More than thinking-about Cat-swapping the Disco

Ted

The pilot formerly known as Twin Engine Ted
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A month or so ago I started this thread on maybe LS-swapping the Disco:

https://www.pilotsofamerica.com/community/threads/thinking-about-ls-swapping-the-discovery.129858/

Our favorite local Cat supporter @NealRomeoGolf started chatting about the prospect of something far more interesting than an LS swap, swapping in a Caterpillar diesel.

Obviously there are some significant considerations with this. For one, the Disco's engine bay is designed around a V8 or a stock diesel 4-cylinder. Typical Caterpillar engines are much larger, with a 3116/3126 like I have in the RV being long enough that it would stick out about 6-12" in front of the grille currently, not to mention weigh around 1200-1300 lbs by itself. Obviously, that's not very practical.

However Cat does make some smaller industrial engines which are of interest, the 3114 and the C4.4. It's worth noting that this same concept is commonly done by others - the Cummins R2.8 and before that Cummins 4BT swaps are popping up all over, and both have been shoehorned into Discos before. I've not seen very many people swap either of the Cat diesels in, but I suspect that has less to do with the engines themselves. It's still been done - there's a 70s Dodge pickup out there with a 3114 in it.

Putting a Cat engine in would be a whole lot more fun than an LS. For one, not many people do it and I'd have the only Cat-powered Discovery in the world (an obvious plus for The Ted). For two, I really am more of a Cat fan personally, and if given the choice between Cat vs. Cummins I'll always pick the Cat. There are some more engine-specific items that I like about the Caterpillar engine we think is the best fit (more in a second on that).

So, looking at them, the 3114 vs. the C4.4 have pro and cons. The C4.4 was originally a Perkins design. Cat bought Perkins in the late 90s, and it's since been rebadged as the C4.4 with some changes along the lines mostly for emissions and to increase power input options. The "Perkipillar" engine is more commonly available, but has a few drawbacks. For one, the rated RPM is around 2,200. This is fairly low given the gearing of the Disco and available transmission options and would give a significant restriction on top speed, while also putting a whole lot of torque through the driveshafts. If I changed the gearing in the pumpkins to be more optimized for a lower RPM engine, that's 1) a lot of extra work and 2) increases strain on the driveshafts which could break other things down the road. Lastly, the later C4.4s which have higher power (and torque) ratings are all computer-controlled and so that would require some sort of electronic throttle setup rather than simply attaching a mechanical cable.

The 3114 makes for a really good option. They have rated RPMs up to 2,800 (a much better fit for this car with the gearing) and they were all mechanical. Out the door they went out to 160 HP. However, it looks as though Cat worked on a 195 HP 3114 that was probably similar to the marine spec 3116 that made 300ish HP. Because the 3114 is mechanical, it seems like it would be fairly straightforward to turn it up some, and because of the application it would be installed in, I would feel comfortable turning up the power quite a bit without concern since the higher horsepower output would be for shorter periods of time. My plan is to upgrade the stock turbo with a $100 Chinese copy of the Holset HX35 (used on the early 12-valve 5.9 Cummins engines) which would provide the extra airflow/boost required for more power. The 3114 has a water-to-air aftercooler (at least most of them do) and does not use a cross-flow head, which makes packaging quite compact and not needing to run air duct hoses all over. The aftercooler normally uses the standard engine coolant, but I should be able to re-plumb it for a secondary cooling circuit to help keep those temps lower.

The 3114 uses an SAE 3 bellhousing pattern. There are a few options that exist for this transmission wise:

1) Bellhousings are sold that will couple the transmission to the NV4500 transmission, which was used behind early 12-valve 5.9 Cummins engines in Rams. Plenty of strength there, and of course as everyone knows, I far prefer manual transmissions.

2) There are adapters to GM bellhousings, which would allow a 4L80E or 6L80E. The 6L80E has better ratios and would be ideal from that perspective, but there doesn't seem to be a stand-alone controller for it, it was designed around having an electronic controlled engine. The 4L80E is easy to control stand-alone.

I also looked at the Allison 1000 transmission that's used behind the Duramax, but it is far heavier than any other option and doesn't seem to make any sense.

