1981 Datsun 720 SR20DET Build.

[Shaker]

Hi Everyone,

 

I own a 1981 Datsun King Cab that was originally a Diesel. I`ve owned it for about 4 years now. After the transmission gave up on me I sent it off to a friends Body Shop 3 years ago and Since it sat waiting for an Engine and Drive-train. 

 

I am Finally able to rekindle the fire on this project and get it to be a glorious little truck. The body was completely redone including the frame *See photos. Body in Nissan Black and Frame Nissan Red, The engine shown never made it any further than the motor mounts made to fit it. I had some Medical issues to take care and while still recovering I am able to work on my Datsun, 

 

The plan starts with acquiring an SR20DET, I live in Canada and have a few options depending on who has stock in January when I order. 

 

First Question for you Folks is S13 or S14 SR? The price is not much different between the 2 and wasn't sure if one was better than another.  I`ll probably end up going with what is available at the time anyway.  Give your 2 cents though and any place I should check out. I`m close to the USA Border so I can pick up State-Side if needed in Washington State. 

 

 

 

[datzenmike]

There are plenty of engine importers in Vancouver. CDN dollar doesn't buy much in the US. Be sure to get the transmission, ECU and the wiring for it. Both S13,S14 and S15s had DET options but the S15 would have more improvements.

 

Have you considered the KA24E from a 240sx?

[Shaker]

Hey Datzenmike, 

 

      I`m in Richmond BC. I`m from out east heading back to NB to do the build after the Holidays. Where are you on the Island? My parents live in Chemainus I`ve thought about the KA option but the SR just has allot more support and aftermarket parts and just seems to be more online about it. I`ve read on here about swapping the front brakes and whatnot from an 86 to be able to get the 2" drop spindles though in the end I`m leaning more towards an Mustang II IFS - http://www.helixsuspension.com/products/ifs-kits/config/?type=custom&model=&year= 

 

I see the S13 & S14 Engine Swap packages with all the fixings including Igniter, ECU Etc, and they seem to run 2000-3000 USD, I`ll have to look at the S15 options!

[Shaker]

Old Images

[wayno]

Poor diesel truck, I like the diesels, but they are not very powerful unless turbocharged, I have a couple of them. :lol:

The diesel wiring harness is a strange animal, you would be better off finding a 1980 L20b equipped wiring harness for your build.

By the way, why didn't you just get another transmission for your diesel? 

[84720FourWheel]

How well did the VG fit in there? Been thinking about that swap for my truck.

[Shaker]

@ wayno - Yeah the diesels are great little engines. I always planned on swapping out the SD22 to turn this 720 into a street truck that could lay down some decent laps. At the time the Transmission went the only one I could find was 2200$ and No Warranty. Did not make logical sense to spend that kind of money on a used tranny. For wiring I`m just going with http://www.wiringspecialties.com/proses14srwi2.htmlor Similar and a Racepak Cluster or Similar. 

 

@ 84720FourWheel - The VG fit in there great, I actually pulled that and Currently in the truck is a VG33ER mated to a 2wd Xterra Auto Transmission. I could sell and deliver to the Border of Minnesota and Manitoba at the Interstate 29 Border Crossing if your interested this Spring. I`m ordering everything in January and Heading out to New Brunswick in February to do the build at my buddies shop. So I`ll be heading back out to British Columbia around March. 

 

Looking forward to doing this build and I`m going to try my best at showing/writing about all steps with the Ratsun Community. 

[Charlie69]

I love your upside down paint scheme!

[Crytek89]

Great looking truck!
 

Datzenmike is up Island - I'm in Victoria.

 

Currently working on a KA24DE swap for mine - was thinking about the SR but the KA matches up with the existing transmission in the 2WD so for mod purposes I went that route.

 

 

I'd start with checking out 240sx enthusiast forums or facebook groups - they have a wealth of info in regards to the SR and stock/aftermarket parts generally 2nd hand for pretty cheap.

[Shaker]

@ Charlie69 - Thanks, I wanted to do something a bit different, Still lots of work to go but look good it will. In my eyes anyway lol.

