TruckA's 1984 720 4x4 gasser conversion to SD22

[TruckA]

Hey,

My name is David and I'm new to the board. I'm wanting to take on a biodiesel project, so I'll be picking up Datsun 720 diesel on Saturday. Its definitely rusted out in many spots, but has 161,000 miles and I'm getting it for $500 and by also selling some of the guy's MGB parts on ebay. Diesels have been hard to find in my area, so I decided to pick this one up, even though it was really against my best judgment. It also has a bad 5th gear I'm told, it whines. I actually haven't driven the truck b/c its been sitting 2-3 years and is loaded with a bunch of stuff. I look forward to fixing it up. I got a Hobart 187 Handler mig welder back in December, so I'll be able to hone my welding skills with replacing sheet metal. I also have some black acrylic lacquer and acrylic lacquer clear from an old project I never used that I'll use to repaint the truck. My other vehicles are a 2001 Subaru Impreza 2.5RS that I use regularly and an '88 Mitsubishi Mighty Max with an Eclipse turbo engine (4g63t) with some other goodies. I dynoed the mighty max at 17psi with a smaller intercooler and it pushed out 262hp, I now have a larger intercooler and run 20 psi, so it may be around the 300hp mark. Anyways, it looks like this site has a ton of resources that will help me out, and I look forward to getting started with this project. I even have the stock 14b turbo from the 4g63t, and I was reading the turbo SD22 thread, so who knows what could happen.

David

Here's the rustbucket as it currently sits:

[bacho]

Mine was in about that shape, I would reccomend buying a gasser with a nicer body than to try to repair that one.

Anyways good luck with your project.

[TruckA]

I've been thinking the same as well, did you part your original diesel out and come out making any bucks? I could do all the repairs on this one, but if I found a cheapo gas truck (preferably 4x4) in decent shape, I'd most likely go for it.

[TruckA]

Well, after taking the bed off and blowing the dust and junk off, I found a rusted through section of the frame. I'm liking the idea of swapping the engine into something else a little more after finding this. So it looks like I could be looking for a small 4x4 truck to put this engine in. I could still consider just making this a flat bed and get some diamond plate steel for the bottom, and just box in the bad spot. I'll figure something out.

[TruckA]

I know I'm reply to my own messages here, but I'm not sure where to ask this question. I found this ad, and I may go look at it:

1981 Nissan 4x4 Truck (Price Reduced) - $750
I think it blew the head gasket about 3 years ago, been parked ever since. Rebuilt 5-speed trans. sunroof, new exhaust, brakes, tool box,AC. Must sell ASAP! $750.00 O.B.O.!

Would my SD22 work in this? I believe it will and if so, I could can my rust bucket and go for the one with a sunroof and AC!

Thanks!

David L.

[asavage]

The SD22 is not a drop-in to the 4x4. If you do a little searching, you'll find a very good thread where member bacho has done this. It requires fabricating a custom oil pan for the engine, and hybridizing the transmission.

Again, it is not a bolt-in.

[TruckA]

Thanks for the info,

I did see that thread when reading but his swap was swapping the sd22 from an 81 or 82 into a 4x4 85. I wasn't sure if the transmissions were the same for his swap, but after reading, it looks like all the five speeds are the same for his application and what would be mine if I picked up the 81 model. I didn't see any info about hybridizing the transmission in that thread other than he mentioned the need to rebuild, you know anything about that? I can cut and slide motor mounts forward and do the oil pan work fairly easily. That little bit of welding work still sounds better than fixing all the rust on the truck I have now.

David


.... I took a look at the truck, the sticker says it was manufactured 3/84. Has a 190K, a supposed bad head gasket. The body looks way better than what I'm dealing with. The engine is a Z24 and the starter is on the passenger side instead of the drivers. I'm very interested in picking this one up, I just still need to be assured that the transmission would bolt up, and know about any other special work I'd need to do to the transmission. Pics are below, let me know what you think.

Thanks,

David

[asavage]

No, the transmission will NOT bolt up. Neither of them.

You take the front half of the SD22's trans case (just the case, not any gears, shafts, guts) and use it instead of the front half of the Z24's trans case. See this post for details (more than you probably want to know), but the previous sentence is the summary, and it's not hard to do, but does require some planning and a lot of cleaning to keep the crud on the outside. Front brgs replacement strongly recommended when you do the case swap.

