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Discussion Starter · #1 · (Edited)
Ok, so here it is. I am a Pipeline Inspector, I specialize in welding inspection, but I do it all, coating, ditching, environmental. So, I need basically a street legal side by side, i.e. a Jeep. Enter one 1987 YJ, that has had many owners, some less than knowledgeable, shall we say. I may also fit in that category, somewhat....
Here we go:

Jeep was bought "running" and trailered home. Lights non-functional, no worries. My dad is an Electical R&D engineer, I can handle simple wiring tasks. 33" tires, old and some damage. Incomplete soft top (x3), full hard doors, seats needed replacing. Halogen headlights, and round trailer LED stop & turns, no reverse lights. MC2150 (?) with crap air cleaner. Adapter plate leaking bad (unknown as of yet). Boxes of old parts and hardware, soft top parts, fabric 1/2 doors in decent shape. Oh and the fenders were in the back seat, also.

SO, my idea was to basically have the mechanic go through it and check for mechanical soundness BEFORE we started fixing and modding and updating. Unfortunately, I was out of town, and this build happened backwards. After a year, it's on the road, and of course it won't do over 50mph. Jokes on me, right?

I replaced ALL the suspension bushings with new. I also upgraded the shackles to boomerangs, and all spring eye hardware is now greasable bolts. Tires would scrub the springs at max turn, and no spare. Backspacing was 5.25", so bought 5 rims at 3.75" backspacing, no tire scrub, and 5 new 33" tires. So now I have a spare. YAY! Axles were finally gone through, and were good except the vacuum on the front wasn't working. Got it fixed and now its fine for the time being. BA/10 trans (ugh) and the transfer case are good, also for the moment. I need it to work, and be stable and reliable, before I start all the crazy stuff lols.

Jeep came with an HEI distributor already, missing the trim cap. Got one free through a friend of a friend, wow! Wiring..... well, some NUT thought the Nutter Mod was to just hack apart the harness and chop out the computer with wire cutters. Nope, I am not kidding!! Ignition was direct wired so it would run, as the PDB went bye bye as well. Which explains why the gauges don't work. No lights work, not even the expensive and new LEDs and the halogen headlights. Heck the taillights were just stuck in the rubber grommets in the sheet metal, unconnected. So, I went through, pulled the engine harness and dash harness completely free and apart, and started to fix splices, hacks, cut bare wires, etc. Replaced the headlight switch, dimmer switch, turn signal wiring in the column, wired up the stop and turns. I have a PDB from an XJ Cherokee, and I plan to rebuild it and use it to run all power through, except the winch and the 3000 watt inverter for my laptop (work vehicle, remember?). Dual battery tray with Optimas and battery isolator. The second battery is one of their deep cycle ones. New seats and bumpers, fenders, winch, LED windshield light bar (hey it was on sale!). Found a hard top on Ebay, in Mass, and my friend's father actually lived 1 mile down the road. How cool was that!! New gaskets and seals for the doors and top. New steering wheel as the one on there was so small it just didn't feel right to me. Oh and someone also decided to spray the exterior with green textured bedliner, straight over the paint. No worries, except they didn't mask anything off, so still cleaning light overspray from the interior in places.

So, all this and more, and only 50mph on the hardball. So, I have to re-gear is what I am confronted with, basically. So I need new carriers to run 3.73 gears and up, which is what I am looking at. 3.73, or 4.10? Some people say 4.56.... Honestly, I am at the loss here. Gear selection is not my specialty at all. I can weld the Crack of Dawn, but this is outside my wheel house.

1) 4.2L I6 engine with MC2150 carb
2) HEI distributor
3) poor man's cold air intake for carburetor, stock exhaust for now...
4) 33" tires
5) Unknown lift @2.5"(it is not stock as the stock replacement bushings didn't fit the
smaller spring eyes) and boomerang shackles
6) Dana 30 and Dana 35 axles (yes I know the 35 is a poor axle)
7) BA/10 transmission and NP 207 transfer case (all stock for that year, and yeah they are not
ideal either)

GEARS: ???? I need to know if the 3.73 will do what I need, or will the 4.10 be a better choice? I know some have said in other threads and forums that 4.56 is the better choice, and 4.10 at a minimum. But, they were mostly looking at off road performance, and this will be a daily driver on the road, with intermediate off road and mud. No rock crawling. Maybe going over the water bars (dirt humps to control water runoff on the right of way), but that's about it.