After doing some measurements on the Land Rover vs. dimensions I could find on the 3114 (and also measuring against the 3126B I conveniently have in the RV) a 3114 looks like it will fit, albeit tightly. It is possible that a body lift of a couple inches might be required for a bit of clearance, but that is easy, cheap, and actually makes it look a little better. Accessories are not particularly difficult to deal with as there aren't many, although I may need to make a few changes to the specific accessories used to help packaging. But really, not too concerning. Obviously the fuel system will require some modification, but still not too worrisome.

The engine weighs more, about 400 lbs heavier. But there are also heavier front springs that are sold today that slide right in. That's a simple solution.

So next seems to come the hardest part - finding a 3114. While 3116s are all over the place and readily available, the 3114 seemed to have been an engine that was put in comparatively few applications with few available. Between Google, local CraigsList, local Facebook Marketplace, eBay, so far we've come up short. The ones we found for sale for a reasonable price (<$5k is the goal) were sold. One place (4Trucks in Florida) does have 2 engines, but they're incomplete and are asking $7,500 each plus a core charge. Admittedly, I haven't worked much with SearchTempest or any of the search engines that search all of these areas better, and I should, but have been busy the past week with mother-related items.

If anyone wants to be part of this project, we could definitely use some help in sourcing an engine. I'm fine with one that may need some work (in fact the one we had looked to purchase had blow-by and would require re-ringing) but looking for a reasonable price on one of these. I'm sure that there is someone out there who has one, and it is likely hidden on some local CraigsList/Facebook Marketplace/etc. location. Sadly, just not right here. They might be listed as a 3114, 3114T, or 3114TA. There are different ratings, but probably none would be different enough to matter.

Yes, I know I'm crazy, but that's part of the fun. :)
 
I remember when the first TerraGator showed up with the Cat-9 engine (replaced the 8.1L John Deere in previous models). It just had a meaner growl to it. Seemed to have better low-end torque for getting out of the hole on turn-arounds when hauling 1600 gallons of liquid 32 (32% liquid Nitrogen) in plowed ground, too.

If you upgrade the engine and transmission, you'll need to think about transfer case, too.

What engine are they putting in the 1/2 ton Dodge pickups these days? Seems like they pop up when I'm doing searches for a 3/4 T diesel.
 
I remember when the first TerraGator showed up with the Cat-9 engine (replaced the 8.1L John Deere in previous models). It just had a meaner growl to it. Seemed to have better low-end torque for getting out of the hole on turn-arounds when hauling 1600 gallons of liquid 32 (32% liquid Nitrogen) in plowed ground, too.

Such things are subjective, but I've always felt that Caterpillar diesels have the best sound to them, even if it's a 4-cylinder. They also seem to be a lot more torque heavy and enjoy lower RPMs. If you compare my 3126B in my RV (7.2L) to my 6.7 in my Ram (they really aren't too different of engines), the 3126B is a much older design yet comes out of the box with a good sum more torque, and peak power at a lower RPM. It also does sound better.

If you upgrade the engine and transmission, you'll need to think about transfer case, too.

That's been part of the consideration. The LT230 transfer case is actually quite stout and I'm not worried about it for the power and torque levels we're considering. That's part of why I like the 3114 the way I'm thinking of it as an option. Transmission wise, the 4HP22 is a weak point and I think would barely handle the 4.8LS I was talking about before, it would definitely not handle the torque and especially torsional vibrations of a 4-cylinder diesel. To be fair in the above comparison of automatic vs. manual, the automatic and its torque converter would help to reduce the impact on the drivetrain of those very high torque pulses, but I still think it would be fine with an NV4500.

What engine are they putting in the 1/2 ton Dodge pickups these days? Seems like they pop up when I'm doing searches for a 3/4 T diesel.

I believe it's some Italian V6 diesel. But it's also something I wouldn't want to use - lots of emissions equipment on it, completely computer controlled. I think in this case it would create a lot of extra work.
 
I believe it's some Italian V6 diesel. But it's also something I wouldn't want to use - lots of emissions equipment on it, completely computer controlled. I think in this case it would create a lot of extra work.

