oldschool90 Posted July 3, 2012 Report Share Posted July 3, 2012 So I'm in the process of putting in a C trans in my B case and I have some parts left over. All parts came off a 720 FS5W71B Z22 motor trans, all prices include shipping, and all prices negotiable. For sale: B series "mongrel box" gear setup. Comes with the input shaft (4th) (with bearing), 1st, 2nd, & 3rd gears, and the counter shaft (includes 50-something mm countershaft bearing). In the Mongrel box setup, 1st-3rd gears are closer to 4th, and 5th acts like a .745 O.D. gear. Taken from a thread I found: DatzenMike had a trans question about the tight spacing between 3rd and fourth on the Mongrel 5 speed (200 RPM difference) in Chapman, I was curious too and Chris was happy to answer. Trans gearing talk is a bit over my head, but I thought I'd share to keep it all in one place: Mike's question: "200 RPM? drop on the 3-4th shift? Most 4 and 5 speeds have a 24% change in RPMs into 4th. This would require a 3rd RPM of 840 to get a 200 RPM drop into 4th. Some competition boxes have a 12% drop so this would work out to about 1,700RPMs in third. Maybe he meant 2,000 RPM drop???" Chris's reply: When I was selling Chapman, my ad copy mentioned that the mongrel transmission had a very close 3-4 gear split. IIRC I think I said the RPM difference between the two was only 200 RPM. I'd like to explain. I combined two transmissions to get this mongrel tranny. I had a truck box with a .833 overdrive, and a 280ZX box with the .745 overdrive. I figured I'd put the .745OD fifth gear into the truck box. When I took the trannys apart, much to my surprise, both 5th gear sets were identical. Nissan manipulated some of their OD ratios by changing the input/layshaft ratios. I swapped input/layshaft gears fron the 280ZX box into the truck box, because I really wanted the .745OD for a long trip. The net result of this was to move gears 1, 2, & 3 closer to 4th. Looking at the truck & mongrel box numbers, the splits for 1, 2, 3 are the same, but the 3-4 split is 24% in the stock truck box, but only 15% in the mongrel box. See the linked images to see the numbers. I hope this explains things a little... Inside an actual gearbox: The gear count charts of the various boxes: Here's some vids I took to hopefully show the rpm drops in the gears, and rpms relative to speed. Here's one I took taking it kinda easy: http://s1023.photobu...ent=P1_0001.mp4 Here's the other I took with me driving more my style :D: http://s1023.photobu...¤t=P2.mp4 I don't have pics of it, but I'll get some tomorrow. Let's say $60, price includes shipping. If you have any more info, I'll be happy to help. Also for sale: B series bearing plate. Includes bearing plate, retainer plate, and screws. $25. Includes shipping. Like new B series syncros. $20 Includes shipping. (I'll get pics tomorrow) Used B series syncros. Pay shipping and they're yours. Pic comparing these (bottom) with a set of new ones (top): I have other little stuff off the B series trans, and also shift rods and forks and a few good bearings, so if you need something, just ask and I'll see if I have it. Also for sale: R1 carbs. Here's the ebay ad: http://www.ebay.com/...nc#ht_667wt_698 Scroll down to see the listing. I bought these to put on my truck, but realized that it'd be far more complicated than what I wanted it to be because of the z22 head design. $120. Includes shipping. Comes with the stacks. Here's a thread with others putting them on their Datsuns: http://community.rat...s-lots-of-pics/ Link to comment
oldschool90 Posted July 3, 2012 Author Report Share Posted July 3, 2012 Would also be willing to trade for any L motor stuff so I can make an LZ22/3. Link to comment
datzenmike Posted July 3, 2012 Report Share Posted July 3, 2012 Good stuff, love the videos. That 3rd to 4th is awesome at highway speeds, hardly any RPM drop, just keeps pulling. Those balk rings are almost $40 new. There is a third transmission with 21/32 input 1.523 ratio which uses the same 33/14 1st gears and changes it to 3.592. It's used in the earlier 4 speeds and the '79-'80 and all 720 4x4 and diesel transmissions. Just for fun I worked out what first gear would be if used on the zx 5 speed.... 1st is 3.701 and 5th is a mere 0.900 or 10% drop into 5th. Link to comment
oldschool90 Posted July 3, 2012 Author Report Share Posted July 3, 2012 Got a pic of the gears today: Link to comment
EricJB Posted July 4, 2012 Report Share Posted July 4, 2012 Oh man I hate you. I just got my gearbox together and working. Very cool, I'm a bit confused. Does 4th gear come off the countershaft on the later models?, because I dont remember it coming off mine. I thought the countershaft was one piece. Will this stuff go into an earlier box? Link to comment
