i recently bought a 71 521 that needed a clutch it has a long shaft 4 speed in it and i find that odd.  It does have an L18 motor in it out of a 74 so that could be why i guess.  know if they all ready put the work to modify it for a long shaft what year 5 speed should i look for.  Now if i do go with a five speed do i have to change the flywheel and clutch set.  the guy i bought the truck from thought it had a L20 motor in it but was clearly wrong because he gave me the new clutch set to put in the truck and it was to big. He had bought the clutch set for a 75 motor. i have never owned a datsun so im not sure but on chevys i have had to change some stuff when changing transmissions

 

Welcome to the forum bigsal!

If your 5spd tranny came off of an L20 then the clutch and flywheel are larger than the L18's.

Do you have any pics of your truck?

phlebmaster wrote: Quote »Welcome to the forum bigsal!

If your 5spd tranny came off of an L20 then the clutch and flywheel are larger than the L18's.

Do you have any pics of your truck?[/quote]The trans has nothing to do with the size of the clutch.  I've used 5 speeds from L20B's in 510s with L16s or L18s.  Use the flywheel and the same type clutch disc, pressure plate and to bearing  that's in the vehicle now.  You can't use the L20B flywheel because it's a 6 bolt but I do believe it's the same size as a 5 bolt L18 flywheel, 225mm.  And the L16 is a 5 bolt 200mm flywheel. 

hey guys thanks.  how do you measure the fly wheel to see which one i got

you said 5 amd six bolts know is that mounting it on the block or the pressure plate to the flywheel

Sal, I think what Stephen is saying is to use your existing hardware, flywheel, pressure plate, clutch mechanism and bolt the 5 speed on to it. I assume the end shaft is the same diameter for all the vehicles. I've only done tranny swaps on GM modles so I'm out of my league here. But what he says makes sense if the 5 speed has the same bolt pattern as your existing tranny. Ken

i think you guys misunderstood me i dont have a five speed

the clutch set that was giving to me to put in my truck from the guy i purchased the truck from is clearly wrong he bought it for a 75 datsun 620 with a l20b motor  the presure plate and clutch were to big.  What i noticed when droping my tansmission was that it had a long shaft 4 speed.  Now acording to the research i have done my 71 datsun 521 came stock with a short shaft transmission. I am not sure what motor i have the guy says its an l20 out of a 75 datsun 620 but the clutch he bought dont fit  so it has left me thinking what clutch set to buy not knowing what motor or transmission is in it for sure my guess is it might be the l20 with the l16 or l18 flywheel and clutch set.  Now if im correct the long shaft transmission came out in the 620 pickups in 74. If it came out in 74 then it would be a l18 flywheel being that year pickup had the l18 motor But the guy who put the motor in could have used the l16 flywheel and clutch set being that the transmission piloit is the same frommid 60 to 74 my guess could be wrong im a chevy guy so i am learning lol

 

sal

bigsal wrote: Quote »you said 5 amd six bolts know is that mounting it on the block or the pressure plate to the flywheel[/quote]5 or 6 is the number of bolts that mount the flywheel to the crankshaft.  The 200 or 225 mm is the measurement of the outer diameter of the clutch disc.  You can tell what engine you have by looking at the first three digits of the engine number which is located on the passenger side of the block just below the head between the 3rd and 4th spark plug.

well it has a 7-7/8" clutch disc

 

sal

According to my rulers(I keep two in my desk just for these kind of measurement conversions   7-7/8" is 200mm.

For info on your original question...which rigs to find the long tail 5spd in.....

here's a Ratsun thread with some references....'82 280z...720 pickup.....

http://forum.ratsun.net/showth...trans

I think that most of the 5spds from about '76 until they went to he NAPZ motor will be the longtail.....trucks or cars.