JNHEscher Posted January 30, 2014 Author Report Share Posted January 30, 2014 LostInTheWoods is no joke lol. I was replacing the fuel lines at the student driver lot last summer. Took me a while to figure my way around. There's a lot that I like here, but I've lived here all my life and am ready for a change. My wife and I have been pondering New Zealand. Quote Link to comment
KlassicMotion Posted January 30, 2014 Report Share Posted January 30, 2014 Yeah, change can be good. "New Zealand" eh, I too was pondering what life down there was like... Seems like the car scene is pretty hoppin'. Quote Link to comment
JNHEscher Posted January 30, 2014 Author Report Share Posted January 30, 2014 Yeah, change can be good. "New Zealand" eh, I too was pondering what life down there was like... Seems like the car scene is pretty hoppin'. Indeed. Some of the coolest ingenuity I've ever seen. And they take all the modern import motors to levels beyond anything in the states. Don't suppose you know of other fellow 620 owners in this area? I love how the Datsun community is always there to lend a hand. Wish I could come dig into projects, but it seems most are on the west coast. Quote Link to comment
GRpufnstuf Posted January 30, 2014 Report Share Posted January 30, 2014 There are a couple Kiwi members on this thread http://community.ratsun.net/topic/59475-shortbed-vs-longbed/ And they mention NZDatsun.com and "OS" as enthusiast websites (I think) Quote Link to comment
JNHEscher Posted January 30, 2014 Author Report Share Posted January 30, 2014 Shweet. The few who's threads I've read were in search of complete beds. They all seem to be flat beds there. Quote Link to comment
GRpufnstuf Posted January 30, 2014 Report Share Posted January 30, 2014 Yeah, if you move you should pack a bunch of long beds and maybe a few short to convert! Quote Link to comment
JNHEscher Posted January 30, 2014 Author Report Share Posted January 30, 2014 Yeah, if you move you should pack a bunch of long beds and maybe a few short to convert! I plan to have all the molds made for both beds by then. Perhaps they'll find carbon fiber beds enticing ;) Quote Link to comment
JNHEscher Posted January 30, 2014 Author Report Share Posted January 30, 2014 Suspicion confirmed. 4.375 driveshaft turns for one tire turn on the 620. Rear end swap will open the opportunity to put shorter tires on so that I get a little more drop and a little more clearance. My housing has "Pu" written on it, which leads me to believe that it too was a salvage yard replacement. Quote Link to comment
GRpufnstuf Posted January 30, 2014 Report Share Posted January 30, 2014 Looks like you're up under things already and maybe have the Trans in or are close... I'm just wondering about the different angle thing. As I understand it a Z tranny will bolt to an L engine but will be leaned over like 15deg or something? Have you planned a fix for this? Maybe just run it and bend up a shifter for it? Or maybe I'm wrong? Maybe I missed a post about it. I'll read back again Quote Link to comment
KlassicMotion Posted January 30, 2014 Report Share Posted January 30, 2014 He can swap the "bellhousings" and with some extra machine work, they will go together. Somewhere on here I've got a some pics of the one I did, plus other's have written about it. And no, unfortunately I don't personally know anyone in your area. :( Quote Link to comment
JNHEscher Posted January 30, 2014 Author Report Share Posted January 30, 2014 I believe the tilt is correct. Doesn't matter much, though. I can just bend the shifter and shape the trans mount. The Z motor sits verticle and L tilts. I presume the speedo gear in the five speed has the right ratio to match the 3.88 rear end. I'll swap the shifter base from my four speed since the five's is rusty. All the front was smashed in the 720 so a little rain would land in the shifter. Only a quarter cup of water was in the oil. Little rust on the speedo gear that I brushed off. All should be good. Quote Link to comment
KlassicMotion Posted January 30, 2014 Report Share Posted January 30, 2014 I would only worry about proper lubrication for the internals, but maybe the trans doesn't sit at as much of an angle as I'm thinking. Quote Link to comment
JNHEscher Posted January 30, 2014 Author Report Share Posted January 30, 2014 I think its more like 5-10°. If I'm imagining it correctly, the trans will tilt to the right if you're looking towards the front, which will raise the fill plug and allow the case to hold more oil. I'll know after dinner. Quote Link to comment
JNHEscher Posted January 31, 2014 Author Report Share Posted January 31, 2014 Dropped my trans and pulled it apart. Tried to pull the shifter rail arm off, but I was going to damage it. Just have to deal with rust. Got the cases put together, but the shifter wouldn't grab 5th/R. Pulled it back apart so I can dick with it in the light tomorrow. Something didn't seat quite right. Quote Link to comment
KlassicMotion Posted January 31, 2014 Report Share Posted January 31, 2014 Yeah, if your swapping front cases, you have to machine the 4spd case down.... I will see if I can find that thread. Quote Link to comment
KlassicMotion Posted January 31, 2014 Report Share Posted January 31, 2014 Found it: http://community.ratsun.net/topic/49396-240sx-5spd-behind-the-l-series-l16-l18-l20b/ Quote Link to comment
JNHEscher Posted January 31, 2014 Author Report Share Posted January 31, 2014 Good read. The 720 71C being an '81, it has the smaller bearing. My front case went on just fine. Sounds like I need to ream out the reverse/fifth shaft hole. That's probably what kept it from moving. I'd say I need to make clearance for the counter shaft cluster since I could hear teeth grazing the case a bit. Quote Link to comment
