6CTA8.3 engine rebuild for Sur Móvil

These ones don't eat metal, as long as you use the correct one for the material. Green for steel/iron, yellow is coarse for aluminum, and white will simply polish aluminum. They literally burn/melt any surface impurities off, be it rust or gaskets yuckies. They are not abrasive type. This on a high speed 90 degree angle air die grinder, and that block deck will look like it just came from the mill.

74M35A2 said:

I find particular interest and respect those who do this on such a budget (or nearly none at all). I throw money recklessly at my truck in random spurts, it is all sitting around as parts in piles of dreams to install, which is the worst situation possible. No $, and no fun stuff installed. Just a waste of both. I really should take one of my vacation weeks from work once the kids are back in school, and see how many of my upgrades I can get done in a week.

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74M35A2 said:

Cold beer in the air for you, Mos. You're rat-rodding (spending no $ on it) forward with every post. Keep going. Love the bottle-jack tower of power. Can't wait to re-hash rocker arm nuts again once you get there.

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That’s the way it feels that I’m doing this, in random spurts with only a general direction. I can only do so much on my military retirement, so I usually have to pick and choose my battles for the month. Rarely are any of those battles what I really want to deal with that month. After I had thought about it some (after removing the head) I think the #5 valve seat dropped, which destroyed the turbo and loosened the valve rocker bolt. Of course I caught the turbo issue, but didn’t notice the rocker until it was too late, which was probably when the #6 valve seat dropped too.

74M35A2 said:

These ones don't eat metal, as long as you use the correct one for the material. Green for steel/iron, yellow is coarse for aluminum, and white will simply polish aluminum. They literally burn/melt any surface impurities off, be it rust or gaskets yuckies. They are not abrasive type. This on a high speed 90 degree angle air die grinder, and that block deck will look like it just came from the mill.

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I love those things, I just don’t have any of them. Unfortunately, I effectively got nothing done today since the neighbor called and asked for some help. Was also working on dumping the videos I’ve recorded on my phone onto the computer since my cloud is almost full and I do need to start editing the next YT video. The only thing I managed to do was to test disassembly of the wrist pin/con rod/piston. Ended up using the 8 ton jack in the 20 press that I still have from the neighbor. Even 8 ton is more than I needed but it just didn’t want to come out by hand. I do need to verify which bearings I have for the con rods, if I have both sets then I’ll have to figure out how to remove the upper bearings for the wrist pins.

Agree completely with 74M35A2. Having no money to speak of myself I totally respect anyone willing to work on these monsters in the "driveway". To me that is the difference between a MECHANIC and a repair technician.

someoldmoose said:

Agree completely with 74M35A2. Having no money to speak of myself I totally respect anyone willing to work on these monsters in the "driveway". To me that is the difference between a MECHANIC and a repair technician.

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In the “driveway” repairs is all that I CAN afford lol oh who am I kidding?!? Even if I was “loaded” I’d still do this work myself, mainly because I don’t trust other people to do what they say they will, or to do the job right.

Finally got a new video uploaded last night so that freed up some space on my phone for some more video. Today I’m just trying to clean up my work area, and my property in general a bit, so that it isn’t as much of a disgrace. Maybe tomorrow I’ll actually accomplish something on the engine.

Was working on assembling one set and found rust on the intended replacement wrist pin. I’m very disappointed that companies these days don’t use any real form of CPC. Fortunately the other pins were fine, but later the first box of pistons rings I opened also showed rust. I haven’t checked the rest since by that point I was just too irritated. I got one set almost fully assembled, but I can’t get the wrist pin retaining rings in place due to ****ty tools, so I have new tools on order. Hopefully the snap ring pliers will be here on Tuesday and I can continue.

Got the head yesterday and just dropped it off at the machine shop. No rocker assemblies or the main oil manifold, 3 broken injectors, at least broken bolt, and one spring missing. Hopefully the repair work on it won’t be too much. The pistons are in the liners and waiting on the head to be installed, also waiting on some fine scotch rite to show up from Amazon so I can clean up one rod journal since the recent rain got to it.

