Spiff Posted March 27, 2018 Report Share Posted March 27, 2018 I have a C200 with a lsd I'm putting in my 720, only thing is it's from a diesel so it's geared way to low(4.875) for my Z20 turbo. So I got a 3.9 gear set from a s14 r200 but what should I do now? Just press off the bearings, put the c200 bearing on the r200 pinion and check/adjust pinion height? Pinions appear to be the same dimension but the preload spacer and also the bearings are slightly different. Quote Link to comment
wayno Posted March 28, 2018 Report Share Posted March 28, 2018 The Nissan dealer told me that the best gearing to be had in a C200 is 4.11 gears, they only came with 4.3 and 4.6 gears, but now you say you have a 4.8 gears, I have never seen that ratio, but i never asked about going that direction, I wanted better freeway gears for my 720 turbodiesel, so what I did was have adapters made to fit my dually wheels to a H190 rear axle with 3.3 gears, and my 521 kingcab turbodiesel also has an LSD H190 with 3.5 gears I found in a Hardbody. There ls likely aftermarket gears that will fit your C200 with the ratio you want, but they are to spendy for me. Maybe some one else on here has done this, hopefully they will respond. Quote Link to comment
datzenmike Posted March 28, 2018 Report Share Posted March 28, 2018 You sure it's 4.875? Diesels are torque engines and not revers. Usually they are below 4. Look on the outer edge of the ring gear for some numbers stamped there like 39:8 = 4.875 37:8 = 4.625 35:8 = 4.375 37:9 = 4.11 35:9 = 3.889 37:10 = 3.70 4.875 would work with 33" mudder tires and a diesel. Quote Link to comment
Spiff Posted March 28, 2018 Author Report Share Posted March 28, 2018 yup, 39:8 is the stamping on the crown wheel and pinion. It's from a 720 diesel 4x4. My current H190 is a 4.6, which I guess it needed with a mere 60hp J16 engine. I guess the equally gutless SD engine needs some low gearing to get going as well... It's any way to low for me now that I have the z20 with turbo and a 5 speed gearbox. 1st gear is pretty much useless and the engine is sitting at almost 3000rpm at highway speed. I would prefer a 3.5 or a 3.7 but they're not as common over here as the s13/14 200sx 3.9 Quote Link to comment
datzenmike Posted March 28, 2018 Report Share Posted March 28, 2018 We didn't get any diesel 4x4s in the 720, all gas engines and 4 or 5 speeds only. Quote Link to comment
wayno Posted March 28, 2018 Report Share Posted March 28, 2018 The SD22 diesels came to this country with 3.9 gears in the rear, they have the torque to move them, but they do not have the HP to move them down the freeway faster than 60mph without suffering major fuel economy loss, the best I got was 27/28mpg on the freeway going 70mph, and when I got to a hill I had to drop gears, one time I ended up in 2nd gear. I now have SD25 engines and drove them for years in the stock configuration, still only got around 27/28mpg but I was going 75/80mph(level ground), since then I turbocharged both my SD25 diesel engines, my 521 diesel with 3.5 gears will do 75/80mph all day long and still get 31mpg, it has gone up every hill so far without dropping speed or down shifting, and my EGTs are mostly good(under 1000 degrees), although when pushing it up a hill when it was stinking hot outside I have seen slightly over 1200 degrees, I have no inter-cooler in that truck. I now have lots of power, in both trucks, but the 720 even with 3.3 gears in the rear don't like going any faster than 60mph, I think it because the former owner had the injection pump turned up, that truck has a shitload of torque, I temporarily turned it into my work truck while the 521 work truck was being worked on. The distributorguy would likely know what to do to fit the 390 ring/pinion into the C200 if it is possible, but I am not sure if he reads these types of threads. Quote Link to comment
G-Duax Posted March 28, 2018 Report Share Posted March 28, 2018 Will the gears from an R200 even fit the C200 ? Quote Link to comment
Roadster-ka Posted March 28, 2018 Report Share Posted March 28, 2018 Pinion shaft should be too long. Can't imagine using that gear set. Quote Link to comment
Spiff Posted March 28, 2018 Author Report Share Posted March 28, 2018 Will the gears from an R200 even fit the C200 ? yes. r200 crownwheel in the c200 Pinion shaft should be too long. Can't imagine using that gear set. No they're the exact same length, and diameter. Shortnose r200. Did some measuring. The only difference is the preload spacer as you can see, and the outer diameter of the r200 bearing is slightly bigger than the c200. So I need to use the c200 bearing. I'm wondering more about what preload spacer to use, the r200 is a chunky item and the c200 looks more like a crush sleeve type, thin walled and like its a one time use and then throw away. And here's an r200 on a c200 axle Quote Link to comment
G-Duax Posted March 28, 2018 Report Share Posted March 28, 2018 If you have access to the R200 pinion shaft shims, go with it by all means. This is interesting. I used an R200 pinion spacer in my H190. I would definitely go through the work of putting a C200 axle assembly in, if I can find another 29 spline R200 Xebec helical LSD. Quote Link to comment
Spiff Posted March 28, 2018 Author Report Share Posted March 28, 2018 This is a clutch style lsd, the carrier has 10mm bolt holes so I need to drill them out since the r200 crown wheel uses the 12 mm bolts. The axle is from a 4x4 though so I need to cut of the mounts and fab new ones to mount it over the leaf springs. Quote Link to comment