JNHEscher Posted January 31, 2014 Author Report Share Posted January 31, 2014 Some good news. Didn't have to shave any metal off. Gear noise was just dry teeth. Shafts all clear perfectly. The stuck shaft was just a bunch of crud stuck under the shift collar that wouldn't let it move. Cases and shifter are all together. All gears work except third. The shaft pulls back about 3mm and stops. The detent balls seem to get stuck and seize the shafts on these trannies. At least that what I've found on these two. Quote Link to comment
JNHEscher Posted February 1, 2014 Author Report Share Posted February 1, 2014 I'm guessing the machine work doesn't apply to the 720 to 620 swap. As datzenmike laid out in the beginning of my thread, all you need is to swap bells. Got it to pop into third and its in the truck. Tried the one piece shaft, but it bottomed out in the trans just before the axle and trans were level with each other. Kept the rear from dropping. Oh, and there was no tilt at all. In fact, just from glancing between the two bells, they looked identical. Quote Link to comment
KlassicMotion Posted February 1, 2014 Report Share Posted February 1, 2014 ..... Yeah, maybe I was thinking wrong. I've been doing that lately :confused: Now that I'm actually sitting here thinking about it.... that sounds likely. Sorry for the miss-lead on that one... :blush: Quote Link to comment
JNHEscher Posted February 1, 2014 Author Report Share Posted February 1, 2014 ..... Yeah, maybe I was thinking wrong. I've been doing that lately :confused: Now that I'm actually sitting here thinking about it.... that sounds likely. Sorry for the miss-lead on that one... :blush: Haha no worries. I'm glad I know what I need to if I ever delve into the other transmissions. I pulled some of the threads that I read when I first bought my truck. Didn't give them much thought because I wasn't planning so many small upgrades. I could have bolted the Z bell onto my L, but that it where the tilt would have came from. The input and counter shaft bearings holes are parallel in the Z bell because the Z motor sits straight up, keeping the trans straight. The L bell has a "twist" to allow the trans to sit up straight while the motor is tilted. Hence using the clocked L bell keeps the Z trans straight. We might be on the same page now xD Quote Link to comment
datzenmike Posted February 1, 2014 Report Share Posted February 1, 2014 L motors are 12 degrees tilt to the passenger side of vertical. Z series are about 8? degrees tilt to the driver's side of vertical.... they look pretty much straight up compared to the L. The difference is about 20 degrees which is way to much for using the wrong transmission. Good read. The 720 71C being an '81, it has the smaller bearing. My front case went on just fine. Sounds like I need to ream out the reverse/fifth shaft hole. That's probably what kept it from moving. I'd say I need to make clearance for the counter shaft cluster since I could hear teeth grazing the case a bit. The 720 only used the 71B transmission. The B and C refers to the shifter type used in them even though some very late B types had some C internal parts in them. The switch from the 56mm to the larger 62mm counter bearing is one of them and was introduced about '84/'85 on the 71B. The first C type transmission used was the first year 300zx (Z31) non turbo in '84. Next was the S12 and the D-21 in '86.5. Quote Link to comment
JNHEscher Posted February 1, 2014 Author Report Share Posted February 1, 2014 Ah, makes sense. Sounds like the truck swap is the easiest of them all. I was trying to hunt down the ratios, but kept coming up with several answers. Doesn't really matter now. Its bolted in and I have an overdrive. I'll test drive it and go from there. Quote Link to comment
datzenmike Posted February 1, 2014 Report Share Posted February 1, 2014 There are 3 internal ratio sets for the 71B. I call them wide medium and close. A wide ratio has a lower first gear for a heavy vehicle carrying it's maximum load and starting on a hillside grade. It's found in the '79 only 620 and '80 720 and all 4x4 720s. Because it is so low, 3.592 all the other gears are widely spaced and there is a big RPM drop between shifts. First gear is mostly used for starting from a stop so really a 3 speed with an extra low 1st gear for take offs. The middle ratio gear set has a 3.321 first gear and the other three are somewhat closer together with less RPM drop between shifts. This is used in heavier cars with larger motors like the 280z and the 810/Maxima, 720 trucks with Z24 motors or with already low differential ratio like a 4.375 in them like the '77-'78 620 and 720 2wd. A close ratio gear set with a 3.062 first gear allows all gears to be much closer together and even less RPM drop between shifts keeping the engine closer to it's power and torque making peak. This would be best in a car not subjected to heavy loads that are a strain on take offs and those with a larger displacement torque motor like the 280zx. Close ratio transmissions are slightly harder to get going from a stop and so are more comfortable on the move. First gear is much more usable at lower speeds than a wide ratio transmission first gear that is just too low. Quote Link to comment
JNHEscher Posted February 1, 2014 Author Report Share Posted February 1, 2014 From that, I would guess that I have the close ratio. The 720 is an 81 2wd with according to the tag a 3.889 rear. Swapping the rear kinda depends on whether or not my L20 has the power with the new ratios. Its a little sluggish. Quote Link to comment
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