Yeah. It seems like the recent diesel offerings are roughly similar to your mom giving you Special K and telling you it's Frosted Flakes. Yeah... It kinds looks similar and technically the underlying ingredients are the same, but it's missing the main point of why you wanted it in the first place...
 
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Yeah. It seems like the recent diesel offerings are roughly similar to your mom giving you Special K and telling you it's Frosted Flakes. Yeah... It kinds looks similar and technically the underlying ingredients are the same, but it's missing the main point of why you wanted it in the first place...

Exactly correct. It makes modern diesels less appealing. And for an engine swap, it makes it much harder if not impossible.
 
Sounds like fun, I'm still fidgeting on what I want to do next..... and buried in fixing my old projects.
 
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Just don't swap in a Cat and end up with a dog.
 
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Just don't swap in a Cat and end up with a dog.

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I should point out a couple of the other motivations behind the swap.

The stock engine in the Disco I actually think is a cool little V8. But it's too small and too underpowered for that machine, which results in what I call "The Trifecta of Bad." It's unreliable (largely because it's working so hard all the time), slow (only 185 HP and 230 lb-ft torque), and gets bad gas mileage (12-14, because of the working so hard part).

A diesel like I'm talking about won't make it super fast, but it should have the same if not more horsepower, and it will make that at a lower RPM (2800ish vs. 4700). Much more torque, and better gas mileage. I don't want to make something that will do 0-60 as fast as my wife's GL550, but it definitely won't be slower than what I have today.
 
I have that shirt. :D

Laurie's favorite hat is her CAT hat (with the CAT logo in pink, hat is camo) that I picked her up at the dealership last year when buying parts for my 3126B. I want a hat that has the "CAT Diesel Power" logo but they don't sell any there. :(
 
It's been a few months, and between a lot going on at home and trying to get the RV back together for trips, plus a lot of dead ends on looking for a 3114, not much had happened.

We ended up missing out on a couple of 3114s. And while I think that engine would be "ideal" from several perspectives, we decided to switch the pursuit to a C4.4 instead. This engine has a few advantages vs. the 3114, most notably:

- Lighter weight
- Smaller dimensions (that will help packaging)
- Newer and more readily available, especially for higher horsepower variants

We found a C4.4 hydraulic power unit (basically a 157 HP engine attached to a hydraulic pump on a stand). The engine reportedly has 3400 hours on it and has good oil pressure. Part of what I like about an engine on a stand that's self-contained is that this will make a lot of the testing to make sure the setup works well easier before installing it in the actual Disco. This will be nice for minimizing downtime on the swap. We use the Disco as our tow-behind for the RV, so we don't want to mess up RVing trips.

The engine will hopefully arrive sometime next week, exact timing depending on the shipping company.

Once the engine arrives, evaluate what it comes with and the overall engine condition. Determine what parts (if any) will need to be replaced as part of install, then I'll get it wired up and running on the stand. That'll confirm what else the engine may require prior to install from its perspective. I will need to do something regarding brackets for certain accessories. Specifically, I'll need to do something for the AC compressor and power steering pump, ideally keeping them in more or less the same locations they're in now so I don't have to mess around with lines.

Because the C4.4 has a 2200 RPM redline, transmission choice is important. The two best options seem to be the T-56 or TR6060 (with a top gear somewhere in the 0.50 to 0.57:1 for the variants I'm looking at), or the 6L80E if I went with an automatic (top gear something around 0.65:1). Really, the manual transmission options are better because the gearing will be better suited to the engine, and my preference is always a manual transmission. With such a low RPM for rated power, the torque is something north of 400 ft-lbs, I think closer to 450, and at a sub-2000 RPM range. From a turbo diesel 4-cylinder, those are some big torque pulses compared to the gasoline V8s normally in front of those engines. However I think with a properly sized (big/heavy) steel flywheel and having a transmission with enough excess torque capacity, I think it will be fine. I'll also probably run thicker oil than the factory-supplied ATF.

A Corvette T56/TR6060 seems like it would probably be a good option. I'm going to be doing some adapting no matter how you look at it, so the fact that they're cheaper on the used market and more readily available probably makes for a better total argument. Plus, since the Corvette puts the transmission in the back connected directly to the differential, that works out more or less like what I'll have in the transfer case.

