More than thinking-about Cat-swapping the Disco

denverpilot said:
I laughed that you said “started off” in good shape.

Do tell! LOL
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They’re still in fine shape. It was more just that if they were frayed or otherwise in bad shape they’d be much more likely to break.
 
So much awesome.
 
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Love this Ted!!!

Stop talking about the 6l80, you know you want a manual


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MIFlyer said:
Love this Ted!!!

Stop talking about the 6l80, you know you want a manual
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Right now the plan is T56/TR6060. I think that makes the most sense for a number of reasons.
 
Yesterday I played around some with getting the engine evaluated a bit. Mostly I got the top cover off the enclosure it's housed on, and also removed the hydraulic pump. So far I'm not seeing anything bad or concerning. Pulling off the oil fill cap and looking in at what I can see of the valvetrain everything looks good inside. No rust or the like.

Doing some measuring, it will be a tight fit in the Disco but I think will fit. The accessories will be a question, and the steering box looks like it may have some questionable clearance. However basic dimensions seem like it will work, and I don't think any of the challenges are insurmountable. I expected a body lift might be required, and I think from initial measuring I still think that's likely to be the case.

With the stock engine, the accessories are mostly mounted to the front of the engine. With this engine, they'll need to be mounted to the side without question.

I'm also likely to have to do some relocation of the oil filter and fuel/water separator as I think the stock locations will hit the frame, but neither of those are big deals to do.
 
The other day I looked at the C4.4 some more, and started trying to sort out the wiring mess they provided. While they didn't destroy the wiring harness, there are no instructions and they had just chopped off the wiring harness that had previously gone to the control unit. Nothing is well labeled.

I figured out the main power distribution on it, though. There's a big 50A breaker that feeds the glow plugs with a relay (activated by the ECU). On this setup, there was also an oil pressure switch that looked to be used to interrupt power in a low oil pressure condition to shut down the engine. It's not factory, and for how I'm going to use the engine doesn't make sense, so I'll be eliminating that.

The next thing I need to do is some pin-to-pin checks to see if I can figure out which wires go to which pins on the ECU and label accordingly so I can then work on the rest of the wiring.
 
charheep said:
I never had the patience for electrical repairs or troubleshooting on my car projects.

Would something like Painless Wiring (tm) be helpful? Painless Wiring (painlessperformance.com)
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Seanaldinho said:
I'm of the same opinion, after rewiring a 72 VW Bug, I never want to do it again. I've heard good things about Painless as well.
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In this case, I'm looking at the ECU wiring for the engine. Painless offerings don't help with that aspect. While there are stand-alone ECUs for diesels, there aren't many and it is a good bit harder to do than a gas engine. I'm far better off just trying to get the factory ECU working.
 
Ted said:
The next thing I need to do is some pin-to-pin checks to see if I can figure out which wires go to which pins on the ECU and label accordingly so I can then work on the rest of the wiring.
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charheep said:
I never had the patience for electrical repairs or troubleshooting on my car projects.

Would something like Painless Wiring (tm) be helpful? Painless Wiring (painlessperformance.com)
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I always liked buzzing out that stuff myself. Kinda just have to know what each circuit it might have and start with the most obvious stuff. Like Ted, main power first, then find the starter, then find the fuel pump... and figure out what is high current and needs a relay and what doesn’t... one at a time. Then sensors...

Tedious but usually not difficult and at least it’s rare to need a large persuasion hammer and penetrating oil and unreasonable amounts of heat and force to remove rusty things.

Will say that doing it on bigger trucks and such is usually nicer because auto engineers on cars like to route wiring where it’s nearly inaccessible. On a diesel like this one at least there’s usually room to get a hand in wherever the worst sensor is mounted.

Deboss Garage just did his video on almost finishing up the wiring on his Cat swapped man lift...


It’s all super sketchy and fun at the same time...
 
Personally I'm not a big fan of wiring work unless I'm in the right mood. It's something I have to be able to devote some time to without interruption and I have to be up for that kind of work. When I do and can just work on that, it can be semi-enjoyable and semi-relaxing. The wiring work on the Cobra yesterday, for instance, was enjoyable. When I can get a few hours in the shop with the C4.4, some masking tape, and a pen to mark all the wires, that'll be when I get that done. And once I have it figured out, I'll probably try to hook up some fuel and start the thing.
 
Ted said:
Personally I'm not a big fan of wiring work unless I'm in the right mood. It's something I have to be able to devote some time to without interruption and I have to be up for that kind of work. When I do and can just work on that, it can be semi-enjoyable and semi-relaxing. The wiring work on the Cobra yesterday, for instance, was enjoyable. When I can get a few hours in the shop with the C4.4, some masking tape, and a pen to mark all the wires, that'll be when I get that done. And once I have it figured out, I'll probably try to hook up some fuel and start the thing.
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No one at CAT can provide a pin-out?
 
SoonerAviator said:
No one at CAT can provide a pin-out?
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I have a pin-out, but I need to 1) confirm that the pins match for the ones I can find (specifically the positive and negative) and 2) then find the cut off wires and label those so I know what they go to for the wiring to the vehicle.
 
Ted said:
I have a pin-out, but I need to 1) confirm that the pins match for the ones I can find (specifically the positive and negative) and 2) then find the cut off wires and label those so I know what they go to for the wiring to the vehicle.
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Gotcha. I misread it as you trying to figure out each pin from the ECU and find out what it did with no reference points, lol. I figured someone had to have a wiring diagram from the ECU so that you could make a new engine-side harness.
 
SoonerAviator said:
Gotcha. I misread it as you trying to figure out each pin from the ECU and find out what it did with no reference points, lol. I figured someone had to have a wiring diagram from the ECU so that you could make a new engine-side harness.
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Yeah, there is already a harness that I can work with. If not, I'm not quite sure what I'd do, but it probably wouldn't be anything with this engine.

At some point I'll make a video on this for my YouTube channel. I'm pretty behind on videos, but been a little busy.
 
I did a bit more of a walkaround on the engine to get more familiar with it and also to think about potential interference/issue points.

Interestingly, the water pump on the engine is gear driven. Never seen that before, but that's interesting to me. The glow plugs have a common "rail" that they all get power from across the top, pretty easily accessible. The water pump is gear-driven, something I've never seen before but makes sense for an industrial engine. I'll be curious to see how loud this engine is as far as mechanical noise goes when it's running.

One of the most interesting (and unusual) features I noticed is that the ECU is fuel-cooled. I've not seen that before but it probably does make sense for an industrial application where there might not be much airflow around the engine. I imagine the ECU produces a lot of heat with the injector drivers.

Another interesting feature is that, although this engine has an SAE 3 bellhousing pattern, it looks like Caterpillar actually offered different bellhousing options for the engine looking through the spec manual, and that bellhousing area is removeable. I don't expect I will remove it, but as I figure out what to do for transmission mounting it gives me another option to consider.
 
Ted said:
I noticed is that the ECU is fuel-cooled.
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Can you explain this a bit? I have never heard of that. Its not bathed in raw fuel, right? Just fuel lines acting as heat sinks?
 
charheep said:
Can you explain this a bit? I have never heard of that. Its not bathed in raw fuel, right? Just fuel lines acting as heat sinks?
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As part of the outer casing there's what amounts to a tube running top to bottom, with fuel lines at either end. Some amount of fuel runs through that passage to absorb heat. No idea what the flow rate is, and I don't know if there's some sort of finned heat sink or the like internally to help absorb the heat and direct it to the fuel better.

Many turbine engines have fuel/oil heat exchangers, using the fuel to cool the oil and the oil to heat the fuel.

Funny enough, on the Jaguar V12s, there was the opposite - a fuel cooler that used the air conditioning to cool the fuel. However that was to prevent fuel boiling due to the high underhood temps those engines tended to have.
 
Ted said:
As part of the outer casing there's what amounts to a tube running top to bottom, with fuel lines at either end. Some amount of fuel runs through that passage to absorb heat. No idea what the flow rate is, and I don't know if there's some sort of finned heat sink or the like internally to help absorb the heat and direct it to the fuel better.

Many turbine engines have fuel/oil heat exchangers, using the fuel to cool the oil and the oil to heat the fuel.

Funny enough, on the Jaguar V12s, there was the opposite - a fuel cooler that used the air conditioning to cool the fuel. However that was to prevent fuel boiling due to the high underhood temps those engines tended to have.
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Google says that the boiling point of Gasoline and Diesel is similar (I'm sure the answer is more complicated as google only says 100-400 C), but is vapor lock not/less of an issue with diesel?
 
Seanaldinho said:
Google says that the boiling point of Gasoline and Diesel is similar (I'm sure the answer is more complicated as google only says 100-400 C), but is vapor lock not/less of an issue with diesel?
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Diesel doesn't really vapor lock under normal circumstances. Sort of an example: Pour a bit of gasoline out on the concrete and it will evaporate within a few minutes, do the same with diesel and you'll be looking at the oily residue for days. Boiling point is less of a measure than vaporization point. Diesel is around 100F, typical gasoline is like -40F.
 
SoonerAviator said:
Diesel doesn't really vapor lock under normal circumstances. Sort of an example: Pour a bit of gasoline out on the concrete and it will evaporate within a few minutes, do the same with diesel and you'll be looking at the oily residue for days.
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That makes sense, I've always been under the impression that a lot of the "evaporation" in gas was the ethanol expediting that. They are very different compounds, so the difference doesn't surprise me. Just something I hadn't considered before.
 
