Bringing Up the Rear Part V: I Love it When a Plan Comes Together

As you can tell from my last entry, the latest round of mods to my Z have been nothing short of ‘interesting’. Basically, it’s kicked our collective asses, and it’s taken alot of blood, sweat, tears, money and patience to have it all come together. But we rounded an important corner, and I think I can officially say that for the time being “I’m done!” (well, sorta).

A couple weeks ago, I took the 8 hour drive up to Buffalo to have Mike from Innovative Tuning finalize the Haltech tune. The car decently enough on the way up, no issues. The ride back was even better, firstly because I found a different way to go, saving me about an hour, and secondly because it was nice to be back in a car that was properly tuned.

Last weekend we decided it was time to tackle the 4.3 final drive install. I’ve written alot about this custom setup in previous entries. It’s been sitting here for probably 6 or 7 months now, just waiting. Of course, this seemingly simple swap was not without it’s drama. First, we had a helluva time getting 1 of the exhaust bolts out. After that was solved, the exhaust came down and we found something that we at the shop call “no bueno”. My midpipe was cracked almost all the way around, right where the resonator meets the piping section. In addition it was developing a second crack at the resonator itself. It had noticeable scrape marks on the underside from numerous incidents. Since the car is so low, stuff like this is inevitable. The exhaust has been in the car for probably 5 years now, so it wouldn’t be the end of the world. Except…it’s titanium. As some may know, welding titanium isn’t exactly like welding anything else. Takes some pretty specialized stuff, that we certainly don’t have here. A few phone calls later and I was hooked up with Joe from Accurate Welding. I immediately ran down there, midpipe in hand, and in no time, I was back on my way!

This is one of the great things about being in NY, and I’m sure other areas of the country too. Everything you can think of is literally a stones throw away. Today we had some spare time so we finished up the install. Unfortunately it’s been raining most of the day, so I haven’t actually had a chance to drive the car yet. Kwame did though, and his words went something like “HOLY SHIT THAT THING IS QUICK!” He was all smiles – I hope I am too!

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Mods Ahead

Organized the new round of bushings going into my car shortly

SPL solid rear differential bushings front/rear
NISMO rear upper control arm bushings
NISMO rear lower link bushing (aka spring bucket – inner)
NISMO Exhaust hangers
Whiteline urethane subframe bushings (traction kit)

Will be doing all this in conjunction with the 4.3/Quaife pumpkin – I hope to have it done in the next few weeks.

Right now, just waiting on my cluster to come back from Racepak with the latest firmware update (odometer…nice!). Will also be getting the USM module so I can integrate the fuel level sensor. Also picking up an oil temp sensor as well.

Bringing up the Rear Part IV

Just a few other pictures Ben sent over to me before it all gets sent to NY for install.

The ring gear is now installed on the LSD, and both were rebalanced – it’s now within 1/2 1000’s true – pretty good 🙂

One of the really tricky things when doing a ring and pinion install is setting spacing of the pinion relative to the ring. Since these are machined parts, there can be some differences in tolerances between one set and another. Shims are used to equalize things, so that the pinion has the right mesh pattern with the ring. This ensures that everything runs efficiently, without making noise, and without producing uncessary heat. You apply some paint to the ring and pinion and spin the assembly, and take note of where the 2 are meshing. When I sent this batch of stuff to Ben, I included a bunch of shims that we had laying around. Nissan sells 14 different size shims for these things, so it can be a bit arduous setting it up. The shims we sent down were close, as you can see from the pattern. Ben’s the consummate perfectionist though, and wrote me “as you can see from the pattern on the ring gear I have more adjusting to do. The pattern is acceptable in most shops but, not mine, I know it can be better. I will have to custom grind a shim about 8 to 10 thousands to get it to a standard I can be happy with”. Gotta love someone who only wants things a certain way when they leave his shop! When you’re out there picking an installer for anything as involved as a rear end, or a motor, etc, this is the sort of attention to detail you want. When that project leaves the shop’s doorstep, it’s essentially being signed off as being “perfect”. If something isn’t perfect, it comes back and bites you in the ass. Picking the right parts is important, but picking the right guy to make those parts work is essential. If anyone out there needs a terrific guy to set up their rear differential and/or ring and pinion, Ben @ PuddyMod Racing is your man!

Bringing up the Rear Part III

Things are nearing completion on the 4.3 final drive setup. Ben forwarded me some additional pics last night. We’ll have one more to share once we’re ready to install it. Here is a quick shot of the Quaife LSD I’m going to use, after being rebalanced. You usually don’t go this far, since time doesn’t allow for it and the parts are relatively well balanced from the factory. But since this thing has been a custom affair from day 1, Ben went the extra mile to rebalance the LSD. He also microfinished and cryo’d the ring and pinion gears. Should be back in my hands soon, then we get to swap it in and try it out – I can’t wait!