For transfer case, I want to keep the stock LT230. For one, it should be plenty strong. But it's also just a really good transfer case, and I like that it's a locking transfer case in both low and high range. I'd rather keep that as-is.

So, there will need to be some kind of adapting between the SAE 3 bellhousing of the C4.4 and the transmission (assuming T-56/TR6060) and then from the transmission to the transfer case.

First will be just getting the engine and getting it evaluated while I think about the adaptation aspect. And then I can run it all on the stand together before install in the Disco.
 
Don't you have a car to build? And an airstrip to build? And an RV to repair? And yard apes to raise?

For someone who claims he doesn't care about my thoughts or what I do, not even a bit, you sure spend a lot of time caring about my posts and threads.

This project scratches a lot of itches. The engine in the Disco is really a poor fit for it, as is the transmission. Despite being low mileage it's also already having oil pressure issues, which are common on it, and consumes a lot of oil. So really, some kind of engine swap on it is going to happen or else the scrapping of the car. But it's probably the only vehicle that all 5 of us in the family universally love, and from a vehicle perspective is in good shape, and unique. Plus it's completely set up to tow behind the RV.

Things this will let me play with that I've wanted to do for a long time, plus some vehicle-specific improvements:

- Swapping a diesel engine in place of a gasoline engine (not done that before)
- Swapping in a manual transmission for an automatic (been 20 years since the last time I did that)
- Playing around with adapting various driveline components together that don't normally go together

With the stand, this drivetrain will mostly sit in the corner of the shop and I can work on it as appropriate. I generally figure I'll work on it over the warmer months and try to do the swap over the winter, when we're not RVing.

The RV is complete and on the road again, with nearly 2,000 miles put on the renovation (I'm behind on that thread). While it has some clean-up items to do, it's essentially "done", with some other projects. I'm not in a rush to do anything on it immediately. The Cobra and the RX-7 are the higher priorities, specifically getting the thing running and driving in the coming months, and also getting some races in on the RX-7 this season.
 
Check your priorities. How's the racecar coming along? :)

We're still tentatively planning a weekend to hopefully get it running and driving next month (May), depending on whether the surgeon tells me I need to get this hernia taken care of sooner rather than later (my preference is to put it off until after the summer since it's not bugging me significantly). Once that's done, it's off to the races! Well, probably starting off with the open "track nights" or the like to evaluate the car a bit better. I do hope to get it off the trailer and in the shop soon, now that there's actually, you know, a shop! :)

It would be so weird seeing a disco roll coal. Like, queenly disapproval, kicking of corgis, monocles popping out of eye sockets weird.

I'm not sure why you'd feel that way. I agree for a Jaguar on that completely. However this generation Discovery had factory diesels (just not sold in this country) as did Defenders, and even some Range Rovers. You could even argue that the C4.4, being originally a Perkins design (I think this particular engine may have even been built in the UK) is about as appropriate of a diesel as one could get. It's likely a more refined diesel than the ones originally offered in the Discos.

While none of these parts I'm putting in were originally offered specifically, Discos were offered with manual transmissions and diesels. So this is just doing better than what the factory offerd.

The fact that I'm "downgrading" from 180 HP to 157 HP on rating is perhaps a question, but I think that because of the rev range of the stock engine vs. this diesel, it will feel faster and be faster for all practical operations than it is with the stock engine.
 
I'm not sure why you'd feel that way. I agree for a Jaguar on that completely. However this generation Discovery had factory diesels (just not sold in this country) as did Defenders, and even some Range Rovers. You could even argue that the C4.4, being originally a Perkins design (I think this particular engine may have even been built in the UK) is about as appropriate of a diesel as one could get. It's likely a more refined diesel than the ones originally offered in the Discos.

