D21 LS Swap Project - Planning Ahead

[JonMortensen]

I picked up an 88 D21 for $250 that is an absolute pile of junk. Body is actually fairly straight, but mechanically it's in really bad shape, 298K miles. NapsZ had the head removed and then the owner died, so it's been sitting for a decade with the head off, engine is junk. Auto trans with column shift. Did have ps and AC from the factory.

Had a 93 Toy and a friend with a 92 D21 and we used to race everywhere back in the mid 90s, so it's kind of an impulse buy / nostalgia thing for me, but I wanted to get this truck, strip it to the frame, mod the suspension, LS swap and just use as a daily and autox it in the winter because my Z runs huge slicks and doesn't come out in the rain. Probably should go buy a Civic to autox in the rain, but this came up and I have an interest in the D21 from the good old days.

I really don't know much about these trucks, so I'm trying to learn and then lay out a plan. I've looked around online and am not seeing much tech info, just a bunch of people lowering with blocks and the odd S13 rear suspension swap. Found Beebani, looks like he makes some interesting parts, but I'm not sure I want to go to a 4 link setup in the rear. Back in the day I had my Toy on leafs with sliders and traction bars and it worked really well. Would like to do coilover shocks in front, but will probably figure out my own solution.

ENGINE/TRANS: Plan is an L33, 5.3 aluminum engine and Colorado AR5 manual trans. Adapter is available, so putting those together will be no problem. Questions are about firewall clearance. I've been told that if you line the Chevy auto trans up with the factory trans crossmember it puts the engine in the right spot and just a little massaging of the tunnel with a BFH is all that is necessary to make it fit. I have no qualms about beating the hell out of this thing, or cutting and welding for clearance. More concerned about having room for radiator and AC condensor. Would like to have AC in it when it's all said and done. Had AC in its prior life, not sure about using the condensor, evaporator, etc with a GM pump. I haven't worked on AC since the early 90s and forgot whatever I knew about it.

SUSPENSION: Seen a few people talk about rack and pinion steering, one mentioned Subaru, which is something Z people did before electric ps became popular. I prefer hydraulic over electric for road feel, and as I recall from driving my friend's truck, the D21 steering has about 57 turns lock to lock, so some upgrade is probably required there, or maybe just install a 2:1 quickener box from a circle track shop. I'd guess you can drop some weight and make it more precise with a rack swap though.

Re: the front control arms, I would like to get rid of the strut rod, found an aftermarket LCA that bolts into the strut rod mount (I think this was Beebani too) and that looked interesting, but was thinking about just starting from scratch, chopping the mounts off of the frame and using circle track parts, as this would enable me to change the brakes and change the bolt pattern. The more I look at it though, the more I think maybe the easiest solution would be to just keep it, and upgrade the bushings to poly, or better, monoballs. Then I could just use a drop spindle to lower, swap to coilovers, upgrade the sway bar and call it a day. Found the V6 front brake swap, that's sufficient for my uses.

Haven't been able to find stock spring rates front or rear. Did find the rate on BellTech's lowering leafs, 130 in/lbs.

REAR AXLE: This is where I'm really stuck. I think I have an H190, not sure and don't want to crawl under in the rain to figure it out. Even if it's a C200, would probably still want to replace, if only to change the gear ratio. Something like a 3.36 to a 3.70 would probably be best for the engine/trans, and that doesn't seem like it's available in the Nissan trans. Saw Beebani's rear disk conversion and thought that looked like the easy button and then just find an H233 and a LSD, but then figured out that they seem to only be available in 4.11 or lower gear ratios, which will put me at 3500 rpm on the freeway with a 25" tall tire.

Really need input on this axle thing. Have been trying to figure out an axle to swap, Ford 8.8 immediately comes to mind, but not sure of the axle width and it would require some fairly advanced surgery, cutting spring perches off and locating on the new axle housing and all of that. Plus I'm not a huge fan of c-clip axles. 9" is an option but building one up is fairly pricey and I don't think any of them came with rear disk, so would need to figure that out too. And not sure if the width is close enough. Could go seriously crazy, get an 8.8, swap 9" housing ends to get bolt in axles and have the axles made, but that's a lot of money to put into an axle. Could probably buy a new Winters Quick Change 10.5 for that kind of money, LOL.

If an easy swap doesn't pan out, will probably go with a 3 link setup with panhard bar and coilover shocks in rear too. That makes the axle choice less important as I'd be cutting everything off of it anyway, just need to find something strong enough with the right width, but would love to find out I'm wrong and there is a taller geared H233 that I'm not aware of, or that I have a C200 with 3.54s in it and R200 LSD fits. I guess the other option is go with huge wheels, but that's going to look pretty stupid on this old truck. Get above 17's or so and it's starts looking wrong to me.

INTERIOR: Plan is to gut it and put some buckets in with a center console. Keeping the dash would be nice to house the AC parts and heater controls, but thinking the gauges would have to go. Could go full race car like the Z, or maybe swapping all of the Z gauges into the truck and then doing a digital dash on it instead. Also driver door lock/latch is hosed. Will have to get in there and see if it's salvageable. PO had some hokey coat hanger solution in there.

Will need a clutch pedal. Hoping this is like the Z, where they used the same pedal box and just didn't install the 3rd pedal, and that I can swap in a used brake and clutch pedal and drill holes in the firewall and call it a day.

EXTERIOR: Not spending a lot of money on this one, that's for sure. Not going to be a show truck. Thinking make some small box flares and then plastidip for paint. Will have to fix the leaky sunroof. On the Z you can swap the roof skin, doesn't look doable on the Hardbody. Might be able to cut the roof off at the pillars and weld it on that way. Will try fabbing up a panel and welding the hole shut with a million tack welds, but worried any welding in the middle of the roof will warp the crap out of it. Needs a front bumper, will delete rear bumper.

Any and all advice and suggestions appreciated, including: "Part it out and buy something else." I'm not married to this thing and I'm sure I could come out a couple hundred ahead by parting out. My Z took 12 years, would like this to be more of a 5 to 6 year project and just be a fun driver at the end that will surprise people at the autox. My Toy would consistently come in the top 1/3 of the field and got a lot of comments from people, basically looking for something like that, but with more balls. Couldn't stand the lack of power from the 22RE.

[Tank.]

Good to see you here Jon. This looks like a great project, I’m kind of doing the same with a 620, albeit a Ka24de swap out of a frontier (and it also took me 12 years to build my Z!).

 

Easy way to tell what rear you have is look in the driver door frame for the axle code. Or bend over and look at the rear, if it has a removable cover, it’s a C200, if not, it’s an H190. And some D21s with an H190 axle came with a locker. I’m actually trying to find one now to swap into mine.

 

Axle codes can be decoded here. http://www.infamousnissan.com/forum/archive/index.php/t-976.html. But to have infinite gearing options and cheap locking options, a ford 8.8 always delivers.

 

I’m looking forward to watching this one, with your skills, it should be a lot of fun.

[]2eDeYe]

Welcome.

 

I recommend a Toyota 4x4 rear axle.

6 lug, lots of gearing and diff options.

[Lockleaf]

Lots of options.

 

Rodeo/passport d44 with disc brakes

Wagoneer d44 with drum brakes

 

I love Nissans but the axles don't leave you many great choices.

 

Consider the LS4. Lower profile engine and no need for cost of aftermarket adapters.  You can use the AR5 with the LS4 using a dodge Dakota bell housing.  Starter takes some work though.

[Icehouse]

Why not just put the V6 hardbody axle in with the factory LSD?  

[petercscherer]

6 hours ago, Icehouse said:

Why not just put the V6 hardbody axle in with the factory LSD?  

Because he want's to be able to change gears to better freeway gears if necessary. I'm pretty sure the the V6 axle with LSD is only available in like 2 ratios. 

[petercscherer]

Snag a set of s10 LS swap motor mounts, they're like $60-80 and will save you some fab time since they're almost perfect out of the box. Be prepared to slice and raise your tunnel for that stick trans, pretty sure it sits higher on the crankshaft plane than the 4l60e. 

[datzenmike]

7 hours ago, Icehouse said:

Why not just put the V6 hardbody axle in with the factory LSD?  

 

1 hour ago, petercscherer said:

Because he want's to be able to change gears to better freeway gears if necessary. I'm pretty sure the the V6 axle with LSD is only available in like 2 ratios. 

 

4.375 and 4.625 4 pinion LSD in the D21 but only through '93 then only after '98 and standard on VG33 4x4s.The Pathfinder also had same gears and LSD but optional rear disc brakes that may fit the D21 housing. Around '98 the 3rd member changed the number of mounting bolts so check this. Non LSD H-233 gears will swap

[JonMortensen]

Big thanks for the welcome and the info guys. I was getting a little frustrated trying to find good tech.

Diff has no rear cover, so definitely H190. BTW Tank, nice job on both of your builds.

I had another thought: I have a T56 in the Z, which is kinda stupid because the .5:1 OD 6th gear is totally useless and the trans is unnecessarily heavy. I think they weigh 140 lbs or so. Looks like I could drop about 30 lbs by swapping in the AR5. The AR5 has a stupid low 3.75:1 first gear where the Camaro T56 has 2.66:1. The AR5 also has 2.26:1 2nd and I have 4.11s in the Z, which would mean 2nd would go to 50 mph at 6250 rpm where the stock oil pumps cavitate. Might actually be good for autoxing if I launched in 2nd. 3rd then goes to 80 mph, which would be good for faster autox courses. Might be testing the strength of 2nd gear with the starts though. At least I'm not drag racing.

Anyway if I did figure out how to swap the AR5 in the Z I could use the T56 in the truck and then calculating it out, I'd be at 2200 rpm at 75 with 4.37 in 6th and a 25" tall tire. I think that might be move there, so then I need to find an LSD H233 4.37 diff. What's the going price on these? Looking at ebay not finding any. Guess next stop is start calling junkyards. Sounds like the H233 is really heavy which isn't really what I want, but I guess it's probably easier than any other solution since it bolts in, would definitely be strong enough, and I suppose if I squint REAL hard I can see that as helping the nose heavy problem pickups all have and not as adding massive amounts of unsprung weight...

Looks like the AR5 has the same 26 spline input shaft so I could probably swap over my dual 7.25" button clutch to the AR5, hopefully using the expensive hydraulic throwout bearing. The pressure plate has to have just the right amount of throw, very finicky.

Toyota axle is an interesting suggestion because when I worked at Randy's Ring and Pinion as a sales guy I built about 10 of them (part of the training) but I don't see them available in anything taller than 3.73 gear ratio. I don't suppose the leaf spring mounts line up, so all that would still need to be done. D44 would be a good option, 8.5" ring gear IIRC, and tons of lockers and gears available. Don't like that you have to shim under the carrier bearings, but would probably only do it once.

LS4 looks interesting, thanks for that idea. Never heard of it previously. Looks like it has displacement on demand which requires some undoing. Will have to do some research there. Looks like they have an odd accessory setup for transverse mounting. Maybe should see it as a bonus as that gives more clearance to the radiator. Truck accessories stick out really far from the front of the block. Not sure which would be the better deal, trying to figure out the starter/bell housing stuff, or just buying a new balancer and camaro accessories.

Also now considering just swapping the whole drivetrain out of the Z and finding an AL block 6L and doing that up for the Z. The Z engine is a L33 with a cam and carb swap and that's about it. It's not a super special build. There was no shortage of power before, but just swapping from the car to the truck would make things simpler from a parts standpoint. Would need to change out flywheel and clutch though. Don't want that button clutch in a street truck. That thing is kinda ridiculous. Shifts fast though!

[Lockleaf]

DOD/AFM is easily deleted.  Just tuning it out will give you a good running engine.  Mechanical delete takes a little work, but its still just cam and lifters and valley plate.

 

Regardless of how you choose to move forward, post your progress.  We are always interested.

[Icehouse]

23 hours ago, datzenmike said:

 

 

4.375 and 4.625 4 pinion LSD in the D21 but only through '93 then only after '98 and standard on VG33 4x4s.The Pathfinder also had same gears and LSD but optional rear disc brakes that may fit the D21 housing. Around '98 the 3rd member changed the number of mounting bolts so check this. Non LSD H-233 gears will swap

 

So those are the two only gear set options?  Did the 300z TT come with the same size diff?  

[datzenmike]

The D21 and WD21 Pathfinder has an H-233 somewhat like the H-190 only sightly larger than a Ford 9". The 2wd H-233 (non LSD) used much lower gears of 3.70, 3.889 and 4.11. The 2wd H-233 ring gears should fit the H-233 LSDs

 

The 300zx TT was IRS and R-230 differential. 

[Icehouse]

25 minutes ago, datzenmike said:

The D21 and WD21 Pathfinder has an H-233 somewhat like the H-190 only sightly larger than a Ford 9". The 2wd H-233 (non LSD) used much lower gears of 3.70, 3.889 and 4.11. The 2wd H-233 ring gears should fit the H-233 LSDs

 

The 300zx TT was IRS and R-230 differential. 

 

AWW I was thinking the diff was like the C200 just the R200 in solid axle form so the ring and pinion would be swappable.  That seems like plenty of gear ratio choices.  Just get the 2WD dff which will bolt in and swap the LSD in.  Way better than a custom job.  

[JonMortensen]

Interesting. So I could find a taller geared V6 2wd H233 and swap in an LSD and then run the 5 speed and not have to make a new trans xmember for the Z, and wouldn't have to figure out the button clutch in the AR5 trans. That sounds like the best idea yet. Wasn't exactly looking forward to figuring out a new trans xmember on the Z.

Saw an H233 LSD 3rd member for $500 on ebay. Looks like there is one for $800 now. Kinda pricey at $800. Still better than R200 stuff where the factory clutch LSD is unobtainium, and the aftermarket stuff is super expensive like OS Giken or crappy like OBX.

Been going down the 4 link vs 3 link vs torque arm rabbit hole too. Was going to do leafs and sliders, thinking about changing the plan there too. No time constraints, so going to do more digging before making any decisions. If I get too crazy with that it probably won't matter which diff I start with.

[Icehouse]

We are talking about a Pathfinder LSD.  Which are super cheap because they came in lots of them.  The pathfinder even came 4 link.  

[datzenmike]

$500??? gees I got an old pathfinder H-233 years ago with rear disc and 4 pinion 4.625 LSD.  $100 for the entire axle assy.

[JonMortensen]

Good to know. Really helps to find this kind of stuff out before putting money down, so thanks again.

[JonMortensen]

Been prowling the FB classifieds and craigslist. Seeing some early Pathfinders come through, some part outs, some just not running. It looks like the whole front end bodywork transfers over, bumpers, grilles, hood, fenders, maybe even doors on the 2 door models. Since my front end needs a bumper and lights, and flared fenders is probably in the cards, this looks like a decent option. Am I missing anything there? I did read that the doors are a bitch to swap, but not why. I know the seats swap too, but I don't think they'll be what I'm after.

My other thought is buy a cheap runner and part it out to get the parts I want and recoup the costs. Not sure about how easy stuff is to sell. Z parts are easy, but from where I'm sitting looks like Hardbody parts or Pathfinder parts might not move so quickly.

 

[Icehouse]

Yeah I've almost bought a few pathfinders for parts.  They come up a lot with bad trannys, clutches or broken timing belts.  Not sure what the parts are worth. 

[JonMortensen]

Is it correct to say that all of those body parts swap straight over?

[petercscherer]

Yeah, I've used pathfinder fenders, hoods, grills, and bumpers on hardbodies before. Also interior parts interchange like seats, consoles, dashes, etc... A lot of the chassis parts will interchange, since both frames have a lot of the same mounting points and holes. Get 4x4 fenders to add 1" on each side. They're also available on ebay reproduction.