G-Duax Posted March 28, 2018 Report Share Posted March 28, 2018 Yup, not a big job to drill the holes out. Have done it a few times. 1) Make sure you drill the holes a tad oversize, as a machined hole is never drilled to the exact size of the bolt that is to be used in it. 2) Be sure to chamfer the holes, especially on the head side, so that the radius from the bolt shank to the head doesn't contact the edge of the hole, as it will lead to bolt failure. Just wondering if there will be any gear offset problems. But you will find out.... Quote Link to comment
Spiff Posted March 29, 2018 Author Report Share Posted March 29, 2018 Great! Thanks for the heads up. I got help pressing off the pinion bearings last night and got them swapped. I measured the pinion height spacers before I put them back on and turns out they where the same thickness also. Gonna try and mount it all up today Quote Link to comment
Spiff Posted March 29, 2018 Author Report Share Posted March 29, 2018 So I put the pinion back in, and tried to put the carrier back in, but because the crownwheel was thicker and the pinion teeth where wider this pushes the carrier more over to the left(or right in the picture) so the stock shims won't work. What's the best way to figure out what shims you need? Quote Link to comment
G-Duax Posted March 29, 2018 Report Share Posted March 29, 2018 Take the ring gear side pinion out completely, set the diff back in the carrier with the crown up tight to the pinion, and use a feeler gauge set to find a close thickness of what spacer you need. But beware, people like me who set up a lot of rear ends, usually have a full selection of shims on hand to do the final fitting. Without having them is frustrating, having to run back to the dealer to pick up another shim to try. Sometimes it's best just to carry the whole thing to a dealer, who has the selection to have the gears set. Did you actually measure the pinion depth, or did you just throw it in, with what ever shim it had on it? Quote Link to comment
Spiff Posted March 30, 2018 Author Report Share Posted March 30, 2018 Yeah I've realised that and have decided to give up for now, I don't have the tools or the equipment to do this correctly. So I'm gonna call a few different shops after easter so it'll be done right. Quote Link to comment
G-Duax Posted March 30, 2018 Report Share Posted March 30, 2018 I've turned the shoulder on the diff down a few millimeters before, so the bearing will slide on further. You can find the pinion depth in any factory service manual for what those gears came out of. It typically is measured from the nose of the gear, to the center line of the diff/axles. If the pinion is sticking too much toward the diff, that effects the location of the crown wheel. Quote Link to comment
wayno Posted March 30, 2018 Report Share Posted March 30, 2018 I keep coming back to what the Nissan dealer told me, 4.11 gears was the best to be had from Nissan in a C200, that makes me think that nothing from Nissan is going to fit and work properly without major modifications unless Nissan made a thinner ring gear but then they would likely have known that, at least an old timer would have. But again I mention there are aftermarket ring/pinions that I read about on another thread that had a link, but I do not remember the thread, I do remember there were not a lot of choices in that link for the C200. Has anyone replying in this thread ever put 3.90 gears into a C200 axle before? Quote Link to comment
noramost Posted April 2, 2018 Report Share Posted April 2, 2018 I agree 4:11 is my favorite. I used a 4:10 punkin out of a 810 automatic and run a 225 tire to get about what I want on my D21 but know this; a perfect diff gear backed up with less than perfect trans gears = having to shift 1/2 way across the intersection. Toyota has perfect gearing, Nissan the worst but I still prefer the Nissan's. Datsun gears way too high and when you add power to the L it gives you top-end power and you have to use a lower gear too bring it down to usable street power. I remember when I was working at the Nissan Dealers and you asked me about the perfect diff gear.This is only true for an inline long stroke motor, short stroke V's different. Quote Link to comment
Spiff Posted April 3, 2018 Author Report Share Posted April 3, 2018 The 3.9 is what my transmission was originally mated to(a 910 bluebird), so by swapping in a 3.9 I'll get an accurate speedometer reading and best of all a better gearing with more useable power. Higher gearing will mean I can stay on boost longer, I'll actually get a useable 1st gear(now it's worthless, might as well start off in 2nd) and around town the car will be better to drive, right now I'm either running high revs in 2nd to keep up with the speed limit or lugging it in 3rd. I definately feel you about shifting half-way through intersections, that's how it is now. Anyways I talked to a shop today and they where confident this shouldn't be a problem to fit, so I'm going up there friday with the entire axle. Quote Link to comment
Spiff Posted June 5, 2018 Author Report Share Posted June 5, 2018 I got it back from the shop now only need to fit the axles and disc brakes. But I have these rust holes in both my axles and on the parts diagram it's referred to as "grease catcher". So I guess if I just run it like this I can risk dirt entering the wheel bearings and/or grease to fly out of it? Quote Link to comment
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