 

@ Crytek89 - Yeah the KA24DE seems to be a good option for sure, Makes sense when your transmission hooks up too. I`m looking forward to cruising around BC, Lots of enjoyable roads. I especially like the one to Gold River, My Dad works up near Tahsis in the summer. I just finished getting the Chevy C10 running I bought when I got to BC. The black Chevy in the photos used to be mine to but its gone now. This is my current daily until the 720 is done. 

[Shaker]

Alright so I`m going to order an S14 SR20DET Engine package. Going to order in the next 2 weeks. I think this is the best deal I found. Its in Quebec and my truck is near Grand Falls, NB where I`ll be doing this project. 

 

Just looking for any thoughts before I go ahead and order this. Thanks Folks!

 

http://www.sunrisejdmmotors.com/engine_details.php?id=37&page=1&F=ME

[Crytek89]

Looks like an alright deal for what's included with it - you'll of course have some adjustments with the exhaust and wiring ect.

 

You can find the link for wiring boxes here: http://community.ratsun.net/topic/28097-canam-production-easy-wiring-boxes-for-efi-works-for-kas-srs-vgs-cas-and-more/?st=0

 

Only thing I'd mention is the SR20/KA stock transmission is going to be longer than stock by approx 2 inches. You'll have to account for this during your installation and positioning of the shifter as well as the driveshaft.

[Charlie69]

Engine and trans mount are an added expense, but if you are like me I always install new mounts.

[Shaker]

@ Crytek89 - Wiring will be with Wiring Specialties and Haltech ECU. Exhaust will be some Fab work for sure. I`m doing this at a friends full on body shop, where it was painted. Driveshaft I was going to get measured up and built. Are the 720 rear ends strong or should I swap it for something else? Thanks for the link. 

 

@ Charlie69 - Mounts will be new or Custom, will decide after I get the motor and able to look at it. 

[Crytek89]

The rear ends should hold up to around 300bhp, I believe there's a difference in overall strength depending on 2WD or 4WD - best ask Datzenmike about specifics.

 

Edit:

 

Here's a quote from 2009 on 720World from Datzenmike regarding the rear end.

 

 

 

An H-190 rear end will easily handle a 2wd stock KA powered 720. If boosting slip an H-233 axle assy. from a V6 Hardbody into it. The H-233 is an inch and a half wider on each side but is larger than a Ford 9 inch! I don't know if the HB got LSD option but the Pathfinder did with 4.375 and 4.625 ratios. The H-233 rear ends are a Salisbury type and the gears can be removed as a unit simply by unbolting and pulling the axles outward to disengage the splines and unbolting third member and lifting out.

 

Link to original

[Shaker]

So from this I understand I need a D-21 Axle housing but the guts from a WD-21 (Pathfinder I assume?) The model years would be what 86-92? Oh and does it matter 2wd or 4wd D-21 Axle Assembley?

 

 

D21 and WD-21 with V6 used the H-233 rear. The D-21 axle tube uses leaf springs the Path uses coils. You would need a HB axle with Path gears with the LSD. Yes I believe only the Path had the LSD option

[Lockleaf]

Long as it's an h233b from a pathfinder it should have lsd. You can check easily. Spin one tire. If the other tire spins the same direction, it's lsd. If they spin in opposite directions, it's open diff.

 

 

You need pathfinder 3rd member at least. However, certain pathfinders also had disc brakes, so if you want to upgrade to discs while you are at it, you can swap all that gear over to a drum axle as well.

 

If you spent a while in the junkyard, you could assemble the whole thing there and get the best price.

 

Also, the differential is a clutch type. If you were to disassemble an extra pathfinder diff and remove the clutch plates and take those, you would also be able to fine tune the brakeaway torque to your preferences.

 

Wd21 ran until 95.

 

There are 3 versions of the h233. A 31 spline 9 bolt carrier. A 31 spline 11 bolt carrier. And a 33 spline 11 bolt carrier. They can mix and match to a point.

[84720FourWheel]

Pathfinder rear end would have to have leaf spring mounts fabbed up. Stock is 5 link coil setup.

 

Stock breakaway torque is 120ft lbs for the WD21 IIRC.

[datzenmike]

Later LSDs had pathetic brake away because soccer moms didn't like the tire chirps. I have an earlier 4.625 H233 LSD

[Shaker]

Thanks for the information on the Rear End. I will have to see how cold it is when I'm ready to do the rear..February on the East coast. I could probably buy a D21 and WD21 with rusted out bodies for cheap back home though and then I have lots of parts haha and just scrap/part out what I can. We shall see. 

