Project Moku: $5K Kubota Diesel Budget Build 1990 YJ Wrangler Islander

[RustyAutoholicGuy]

Hey TJer's

First off all I want to thank @Chris for letting put this build here because technically this is not a TJ

The most common question I get is how much does the Kubota Diesel Swap I'm doing to my TJ cost. That is actually a difficult question to answer because I did a lot of trades and because I did a lot of prototyping for KubotaSwappers, I got the parts much cheaper because I was helping with the R&D. Also I went of the deep end with the doubler transfer case thing and that just skyrocketed the entire build . . . completely.

CHALLENGE: Buy a Wrangler and convert it to a Kubota Diesel engine for a total of $5000.

I will be documenting the entire build on my channel, however I will be finishing my RHD Wrangler first. I will be posting the ads and all the prices for everything I spend on this project so everyone can follow along and see how much I'm spending to get this project done! I think I can do this for $5000 but I might go slightly over, I'm not sure honestly but that is part of the fun! To be complete transparent on the build, I will have three different categories for the budget. Purely Diesel Swap, My Cost and Your Cost. I'll go into the details of those categories later!

One quick note, I will be using my Langmuir Crossfire CNC Plasma Cutting table, so I will be including the price of the metal material I'm using but not the cost of the machine since I already own it.

The Wrangler: I found a 1990 Jeep Wrangler Islander that has been sitting in a temperature controlled storage unit for 10 years. No rust, no top, 107K original miles, and it's a 4.2l carbureted inline six cylinder with a 3-speed automatic on the column with AC. I was the 8th guy in line for the Wrangler and somehow I got it! I bought the Wrangler as-is for $2500 so my budget just got cut in half.

Finally for the name. Moku is Hawaiian for Island, I thought it seemed appropriate since this is an Islander edition Wrangler! Now for some pictures!

Pictures from the ad:

Picture of when I got it home:

And the Wrangler in the shop!

Current Cost:

Budget	$5000
1990 Wrangler Islander	$2500
Remaining Budget	$2500

I've already done a little bit of work on it and I'm working on editing that video now and will upload sometime next week!

Let me know what you think! Again thank you again to @Chris for all the support and allowing me to post this build on here even though it's not a TJ!

Thanks
Grant

 

[StG58]

Whoo-hoo! Nice score Grant! $5k, including the Wrangler!? This, I gotta see.

 

[Chris]

Can’t wait to see this, I agree!

 

[RustyAutoholicGuy]

Whoo-hoo! Nice score Grant! $5k, including the Wrangler!? This, I gotta see.

Yeah it would have been WAY easier to do $5000 for just the conversion, but I want to try to show everyone that even on a budget you can have a diesel Wrangler that you can upgrade and lift later on! There will be no lifts or big tires on this build, this is just purely converting a Wrangler to Kubota Diesel and getting it running on the street! The nice thing about the 1990 Wrangler is that is so old, it's except from emission in many states now which makes this build more realistic for many people!

Can’t wait to see this, I agree!

Again thank you so much Chris! I'm excited about trying to tackle this build and seeing if I'm able to pull it off!!! I have a feeling I will be counting pennies by the end of the build!

-Grant

 

[Chris]

I think you will indeed be counting the pennies! Still, it will be fun to watch.

 

[StG58]

If you pull this off Grant, you have no idea how much "trouble" it's going to cause around the ranch.

I'll have Jeep parts stacked everywhere. The guys in the fab shop will run when they see me coming. The machine shop guys will stop talking to me. My boss will counsel me on the use of company time. Then there's the wife...

Oh, I have the OK to have parts shipped to the company. Everything big or heavy can come in commercial freight and I'll get a call when it hits the dock. It's all about logistics, planning and engineering. The rest is twisting wrenches.

 

[RustyAutoholicGuy]

If you pull this off Grant, you have no idea how much "trouble" it's going to cause around the ranch.

I'll have Jeep parts stacked everywhere. The guys in the fab shop will run when they see me coming. The machine shop guys will stop talking to me. My boss will counsel me on the use of company time. Then there's the wife...

Oh, I have the OK to have parts shipped to the company. Everything big or heavy can come in commercial freight and I'll get a call when it hits the dock. It's all about logistics, planning and engineering. The rest is twisting wrenches.

