Diesel 5 Speed Alternative Discussion
started by Daryl Smith
Published 2014 Updated 2021
I have read where a couple of people have adapted a Z 5spd to a roadster.
After checking into this I find that the Nissan 5spds (other than the roadster) have a one piece bell/gear housing like our 4 speeds. Same as the 4 speeds in the Z's. ????
So.... 1. Where did the bell housing come from that they used to mount the Roadster 5 speed to the L series engine?
2. How have these people adapted the Z/SX tranny to a roadster? Cut and weld?
3. Is there another 5 spd that can work in the roadster? From an "A" series engine maybe?
Confused
Uno, you've got the "gears" turning in my head on this one. I dug out my How to Modify Datsun 510, 610, 240z Engine and Chassis book and here is a partial answer to your queries;
The roadster 5 speed can hooked up to an L series engine by using an early Z bell housing, 5 speed tranny mount and the correct drive shaft....this is for the Datsun 510.
The early Z trannys had a separate bell housing. The later ones had an integral case.
You can put a Roadster 5 speed in a Z but you will need a; Z bell housing, a new tail housing, a new main shaft, and the correct five-speed drive shaft for the model you are converting. The transmission must be disassembled completely to allow installing the new main shaft. A pain the butt, if you ask me.
I'll add this paragraph, quoted directly from this book, to confuse all of us even further....."In case you do some of your parts buying in wrecking yards, you might like to know the bell housing sections of a Z four-speed and five-speed are identical--while that of the SRL311 2000 (two-liter) roadster are different. This is because the 2000 is a U-Series engine with the starter on the opposite side. The center section (actual gearbox) of all five-speeds (except as supplied in late '72 and later Z's) is the same. The tail shaft housing for the SRL 311 and the 510 are alike; that of the Z is longer."
Remember that this book was written in 1973, contemporary to the times, and I'd bet that finding parts to do any of this is problematic. I was initially intrigued that a newer synchro Z tranny could be bolted up behind our Roadster bell housing. It would appear though that since the center section of the early Z and the Roadster 5 speeds are the Servo Synchro style (very pricey to repair versus the later Borg-Warner single-brass-cone-synchro-system-tranny of the Roadsters and perhaps the Z cars with their integral bell housings) that we are doomed to suffer along with what we have.
Given what I've said here, I still love Datsuns. Many parts between models are interchangeable and modifiable, but just like an Egyptology, you must be able to decipher the hieroglyphics....
Okay, after some discussion on the Roadster Mailing List (It is STILL a fantastic resource, a lot of knowledge over there to benefit from! And a lot of nice folks too!), some comments were made regarding diesel truck transmissions. Thanks to Ron Hamilton, Stan Chernoff, and slowboy for the info.
I went to the wreckers and was able to locate and buy one (81 - 83 Datsun Diesel P/U).
I now have a diesel truck tranny to go with the forklift motor in my sports car!!
From looking at it I am sure it will bolt up to our cars. I will not be able to actually try it for a week or so. but it looks like a keeper. This is the same basic transmission that was used in the 200SX, 280Z & ZX, and in the 300ZX as well as almost all the pickups, and the 240SX. The difference is in the bell housing on the diesel which moves the starter to the drivers side for our cars. A few points from visual inspection and little info I have been told (this is yet to be rock solid confirmed):
1. Same length as 4 speed, looks like same shifter position. There are different tail shaft lengths, so this should be able to be different if required for a 5spd roadster.
2. Transmission mount is about 2" further back.
3. Speedometer connection is further back, and on the opposite side
4. It is a very nice shifting transmission, and I'm told quite robust.
5. The 1600 drive shaft just slides right in.
The only things I can see that need modifications right now, are the transmission mount, and the speedometer connection. I will make an update as soon as I am able to finish the install.
Hope some of you can benefit from this info.
One last thing: **NOT CONFIRMED** I believe I read somewhere that the front half of this series of transmission is the same, whether a 4 speed or 5spd. SO..IF there was a diesel sold with a 4spd, and that is all you can find, you MAY be able to mate it with a 5spd back half. ***MAYBE*** I have not been able to find any info specific to the diesel trucks at all, so there is some home work for someone else to do......
I have taken some pictures of the transmission beside a roadster 4spd for comparison, but being somewhat of a computer idiot, I can't figure out how to put them up. email me and I will forward them to you.
Update.
I picked up a low mileage (135,000KMS-84,000miles) 1990, 240SX transmission because I wasn't sure about the ratios in the truck tranny, and the newer shifting mechanism is supposed to be better.
Comparing them, the 240 tranny is longer. BUT I got a tape measure out to measure the actual shifter position and the 240 transmission. looks to be exactly the same as the roadster @ ~31.5" from the front face of the bell housing to the center of the shifter. The truck shifter position is actually about 2" shorter. I never noticed the difference between the roadster and truck because the roadster shift mechanism is missing the pin and was flopped forward, when put in it's proper place it actually hangs out past the end of the tranny.
I have been told by the transmission mechanic that the two bell housings can be swapped. Won't know for sure till next week.