 

For now I need to order the Engine, I`ve talked to a few companies and only 1 has actually had what they posted. So this with a little luck will be there 10 days from now when I can order. 3000 USD / 4034 CAD  Includes Shipping. 

 

JDM SR20DET S14 ENGINE SR20DET ENGINE S14 KOUKI 240SX LOW MILEAGE Jdm engine :JDM SR20DET S14 TURBO ENGINE SWAP FOR 240SX AND 180SX ENGINE DIRECTLY FROM JAPAN

Milleage : 35-55000 milles

Your Swap comes with :

Engine
5speed transmission
Engine Wiring Harness
Engine Control Unit (ECU)
Intake Manifold
Exhaust Manifold
Turbo Charger
Turbo Manifold
Injectors
Fuel Rail
Distributor
Power Steering Pump
A/C Compressor
Alternator
ignitor chip

[G-Duax]

Just to chime in here on an H190 size diff.

The H190 LSDs take the same internal plates as the Nismo R200 LSDs meant for the SR20DET cars in Japan.

They even have the same spline count as the turbo cars in Japan.

 

The reason some H190s seem soft is because of the way they are assembled.

 

The ones that lock better, and may cause a little tire chirp that can annoy a house wife, have their plates stacked 1 inner, 1 outer, 1 inner, one outer, for the most contact surface possible.

The house wife friendly LSDs have their plates stacked 2 inner, 2 outer, reducing contact area by 50%.

Toyota also does this.

In their Supra, they set it up for max holding power, but in the Cressida, with the exact same LSD, they pair the disks to keep the wife happy.

 

I have both the Nismo R200 and the H190 LSDs sitting here, and when I built my truck diff, I actually removed the spring plates that supply pre-load, and replaced them with disks from the R200, so it's softer off throttle (no spring pressure), but when I get on it, the cam plates tighten up, and I will have even more holding power.

 

By the way, only the first year of the 720 had an odd-ball C200 size diff in them. After that, Nissan went back to the H190 in all 720 RWD trucks, and kept it into the 4-cylinder, RWD D21s.

[Shaker]

@ G-Duax - So what I get is in my truck I would have the H190 and the I can swap in an Nismo R200 LSD or just use parts from it? I`m new when it comes to LSD's and Rear end internal. Most I've done with rears are seals, Wheel bearings and axle changes never changed out a center before. And use current axles or...?

 

I`m going to pick grab the textbooks and do some reading on rears. 

[Shaker]

http://www.tractionconcepts.com/Nissan-H190-Diffs-LSD-kit-p/tcxni9301.htm

[G-Duax]

No, you can't use the R200 in the H190, or parts from one to make your open diff into an LSD.

I just said that the internal parts are the same between the H190 LSD and the R200 Nismo, to show that the power holding capacity of the two is identical.

And since the R200 Nismo will take over 600 hp, a stock-ish SR20 turbo won't strain the H190 at all.

 

The H190 LSD from Nissan is a 2-way, meaning it locks the same in both acceleration & deceleration.

The Nismo LSDs are available in 2-way, 1.5 way, and 1-way.

A 1-way locks under acceleration, but not under deceleration, and a 1.5 way is in between, as it only locks 50% under deceleration, as it does under acceleration.

This has to do with the angle ground into the cam plates.

I haven't had my hands on an R200 1.5-way in many years, or I would see if the cam plates would also fit the H190 also.

 

This Cusco diagram explains it:

 

[G-Duax]

http://www.tractionconcepts.com/Nissan-H190-Diffs-LSD-kit-p/tcxni9301.htm

 

Stay the fruck away from those silly 'Jam-a-Block' wana-bee LSD conversions.

They just force the spider gears into the housing to obtain the illusion of lock-up.

An open diff isn't designed to use their trust surfaces act as clutch surfaces, and quickly wear out.

And they don't even have as much lock-up as the wife style H190 does, that will last forever,

and have no where near the holding power as an H190 with the plates staggered for max lock-up.

 

Here is my H190 LSD that will go into my 620, using the later 720 iron housing: