6CTA8.3 engine rebuild for Sur Móvil

No need to bleed anything. The Bosch in line pumps self bleed. Hold the throttle pedal to the wood and crank it. Mos, no break in oil needed, just run it 'til the next oil change interval, unless you were dirty going together, like lots of dirt/dust flying around with things open. I am not a fan of syn oils, I get the idea, but good 'ol petro based for me, Valvoline is my go to, has been forever. I even put 15w40 in the Jeep.

Hey Mos, you DID replace the aftercooler, didn't you? All the pieces of the dropped seats find their way to other cylinders via the intake. They are moving at a very high velocity and some pieces like to get wedged in the aftercooler core. YOU will not be able to see them or get them out, but, guaranteed they will come out by themselves and do the same damage you just fixed as well as take out the turbo.You did a turbo rebuid AFTER the failure was found, correct?

Thanks! You just gave me one more reason to go with a complete different motor for my truck that has all the same engine damage.

Jbulach said:

Thanks! You just gave me one more reason to go with a complete different motor for my truck that has all the same engine damage.

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Yours blew up too? When was this?

Jbulach said:

Thanks! You just gave me one more reason to go with a complete different motor for my truck that has all the same engine damage.

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Unless the block is cracked between the liners, it can easily be fixed in chassis. The parts just need replacing. IF what happened to Mos' engine was a warrant able failure, it would have got a new head, turbo, up to 6 cylinder kits, aftercooler, rods as deemed necessary by the inspecting mechanic, injectors in any affected holes. Inspected and replaced if necessary would be push rods, upper rocker shafts, rod bearings. These plus the gaskets, oil and filter and consumables...parts cleaner,, etc.
The cummins warranty manual also said to inspect the lube pump. I always found that to be a procedure, for this type of failure, nothing in the oil side, only in cylinder, to be a big waste of time.

So, just because there is a failure, don't think you need to swing a complete engine, that's alot of work that does not need doing.

WillWagner said:

Hey Mos, you DID replace the aftercooler, didn't you? All the pieces of the dropped seats find their way to other cylinders via the intake. They are moving at a very high velocity and some pieces like to get wedged in the aftercooler core. YOU will not be able to see them or get them out, but, guaranteed they will come out by themselves and do the same damage you just fixed as well as take out the turbo.You did a turbo rebuid AFTER the failure was found, correct?

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Nope, didn’t replace it. Matter of fact, I didn’t think of it all, but you made a good point.

I just did a second rebuild on this turbo because of the engine. First one way back when this whole shebang started I bought a full cartridge and swapped it in easy, this time I only got the turbo shaft since everything else was fine. More details in video specific to the this turbo.

The motor didn’t go back together with dirty oil, brand new conventional oil from the big O. Normally I run the oil until the oil sample dictates that it needs to be changed (military standard practice), but I’ve been thinking of going to set interval changes. Any thoughts on this from the peanut gallery?

71DeuceAK said:

Yours blew up too? When was this?

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Thankfully just a cheap truck I bought for parts.

It dropped a valve on the previous owner, he pulled the head and let the cylinders rust up. It needs at least a head, turbo, two injectors, 6 pistons/liners, and after cooler, just for starters.

I have only robed a few small goodies off it and would like to get it back to running. Ive been keeping my eye on all the cheap, beat down road tractors, waiting for the right one in the right place. Maybe something to keep Simp and 74m in check, or just something more practical, that I can slap together quickly, only $ will tell.

WillWagner said:

Unless the block is cracked between the liners, it can easily be fixed in chassis. The parts just need replacing. IF what happened to Mos' engine was a warrant able failure, it would have got a new head, turbo, up to 6 cylinder kits, aftercooler, rods as deemed necessary by the inspecting mechanic, injectors in any affected holes. Inspected and replaced if necessary would be push rods, upper rocker shafts, rod bearings. These plus the gaskets, oil and filter and consumables...parts cleaner,, etc.
The cummins warranty manual also said to inspect the lube pump. I always found that to be a procedure, for this type of failure, nothing in the oil side, only in cylinder, to be a big waste of time.

So, just because there is a failure, don't think you need to swing a complete engine, that's alot of work that does not need doing.

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Yeh, a few more items, some I knew and a few I didn’t, I’m just cheap, and like to build “different junk”. Maybe I can eventually sell the crank, rods, and block, to recoup some cost.

Will, can you elaborate on what your looking for, other than the obvious, when inspecting the connecting rods?

Mos, I think Will assumed new oil, but was asking more about the cleanliness of you work environment (clean shop vs laying in the desert dirt).

Jbulach said:

Mos, I think Will assumed new oil, but was asking more about the cleanliness of you work environment (clean shop vs laying in the desert dirt).

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Yeah, there’s no way around that for me. I don’t have the luxury of having the truck in any kind of building. I did my best to keep the weather and elements out of the engine, but you’ve all seen how well that has gone.