Using the 240/truck combination may require shortening the drive shaft.
Okay, so if I have this straight (from Victor's email below), there are potentially TWO slightly different transmissions on the diesels that we could use:
1. FS5W71B - 1981 to 1985(? maybe earlier?) diesel p/u - which is the one I have. Same length as the roadster 4spd, but shifter 2 1/2" forward. Could probably cut and weld a piece on the shifter itself to move the shifter back to useable position. 1600 drive shaft would slide right in. Unknown ratios at this point. I put a 1600 backing plate up against it and all the important holes line up. The bell housing portion of this transmission requires only slight modifications to bolt up to the newer FS5W71C (email, link below) A Nissan dealership in the area could not find a price on the bell housing so may be NLA. Part # 32101-E916Z (from 32101-E911Z)
- I have read that the 4 speed bell housing (of this series of transmission) is identical and could POSSIBLY(?) be swapped/modified for use.***
2. FS5W71C - 1986 to 1988 diesel P/U (?) - This transmission (different bell housing) was used in 240SX/200SX/300ZX/Van/pickups - 1986 to 1996(?) I have not seen one of these (diesel) yet. On a lark I phoned the dealership and the bell housing is available out of Japan for $673.00 (Canadian). I don't know if it will work (haven't seen one), but chances are good (if it is used on the same diesel engines). This transmission (from other than diesel) will work with a modified "B" bell housing. It is longer than the "B" so shortening the drive shaft would be required. Part # 32101-10G76 (from 32101-10G68)
Transmission mount modifications would be required with either transmission.
My install is a ways away yet. If you know any of this info to be incorrect please let me/list know. Also if you come across a "C" transmission (diesel), I would appreciate knowing (rather than speculating) if it would work.
Thanks Daryl
Original Message -----
From: Victor Laury Sent: Saturday, July 23, 2005 9:42 AM Subject: Re: Diesel Truck/KA(240SX)
>I have been told by the transmission mechanic that the two bell housings can be swapped. Won't know for sure till next week.
Yes it can. I saw the photos of your gear box today and found out I was mistaken. It's a FS5W71B gearbox and not the FS5W71C that I first thought. The front cases of these boxes can be swapped, with a minimal bit of machining in the counter shaft bearing pocket.
Also from Victor: 1970-74 models use an F4W63 4-speed transmission.
1975-83 models use an F4W71B 4-speed transmission. or an optional FS5W71B 5-speed transmission.
1984-86 models (720-D series) also use the FS5W71B 5-speed transmission
1986-87 models (D21-D series) with the Z24i or SD25 engines use an FS5W71C 5-speed transmission, while 1988 models use an F4W71C 4-speed transmission or the FS5W71C 5-speed transmission.
1986-88 models with the VG30i engines use an FS5R30A 5-speed transmission.
For those that may be following this thread, I am going ahead with trying to combine the above transmissions for my roadster. FS5w71B Diesel bell housing with the rest being 240SX (FS5W71C). Will post results and "how to" when I complete sections of the build.
Okay. The transmission is built, and bolted to my stroker engine in the car.
I took lots of pictures so there will be a write up soon, but I have to finish putting the car together and take it for a drive first.
How long should it take to bolt the body down, attach all the wiring, install manifolds, carbs, rad etc in engine compartment, and install dash (mostly wired already) after Classic Instrument gauge refit?
Hopefully soon.
Found a couple of truck manuals at a Nissan dealership and thought I would post this in case it helps anyone.
For 1984 &'85 the diesel truck 2wd 5 speed ratios were: 1st - 3.592:1 2nd - 2.057:1 3rd - 1.361:1 4th - 1.000:1 5th - 0.813:1
For same year Gasoline 2wd trucks: 1st - 3.321:1 2nd - 1.902:1 3rd - 1.308:1 4th - 1.00:1 5th - 0.833:1
Both are the FS5W71B transmissions mentioned earlier in this thread.
Cheers
Easiest solution: Put in the 2000 5 speed.
But you have choices. The 260/280 5spd and the 240SX 5spd can be made to work using a diesel p/u bell housing (or the whole transmission....). The 260/280 would be next easiest (less mods required) than the 240SX. I guess this "may" vary depending on whether you find a diesel p/u with a "B" or "C" (?)style transmission.
I used the diesel bell housing to fit a 240SX 5spd into my '66, but I had to:
1. Do some machine work inside the bell housing 2. Cut and weld the frame to make it fit (your install may differ) 3. Cut a chunk of "webbing" on the side of the bell housing to clear the body on the drivers side. 4. Shorten the drive shaft.
This required that I remove the body from the frame (not that hard) and takes some time and somebody with fabricating/welding skills.
I have yet to drive the car as I haven't sorted the new engine, but hopefully very soon.
Also a "mikew" in Australia has a 260Z trans mounted:
http://www.311s.org/phpBB3/viewtopic.php?p=15520
I am a little behind on the writeup I promised the list but, have lots of pictures. If anyone would like a few let me know and I'll try to put some together in some sort of order.
