So I have a 68 Datsun 520 truck, and I just purchased a 81 720 with a sd22 with 185 000 km. I have done the measurements and it looks like its going to fit.
I know nothing about Nissan diesels or any diesels, so I have a few questions.
1 How do you get the glow glow plugs to turn on in the 720 truck?
2 What is the gear ratio of the rear end in the 720 truck?
3 I am going have to run a electric pusher fan because the sd22 is too long for the engine bay of the 520. Does any one know of a electric fan controler that I can use?
Thanks for you help and here a few pics of what I am working with
I believe that truck (720) has a H190A diff. In the D21 that I have the GR for that Diff is 3.889:1. I would think that will be close to what you have there.
As for the glow plugs you may just want to install a relay and push button in the cab to control them manually.
If you get the SD in that little green guy I should imagine that it will go pretty good as it is no doubt 1/2 the weight of the 720.
In regards to the fan, you can go to one of the local speed shops and ask them for an electric style fan. There are all kinds available and you can even to go Useable Used Auto in Lethbridge and see Darcy there. He is kind of the local guru when it comes to Nissan's and Nissan diesels. He may even have a fan there that will fit into what you are trying to do. http://www.useableused.com/
I have seen sensors that fasten to the rad hose near the thermostat housing and held there under the hose clamp. Some of them are adjustable with a tiny screw for when they come on and off.
HTH
P
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN
in '68, the 520 could have the A14 engine, or the (then new) L13, IIRC.
The A14 is short, but the '68.5 got the OHC 'L' Nissan engine and it should be pretty close to the same length as the SD. In both cases, I think the size of the engine bay is the same.
I have installed many electric fans over the years. Pusher fans are harder to find from JYs, but are certainly available aftermarket. I can't recommend one brand over another. It's much easier to fit a fan to pull, rather than push.
There are several aftermarket temp controllers, I used a style that has a capillary bulb that I inserted into the upper radiator hose, and the bulb leads to a mechanical adjustable switch. Worked very well, but that type is probably no longer available, what with the proliferation of electronics these days.
I doubt that there is a significant (ie greater than 400 lb) difference in the weight of the 520 vs. the 720.
The brakes! Argh, I know those 520 brakes well. The design, like that of the A14 engine, is lifted straight from British cars of the preceeding era. To my eyes (back in 1981), the rear sliding, single-acting wheel cylinders looked like they would bolt directly on to my 1960 Hillman Husky (see my avatar to the left). The fronts are two singles, IIRC. Not suitable for heavy-duty use. The SD engine is much heavier than either the A14 or the L13 it will replace -- keep this in mind.
You will want a Factory Service Manual for your engine. Get a 1982 or 1983 FSM, as the 1981 FSM does not include any information on the SD engine -- that was only available via a separate diesel engine supplement, which is a rare item 30 yrs on. The 1982 720 FSM is cheap on eBay and similar. You will definitely need the FSM to work with the DPC (IP Controller) and the GP (Glow Plug) systems.
While using a manual pushbutton + relay to drive the GP system will work fine (as long as you use stock 1981-82 GPs!), the DPC really only works well with the OEM control system, unless you do a stellar manual system to replace it. A Bowden cable ("choke cable") can be used for the Stop & Run positions, but not for the Start position, in my experience. Depending upon your local weather, you may or may not need to use the Start position on the IP. If you see low temps, keep that in mind, too.
Read up on the DPC -- there are several good threads on how it works.
I just finished putting a sd22 into a suzuki samurai. Lots of trips to the local auto wrecker to find stuff. I used a push style fan off a toyota corolla. so far works fine. Got a fan control from the local lordco for about 60 bucks. Has a temp probe that goes through the fins on the rad. Can set the temp to come on at higher or lower temp. Easy hook up. Take your time and attack one problem at a time. I had to custom make all motor mounts, tranny cross member, exhaust etc. good luck with your build. Norm
Well this weekend I pulled out the j13 out of the '68. I pulled the wire harness out of the '81 then used the wire schematics and wire diagrams from asavage's site to separate the glow plug,ipc circuits and alternator circuits from the main harness. I have installed the glow plug ipc and alternator circuits into the '68. Then I finally pulled the diesel engine and transmission. I had to pull the differential because the gear ratio of the '68 is 4.88:1 and the ratio of the '81 is something like 3.9:1. I am going to use the original gas tank in the '68 I am just going to have to run a fuel return line.
My Dads is going to pick up the '68 to take it to his shop where we are going to pull the cab off so it will be easier to fab up the mounts and install the engine and transmission. Then hopefully the recyclers come tomorrow to pick up what is left of the '81.
If it weren't for this site I would not have gotten this far so fast. So Thank-You guys for your help and knowledge.
John
If you can still remove the fuel tank from the 81 and find a way to use it that may still be your best bet. I believe there is a topic in this forum someplace to do with interior galvanizing on a "gas" tank as opposed to a "diesel" tank and the effects of diesel on that galvanizing that may cause you some issues down the road. ( so to speak ). I will try and find it and send you the link for it. Just something to consider that is all. If you are "fabricating" anyway why not fit the diesel tank at the same time.
Edit: Found the page(s) here: http://nissandiesel.dyndns.org/viewtopi ... 0705#10705
Also click on the "As Previously Mentioned" in that link and there is some more info there.
P
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN
Looks like a tight fit-I'm following your progress as I've been thinking of doing a similar swap but am a little afraid of taking on a big project, so keep the postings going!
elminero67 wrote:Looks like a tight fit-I'm following your progress as I've been thinking of doing a similar swap but am a little afraid of taking on a big project, so keep the postings going!
I t a very tight fit. My Dad had to move the rad support and every thing that comes with it like the hood latch one inch, now I can run the mechanical fan that came with the j 13 engine. We had to raise the body 1.25 inches so the body would have clear the transmission. We also cut the transmission tunnel and rebuilt it. Now basically the engine is in all is left to be done is the easy stuff plumbing and electrical and changing the 4.89 differential to 3.78 from the 720 and shortening the drive shaft. If you have any questions I would be more than happy to answer them for you.
John
Sorry I would post more pics but I had complaints about how long this post takes to download on dial-up connections..................... I didn't know any one even used dial-up any more
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I didn't know any one even used dial-up any more 