You been a bizzy fella. Hope ya get good head and we soon hear a baritone roar.

Got some parts painted with some high heat exhaust paint. Turbo housing, exhaust manifold, and the two brackets for the coolant reservoir that bolt to the exhaust manifold.

Since I didn’t want to wait nearly a week for vinegar to do most of the work (besides the fact that I didn’t have enough) I used muriatic acid and just checked it and cleaned it up every 30min to an hour.



Then threw them in the blasting cabinet to clean up the rest and the flash rust after the acid bath.



Then some of Eastwood’s High Temp Exhaust paint in Cast Grey.

Well, compared to the past there has been a ton of progress since my last update. I got the injection pump retired for a couple degrees advanced, timing cover gasket replaced, front main crank seal replaced on the timing cover, new pistons assembled and inside the new liners, got the piston and liner assemblies in the block (still need to torque the rod caps, got the “new” head assembled (even found another nugget for 74M35A2) and installed and torqued in place. Exhaust manifold is in place but not torqued or tightened since I need to replace all of its bolts. Turbo exhaust housing is in place as well, but not tightened until the manifold is torqued.


Piston & liner assemblies installed.



74M35A2, here’s another for ya. I’m just glad I caught this one before it failed in the engine too. After 2 failures (33% failure rate is completely unacceptable) I’m going to buy 6 new rocker pivot shafts from Cummins and replace all of the as soon as I can.



Head pieces inspected and assembled



Head torqued, torque + 90 degrees. Per QS mine was 107ft for the long bolts, and 52ft for the short bolts.



Once again I’m waiting on payday, need to get exhaust manifold bolts, oil pan gasket, oil and coolant, and I’m sure I’m forgetting something I still need to get the beast running again. I do still need to find my electrical gremlin too, I opened my PCB since I 100% sure that it was the problem, but alas it looks like I might’ve been wrong (still haven’t actually tested the PCB part of that box.

Buy all of the hold down bolts too, they stretch when rocker shafts break. Make sure you loosen and back the valve adjuster screws out. A heads up, the torque to yield method is ONLY used if you have the TTY head bolts. Using this method on non TTY bolts will result in broken head bolts. If you need help doing the overhead, PM me. I'd hate to see the same thing happen. While you had the front off I hope you verified the cam/crank timing. If not, since you still don't know WHY all these issues started, it would be a good thing to look at.

Mos,

It looks great. It is easy for us to throw bolts and wrenches at you from our arm chairs while you work on it and we don't. Not a lot of people here have deep dove into the 8.3's, so this is interesting. They are usually pretty robust engines, and yours has some pretty unique failures, so as Will said, try your best to figure out what caused it so we (you) are not doing this again 4 months from now. I would guess the only way a rocker shaft could fracture like that is from the bolts loosening up.

You said you advanced the injection timing? Don't go past 16 degrees (from the RV guys with the 8.3's). For the way your engine came apart, I'd probably just start with stock, since it is easy to set it that way with the factory push-pins (called pin timing). That is, if you believe the injection pump has not been messed with. Did you have a shop advance the pump internals, and to what degree? Then you can still pin time it (super easy to do). Make sure your tapered interface for the injection pump gear was completely free of grease/oil, they are known to slip if even a small amount of anything slippery on the tapered pump shaft or mating tapered gear bore.

PCB looks hot in 2 areas of the board. It should not have caused engine failure though, it really only controls dash power and crank signal to starter. The circuit board on it is just to prevent re-engagement of the starter once the engine is running. Not all PCB's have it. This is done by detecting AC voltage at the alternator (before the rectifier) or oil pressure. I see you also have the fuel pressure sending unit atop your mechanical lift pump. That is usually just for the diagnostic tool, kind of useless. Watch that area for fuel leaks, it is a known issue. OK to remove sensor and cap.