That is what I meant, the environment it was in while opened up.

The size of the hit on the piston and head is what would determine the reuse of the rod. One little piece stuck in a piston from a failure in another cylinder, it would be ok. If the crown is unrecognizable, time for a rod.

Traded some effort and use of my torque multiplier for the wheels so I could get another protective control box from another SS member in AZ. Just got back and put it in. He said he wasn’t sure if it worked or not since it was under his seat when he got his truck from auction. We did at least know that it was a correct box for the 939 since it was the same exact box that was running his truck. Fortunately the gamble paid off, the truck cranked right over. Now all I have to do is deal with the neutral safety switch, whether it’s just a matter of cleaning it up or replacing it. Right now that is jumpered so I can get it to crank over.

WillWagner said:

That is what I meant, the environment it was in while opened up.

The size of the hit on the piston and head is what would determine the reuse of the rod. One little piece stuck in a piston from a failure in another cylinder, it would be ok. If the crown is unrecognizable, time for a rod.

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Soooo, I guess a valve stuffed into the piston automatically warrants a rod...
Thanks for your wisdom sir!

Only been a couple days since the last update but A LOT has happened!

A couple days ago I got the #4 fuel injector line I was waiting for so I decided to get back to work. Got a few more things taken care of on the engine, just enough to try to start it. I bleed the fuel lines again and she started right up, but that’s where my excitement ended as I realized almost instantly that she was trying to over-rev. Fortunately I was standing right next to the engine so I immediately reached down and manually operated the fuel cutoff. It was VERY stiff and took a considerable amount of effort to turn with just one hand since the solenoid was in the way. Fortunately, I got it shut off before the engine RPM got too high. My first thought was that my readjustment to the excess fuel screw was too much, or in the wrong direction, since that was the only thing I had touched since the last time motor ran. I took care of a few more things on the engine now that I knew that everything was fine with the engine itself. I finally got back to starting the engine, but this time she flat out refused to start. After a bit of fiddling around trying to get it started I grabbed some starting ether and she fired right over, but only long enough to run on the ether. “Well this is confusing”. I could smell fuel in the exhaust but there obviously wasn’t enough to get the engine running. Another thing I had noticed was that when I cracked the fuel lines, I wasn’t getting fuel to the #6 cylinder. By that point I was thoroughly confused, so out came the TMs, but they didn’t do me any good at all. Only thought I had at that point was that the pump needed resetting since I had used the emergency fuel cutoff. I know it didn’t make any sense since I was smelling some fuel but at this point I was grasping at straws. When I looked at the TMs, and you FINALLY find the right work package, it clearly states that only the A0/A1s have to be reset after using the emergency fuel cutoff, the A2s don’t need it at all. Which makes perfect sense since the A2s use the same action to shut the engine off during normal operation, only difference is that it’s done electrically. I was still certain the pump was the problem somehow, I just wasn’t sure how.

Today I called Southwest Diesel down in Phoenix and talked to them. I had called originally to find out some simple answers but ended up talking to the experienced tech there about the issues and history with the pump. Didn’t take him long to “figure out” what the issue was. From my descriptions he thinks that the plunger and barrel for the #6 cylinder was “seized” and put the pump into a full-rack position, basically full-throttle. And when I manually operated the fuel cutoff it changed its position to essentially nearly cutoff all fuel to the engine. Now I’m debating if I want to have the shop fix it which would mean $$$$$$$, or to have someone with no experience work on my fuel pump (me lol)

At least now I know what the problem is...even if I’m not sure how I’m going to fix it yet. If there was a lot more info out on the web for this pump I would certainly be more inclined to fix it myself, but there isn’t hardly anything. It was hard enough just finding the manual for the pump. I guess I’ll update when I figure out what I’m going to do.

Take it to the shop

Jbulach said:

Soooo, I guess a valve stuffed into the piston automatically warrants a rod... View attachment 741714
Thanks for your wisdom sir!

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Yup, that's a good one!

Hey Mos, sorry you can’t catch a break!

Weren’t you playing with the injection timing shortly before this all started? I think I remember that the pump itself can be advanced, maybe a good time to have the pros due that as well, so you can just pin time your pump back on.

I was also wondering the quality of the fuel you’ll encounter once you take the truck south, and if there would be a timing that would work best in that case? Guessing dirt and water would be the biggest issue you’ll run into though...

I can't believe the luck, and stamina you have. 9.8 out of 10 people here have no issues with the 8.3L. It is pretty well hardened and proven. You are on the way to knowing more about this engine and configuration than anybody else here.

I see the military 8.3L MW pumps on ebay for relatively cheap. I would pull the end cap off of yours, and see if you can work the rack rod back and forth to free it up. It sounds like you moved it once already, so it is not totally seized.

