'm just going to live with it for now, we'll see what the oil looks like after I put some miles on it.

Autocross this sunday!

 

I also got a hint of the new starter this morning.... it's pretty epic.

but I need to do this:
https://www.rx7club.com/3rd-generati...thread-771831/

relay mod to the starter solenoid so it actually gets 12V. I think this is most of my starting issues, and why sometimes it cranks slow and sometimes it cranks faster.

 

I wouldn't worry about the gear noise.

The noise is from how the front of the diff is mounted to the rear subframe.

Mazda used a very soft coupling between the diff nose and the subframe to soften diff vibrations to the chassis through the subframe and hung a huge rubber damper off the coupling/diff mount as well.

If I adjust my runner pinion snubber so it touches the top of the stock TII diff nose the stock Mazda rear end gear whine is very noticeable, so I have it with a slight gap so it just whines when I accelerate.

Congratulations, you just got a new race car noise.

 

that would explain a lot. Good info on the snubber. I should remove a washer from mine for this exact reason. However, everything else is solid as well so it may not work the same for me.

 

I'd also go around and check your grounds. Yes I know the starter is directly grounded to the transmission, but check to make sure that it grounds well to the chassis. You may even benefit more from a dedicated ground straight to the battery from the starter.