Engine Options, Cat 375L

[JDOFMEMI]

Well, the engine in my 375L decided to lay an egg today in the form of a rod and part of a liner out the side of the block. Machine serial 8XG00304


I am looking into economical options to repower it. Possibilities include a 3406E from a truck. I can get a good deal on one with low miles from a wrecked truck. I do not have the serial number yet, but will post it later.

Does anyone know of a good solution for the E model engine to be able to "talk" to the machine computer to control the pump settings? How about the correct way to get throttle input to the engine?

I know there are many other things, and due to the age and condition, it needs to be an economical project. No new crate engine here, though it would be nice, it is simply not in the budget.

Thanks in advance for any help you can give.

 

[DPete]

Sorry to hear Jerry, always something in this biz. Best of luck on a solution

 

[Nige]

Jerry, are you working against the clock on this one..? If not maybe you can build up an engine into the correct arrangement to suit your excavator by using a short block assembly taken from an older engine. That way you'd still keep the electronics you need in order to interface with the implement hydraulic system controls.

 

[JDOFMEMI]

Nige

I have a bit of time, but not too much. It is costing production while I am filling in with a smaller rental machine, and eating overtime to make up some of the difference.

The sad thing is this happened about 3 hours after resurrecting the old girl from a failed swing drive.

The leading option is to put a 3406E, early 2000's vintage, into it. My mechanic has worked out how to run the 12V engine in the 24V hoe, and plans to use the original throttle assembly to push on a potentiometer to control the engine. The original setup will still feed the machine computer to control the hydraulics.

Does that sound like a viable solution?

The later E model engine will help out on the emissions regs as well, though with my fleet I would not have needed to worry about this machine for the rest of its natural life.

Part of the motivation for doing it this way is the deal available on the E model engine through a partner I trade with often. Part is also that I feel this may be the fastest solution as well.

This is not the first time swapping a truck engine into an excavator, though each machine has its own specific challenges. We have done 2 Cat 350L machines, one with a truck engine, and one from a farm tractor. Both ran many useful years after the swap.

 

[Cmark]

I think you may be underestimating the job. That engine has an engine oil lubricated rear gear train to run the swing pump, amongst other things. I tried to replace one with a 3406B from another machine some years ago and it wasn't straightforward. There was something fairly unique about that arrangement but I can't remember what I'm afraid.

 

[JDOFMEMI]

Is there any way to find out before I pull the truck engine and look to see if it has the right oil port needed to oil the gear train?

We are familiar with the requirement, which is why we did not update it to a low hour Cummins engine I had on the shelf years ago. We are hoping the oil port is there and just plugged in the truck block, as it was on the 350L's that we converted.

 

[02Dmax]

Nige and Cmark are much more qualified to be answering this than me but it sounds like an undertaking that will end up just kinda sorta correct. I know a truck engine will "fit" or "work" but you're going to have to strip it down to almost a bare engine to install the correct housings and covers and pans if I'm not mistaken.

There's not a 3406 short block anywhere nearby that could be picked up on the cheap? I've had multiple customers ask to replace an engine with one out of a truck and I always just simply refuse. Fuel settings are different, ratings are different, and usually alot of hard parts are different.

I understand being in a pinch though, just hope you can make something work.

Good luck!

 

[Cmark]

The only thing I can suggest is post the serial number of your donor engine and we'll see if it has anything in common with your 41Z05616 engine.

 

[Plebeian]

Where did you end up with the engine fix?
Online Diesel engine finders usually provide a lead where possible solutions can be found.
http://www.dieselengineindustries.com/

 

[JDOFMEMI]

Well, it is moving, though not as fast as hoped. Other machines needing attention, and bad luck with the donor.

Physically the truck engine will work. Some modification is needed, but nothing that looks too hard. The big thing is the pump drive and it looks to be no problem.

I do have a question though. I have conflicting views on this from other people. The truck engine runs on 12 volts. The excavator is 24 volt. Does it matter to the engine ECM what the input voltage is? I have heard it will run fine, but myself and my lead mechanic are skeptical. Does anyone know for sure? If it needs to remain at 12 volts, we can convert the voltage for the engine ECM to 12 while leaving the machine systems 24.
The engine serial is 5EK61484, and arrangement is 126-8614

The other note is my "low mile" donor engine. We started it and ran it in the frame of the truck to check for problems prior to going through the work of the swap. It runs good, no smoke or noise, BUT, it makes water. Further investigation shows at least three holes with water running into the liners, so it is going to get rebuilt before going in so we know what we have.

 

[Cmark]

The ECM will be fine on 24V but it will probably throw up some error codes because of it. You may have to get it reflashed or I seem to remember someone on here having that problem a while ago and there was a software switch to change it over to a different voltage. I'll check.

 

[Cmark]

Here you go~~~

https://www.heavyequipmentforums.com/showthread.php?48568-24Volt-Cat-C15-ECM-convert-to-12-Volt

 

[jprefect]

Maybe a dumb question but why can't you use the ecm from the old motor? The old ecm was fine it was just the motor that went bad right?

 

[Nige]

Maybe a dumb question but why can't you use the ecm from the old motor? The old ecm was fine it was just the motor that went bad right?

There may well be some parts or components on the donor motor that require the use of the ECM from that motor in order to prevent Diagnostic Codes appearing. I would suggest using the donor motor ECM as the preferred option and only if all else fails consider using the ECM from the original motor.

 

[Cmark]

The original is a 3406B with a mechanical fuel system which, to be frank, is why I'm struggling to see the logic in repowering with an electronic engine instead of rebuilding the original. But JDOFMEMI has clearly been around the block a few times so I'm going with the flow and helping out as best I can.

