1967 Datsun 520 swap?

Dwight, it's been several years, so i may be wrong, but isn't the front frame a bit different on the 520 from the L-Series 521? I remember a friend going through some issues swapping an L into his '69 because there wasn't a spot to put the motor mounts.
I totally agree with going the L series route, because it is easy and clean. However at LEAST go with an L20 so you have some power!
The transmission you'll want is from 77-79 200sx- the famed "dogleg 5 speed". The upside is that it will almost bolt in place of an L series 4 speed, but you'll have a bit of overdrive with that 5th gear. Shifter location is also unaffected, which is a plus versus the Z 5 speeds. However, the 5th gear is still pretty high (numerically) compared to others, and you'll definitely want a lower rear end ratio so you can cruise the highways.

My 521 had a warm L18 with the SX 5 speed and a 4.11 rear end, and it was turning about 4-4500 rpm keeping up with traffic on the freeways. Not so fun driving 3 hours to Shasta!

Good luck with your project- they're a TON of fun (well, closer to 2100 pounds, but who's counting!)

-Phil

Edited: 12/22/2006 9:18:38 AM by AiredOut

Originally posted by framelayer521



Dwight, it's been several years, so i may be wrong, but isn't the front frame a bit different on the 520 from the L-Series 521? I remember a friend going through some issues swapping an L into his '69 because there wasn't a spot to put the motor mounts.I totally agree with going the L series route, because it is easy and clean. However at LEAST go with an L20 so you have some power! The transmission you'll want is from 77-79 200sx- the famed "dogleg 5 speed". The upside is that it will almost bolt in place of an L series 4 speed, but you'll have a bit of overdrive with that 5th gear. Shifter location is also unaffected, which is a plus versus the Z 5 speeds. However, the 5th gear is still pretty high (numerically) compared to others, and you'll definitely want a lower rear end ratio so you can cruise the highways.

My 521 had a warm L18 with the SX 5 speed and a 4.11 rear end, and it was turning about 4-4500 rpm keeping up with traffic on the freeways. Not so fun driving 3 hours to Shasta!

Good luck with your project- they're a TON of fun (well, closer to 2100 pounds, but who's counting!)

-Phil

You might be right, im not to sure. I was told that the 520 and 521 frame are the same, but i dont know. There are hardly any 521 out here on the east coast, and deff no 520's. thwalr1 you need to check out www.NWDE.org its a wonderful site with lots of info. That would be you best bet as far as datsuns go.

I know that one major difference between the two frames is that the 521 had a 2 piece driveshaft with a carrier bearing (and a crossmember), while the 520 has a one piece shaft. They are interchangeable, if anyone cares to know!

I just remembered something else, too: if you swap out for that 200sx 5 speed, it's made to work with a slip yoke on the driveshaft. The 521 4 speed has a yoke that's held to the trans with a nut, because of the carrier bearing. Make sure you get that yoke off the old tranny before you throw it out!

-Phil at FBI

dont overstate the need for a cruising rear gear either. In the US we are used to high torque motors and low freeway rpm, but in other countries they are more accustomed to higher freeway revs. If you over gear a small motor, it will have less torque multiplication on the rear end and you will find yourself shifting and shifting and shifting, where a higher numerical rear end allows the motor stay in its powerband.

I bought a 72 2002tii in Orlando Fl with a 3:45 rear and 1:1 top gear and drove it home 23 hours straight at 4200 rpm. No ill effects, in fact the advance springs dont even open fully till 4000 rpm so my max fuel economy was above that rpm. Compare that to my 98 318i which turns 3400 rpm at 75mph. It has the 4:10 rear in it, and if I could find the rare 4:45 LSD I would use it in half a heartbeat. If I went the other way to a 3:73 I would actually LOSE top speed (the numbers would allow a higher top speed but the engine torque would never overcome the rear gear) and acceleration and fuel economy to boot!

Going from a 4:88 to a 4:10 like Dwight said is about as extreme as I would do. If you buy a trans with an overdrive gear, make sure the target rpm in top gear with the rear gear ratio is right at or below the engine powerband, or you will always be shifting to go up hills or make small passes.

and dwight if you need help with your efi swap, I'm so down I'm underground.

Edited: 12/22/2006 12:36:40 PM by AiredOut

Originally posted by framelayer521



I know that one major difference between the two frames is that the 521 had a 2 piece driveshaft with a carrier bearing (and a crossmember), while the 520 has a one piece shaft. They are interchangeable, if anyone cares to know!

I just remembered something else, too: if you swap out for that 200sx 5 speed, it's made to work with a slip yoke on the driveshaft. The 521 4 speed has a yoke that's held to the trans with a nut, because of the carrier bearing. Make sure you get that yoke off the old tranny before you throw it out!

-Phil at FBI



You are incorrect there Phil, only 70 and later datsun with the L series motor had the 2 piece driveshaft. My 69 521 with a J13 has a one piece shaft. All J series 521 had 1 piece drive shafts and a different tranny than the L series trucks.

But, it is nice to know that the 200 sx tranny has a slip yolk.

Originally posted by Russ-D



and dwight if you need help with your efi swap, I'm so down I'm underground.

Thats good to know. If i dont use a KA24de, im planning on the L16 with ITB's.