I'm not objecting to the diesel at all. In fact, I'm trying to orchestrate a 2.0TD JDM swap for my Subaru Outback

It is just the juxtaposition of a Land Rover, which I picture most owners driving with pinkies outstretched, a ceramic cuppa of earl gray near the shifter, and a nice and tidy lace doily on the steering wheel -- vs the hoonigans I see in their terrible Dodge Ram 1500s with the 6" smokestack exhaust running around crop-dusting certain lanes of the interstate for sheer truck-nut-jiggling funnylaffs. My brain can't properly paint the venn diagram between these two types of people, but you're creating a contraption which does just that. :D
 
I'm not objecting to the diesel at all. In fact, I'm trying to orchestrate a 2.0TD JDM swap for my Subaru Outback

It is just the juxtaposition of a Land Rover, which I picture most owners driving with pinkies outstretched, a ceramic cuppa of earl gray near the shifter, and a nice and tidy lace doily on the steering wheel -- vs the hoonigans I see in their terrible Dodge Ram 1500s with the 6" smokestack exhaust running around crop-dusting certain lanes of the interstate for sheer truck-nut-jiggling funnylaffs. My brain can't properly paint the venn diagram between these two types of people, but you're creating a contraption which does just that. :D

I think you're out of touch with both groups. :)

For one, the Ram 1500s are only (recently) available with the "EcoDiesel". The 2500 on up have the Cummins diesel which has the stacks (6" is small, normally you're seeing 8+") and rolling coal.

Remember this is a '97 Discovery. Although they were some of the earlier luxury SUVs, these are still extremely capable off-road vehicles. Yes, growing up on the Upper East Side of Manhattan we saw plenty of them around (many are still there) back when they were new. However, unlike the various 2005ish and later Land Rovers which have moved towards low profile tires and a distinct lack of the off-road capability. In the used market, most people who own Discoveries nowadays have them specifically for the off-road capability. Nobody wants the 18" rims because the 16" rims result in better handling. Good number of lift kits and bigger tires put on these things, although frankly there's rarely a need as the stock vehicle performs quite well. They're not the same group as rolling coal per se, but it's not as far apart as you imagine, not too many people with their pinkies outstretched while drinking tea.

That said, this engine also shouldn't be rolling much coal - it's a newer design, electronically controlled. And while I do expect I'll likely tune it to get a bit more horsepower out of it (ideally back up to the 180 HP or so of the stock 4.0L I'm removing), the people who are making their diesels really roll coal are doing fairly dumb mods to them.
 
All personal opinion here:
Man, why mess with a Disco 1? - the sweet spot for LR overlanding before the onset of superfluous electronics and their resultant failures (the three amigos mean anything to you?), and bag suspension (not if but when mean anything to you?)
Want a diesel? - drop in a 300tdi. Just don’t screw up an icon.

I’ve been sitting back just waiting for a SD Disco1 to find me....my cars and airplane present themselves to me at the appropriate times.
 
All personal opinion here:
Man, why mess with a Disco 1? - the sweet spot for LR overlanding before the onset of superfluous electronics and their resultant failures (the three amigos mean anything to you?), and bag suspension (not if but when mean anything to you?)
Want a diesel? - drop in a 300tdi. Just don’t screw up an icon.

I’ve been sitting back just waiting for a SD Disco1 to find me....my cars and airplane present themselves to me at the appropriate times.

As someone who spent years and thousands of hours wrenching on Jaguars with genuine Jaguar engines that were often "lumped" with others, I get where you're coming from. We tended to thumb our noses up at "lumps" (Jaguars with Chevy V8s thrown in or other engines). With that said...

The 4.0L V8 coupled to the ZF 4HP22 transmission in the US Discos just wasn't a good engine or transmission combination. I actually like both the engine and transmission individually, but I don't like them in the application of the Disco. The engine is what I call the "trifecta of bad". It's unreliable, underpowered, and gets bad fuel economy. There's really nothing to like about it in the Disco. The 4HP22 is a good transmission, but it doesn't handle the torque well for a vehicle weighing as much as the Disco does. There are fewer complaints about it than the engine, but the engine really doesn't perform in any respect, and with only 75k miles on it, it's already having oil pressure issues (which is common on these things). As a combination, the engine makes peak torque at 3,000 RPM (and a pathetic 230 or so ft-lbs) with peak horsepower at 4750ish RPM (an even more pathetic 180 HP). In normal driving without flooring it, you rarely get above 2,500 RPM (and if you do the engine sounds way overworked) so it just doesn't work well together. I would love this engine for another, light weight, application. I will save it and I plan to use it elsewhere.