 

[JDOFMEMI]

The original is a 3406B with a mechanical fuel system which, to be frank, is why I'm struggling to see the logic in repowering with an electronic engine instead of rebuilding the original. But JDOFMEMI has clearly been around the block a few times so I'm going with the flow and helping out as best I can.

Cmark, Nige, and others

First, many thanks for the help. It is greatly appreciated.

After troubleshooting, it seems the original engine suffered from a failed fuel injection line under the valve cover. This diluted the oil rapidly, and set off the low oil pressure alarm. By the time my operator got it shut down, it had a rod hanging outside of a rather large hole in the block. It is well beyond rebuildable.

The E model engine was available for a reasonable trade, and here in the Republic of Kalifornia, we are under CARB regulations requiring the cleaning up of the fleet. While the donor engine is not the latest and greatest, it is a strong step up in the emissions department, so I will receive credit for that. It will take some work, but I have a competent man on it, and we have done several swaps like this before.

Today we have verified that we can physically make everything work. We have to do some work on the fan drive mount, and an alternator and AC compressor bracket will have to be made from scratch. All other items will function as is with a few changes. The oil pan and pick up from the original will be used, the pump drive bolts right on, and even the exhaust and muffler will work. Aftercooler piping will work using a mix of old and new piping. There are other differences, but we are thinking they will not cause problems. After we run it, that thinking may change, but for now it looks good. The electronic engine MAY even save fuel, or not, since it is higher horsepower.

Based on past experience with truck engines in an excavator, while it is not perfect, it is much more economical for a machine near the end of its useful life. We can do this and hope for a few more years from it, and it will be well worth the work. I know that the torque curves are different for these two engines. The truck engine is designed to run at near 1500 rpm, +/- 200, for peak performance. That is where the peak torque is available at, and it falls off in the upper RPM range.
The excavator on the other hand is designed to run 2,000 RPM all day long, and I suspect the peak torque is in the 1800 to 1900 RPM range. I would like to see a torque curve for the two engines to compare, if anyone knows how to get that information.
What I am hoping for is that the increased power of the truck engine makes up for the different RPM range for the peak torque. If that is the case, it will have no problem holding RPM when the pumps load the engine. If not, it will still work, but RPM could drop, leading to reduced performance and longer cycle times. I can live with that as long as it is not excessive.

If we do all this and it does not work out, I will have a rebuilt engine to put into one of my road trucks, but I am confident we will make it work. The ECM thread should be helpful for sorting out the issues there, and that will allow us to keep all of the machine electronics as is.

I will fill you guys in as we progress.

Thanks again for the help.

 

[Cmark]

Thanks for the explanation of your reasoning for this; government mandated work. That explains a lot!

Anyway, here are some more thoughts, presupposing you can get all the physical fuel/coolant/CAC/pump connections sorted out.

You need to address two separate systems between the engine and the machine. Firstly, the engine oil pressure, coolant temperature and voltage. Easily done by taking the senders and alternator off the original engine and putting them on to the donor engine.

Secondly, and much more difficult is the AEC (automatic engine control) system. This requires two interfaces which are; engine RPM and throttle control. The RPM is simple; the two-wire sensor should screw straight into the bellhousing. The problem lies with the throttle control. Ideally you would make up some sort of bracket which makes the existing throttle stepper motor directly control the 3406E's PWM throttle position sensor. Whether this would allow the EPC to calibrate the throttle is another thing given the different torque curves. It would be a case of suck-it-and-see.

A second option would be to run three wires to the cab and mount the PWM controller on the console and give the operator direct control over the engine RPM, in effect meaning either idle or wide open. Because in this case the EPC would sense a fault because it's not receiving feedback from the stepper motor, you would lose control of the PRV for powershift pressure and would have to send it a fixed current as if the machine was in manual control mode (you know, the switches on the back of the RH armrest). This would almost certainly mean either the operator having to feather the controls so as not to bog down the engine and/or increased fuel consumption and/or lower cycle times.

 

[mrappels]

i just want to say that you guys are an inspiration to up n coming guys like myself. thank you for sharing your experiences

 

[CaptainAnalyzer]

I feel like I'm smarter already having read this thread. Jerry, you remind me of the company that I work for in Illinois. Make it happen!

 

[JDOFMEMI]

To update this thread, the now rebuilt donor engine is paired with the now resealed pumps, the engine runs fine, and we are nearly to the point of installing it. Probably next week. As CMark says, we have used all of the donor engine sensors and wire harness to supply the ECM with the data it needs, and have added the sensors the machine is looking for so the gauge panel will work, as well as the rpm sensor so the machine computer knows what is going on as well. We are also going to run the check engine light into the machine control panel.

For the throttle, we are going to connect the cable from the stepper motor to push on the throttle pedal from the donor truck. A little work on the ratio of the lever to get the cable stroke to match the throttle lever throw and we should get close enough for the computer to calibrate the throttle settings.

The biggest structural problem is the fan drive, as the front ends are different between the engines. We have two original holes that line up, plus we can drill the old fan drive to catch two more holes, but it will be less well supported than the original. To counter that, a brace will be added to the upper engine lifting bracket that should overcome the shorter span between upper and lower bolt holes.

The alternator and AC brackets need modification as well, but are less critical and easier than the fan hub.

We are planning to keep the engine ECM running on 12V, and the machine on 24V, so there should not be ECM or injector issues. There is basically double wire harnesses on the engine, one for the machine, and one for the engine. The starter is still 24V, and running off of the machine harness.
The engine will not know the machine is 24V, and the machine will not know the engine is 12V, since each will be getting its own feedback.

The tale should be told by the end of next week, and I will post another update as the project concludes.