***Please keep in mind that I am planning a 4.0 head swap asap, and also go to a Banks header and 2.5" exhaust, but that still wont fix my speed/gear issue. If anyone has driven around Atlanta GA on I-285, you know that 50 MPH is asking to get killed. I need something that I can do up to 70, and not be straining itself. Yes, I should probably have used a TJ or even newer. More on that Later. I want the hard top to protect my equipment and gear, and keep dust and thieves to a minimum. I have no computer to worry about, and no smog rules. This is basically more like a CJ as far as the engine goes right now. ***

So, I need help with the gearing question. And, if anyone has good clear wiring schematics of what engine circuits are present, and amps, I would appreciate this for the Power Distribution Box and install. I do have air conditioning also, looks factory and does work. All accessories and lights etc will go through fused relay system, and all power except the winch and inverter will go through main fuses. I want to do this "right". :pullinghair:

Ok, now I am sure many of you are laughing along WITH ME so far, and that's good. Yes mistakes were made. Great learning experience. Like the fact that I never knew that Jeep made a modern version of the old CJ-8 Scrambler, the LJ Unlimited. Yes that is the ideal platform in my opinion. But, I need to get this one to do the job I need it for, for the time being. It's so close already, and the re-gear would happen anyways, even if I retire it to trail and weekend duties only (later).

I will try to get what pictures I have organized and post them, along with the specific parts I have used along the way. Thanks for reading this wall of text. I felt you needed to know my thoughts, and the process, so you can see where I am at and where I need to be and why. Thanks in advance for all your help and comments, and yes for your laughter also!!!:beerme:

Clay :beerdrinking::funnypost:
 

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Some of the other posters can give you a link to a gear ratio/tire size chart.
I don't have a link handy right now.

I'm running 31" tires and I have a set of 4:10 axles that will be going in soon. The 4:10 axles will put me right back to stock final drive gearing.
With your 33s, 4:56 should do about the same for you.

Good Luck, L.M.
 
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I would suggest 4.56 gears for a street driven rig with 33” tires and the 5 speed transmission. Had that setup on my 89 YJ with positive results. The difference in off-road performance is negligible between 4.10 and 4.56 but the 4.56 gearing will perform better for on road driving.

The only way to realize significant off-road gearing performance is to install a lower geared transfer case such as an Atlas or TJ Rubicon RockTrac case.
 

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Discussion Starter · #6 ·
I would suggest 4.56 gears for a street driven rig with 33” tires and the 5 speed transmission. Had that setup on my 89 YJ with positive results. The difference in off-road performance is negligible between 4.10 and 4.56 but the 4.56 gearing will perform better for on road driving.

The only way to realize significant off-road gearing performance is to install a lower geared transfer case such as an Atlas or TJ Rubicon RockTrac case.

Thank you!! I have seen charts that say 3.73 for highway, and others that say 4.10 or even 4.56 for highway, and to me that’s just confusing. I mean, how can there be three different correct answers to this? My own math is 3.07 x 33 / 28(or 27) = @3.73, so with a little room for more weight on the tires (as recommended in all the articles I read), I was leaning towards the 4.10 gear. I understand I need to re-gear to get better ‘leverage’ for the motor and put it back into its power band, but I have no experience to draw upon to truly understand the difference between the different gears versus the 33”tires, and make that decision. Yes it’s my rig, and my decision. I’ve been looking for someone to say that this is what they did, and how it performed. Thank you, for answering my question.
 

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I would have preferred 4.10 gearing with 33's with my 4.2l and manual gearbox. 4.56 was a little low for 33's and freeway speeds that put the jeep in a bad rpm for fuel mileage and wear travelling 65-75mph which is the main reason I traded those 33's for 35's. If you only mostly drive highways (50-60mph), roads, mountain roads and trails, 4.56 would be better. I think 4.10 gears on a mostly stock jeep are probably ideal for 32 inch tires, but 31's and 33's are on the low and high side of that range.