Speaking of gear ratios, the stock 240SX overdrive is a tall .759
I was worried my little 1800 would not have the torque for that so had it changed at the tranny shop while they had it apart.
Put in a .833 @ $95.
A couple of pics of the trannies: 1st two pictures to compare Spl 4 spd with diesel 5 spd.
cut/weld required to mount diesel/240SX transmission
Fitting diesel/240SX transmission
Update on the shifter:
The 240SX transmission shifter position is slightly toward the back of center of the '66 shifter cutout in the body. And the 240SX shifter is angled back by 30* or more also, which means it hits the back edge of the cutout..... :x I cut some of the tunnel away but really didn't like that solution, I picked up a shifter from an '86 200SX which is straighter, and the same style transmission, but the pieces are slightly different and won't just bolt in..... :evil:
So..... I turned the shifter around so the angle is facing forward! Works perfect! Shifting position is good and you hardly notice the angle. :D
At least,.... so far,.... in the carport,......Still waiting on my exhaust before I can tune the EFI and start driving again....... :cry:
Now I have to find some sort of gearshift boot setup......Any suggestions?
Dave Brisco Get a boot for a Dodge Dart/duster..Oval, right size.
Otherwise, Hurst had a good assortment last time I looked.
Now that it works, send one to Will, if it survives, it's the ultimate trans swap.
I have 3 - 400 miles on this tranny now, the last outing was December 8th, for 4 or 5 hours with lots of runs through the gears, and a highway run where we hit 95 mph (according to my non-calibrated electronic speedometer). I am very happy with the way the tranny shifts :D , and the ratios seem very good for everyday driving with this engine (1800)/rear diff (3.9)/ tire (185/65/15) combo.
Reading the other transmission thread reminded me that I hadn't posted some of the swap info, so here is what I had/did at the clutch end of the swap.....wish I'd kept better track of parts....... :smt017
1) Throw Out Bearing: I used the U20 bearing supplied with the clutch kit. Both the diesel and 240SX bearings will fit on the mount/slider (don't know the proper name for this part). Are there any advantages/disadvantages to using one of the newer, larger bearings??
2) Bearing Mount/Slider: I ended up with 4 different Nissan pieces - Roadster 1600, 240SX, diesel, and one unknown. Unfortunately, I didn't keep them separate/labeled and don't know which I used..
3) Flex Plate: I used the 1600 plate. Using a yardstick for a straightedge and a measuring tape to measure the distance out from the transmission housing to the end of the taper of the clutch spline on the main shaft, it was very close, but looked like it would work without binding on the crankshaft. So Far, No problems. A U20 flex plate is significantly thicker, and may be a better solution. Someone with better measuring tools/experience would be able to give a better answer to this query.
4) Fork / Pivot: Again I had several of these on hand from the different transmissions and when the roadster or diesel parts didn't fit, I mixed and matched to get everything to work properly. Sorry, again, I didn't keep track of the parts used.
So....I guess if you are going to do this swap, you may want to have some different parts on hand to make it work.........
I came across a 1980 280ZX at Ralph's auto wreckers on Scott Road in Surrey today. This has the FS5W71B transmission. It can easily be mated with the Diesel tranny front half to adapt for a roadster. The reason I bring this up is, according to notes I've been given, the lower ratios are very close to the stock U20 5spd ratios with 5th being a good bit higher. 3.062 1.858 1.308 1.000 0.773 With this transmission, you could run a 4.11 rear for good acceleration for autocross etc, and still have good legs for the highway, keeping the rpm down.
Running the #s I get 2760 rpm @ 60 mph in 5th with a 4.11 rear and 195/60/14 tires...........
I always find Ralph's a little pricey tho. They want $300 for the tranny. Don't know if or how well they will take to bargaining.......
Random Datsun Transmission info:
Seems there was another 5 speed used with the L series engines - FS5W63A. I have been reading that these were referred to as a 'dogleg' transmission. I am wondering if the FS5W71B came in a dogleg version at all, and possibly if you pick up a 'dogleg' tranny, the diesel bell housing may not fit! However, it may be possible(?) to swap in an A series bell housing??? if the a series matches with the R/U engines....just saying .......haven't had a look/compared the bolt patterns.....
From nicoclub.com forum: FS5C63A: That's the L-series dogleg. Came in both L-series and NAPS-Z type front housings. The L-series ones are more common as the 200SX '77-79 had it almost in every car. The '77 710 and the '78-79 510 had it as an option on everything but the Wagon. The NAPS-Z version was only used as an option on '80-81 510s and was very uncommon. In '81 they even tried the 60L below. Bad move...
FS5C60L: Another dogleg, used on some late '81 510s but usually used on 210s (2 different cases, A-series and NAPS-Z). You do NOT want that tranny. Reason below.........
You cannot use a the A series 5 speeds as the input shaft is much smaller and the pilot bearing is a different size. I have quite a few of the A series 5 speeds and 8 of the L series 5 speeds.(some of which have reverse where first is normally)
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