Master-O-Turbonics Posted July 4, 2012 Report Share Posted July 4, 2012 4th gear is not a gear at all, It just links the input shaft to the output shaft for direct drive. The countershaft just "freewheels". Mike, is 3.701 the highest first gear ratio possible? I want to help raise the crawl ratio/maximize the SD22's power as much as possible in my truck and have a couple transmissions to steal parts off of... 81 720 4x4 long tail 4 speed 290,000 miles but shifts fine and nothing broken later 720 stubby 4x4 trans(not sure what year) 84 maxima gear set(input shaft failure, damaged the output shaft, but all gears other than input/counter gears look fine) 82ish SD22 5 speed in great shape I need to end up in the SD22 bellhousing and with the stubby output shaft and tail housing(hopefully) and the lowest possible 1st gear ratio. Wish I had access to a 18:32 input shaft set from a Vanette LOL Link to comment
datzenmike Posted July 4, 2012 Report Share Posted July 4, 2012 Actually I 'reverse engineered' here. I know that there is a 3.592 first gear ratio and an input of 21 and counter of 32 works out exactly. I have two of these transmissions apart in my 'shop' and will confirm the gear counts of 21/32. If these 21/32 sets are installed on an '80-'83 zx 5 speed like in the post above, first would be lowered to 3.700 and all the other gears spread out wider. Even the 5th overdrive would be lowered to only a 10% drop in RPMs. Link to comment
goonfan Posted July 4, 2012 Report Share Posted July 4, 2012 I like the gearing of that mongrel box. Have a link to that thread? If I had any idea what to do with those parts I'd be interested. Link to comment
oldschool90 Posted July 4, 2012 Author Report Share Posted July 4, 2012 Oh man I hate you. I just got my gearbox together and working. Very cool, I'm a bit confused. Does 4th gear come off the countershaft on the later models?, because I dont remember it coming off mine. I thought the countershaft was one piece. Will this stuff go into an earlier box? Here's a pic that datzenmike showed me a while ago that might help you: I like the gearing of that mongrel box. Have a link to that thread? If I had any idea what to do with those parts I'd be interested. http://community.ratsun.net/topic/26400-fischs-71-510-lz22-chapman-the-bonsai-bruiser/page__st__100__p__386260?do=findComment&comment=386260 You mean like how to install it? It's pretty straightforward, just a bit of a pita. I can give you a quick list of what you'd need to do to install it if want. The only special tools you'll need is a big-ass adjustable wrench, a pair of super heavy duty snap ring pliers, and a star bit for the adapter plate. Link to comment
goonfan Posted July 4, 2012 Report Share Posted July 4, 2012 Sure post the BOM. Don;t know if I'll take the plunge but maybe. Link to comment
EricJB Posted July 4, 2012 Report Share Posted July 4, 2012 4th gear is not a gear at all, It just links the input shaft to the output shaft for direct drive. The countershaft just "freewheels". I get that part. but the diagram shows the 4th (input gear ) being swapped out on the countershaft. Niether of mine are removable. Edit, Holy shit it does come off!!! It's my dead dogleg thats 1piece. Link to comment
goonfan Posted July 4, 2012 Report Share Posted July 4, 2012 If you wanna spoon feed.... Can you tell me what would gearing I would have with a 84' 200SX trans if I did the same swap to get the .745 OD I think this is the stock gearing 3.592 2.057/43% 1.361/34% 1/27% 0.813/19% Link to comment
oldschool90 Posted July 4, 2012 Author Report Share Posted July 4, 2012 I get that part. but the diagram shows the 4th (input gear ) being swapped out on the countershaft. Niether of mine are removable. Edit, Holy shit it does come off!!! It's my dead dogleg thats 1piece. 4th gear doesn't actually have gears for it. When you shift into 4th, it locks the input shaft to the mainshaft. Basically, 4th is like having a driveshaft attached from your engine to your diff. Here's a pic I made to show the power routes when you're in different gears: The input gearset is used to power 1st, 2nd, 3rd, & 5th. The countershaft is just along for the ride when you shift into 4th. Hope that explains it a bit better. :) Goonfan, I'll have to work on that list later, I have to head off to work in a few minutes. Link to comment