Seanaldinho said:
Google says that the boiling point of Gasoline and Diesel is similar (I'm sure the answer is more complicated as google only says 100-400 C), but is vapor lock not/less of an issue with diesel?
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It's not. The other thing is that this appears to be fuel cooling on the return side, so the fuel would be going back to the tank and then circulating around.
 
Ted said:
It's not. The other thing is that this appears to be fuel cooling on the return side, so the fuel would be going back to the tank and then circulating around.
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Wonder if that's as much for heating the fuel in the tank (anti-gelling) as it is for cooling the ECU?
 
CJones said:
Wonder if that's as much for heating the fuel in the tank (anti-gelling) as it is for cooling the ECU?
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The Cat manual says that if you opt for the non fuel cooled ECU that there needs to be sufficient “under bonnet” (Perkins/UK influence apparently) airflow. So it seems that it has to do with the application where they’re expecting not much air cooling for the electronics and not due to the fuel. Usually that’s handled other ways, and the ECU won’t make that much heat.
 
Seanaldinho said:
Google says that the boiling point of Gasoline and Diesel is similar (I'm sure the answer is more complicated as google only says 100-400 C), but is vapor lock not/less of an issue with diesel?
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The answer is more complicated. Gasoline is a mixture of hydrocarbons (C5 to around C8) with a range of boiling points. They add things such as toluene, xylenes, and various alkenes to increase the octane, and yes, ethanol, too. The formulation often changes in summer and winter.
 
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This evening I got some more time in to do some looking at the engine. I traced out the wires from the main connector to where the control panel wiring harness had been cut off. Here's where I ended up:

2021-05-14.jpg


The connector is 64 pins, of which a bit more than half of them were assigned to something and present within the wiring harness. After confirming that the power and ground wires looked to be correct and matched the drawing perfectly, I then went through to find as many of the rest of the pins as I could. It looks like this engine was set up to have both some sort of standard throttle and also a "PTO mode" (basically cruise control) based on the wires that were present and went through to the harness. That's good news for me.

As you can see in the picture, there are around 10 wires or so that aren't accounted for. I'll do some more checking tomorrow, but they don't appear to go to power or ground, and I checked all the wires for each pin in case multiple wires went to the same pin (for a few they did). I haven't yet found the starter wire either, which I think must be in that bunch somewhere unless I'm missing something, I may just not have been getting a good connection at the starter for that.

More wiring checking, and then I need to start figuring out how I hook this thing up to run. I'll also need a lift pump of some sort, which is called out by the manuals.
 
Hasn't Tinker already done this? Or maybe that was a Cummins. Same idea though.

 
Silvaire said:
Hasn't Tinker already done this? Or maybe that was a Cummins. Same idea though.

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Yeah, the Cummins 4BT and R2.8 swaps have been done before and are more or less ubiquitous. You don't see it being done with Caterpillar engines. The R2.8 is of course specifically intended as a package for engine swaps (using an engine that Cummins has been making for years and still sells in other markets). The 4BT is basically a 4-cylinder version of the original 12-valve 5.9L I6 used in the earlier diesel Rams and in many other vehicles. Although 4BTs are harder to find.

Like I said, you don't see it being done with Caterpillar engines much. Deboss Garage has been putting a 3126 into a mid 90s F350 (the F-tree-kitty as he calls it) and I haven't been following it. That's more taking the Cat flavor of the "Fummins" swap, where people put a Cummins into a Ford and is a really cool project.

That 4BT in the Disco swap is nice, but just looking at how much that plumbing is sticking out of the hood even with what looks to be a lifted truck definitely creates some issues. This engine is short enough that, while I think I may need to do a 2" body lift, that should be it. And I may not even need to do that.

Plus, this way I can put a "CAT" sticker on the Disco and some sort of appropriate custom plate for it. :)
 
The first video on the Diesel Disco project is up on YouTube:

 
That new shop of yours has really given you a whole lot more elbow room for your projects. It all looks like a good time.
 
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Matthew said:
That new shop of yours has really given you a whole lot more elbow room for your projects. It all looks like a good time.
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This shop has been a lifelong dream come true and I feel very fortunate to have been able to build this and now start using it.
 
I still need to work on getting the engine running (which is the first step before I buy other stuff), but after looking at the bellhousing that came with the oil pump, I think I'm going to be able to reuse that with the T-56 transmission. I'll have to make an adapter of some sort to connect it to the transmission, but the transmission is mounted hub centrically, and the bellhousing has a hub centric mount where the hydraulic pump was attached. So really, all I'll need is an adapter that goes between the two, and get the lengths correct for the input shaft. In the end, I think this will be easier than the other options I was considering.

But, get the engine to run first... that matters. It looks like these C4.4s are specified to have lift pumps (external, electric) which this doesn't have on it. Since there was no included fuel tank it's hard to say whether this had one installed or not, but I figure that since it should have one, I will probably see if I can find one to buy as I'll likely need it in the Disco anyway, and that should help with getting it started the first time.