Yes I am running 33's and 4.56 gears now, but I have a different transmission with a lower overdrive now (0.70:1) vs the jeep 5 speed manual (0.79:1)
 
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The only way to realize significant off-road gearing performance is to install a lower geared transfer case such as an Atlas or TJ Rubicon RockTrac case.
Lies! A better/cheaper option is low geared offroad manual transmissions such as an SM420/465, np435, or T18. An automatic also does "lower" crawl speed with the help of the torque converter that puts you in the torque band of your motor and keeps you nice and slow. Low geared 2 speed transfer cases are annoying for things such as sand, snow and mud. Good basically only for playing on rocks but I'd still rather have a doubler transfer case with an sm465 for a rock rig.
 

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***Please keep in mind that I am planning a 4.0 head swap asap, and also go to a Banks header and 2.5" exhaust, but that still wont fix my speed/gear issue. If anyone has driven around Atlanta GA on I-285, you know that 50 MPH is asking to get killed. I need something that I can do up to 70, and not be straining itself. Yes, I should probably have used a TJ or even newer. More on that Later. I want the hard top to protect my equipment and gear, and keep dust and thieves to a minimum. I have no computer to worry about, and no smog rules. This is basically more like a CJ as far as the engine goes right now. ***
Also, if doing the 4.0l headswap, consider this thread https://www.jeepstrokers.com/forum/viewtopic.php?f=6&t=24 or just get a whole crashed 4.0l cherokee for $500 like I see them on craigslist and swap the whole 4.0l engine and EFI over.
 
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The only way to realize significant off-road gearing performance is to install a lower geared transfer case such as an Atlas or TJ Rubicon RockTrac case.
Lies! A better/cheaper option is low geared offroad manual transmissions such as an SM420/465, np435, or T18. An automatic also does "lower" crawl speed with the help of the torque converter that puts you in the torque band of your motor and keeps you nice and slow. Low geared 2 speed transfer cases are annoying for things such as sand, snow and mud. Good basically only for playing on rocks but I'd still rather have a doubler transfer case with an sm465 for a rock rig.
Good call. Spaced out on the transmission swap.
 

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Guys take it easy on this guy.... the ONLY thing a pipeline welding inspector knows how to do consistantly is PARK IN THE WAY EVERY TIME.... (I'm a boomhand) Lol

Sorry I didn't make it all the way through your book above without skipping through....

Don't waste your money on that banks header.... negligible if any improvement over a dorman stock replacement

I would STRONGLY recommend 4.56 gears w 33's and a 4.2 5 speed
 

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Discussion Starter · #12 ·
Guys take it easy on this guy.... the ONLY thing a pipeline welding inspector knows how to do consistantly is PARK IN THE WAY EVERY TIME.... (I'm a boomhand) Lol

Sorry I didn't make it all the way through your book above without skipping through....

Don't waste your money on that banks header.... negligible if any improvement over a dorman stock replacement

I would STRONGLY recommend 4.56 gears w 33's and a 4.2 5 speed
Well, if the FORESKIN-I mean fore person would set their site up, and not be a sneaky lying POS, then we would not sit right on top of ya. Give me a place to park out of your way, and let me know when you are calling the welders, and I’ll walk on down when you need me. Simple, and easy. Start welding without me there and it’s cut out city and treat you like a lying child. Simple, easy.

Thank you for the input. :) :)
 

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Discussion Starter · #13 ·
Also, if doing the 4.0l headswap, consider this thread https://www.jeepstrokers.com/forum/viewtopic.php?f=6&t=24 or just get a whole crashed 4.0l cherokee for $500 like I see them on craigslist and swap the whole 4.0l engine and EFI over.
Thanks, yes I have seen that and that’s why I was thinking about it, but thanks for making sure I was aware of it. At this time I am not going to do the whole EFI swap over. I don’t know enough about it yet, and basically I want to keep the wiring to a minimum at this point. But it IS an item on the menu for later consideration! :):)
 

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Thanks, yes I have seen that and that’s why I was thinking about it, but thanks for making sure I was aware of it. At this time I am not going to do the whole EFI swap over. I don’t know enough about it yet, and basically I want to keep the wiring to a minimum at this point. But it IS an item on the menu for later consideration! :):)
The EFI is a huge Horsepower and usability gain even on top of the head swap, just something to remember. You also don't need to use expensive hesco parts like the harmonic balancer CPS or vss. When and if you do the AX15 swap in place of the pukey, just get a later flywheel from a 4.0l and that will have the nubs for the sensor and the ax15 will have allow for mounting the sensor. As for the VSS, find a 1991 cherokee at a pick and pull and grab the VSS as it will have the mechanical speedometer threads and be a VSS.
 