If not, then simply replace it with a $200 eBay pump. Or go big and throw a P-7100 on it, but I think you really just want it running for now. Target 980hp later......

WillWagner said:

Take it to the shop

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I’m already leaning that way at the moment. I have found some info on the pump, and the after reading the manual some it actually has more info in it than I had anticipated. Only problem is that the plunger/barrel assembly (matched sets) are pretty expensive for this pump, which is why the rebuilt/reman ones go for a very pretty penny.

Jbulach said:

Hey Mos, sorry you can’t catch a break!

Weren’t you playing with the injection timing shortly before this all started? I think I remember that the pump itself can be advanced, maybe a good time to have the pros due that as well, so you can just pin time your pump back on.

I was also wondering the quality of the fuel you’ll encounter once you take the truck south, and if there would be a timing that would work best in that case? Guessing dirt and water would be the biggest issue you’ll run into though...

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Yeah, I had tried to advance the timing once before and immediately hanged it back to stock, or what it was before I changed it. Of course now I don’t remember why I did that, but that was one of the questions I asked when I was on the phone with them yesterday.

Ive also wondered about the fuel quality down there as well, but not much I can find out about that without actually going there in person.

74M35A2 said:

I can't believe the luck, and stamina you have. 9.8 out of 10 people here have no issues with the 8.3L. It is pretty well hardened and proven. You are on the way to knowing more about this engine and configuration than anybody else here.

I see the military 8.3L MW pumps on ebay for relatively cheap. I would pull the end cap off of yours, and see if you can work the rack rod back and forth to free it up. It sounds like you moved it once already, so it is not totally seized.

If not, then simply replace it with a $200 eBay pump. Or go big and throw a P-7100 on it, but I think you really just want it running for now. Target 980hp later......

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Thanks man, it’s certainly been a trying time while this truck has been down. Even this pump is normally bulletproof, but this time I’m fairly certain I can say that it was my fault. I forgot to cap off the delivery valves on the pump and with being exposed to the weather for a better part of a year I’m lucky it wasn’t worse than this. I could just take the delivery valve off, and then try to work with that barrel/plunger assembly with it still in the pump. Basically see if I can get it to free up, but there’s no guarantee I can get that to work, or that I won’t do some damage to the finish inside the barrel. I might soak it with some WD-40 and see what that does. I don’t think I would need to get inside to play with the rack if it is only a plunger that is stuck, but we shall see. I just don’t want to have to get inside this pump if I don’t have to, there is at least one tool I don’t have that I would need if I had to do a full rebuild on it.

I did take a look on eBay and saw a few PES6MW pumps, but they were all rebuilt/reman units and were close to or right at $5k on average. Of course I’m not willing to spend that kind of money at all, mainly because I just don’t have it. At this point I’ll be lucky if I have $750 next month before the bills. I have seen other Bosch inline pumps for much cheaper, but I don’t know enough of the inner workings or what is compatible with what since most of those don’t have the same governor housing like our trucks have.

The Bosch P7100 pump did cross my mind, but I’m not sure what else would have to be changed to make it work on this engine. Yes, I know others have done it, but I haven’t bothered to look since I wasn’t ever planning to change to that pump. Besides, only power increase I might go to is ~300hp/950ftlb, which is the upper limit of the transmission. Overall, I haven’t been upset about the power of this engine (except when I was limping it home ) , I’m only upset about the lack of any kind of overdrive in this transmission. I have an idea to remedy that, but I’ll save that for a different thread.

Gear housing, pump drive gear, fuel lines need changing. For the lines you will need an ESN for a P pumped C with an aftercooler so you can get the lines. When the P pump was introduced, IIRC 1994, the engines went from aftercooled to charge air cooled. Industrial kept aftercooling for a time and still used the MW and A pumps, so, it might be a tad difficult to find the correct lines.

Pull the pump, have the shop clean it up, SOMETIMES the B&P can be lapped and be OK, and tell them that you want the timing advanced to what ever degree you want and to set the fuel rate up a bit. In the end, you will be ahead. Think about it, how much have you put into this repair. IF the pump decides to WFO on it's own, seen it happen from f-ed up delivery valves, you will be doing the repair you just did over again, IF the liner doesn't break and take out the block. Yes, seen that happen too, had to step across the engine as it was spooled up farther than the tach read. I was skeered.

Forgot to update. Got the pump to the shop for a quote. All total it’s about $1150 to have it repaired, had to pay $160 to get it back from them, but that cost will go towards the rebuild price fortunately. I will have to wait until next month to take it in and have them do the rebuild. Next month I will also build a new intake shell from scratch to replace my aftercooler, then I will get a water/meth injection setup to take care of turbo heat in the intake charge. Water/meth system will probably wait until the following month, which is no big deal since I have to wait until then to renew plates and registration anyways. I hope to have the beast rolling again by mid next month, and road legal the following month.