[Lockleaf]

I've even seen a build where a guy put a D21 cab on a pathfinder frame so he had a 4 link swap already done.

 

H233 are basically all clutch LSDs and they are HIGHLY stackable.  You can stack plates in the diff until you basically have a permanently locked diff, or go the other way and unstack to open diff function.  It would require some labor, but pulling apart any LSD H233 (wd21 or R50 pathfinders) in the junkyard would net you all you would need to fine tune the breakaway torque to your desired spec.

 

[datzenmike]

Early ones have high break away torque LSDs but later ones are only 28 pounds for soccer moms that don't like the tires hopping and chirping when they back out of the parking stalls.

[Lockleaf]

Its true, the LSD in my 96 R50 pathfinder was a joke.  It was so low it would brake away from a slick puddle.

[JonMortensen]

Well, this project has taken a sad turn: I went to buy a 95 Pathfinder that is supposed to run great but has a bad clutch today. Deal went south, guy's car got stolen with the title in it and I wasn't about to buy it without the title. So I spent a whole day prepping to buy it and didn't happen. Was talking to the wife about it, she started asking "why do you need the Pathfinder, why do you need this axle, why do you want that steering?" The further I went into it, the more she realized I was about to embark on another years long autox build, and she kinda cut that short by saying, "Let's see what our tax refund is and then buy you a car that you can autox in the winter and also drive the kids around in" so probably be picking up a 4 door G35 or something in April. I don't think the back seat of a BRZ is functional for kids over 4 years old. Something along those lines though, sporty 4 seater. I was moving the D21 off of the trailer today to put the WD on, and it is pretty rough, it was easier than it should have been for me to let it go.

Just to round out the story, here was my plan: offset 3 link (no bind and compensates for torque steer). Panhard bar because it allows a lower roll center that doesn't move. A Watts link controls the side to side motion better, but the roll center moves up and down as it moves. My friends at Maximum Motorsports worked out the side to side motion of a Mustang axle through it's normal range of travel with their Panhard bar at .050" which is a lot less than sidewall flex will give you, so it's not really an issue.

L33 or LS4 with AR5 trans, light flywheel and clutch, medium sized cam, something in the 228 degree range. Was going to take the Pathfinder front clip off and put on the D21, it had a nice looking grill and bumper with Hella offroad lights that I wanted to keep, along with the pedal box, doors (power windows), dash, figured it probably had tilt steering, seats and console (seats if only for the sliders), maybe even the front carpet if it would fit.

Front suspension I was going to hack off the strut rod mount and make a bracket for a heims jointed strut rod like I did for the Z. Monoball the control arm pivots and convert to rack and pinion, probably Subaru. Was going to measure all the angles on the suspension and then see if straight lowering with coilovers would be better or if a drop spindle to retain the higher RC was advantageous. Stock RC looks pretty high, so was really interested to measure this all out and see how it worked out. Plan was to lower it 2/3, my hunch is it would have been better just to lower it than to run a drop spindle, especially with the much lower rear RC with the Panhard bar. Heims jointed sway bars front and rear. Mount the rack to minimize bumpsteer.

Wanted to run AC and heat, have a nice little stereo (Pathfinder had a bluetooth stereo and speakers in it) and run a 17 x 8 or 17 x 9 wheel with a 225 or 245 wet weather tire like Toyo R1R. Was going to pull fiberglass flares off of the front of the Pathfinder and put on the D21, move the gas tank door if necessary. Paint Mazda red from the early 2000s, they had a Mazda 3 that was just the perfect red, bedliner the bed and the floor of the cab, run a Racepak or similar digital dash place of the original gauges. 

That is the truck that will never be. Thanks again for all the advice. Found a couple good guys on FB who gave advice about V8 mounting and some other stuff, but you guys filled in a lot of the gaps in my D21 knowledge. Guess I'll start posting my Z stuff as I work on it over the winter.