I want to say I'm sorry but I'm really not

Part of the reason for this build was being told that this was a $20K build I was doing on my TJ Wrangler, and that the average person couldn't do this swap OR the one I hear the most "Just drop an LS in it, it's cheaper". I really don't have many bad things to say about the LS engine other than I'm a diesel guy and a small diesel engine guy at that. I've only owned 4 cylinder diesels, and nothing over 2.8L either.

Also I get told constantly "You don't buy a Jeep for the fuel economy". I wonder how many people on this forum alone would like to speed 5K to get a Wrangler, admittedly this one is YJ, and convert it to diesel and get around 30+mpg

The crazy thing about diesels is that if you lift it and put slightly bigger tires but leave the gearing the same, you can actually increase your MPG because of the low RPMs on the engine but also the way the load on the engine works. I'm not sure exactly how that works, but I have talked to KubotaSwappers indepth about it on my TJ build, he really thinks if I do a small lift and go to 31s ~ 33s tires, I'll even get better fuel economy with the same gearing.

-Grant

 

[StG58]

I want to say I'm sorry but I'm really not

Part of the reason for this build was being told that this was a $20K build I was doing on my TJ Wrangler, and that the average person couldn't do this swap OR the one I hear the most "Just drop an LS in it, it's cheaper". I really don't have many bad things to say about the LS engine other than I'm a diesel guy and a small diesel engine guy at that. I've only owned 4 cylinder diesels, and nothing over 2.8L either.

Also I get told constantly "You don't buy a Jeep for the fuel economy". I wonder how many people on this forum alone would like to speed 5K to get a Wrangler, admittedly this one is YJ, and convert it to diesel and get around 30+mpg

The crazy thing about diesels is that if you lift it and put slightly bigger tires but leave the gearing the same, you can actually increase your MPG because of the low RPMs on the engine but also the way the load on the engine works. I'm not sure exactly how that works, but I have talked to KubotaSwappers indepth about it on my TJ build, he really thinks if I do a small lift and go to 31s ~ 33s tires, I'll even get better fuel economy with the same gearing.

-Grant

...And all of that is exactly in my wheelhouse. The wife and I spend a week to ten days out in the boonies several times a year. On top of that, the SE is a very mild build, with 31 or 32 inch tires on it. Off road, yes, but not rock crawling off road. Running the numbers on Grimm Jeeper puts the RPM's at 1,700 to 2,200 at all the speeds I usually cruise at. Right where these 03 Kubotas seem to be happiest. That really got me going. Add in the fact that my cruising radius about doubles, and it's almost a no brainer. Plus simplicity, better torque right where I need it, fuel availability, parts availability, conversion cost...the list goes on.

It turns my perfectly adequate TJ into an absolute monster for my usage.

I'm actually in the early planning stages right now. Reading everything I can find, making lists and notes, collecting pictures...

You started something here, and I gotta thank you again. Without these threads, it would have never occurred to me.

I've got a ton of questions and ideas, but don't want to pollute your good work here. I may start a build thread of my own for that.

 

[RustyAutoholicGuy]

...And all of that is exactly in my wheelhouse. The wife and I spend a week to ten days out in the boonies several times a year. On top of that, the SE is a very mild build, with 31 or 32 inch tires on it. Off road, yes, but not rock crawling off road. Running the numbers on Grimm Jeeper puts the RPM's at 1,700 to 2,200 at all the speeds I usually cruise at. Right where these 03 Kubotas seem to be happiest. That really got me going. Add in the fact that my cruising radius about doubles, and it's almost a no brainer. Plus simplicity, better torque right where I need it, fuel availability, parts availability, conversion cost...the list goes on.

It turns my perfectly adequate TJ into an absolute monster for my usage.

I'm actually in the early planning stages right now. Reading everything I can find, making lists and notes, collecting pictures...

You started something here, and I gotta thank you again. Without these threads, it would have never occurred to me.

I've got a ton of questions and ideas, but don't want to pollute your good work here. I may start a build thread of my own for that.

Hey if it would help, you can send me a PM and I can answer questions that way, or if you want to send me a list I might make it a Q&A video on my channel.

I started my first build and my channel for this reason exactly. Yeah I'm SUPER behind on my TJ but I wanted to show everyone EVERY single step to convert a Wrangler to diesel and the benefits of doing so as well! I'm all for sharing knowledge and making it easier for someone how has never done this project before to get a head and see what they will or will not need for the swap!

Unfortunately this Wrangler YJ build is delaying the build I want to do the most, my 1947 CJ-2A build, and that one has really gone off the rails in terms of custom!!!