[TruckA]

No, the transmission will NOT bolt up. Neither of them.

You take the front half of the SD22's trans case (just the case, not any gears, shafts, guts) and use it instead of the front half of the Z24's trans case. See this post for details (more than you probably want to know), but the previous sentence is the summary, and it's not hard to do, but does require some planning and a lot of cleaning to keep the crud on the outside. Front brgs replacement strongly recommended when you do the case swap.

Thanks for the helpful information again asavage. I can tell that you definitely have alot more auto experience than I from reading your posts. I've never really torn into a transmission to do any type of work, but I've ripped into a few broken transmissions to scrap for bolts before recycling the metal. I have done pretty much everything else to automobiles from complete engine rebuilding and swapping, painting, wiring, etc. I can easily pick up manuals and follow directions to a tee, so when you say that its not hard to do the case swap, do you think I could figure it out? If its just the case that needs to be swapped, then I figure that everything lines up the same on the inside of both transmissions, so the case swap is essentially like a bellhousing change on other types of vehicles to get the bolt patterns correct to the engine. The transmission in the truck was supposedly rebuilt, so I should be able to inspect everything to see if the bearings and everything else is good. Also, would I need any special transmission tools needed in swapping the case between the two?

Thanks again,

David

[asavage]

When I say it isn't hard, you've got it right: it's basically the slightly-messier equivalent of swapping bellhousings, except you have to seal the joint, so you need one gasket, one shaft seal, and some RTV. Also, removal of the case from the guts is done exactly as the FSM outlines: deadblow hammer right where the FSM picture shows.

No special knowledge or tools are required, just cleanliness.

Standard jaw and split collar brg pullers and snap ring pliers are all that I recall being needed to replace the two front brgs (the ones that disintegrate first).

With your experience, you should have no problem swapping the trans case halves.

[TruckA]

That all sounds good and very doable, looks like I'll make the call to bargain with the guy, it would be a relief to not have to mess with all that rust. Now I just need to find a place to take the '82 Datsun for recycling since I'll have to get a tow dolly to get the '84 Nissan home and I'd like to make a few bucks on the scrap if possible.


...

I bought the truck last night and had a nice and friendly black snake sitting on top of the battery when I opened the hood, that was fun. Anyways, I also found a manual, so I should be able to pull all of what I need for the swap. The guy couldn't find a key, hopefully he'll find it from his son in the next week, if not, I'll just keep the ignition switch parts from the datsun, they look about the same.

[TruckA]

Started to work on getting the SD22 in the 4x4. I test fitted the engine to see where the mounts would end up, and I'm just about done with the oil pan. I hope to start tearing apart transmissions pretty soon to start installing the 4x4 guts into the sd22 diesel transmission. Here are some pics:

The pan was filled with gas when I drained the oil, and I found these parts inside the pan:


A hard surface to work on is so overrated


Pretty close!


Close on the other side.


Pans




Point of no return.




Still honing my welding skills




That's it for now.

David

[TruckA]

The pan and oil pickup is done, so now I moved to the transmission gut swap.

After some powerwashing, SD22 transmission is on the right, the 4x4 on the left:



4x4 on the left, SD22 on right:






Free silver paint? This oil doesen't look too good coming out of the SD22, good thing I won't be using these parts again:



Countershaft bearing damage:



This transmission was ridiculously easy to take apart, I feel silly now about asking how hard it would be to do:





A little chewed:



This can't be good either:









Some bonus parts!



The cleaned 4x4 guts hanging out to dry, I had to powerwash after finding some rust that I had to scrape and sand smooth, the assembly wouldn't turn. This transmission has indeed been rebuilt before as the seller told me, it looks like a new front plate and input shaft, plus newer bearings:





You can see the rusty parts, I guess the oil didn't cover these parts while the truck sat for a few years:



More rust, I blew everything dry and splashed on a coat of PB blaster to keep it lubed and wrapped it in a garbage bag to keep it clean before reassembly:

[asavage]

Great pictures! Thanks for taking them and posting.

[philip]

Great pictures! Thanks for taking them and posting.

DITTO !