Also, neither the engine nor transmission are truly Land Rover components. The engine was originally a Buick 3.5L V8 that Rover bought the rights to and then made changes/improvements to, but this is not a special engine or transmission by any means. It's not like taking a Jaguar V12 (a proper Jaguar engine) and replacing it with a Chevy V8.

The only special part of the drivetrain, the LT230 transfer case, I am planning on keeping. That really is a great transfer case and I think is part of the off-road capability of the D1s, and why I absolutely do not want to mess it up by throwing in some American transfer case that would easily bolt up to some American transmission. This will take extra effort but I think is worthwhile.

It's also worth noting that I'm not the first one to do an engine swap in a D1 for the exact reasons noted above. LS swaps are pretty common, as are Cummins 4BT and Cummins R2.8 swaps. Everyone who's done one of these engine swaps is very happy with the result (at least from those I've read).

In other words, I'm keeping all of the parts that made a D1 such a great vehicle, and improving the parts that were its downsides/Achilles Heels.

Lastly, this D1 is not a pristine, perfect, original example. It's lower mileage at 75k or so on the clock, no doubt. It's mostly rust-free (although driving on the beach on South Padre may have changed that). But this is what it looks like currently:

upload_2021-4-21_21-27-0.png

Note the orange paint and G4 Challenge badging. That is not original. It was a "tribute" to the G4 Challenge Land Rovers from the early 2000s, originally painted white. Only one thing - D1s didn't participate (at least as far as I understand - they were D2s). So really, it's already been changed somewhat. We bought it because of its lower mileage status and generally good condition, plus it was local.

I get that what you're looking at is originality, and for many vehicles that's what I advocate. A friend of mine recently bought a 17k mile all original Corvette Z06, and I'm trying to convince him to not do anything that is difficult/impossible to reverse. What I'm looking at is practical changes for a vehicle that we use and enjoy that 1) don't reduce its performance (rather increase it) and 2) will improve its reliability for something that we use regularly and is already not perfect.
 
I vote for a TPE331 swapped Disco.

Talk about exhaust note....
 
I vote for a TPE331 swapped Disco.

Talk about exhaust note....

I know the post is in jest, but really a turbine-powered vehicle of any sort offers little in the way of practicality and is just a novelty. Plus, while I enjoyed flying the MU-2, turbines don't have as much soul as pistons.
 
The C4.4 has arrived!

upload_2021-4-23_12-33-39.png

(if the above photo doesn't scream "Hold my beer" I'm not sure what does)

I'm waiting for a bit more work to get finished up in the shop this afternoon before I can get it inside.

Doing an initial evaluation, there are a few things noted that weren't clear in the pictures.

First off, the engine does have ports that can be used for the heater core. That's nice because I wasn't sure how that would work. I'm not sure what they would've been used for in the engine's application, but they're there. When I opened one of the valves, a little bit of what looked to be Cat ELC coolant came out, which is a good thing.

Originally, this engine was yellow. For some reason, it has what appears to be a somewhat fresh coat of blue paint on it. My guess is they did this at the engine sales company before shipping it out to help make it look more appealing sales wise. The coolant fan even has some blue paint on it from overspray. Don't know why they didn't just paint it yellow, but ok. I'm going to paint it yellow.

There was some kind of a control box for this unit. It got cut off with the entire wiring harness going to it, so the first real step is going to be figuring out what the wiring diagram is supposed to look like so I can try to hook up enough to get the thing fired up and running.

It has a standard J1939 connector (9-pin) which I didn't know if it had previously, so that does help to make interfacing with the engine sensors better/easier. And the sensors for the engine itself all seem to be there and hooked up.

The unit also comes with the hydraulic pump attached to the back, which I need to remove. So next step will be getting the plastic off (then I can get a better idea of what I really have to work with), pull the hydraulic pump off, and start work on wiring.
 
Careful with that strap going over the edge of the bucket. Looks like it could slice right through.
 
Careful with that strap going over the edge of the bucket. Looks like it could slice right through.

It would definitely be a terrible idea to handle items like this as standard practice. However for moving one a couple hundred feet with straps that started off in good shape, it worked fine. The engine is now in the shop.

More later. :)
 
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