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Oops... I forgot about making excuses for parking in the way... they do that well too.... lol

Dude.... V8 swap that beast....

Oh and btw I'm just razzing ya... just the fact that you aren't rolling a 4 dr jk on 37's w 3 tons of bolt on armor down the row puts you in the top 5% of inspectors ;)
 

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Discussion Starter · #17 · (Edited)
Guys I have to say THANK YOU!!! You have given me some great advice, and pathways forward. For the record, I spent 10 years in the Army, mostly in the Airborne side of things, so I can definitely take any razzing thrown my way, just fair warning that I dish it back too!!!))) Yes the wall of text is kinda long, I just wanted to put out the details I have, so you know what I know up front. And yeah, what I know now is a world more than what I did 14 months ago. The whole re-gear issue was something I wanted to avoid, and I see now that that was never going to happen. I was always going to have to re-gear. I probably should have gotten 31’s, but it came with 33’s so I just straight replaced them, never thinking about if I needed a gear swap. You know what they say about assumptions being the Mother of all Frak-ups. Anyways, the whole wiring/Nutter-Nut hack job was an issue also. I am in the process of rebuilding a YJ PDB as I saw in one of the YouTube videos, to run all power through there, ignition, and other stuff. I have a separate 6 gang switch assembly from Amazon for a later Jeep that I have all the aux lighting running through.

I am probably going to do the full EFI swap later, I’m just trying to get this to run down the road safely right now, and get some use for all the $$ I have already spent, lols. I also have learned about the LJ Unlimited Jeep, which basically to me is a modern version of the Scrambler. So, I am looking hard at finding an LJ for the extra room (and maybe being able to keep the back seat?), and building that to be the real work truck, and retire the YJ to weekends and recreational use. Maybe keep the 4.0, maybe look at a V6 or V8 swap on the LJ. That is all in the future now though. I am learning a lot, so thanks, and please don’t be shy about offering any tips or suggestions. Like the Banks header. I was looking at that because of the 2.5’ collector. Other than that, and of course Banks quality and reputation, I am open to anything that gets the job done. Cheaper is better, as long as it is done and reliable. I was going to just buy an exhaust kit and install it, but I may be able to get a custom exhaust bent and installed for cheaper than buying a bolt in kit. I’m not knowledgeable about EGRs, carburetors, or any kinds of the computer controls really. I can turn a wrench, replace bearings, brakes, clutch disc, shocks, things like that. I leave alignments, tuning, carb and EFI adjustments to the professionals. Yes, I really should learn more about that stuff especially the carburetors.

I am going to do the re-gear first, got all the parts picked out, 4.56 gears and new carriers, and some are on the way, some will wait a cpl weeks as I get paid every other week so. Then get it on the road on weekends, test driving and doing the gear break in. While I am doing that I will finish the new PDB and install it, and finish the new inner fenders. Maybe see about a radio and speakers, and whatnot. I put all new seats and risers in, and I will need to go back to the old risers, the new one is much taller and I’m only 5’8”. So that’s the current plan for the next few weeks.

OH. Is it worth putting a limited slip differential in the front Dana 30 axle? I can put in this;

https://www.amazon.com/Powertrax-GT...=1579788949&sprefix=Powertrax,aps,199&sr=8-18

and not break the bank. Otherwise I’ll just use an open diff for now. Lockers, Dana 44 or Ford 8.8 are later. Other good news is that I do have an NP231, not the 207 as the book said. So that’s good news too!!! I may decide to swap the doors on the YJ for TJ doors, I like the vent window but my doors would need a new drivers vent window hardware, it’s not in good shape, and they are in the way of the mirrors. Another day lols.
 

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Tj doors don't fit yj's...
The dana 30 is all you need for 33's and even 35's with better shafts.... the 35 is fine for light or moderate use w 33's and an open diff... I've been beating mine hard w 33's and a 4.0 for almost a decade...
 

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Surprised no one mentioned a set of axles out of a 4 banger 5spd. They have 4.10 gears and bolt in for what a grand less than a re-gear. Throw a Aussie or Lockright in the D30 and you would be good to go. All of this is easy enough to do in the driveway. While you're at it add some Powerstop calipers and Z36 pads on the front along with a dual diaphragm brake booster and master cylinder for a '95 YJ for better stopping power.
 
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