Bringing Up the Rear Part I: 4.3 Equipped Rear Differential in Progress

(Warning – this is a long one)

One of the weird projects I got started with on my 350Z has been installing a 4.3 ring and pinion. The car currently sports a 3.9 ring and pinion mated to a Cusco RS LSD (stock ring and pinion was 3.54 for manual transmssion cars). I figured the 4.3 would nicely compliment the high rpm’s that my engine turns (current redline is 8400), and give the car alot more punch all through the rev range, plus it would be another something to help set the car apart from the rest. It was only after acquiring all the parts that I realized just how difficult this would be!

I started by picking up a spare pumpkin and set to work on dismantling it. That proved to be easier said than done. I don’t know what this rear went through, but the pinion flange would not come off at all. We tried torches, freezing it then torching it, even a 20 ton press – it wouldn’t budge. Strike 1. If at first you don’t success, and the BFH doesn’t work, you go to plan B.

I was able to pick up a spare, empty pumpkin from my buddy Gio (who has a badass G35 coupe that we’ve featured before). With the spare pumpkin in hand, it was time to get to work on piecing this thing together. I decided this time we would try a Quaife LSD. I had a spare one at the shop that had been shipped to a customer but never used. See, he had an auto, and Quiafe mistakenly sent us one one for a manual car, which we sent to him. He tried to install it but it obviously wouldn’t work. So, we sent over the correct one and I decided to keep the returned unit for myself. It had never been used, and I figured I’d rather try it for my own car, rather than take a hit selling it. This took place before Quaife released their drop in differential for factory VLSD equipped cars, so the unit I am using is technically for a base model. No big deal though. A quick call to Nissan and I had the base model output shafts on their way, along with fresh bearings, seals, ring gear bolts – everything needed for the install.

So where was the problem? The ring and pinion itself! See, the 4.3 was sold as an upgrade for 240sx and naturally aspirated 300zx’s. I believe these originally came stock in the S13 180sx in Japan (someone correct me if I’m wrong). As it turns out, while these cars all used an R200 rear (350Z included), there are some differences. I knew this going in, I was just hoping it wouldn’t affect the swap. As it turns out, it did. The problem is basically 3 fold. First, the ring gear. The “old” R200’s use a smaller bolt vs newer R200 in the 350z. Thankfully the bolt hole spacing is the same, so acquiring the new bolts from Nissan easily solves this. The pinion issue is more difficult, and really required some out of the box thinking. First off, the pinion length is at least the same on the old vs new R200….thankfully, something went our way! The problem is that the old R200 uses a thinner diameter pinion shaft vs the later R200. This creates 2 issues. First, the rear pinion bearing for the Z won’t fit, and second, the flange for the driveshaft that goes on the end of the pinion is different. At this point, I decided I was in way over my head, and enlisted the help of an expert. Enter my buddy Ben from Puddymod Racing. Ben is widely known on the S2000 forums as the go to guy when it comes to rear end assembly. He’s meticulous when it comes to this stuff, and he knows the ins and outs of properly putting stuff together. Plus, he’s not afraid of funky projects such as this (his own S2000 runs a bit of an oddball setup). So I spoke to Ben at length about the hodgepodge of stuff we had, and he enthusiastically said to “ship it all down, we’ll make it work”. And off it went.

Fast forward a couple months and there is light at the end of the tunnel. Ben’s been tied up with his day to day stuff, and I’ve been going through the trials and tribulations of the now-abandoned ITB project. Ben contacted me today with some good news and a bit of a “how we did it”.

First, the bearing issue. You have a pumpkin that needs a pinion bearing with a specific outer diameter. The Nissan part for the job for the 350Z fulfills this need, but it’s inner diameter is too big for the pinion gear for the 4.3 setup. The pinion gear that would go with the 4.3 setup has the right inner diameter, but the wrong outer diameter. The solution? Sleeves. Basically what is done is your building up the surface of the pinion shaft so it will accept the larger inner diameter Nissan pinion bearing for the Z. Check the picture above and you’ll see the pinion being worked on.

Part of the process Ben is doing for me is not only deburring the ring and pinion, but also microfinishing them as well as cryo treating. Everything is fully blueprinted, so the tolerences are kept in check, just as you would do to a properly built engine.

The second issue is of course the flange. This is easier to solve but still needs some customization. I’ll post some pictures and details in the next installment.

The labor associated with this project is pretty insane. I’d say 20-30 hours when it’s all said and done…and that doesn’t include R&R of the pumpkin itself. As such, I don’t see it being a feasible thing for us to offer, unless someone has the right engine setup and deep pockets. y reason for going forward with it was pretty simple. I had already invested $ in spare pumpkin #1, and I had the Quaife differential. I had also purchased the ring and pinion from NISMO. At that point, I had already spent the $ on the hardware, that simply ditching it was not really an option.

Next up I’ll post some pics of the finished product, and go into a bit of detail on the pinion flange. This is going to be topped off with the SPL Solid Rear Differential Bushings …maybe even Whitelines Urethane rear subframe set too