WillWagner said:

Buy all of the hold down bolts too, they stretch when rocker shafts break. Make sure you loosen and back the valve adjuster screws out. A heads up, the torque to yield method is ONLY used if you have the TTY head bolts. Using this method on non TTY bolts will result in broken head bolts. If you need help doing the overhead, PM me. I'd hate to see the same thing happen. While you had the front off I hope you verified the cam/crank timing. If not, since you still don't know WHY all these issues started, it would be a good thing to look at.

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Thanks for the heads up Will, I’ll be sure to add those bolts to my list as well then. As for the TTY bolts, yes I have them, they are stamped as much on the top of them, I also followed the QS manual per my application, post-1991 with used bolts. I know I didn’t get into much detail here, but I covered more detail in my YouTube video. Yes, the cam/crank are timed correctly to each other, I verified that when I was retiming the injection pump. I hate to say it, but this may be one of those few times where we don’t know why something failed (in this case, why the rocker bolts came loose in the first place)

74M35A2 said:

Mos,

It looks great. It is easy for us to throw bolts and wrenches at you from our arm chairs while you work on it and we don't. Not a lot of people here have deep dove into the 8.3's, so this is interesting. They are usually pretty robust engines, and yours has some pretty unique failures, so as Will said, try your best to figure out what caused it so we (you) are not doing this again 4 months from now. I would guess the only way a rocker shaft could fracture like that is from the bolts loosening up.

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I know, nothing has been taken to heart. Unfortunately I know I’m one of the very few that have gone this deep into the motor, that’s why I’m trying my best to document everything really well so that someone else might have an easier time than I have when they do theirs. I would agree that the bolts coming loose are the only reason for the rover pivot shafts to break, but why did they come loose in the first place is what I’m wondering.

74M35A2 said:

You said you advanced the injection timing? Don't go past 16 degrees (from the RV guys with the 8.3's). For the way your engine came apart, I'd probably just start with stock, since it is easy to set it that way with the factory push-pins (called pin timing). That is, if you believe the injection pump has not been messed with. Did you have a shop advance the pump internals, and to what degree? Then you can still pin time it (super easy to do). Make sure your tapered interface for the injection pump gear was completely free of grease/oil, they are known to slip if even a small amount of anything slippery on the tapered pump shaft or mating tapered gear bore.

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I can’t say I know the exact timing angle now. Like I said above, I go into more detail in the video, but I followed the instructions of one of the pump veterans when I called to ask about retiming the pump. I’m 99.9% sure this pump hadn’t been adjusted by anyone prior to me, it still held gutless like the rest that I had drive when I was still in the service. I don’t have the pin for my pump and it seems to be a difficult bugger to find. Yes, no worries, the tapered shaft was clean as a whistle, as well as the pump gear.

74M35A2 said:

PCB looks hot in 2 areas of the board. It should not have caused engine failure though, it really only controls dash power and crank signal to starter. The circuit board on it is just to prevent re-engagement of the starter once the engine is running. Not all PCB's have it. This is done by detecting AC voltage at the alternator (before the rectifier) or oil pressure. I see you also have the fuel pressure sending unit atop your mechanical lift pump. That is usually just for the diagnostic tool, kind of useless. Watch that area for fuel leaks, it is a known issue. OK to remove sensor and cap.

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Yes, there are two spots that have seen some heat on that PCB, but nothing to the point of failure. One is a resistor right next to a couple of MOSFETs and the other is on a pin for a diode. I still need to verify a few places on the PCB to make sure it is still functional, but now I’m pretty sure that this box wasn’t the point of failure in the electrical system. No dash power and no cranking power is the reason I automatically thought it was this box, especially with the fact that they are known to fail when the voltage regulator fails in the alternator.

Thanks for the heads up on the fuel pressure sensor, if it starts to leak I’ll be sure to do that.

If anyone has copies of the -10 manuals, or wiring diagrams, please let me know. I’ve looked, but I’m having difficulty finding anything.

Your font size will keep anybody over the age of 19 from reading your post. Ha.