That's a lower priority, but I should keep an eye on CraigsList for a good price on a Corvette transmission.
 
Ted said:
I still need to work on getting the engine running (which is the first step before I buy other stuff), but after looking at the bellhousing that came with the oil pump, I think I'm going to be able to reuse that with the T-56 transmission. I'll have to make an adapter of some sort to connect it to the transmission, but the transmission is mounted hub centrically, and the bellhousing has a hub centric mount where the hydraulic pump was attached. So really, all I'll need is an adapter that goes between the two, and get the lengths correct for the input shaft. In the end, I think this will be easier than the other options I was considering.

But, get the engine to run first... that matters. It looks like these C4.4s are specified to have lift pumps (external, electric) which this doesn't have on it. Since there was no included fuel tank it's hard to say whether this had one installed or not, but I figure that since it should have one, I will probably see if I can find one to buy as I'll likely need it in the Disco anyway, and that should help with getting it started the first time.

That's a lower priority, but I should keep an eye on CraigsList for a good price on a Corvette transmission.
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Car-part.com has been really helpful to me
 
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I just posted the next video in the series, this one is about going over some of the features of the C4.4:

 
Today I spent some more time in the shop toying with the engine. I managed to identify the remaining pins on the wiring harness that I hadn't yet found, both on the ECM side and also on the harness side. Turns out, the harness that went to the control box (this was what got cut off) had wires going to every pin on the twist-lock connector that then went to the ECU, but 10 of those wires were unused. I've positively identified all the pins on the ECU, the main power arteries, the starter wire, and the CAN (J1939) and CAT data links.

This engine has a "PTO mode" which, assuming it works like on the RV, lets me set high idle but doubles as the cruise control. I managed to find some data on the throttle position sensor, which is apparently an 8V PWM signal (5-95%). Cat makes a converter box that lets you connect a 1 kohm potentiometer and then it will output the PWM signal. I think I want to get the engine running before ordering one of those boxes. I can use the PTO mode to (theoretically) demonstrate basic engine control beyond idle.

I'm also debating what I want to do regarding attempting an OBD interface. Heavy duty/industrial diesels use J1939, which is still done on a normal CAN BUS. Caterpillar has their own diagnostic system as well, which I may end up wanting/needing to buy, but I think I'll start off without that at least to get the engine running. I have an OBD2 reader that claims it will read J1939, though, so I may just get an OBD2 pigtail, wire that up to the CAN wires, and see if that works. That's probably the simplest first step, although alternately I may get a J1939 pigtail and then an OBD2 to J1939 adapter, which would allow any of the Caterpillar tools to more easily be connected.

At this point, though, I need to get a fuel pump of some sort (low pressure to supply some fuel to the engine), hook up some wiring, and put new filters on it (oh yeah, and put some oil in it) and I should be able to make it run. Like with the Cobra I want to bring the ECU online on its own first and try to make sure that things look like they're working before attempting start. But, I might be able to get it running sometime this month.
 
Ted, when I grow up, I want to be you.

—-

No, that’s not it. You never completely grew up, and that’s a compliment. You inspire me to better things, and I suspect I’m not the only one who feels that way.
 
Spike, you give me far too much credit, although the "Never completely grew up" is spot on. :)

I'm really looking forward to getting this thing running, followed by the various incremental steps to get it driving. It should be a great end result.
 
I did some more digging on the OBD/CAN/J1939 question. One thing with J1939 connectors is that there's a level of variation in how they're pinned. OBD2 has a level of variation, but the basic power, ground, and CAN (i.e. OBD2) pints are standard. Then you have various over the top pins/busses that get used. With J1939, power and ground seem to be constant, but beyond that you have a number of items that are not so constant. Because of this (and finding a $9 OBD2 pigtail on Amazon), I decided to start off by going with the OBD2 pigtail option, and I'll see how that works with my Bluetooth OBD adapter that claims to support J1939. Once I get that wired up, I can see what I can discover, and go from there.

If it works, it's appealing to use some sort of CAN-based instrument cluster. However I haven't found anything out there that seems particularly feasible/reasonable at this point. I'm not sure what of the factory instrument cluster will work with this project, and frankly don't care a whole lot as instrumentation is something I can figure out a way to deal with one way or another. But something CAN-based has appeal since the ECM knows the most important things already - oil pressure, coolant temperature (probably oil temperature as well, not certain), boost level, engine RPM. The only things I care about that it won't know are vehicle speed and fuel level. So, something to think about/consider.
 
I have used a 7 inch tablet running Torque with a wireless OBD2 with great success. It's cheap and it works well.

I suppose it could be made permanent with a fixed display and a small Android box. That's all the expensive displays are, anyway...
 
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