-Grant

 

[StG58]

I'm actually thinking of doing a build thread here. That way I can share a lot of the planning and logistics stuff that never gets talked about and is a major part of any successful build. Plus, the questions and answers are ones that everyone doing this conversion will probably have and need answers to. Follow in your footsteps as it were, just more basic and without the videos.

I've already eliminated or modified items on my existing build sheet for plugging in a V2203-DI Kubota. There's a surprising number of things that are actually not required or change from a manual 2.5 gas to a manual V2203-DI swap.

I'll get that started in the next couple of days.

 

[RustyAutoholicGuy]

I'm actually thinking of doing a build thread here. That way I can share a lot of the planning and logistics stuff that never gets talked about and is a major part of any successful build. Plus, the questions and answers are ones that everyone doing this conversion will probably have and need answers to. Follow in your footsteps as it were, just more basic and without the videos.

I've already eliminated or modified items on my existing build sheet for plugging in a V2203-DI Kubota. There's a surprising number of things that are actually not required or change from a manual 2.5 gas to a manual V2203-DI swap.

I'll get that started in the next couple of days.

Another build thread would be awesome!!! I have wondered if going from the 2.5l/2.4l four cylinder to Kubota 03 series would be easier than the 4.0l engine.

If I had to guess I would say the motor mounts will be easier on your rig compared to my rig if I had not gone with the doubler setup.

I'm looking forward to you build thread @StG58

-Grant

 

[StG58]

Another build thread would be awesome!!! I have wondered if going from the 2.5l/2.4l four cylinder to Kubota 03 series would be easier than the 4.0l engine.

If I had to guess I would say the motor mounts will be easier on your rig compared to my rig if I had not gone with the doubler setup.

I'm looking forward to you build thread @StG58

-Grant

Thanks Grant.

It's looking like, at least at this early planning stage, the engine swap is actually pretty straight forward. Especially with the Kubota swappers adapters. Right now I'm looking at the brakes and heater / AC controls, but those don't seem to be a huge issue either. Just need to dig up years and part numbers. Turbos are a thing though. I'm reading about lots of complexity around that system. Mostly from people who are trying to push the limits of output. I'm not one of those people though, so we'll see.

Just got done looking into the legality of the swap. Now THAT was interesting! Both Federal, and Oregon. Oh well, I've been an outlaw most of my life.

 

[BugoutJeep]

The crazy thing about diesels is that if you lift it and put slightly bigger tires but leave the gearing the same, you can actually increase your MPG because of the low RPMs on the engine but also the way the load on the engine works. I'm not sure exactly how that works, but I have talked to KubotaSwappers indepth about it on my TJ build, he really thinks if I do a small lift and go to 31s ~ 33s tires, I'll even get better fuel economy with the same gearing.

-Grant
[/QUOTE]

RPMs, speed, fuel/torque curves seem to matter a bunch for the extra bit of MPG. From my understanding taller/narrower tires have less rolling resistance. Is the height for stuffing the tires or do you think it's an air flow to the engine kind of a thing?

Really it doesn't matter that much. IMO once you're consistently in the mid-20s MPG for a 4x4, I stopped caring as much after dealing with under 15 MPG for everything 4x4 until I got a big truck to improve my MPG and just all around driving experience and now having a pretty capable Jeep that rivals Camry and similar sedans in MPG and stuff that can barely make it out of a pot hole.

What stinks is that I haven't seen a Jeep or small truck or a diesel vehicle or engine I don't want to take home.

 

[RustyAutoholicGuy]

Hey TJers,

I'm WEEKS behind on video edits, I need to find the time to just sit down and get through my backlog of videos!

Anyway here is the first video for this project!

Let me know what you think, I will be bouncing between this project and my RHD TJ Wrangler swap, but will mostly be the other Wrangler until I get it finished!

Thanks
Grant

 

[RustyAutoholicGuy]

Hey TJers/YJers

Sorry for the long delay in an update between going to Disney and July 4th, I decided to just take some time off with my family and not worry about videos and updates. Felt great to just focus on the family but the Jeep itch just couldn't be contained so I'm back at it!

Here is the next video!

We got the Wrangler running, turns out the only part we had to spend money on was the ignition coil, once we got that replaced, everything else started to fall into place!

I've got a backlog of videos to post on both this project and my other TJ build so I'm going to try posting two videos a week for a while to get caught up on everything!

Let me know what you think!
Thanks
Grant