Congrats on your engine assembly, you have a lot into it. Don't kill the starter! Wait, too late. If you think everything is together right, prime the fuel system with the plunger up to the injection pump, crack the lines open at each injector, crank until wet, tighten the lines, then go for a start. The 8.3L can be self bleeding, but it takes a lot more cranking effort to do so. No reason to kill batteries and starters. Get fuel to the injectors, then let it rip. Your 5gal oil should be close to required amount.

Good luck! Don't let it idle a long time. Rings like heat and load to seat properly if new. Throw some pics of the turbo cartridge rebuild and p/n's used if you can, I don't think many here have done that yet, but they are aging so will need soon.

Cool on progress...unlike OTHERS!!! What happened to your font size Load the pig as soon as you can, no idle, no stop and go.

Yeah I don’t know what happened to the **** fonts


I might idle it for a minute (not enough to get hot) just so I can double check a few things, but the first stop will be the fuel station since the truck is on E right now lol

i can’t drive it right now even if I had everything back together, I had to order a new #4 cylinder fuel line and I still have to renew both my registration and insurance before I can take it out on the road.

Hey Will, how long should I run this break-in oil? I’m just using O’Reilly’s conventional 15W40 oil, but I’m not sure when I should/could change it to full synthetic oil (probably AMSoil since I have a dealer next door)

74M35A2 said:

Your font size will keep anybody over the age of 19 from reading your post. Ha.

Congrats on your engine assembly, you have a lot into it. Don't kill the starter! Wait, too late. If you think everything is together right, prime the fuel system with the plunger up to the injection pump, crack the lines open at each injector, crank until wet, tighten the lines, then go for a start. The 8.3L can be self bleeding, but it takes a lot more cranking effort to do so. No reason to kill batteries and starters. Get fuel to the injectors, then let it rip. Your 5gal oil should be close to required amount.

Good luck! Don't let it idle a long time. Rings like heat and load to seat properly if new. Throw some pics of the turbo cartridge rebuild and p/n's used if you can, I don't think many here have done that yet, but they are aging so will need soon.

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Thanks. It’s certainly been a trying time with it down, and especially for so long. I hope I didn’t fry the starter, but when I checked today it looks like it’s a neutral safety switch problem instead. I’ve got voltage out of the PCB and to the start switch, but nothing on the return to the PCB on that circuit so it can energize the second relay for the starter. I’ll jumper/bypass it tomorrow to test for the starter.

The turbo rebuild I actually did a separate video for on YouTube. PNs were a real PITA, I eventually gave up on using PNs and just used the general HX40 search and my calipers to make sure I got the right parts. If I had used the PN that QuickServe Cummins supplied I would’ve been livid because I would’ve gotten the wrong one. QS PN ends up being 67x76 but mine is a 64x76. I’m just glad I measured everything before I bought anything for the turbo.

Keep us posted, don't give up now! I myself have a nonrunning M928A1 I'll hopefully be tearing into starting in a few weeks.

74M35A2 said:

Your font size will keep anybody over the age of 19 from reading your post. Ha.

Congrats on your engine assembly, you have a lot into it. Don't kill the starter! Wait, too late. If you think everything is together right, prime the fuel system with the plunger up to the injection pump, crack the lines open at each injector, crank until wet, tighten the lines, then go for a start. The 8.3L can be self bleeding, but it takes a lot more cranking effort to do so. No reason to kill batteries and starters. Get fuel to the injectors, then let it rip. Your 5gal oil should be close to required amount.

Good luck! Don't let it idle a long time. Rings like heat and load to seat properly if new. Throw some pics of the turbo cartridge rebuild and p/n's used if you can, I don't think many here have done that yet, but they are aging so will need soon.

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There is zero reason to crack injector lines on an 8.3. For priming. There is a bleeder screw on the inside front side of the pump: loosen and hand pump until a steady stream of fuel with no air comes out. Tighten it up and crank it over. She'll fire right up. It's the process in the TM and works perfect.