datzenmike Posted July 4, 2012 Report Share Posted July 4, 2012 If you wanna spoon feed.... Can you tell me what would gearing I would have with a 84' 200SX trans if I did the same swap to get the .745 OD I think this is the stock gearing 3.592 2.057/43% 1.361/34% 1/27% 0.813/19% Yes these are the CA18ET and the CA20E ratios for that year S12 200sx. If you swap the 280zx input and counter gears... that's these two gears... The very top shaft with the bearing and gear on the left side... and the matching gear on the shaft below it on the extreme left side. On the second shaft the bearing and the gear can be removed with a gear puller and hammered onto your counter shaft. This will give you the 'mongrel box' gearing. I have to warn you that if you have the CA18ET motor this isn't the best idea as the lower gearing in first is to get the turbo spooling up faster. On a CA20E motor it helps this small 2 liter engine move the heavy S12 200sx. Going to higher gears will make this car a pig to drive in town. Link to comment
goonfan Posted July 4, 2012 Report Share Posted July 4, 2012 Yeah, that's what I was thinking. I don't have the CA18, I've got an NA 2.8 w/ 3.90 rear. How do I sort out what a 200sx mongrel would end up with? I'm probably just missing something as I'm not that familiar with gear swaps. Link to comment
datzenmike Posted July 4, 2012 Report Share Posted July 4, 2012 Well I got out my diesel 5 speed, which has the 3.592 first ratio, (same as the CA powered S12 200sx) and sure enough it has a 21 input and 32 counter gear for a 1.52 initial ratio. Link to comment
datzenmike Posted July 4, 2012 Report Share Posted July 4, 2012 Ah I saw 200sx 5 speed and.... If you put the 23/29 input gears from an '81-'83 280zx (non turbo) into your '84 200sx 5 speed you will end up with the mongrel box ratios AND the 0.745 overdrive. This would be a great box for a larger 2.8 motor. Be sure to use the 56mm 280zx counter bearing that is just in front of the 32 tooth counter gear you are swapping. The '84 may have the larger 62mm bearing and it will not fit your L series 5 speed in your car. I have an '85 5 speed and it does have the larger 62mm bearing. Link to comment
oldschool90 Posted July 5, 2012 Author Report Share Posted July 5, 2012 On the second shaft the bearing and the gear can be removed with a gear puller and hammered onto your counter shaft. Just be ready to switch out the whole shaft if that doesn't work. I tried that when I got it for mine, but the puller couldn't do it. I don't know how much force a puller for that can exert, but when I took mine in my mechanic said it took 20 tons to pull it off. Still kinda busy at work and it being the 4th and all, so I probably won't be able to get to that list tonight. Link to comment
datzenmike Posted July 5, 2012 Report Share Posted July 5, 2012 The counter bearing is just a press on. The counter gear is splined as well. I used a two prong puller... it was tight but came off. Link to comment
goonfan Posted July 5, 2012 Report Share Posted July 5, 2012 Oh cool. Sounds like I wouldn't have the machine the retaining plate of my bellhousing to fir the 84' if I don't want to. Here's one more question, and it my be a dumb one. Could I swap the gears out to change the 1-2 drop? If there was a way to do that I'd be pretty pumped about it. I'd have my own mongrel "C/R" 5 speed. That would really make my Z a lot more fun to drive.... When it's on the road, lol. Link to comment
datzenmike Posted July 5, 2012 Report Share Posted July 5, 2012 There are no stupid questions...... ok there are, but this isn't one of them. Questions get people thinking and info gets passed around. On the mongrel box just above... the counter shaft with the 28 20 14 gears is all one piece and would have to be completely changed to another. The gears above it are all separate but they have to match and mesh with the counter shaft below. Besides, it you move second gear closer to 1st you widen the jump between 2nd and 3rd now. For the 71B it looks like there are two gear sets used and three input sets giving a wide, mid and close ratio transmission. There are Nismo competition boxes with even closer ratios . Link to comment
goonfan Posted July 5, 2012 Report Share Posted July 5, 2012 See that's why I asked.... I knew it would change the whole thing but did'nt know by how much.... what I didn't get my head around is the the counter shaft is where the 28-20-14 were coming from and that they were basiaclly a unit. I was hoping something like 2.9, 1.8, 1.71, 1, .74 was doable Link to comment
datzenmike Posted July 5, 2012 Report Share Posted July 5, 2012 Just noticed that the 3rd and 2nd gears are the same 28 tooth while the counter gears below are 27 and 19. I see a note below that says 1st and 2nd are course pitch teeth. This now makes more sense. Link to comment
datzenmike Posted July 5, 2012 Report Share Posted July 5, 2012 I was hoping something like 2.9, 1.8, 1.71, 1, .74 was doable Something wrong here.... 2.9 1.8........... 38% 1.71......... 05% 1.0........... 41% 0.745....... 25.5% Probably a wrong 3rd gear written down. There is a Nismo competition gear set that is... 2.906 1.902... 34% 1.308... 31% 1.000... 24% 0.864... 14%.... much better. Link to comment
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