What transmission and differential are you running?

 

F body T56, currently running a Getrag rear end out of a CTS-V, but a Ford 8.8 is about to go in.

 

CTS-V rear about to depart this world?

 

it’s been noisy and clunky since day one… I’ve had two of them in there, a 3.73 that I bought brand new, and since then a 3.23 that I bought out of a junkyard. Even the one that started out brand new made a **** ton of noise.

So that’s the first thing that bugged me, the noise. The other thing that bugs me is that you can’t get them any more, and nobody can repair them, they’re put together really strangely.

The Ford rear end is cheap, and available anywhere. Parts are also available anywhere and everybody knows how to build them.

 

Mike, you have to put gear oil in them.
C'mon, you laughed.
Did you get a ford rear?

 

Yes, I got a 3.08 to replace the Getrag 3.23, but it's not going in until after summer. This is a convertible, summers are for driving the car, not working on it. Especially here in the Seattle area. :-)

 

Hey,

been watching your thread for some time.. I have a mostly running LS3 NA miata as well. you drive yours quite a bit more than me, and mine is currently in its second year of living. I have a 3.72 with a 8.8. i have replaced the axle seals twice now in 1500 miles and my drivers side is still leaking. this seems to be semi-common issue. i will be keeping an eye to see how your upgrade goes.

 

I replaced the axle seals on this one (sourced from a junkyard) when I put it in. Started leaking after a while. Put in two new seals. Still leaking. So then I started paying attention ...

I found several gouges in the aluminum case that I presume were caused by the seal removal tool, even though I **thought** I was just hooking the seal. I sanded the rough edges off of the gouges, and put a *tiny* smidge of black RTV in them. Then, while that was still wet, I installed the seals, with a *tiny* bead of black RTV around the circumference of the seal where the metal part seats on the differential case.

No leaks since.

 

Oops, just noticed you’re talking about an 8.8. If you have an aluminum case, I suppose you may have the same issue.

I got a cast iron case 8.8.

 

mine is the aluminum case. googling around it seems to be a not uncommon issue with leaks coming out of the axle to seal interface. i am starting to wonder if my issue is the axle bearing allowing too much play for the seal to work, or possible axle to bearing/seal diameter wrong. anyways i wish you luck as its not so fun to have axle oil flung over the back of the car/exhaust.

 

Good progress

 

Dude, that pic was FIVE years ago!
Troll elsewhere, please....

 

The car currently isn't running. Needs a starter, therefore needs engine out (this is the only "normal" maintenance job that can't be done with the engine in the car). Well, that and the clutch, which is also engine out. The LS in this car is like a ship in a bottle. I have done some work to make "engine out" less painful ... it's probably about 6-8 hours of actual work in each direction. I’m retired, I don’t have to fit it in around working. 🙂

Anyway, other stuff besides the starter is in the works. I have the 8.8 rearend and all the associated parts ready to go in, I have a digital dash ready to go in (so the tach will keep up with the engine, and I'll have shift lights across the top of it). Also, a complete set of spherical bearings is going into the suspension. No binding, and hopefully will lose the creaking noise that the delrin bushings create when they’re warm.

The big change will be the new engine. A buddy tracks his SBE LS3 *very* hard, and just put a rod through the block. So apparently, "7500 rpm all day" isn't necessarily true for a SBE LS3 on track... and this car will see the track now and then. I decided I wanted a forged bottom end in mine. I also wanted an extended rev range. So ...

Tony Mamo and Scott (Che70velle) are working together to build me a new engine. It will be 4.155x3.75 (406 cid) with a fairly mild cam (231/245 115+3) and ~11.25:1 SCR. Sleeved aluminum block. I dropped the CR a bit from my current 11.8:1 SCR because I feel like I might be better off with a bit less compression and a bit more timing (or at least, timing margin). MMS 26X rectangular port heads. FAST 102 with mid-length runners to extend the top end a bit. I know this gives up some mid range torque, and IDGAF... my car weighs 2400#. If it was up to me, this would have been done on a stock stroke, but Tony was hesitant to run these heads on a stock displacement LS3, so I let him talk me into a minor increase in stroke, and thus displacement. I will still likely be handicapped a bit by the exhaust that I can fit in this car ... 1-3/4” primaries, and 2-1/2" pipes once past the transmission crossmember. I **may** be able to sneak a full length 3" exhaust in there, but I'm not counting on it.

The current engine will be for sale at some point.

It may be a while before it's running again, I am currently working on an '89 Toyota MR2 that belongs to a friend. As it turns out, I shouldn't have signed up for this. It's taking waaayyyy too long. So I made myself a rule that I can't work on the Miata until the MR2 is out of here. I expect to be working on the Miata in early Spring.


Getting ready to stick the built (forged pistons, rods, crank, mild cam) engine and 6 speed transaxle (5 speed is stock) back into the MR2.

 

The new engine got here today … it will be a while before I get to it.

 

I’ve seen that somewhere before…glad it made it Mike. Gonna be a freaking rocket!

 

What are the specs of that motor? Sorry if I missed it earlier in the thread

 

Look three posts up.