6CTA8.3 engine rebuild for Sur Móvil

[WillWagner]

Just enough to take the squared off edge and split it on the same end, the radius allows it to slip into the tappet easier and the split you make allows the dowel to be pushed into the pushrod area of the tappet, it is a shade under .500. You need to pull the fuel pump gear, time the engine and pump before disassembly, it makes things easier. Lube pump runs off the crank, water pump is belt driven

 

[Jbulach]

Whats your best guess on what your engine ate? Also anyone know if these heads where prone to crack between the valves, or did something abnormal cause that?

 

[WillWagner]

Post 71, Don't know if he noticed, but he took very good pics of the failure. 5 and 6 cylinder exhaust seats dropped.

When they drop, they break up into little squares/rectangles. The pieces will migrate back into the intake and get into other cylinders and the air compressor, remember, it takes air in from the middle or so of the head. IIRC, didn't he rebuild a turbo on this too? If he ran it in the condition it is in now with the rebuilt turbo, there is a good possibility that there is damage to the turbo again from the pieces parts in cylinder.

And, if the compressor wheel got chunks taken out of it, the air filter should be replaced because the fins that leave the compressor wheel WILL bounce back up the clean air pipe and lodge in the pleats of the filter. When they decide to come out, they take out the turbo....again.

 

[winfred]

this thread has info on doing cam and lifters on a 5.9, i don't think theres a huge difference https://www.dieseltruckresource.com...replace-your-camshaft-lifters-n-stuff-255129/

 

[Mos68x]

Post 71, Don't know if he noticed, but he took very good pics of the failure. 5 and 6 cylinder exhaust seats dropped.

When they drop, they break up into little squares/rectangles. The pieces will migrate back into the intake and get into other cylinders and the air compressor, remember, it takes air in from the middle or so of the head. IIRC, didn't he rebuild a turbo on this too? If he ran it in the condition it is in now with the rebuilt turbo, there is a good possibility that there is damage to the turbo again from the pieces parts in cylinder.

And, if the compressor wheel got chunks taken out of it, the air filter should be replaced because the fins that leave the compressor wheel WILL bounce back up the clean air pipe and lodge in the pleats of the filter. When they decide to come out, they take out the turbo....again.

Thanks Will, hadn’t thought of that at all but it makes perfect sense. Whatever it was, it looks like there is a piece still stuck in the #3 piston. If I can remove it from the piston we will see what it was for sure. I’ll also compress the springs on those two valves and see if there is anything left of the valve seats, which I’m 99% sure there won’t be. I’ll be sure to take pics of that as well.

 

[Mos68x]

Whats your best guess on what your engine ate? Also anyone know if these heads where prone to crack between the valves, or did something abnormal cause that?

I’m curious about the cracks as well, especially since every cylinder has them.

 

[WillWagner]

Older C series engines were prone to cracking in a few places, injector bore to valve, between valves, spring seat area and between the liners. If you get a newer casting head as a replacement, the head cracking issues will be no more. Look between the liners for cracks. If there are cracks, only 2 things can be done, put it back together, hope it does not leak coolant or use coolant, if it does, you can try Barrs Leak and maybe that will patch it, or, replace the block/engine. You have alot of issues, if it were mine, I would drop the pan and look up the belly to see if the cam is failed. if it is, that means turbo damaged, head is junk, cam and tappets junk and IF the block is cracked, you have a piece of cast iron that might/might not seal up, lube pump and oil cooler full of metal if the cam is wiped out. I would look for a replacement engine. Block cracking went away with a new block casting and, IIRC, liners, I think the deck was made thicker and the liner upper was less on the OD allowing more material between the liner bores....I think, that was a looonnnggg time ago

 

[Mos68x]

Older C series engines were prone to cracking in a few places, injector bore to valve, between valves, spring seat area and between the liners. If you get a newer casting head as a replacement, the head cracking issues will be no more. Look between the liners for cracks. If there are cracks, only 2 things can be done, put it back together, hope it does not leak coolant or use coolant, if it does, you can try Barrs Leak and maybe that will patch it, or, replace the block/engine. You have alot of issues, if it were mine, I would drop the pan and look up the belly to see if the cam is failed. if it is, that means turbo damaged, head is junk, cam and tappets junk and IF the block is cracked, you have a piece of cast iron that might/might not seal up, lube pump and oil cooler full of metal if the cam is wiped out. I would look for a replacement engine. Block cracking went away with a new block casting and, IIRC, liners, I think the deck was made thicker and the liner upper was less on the OD allowing more material between the liner bores....I think, that was a looonnnggg time ago

There are no visible cracks between the liners, I checked for that yesterday mornin while I was thinkin of if. Of course, there is no definite answer to that without the tools to mag check the block.

 

[98G]

Silverstate55 has blocks, new unused.

 

[Mos68x]

Silverstate55 has blocks, new unused.

I hope it doesn’t come to me needing to replace the block as well, but if I do thanks for the info. I have an idea for super cheap way for us to mag check our parts, might be able to get away with a little powder. No other option really since I can’t just take the block out to have a local shop take a look at it.

 

[Mos68x]

Hey Will, since this motor is sleeved the things I can think of to cause the block to crack between the cylinders is extreme overheat and frozen coolant/water. Any other known causes? I’m assuming that over boosting the motor would just cause head bolts to stretch/fail and maybe valve float/failure. I haven’t done anything to the motor except turn up the governor and fuel slightly, so I can’t think of anything I’ve done to cause the block to crack, though I could be wrong. The motor has never overheated while I’ve had it, and I’m 99% sure the coolant I drained from it was from what the military had in it.

 

[SimplexCoda]

I hate to say, but I’m wondering if, by the time you factor parts and time, it would have been faster/cheaper to find a salvaged 8.3. Of course, you still risk it being in bad shape when you buy it.


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[Mos68x]

I hate to say, but I’m wondering if, by the time you factor parts and time, it would have been faster/cheaper to find a salvaged 8.3. Of course, you still risk it being in bad shape when you buy it.


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Trust me, I’ve been thinkin that too. Only two reasons why I haven’t gone that route, 1) replacement head/block could be cracked and I’d lose the money from that, 2) I’d still have to rebuild them anyways before I put it back in the truck. No way I’m going through all this effort and not getting a rebuilt motor out of it. I’m still waiting to hear back from Raines in NC on how much they wants for an engine they have.

 

[Jbulach]

I hope it doesn’t come to me needing to replace the block as well, but if I do thanks for the info. I have an idea for super cheap way for us to mag check our parts, might be able to get away with a little powder. No other option really since I can’t just take the block out to have a local shop take a look at it.

We used to use a aerosol spray on penetrant dye for checking welds, was some incredible stuff, I’d bet it would light up the smallest cracks in a block?

 

[74M35A2]

I knew you were an Aqua-Net kind of guy. Knew it.

 

[Jbulach]

Only in the potato canon, and... only because oxy-acetylene proved way too dangerous. It was the 80’s you know, dang... the memories you just stirred up!
Now back to blowing up engines...

 

[WillWagner]

The cracks between the liners are naked eye visible when they happen. You can wipe the block off good, spray rust penetrant on the deck, let it sit a bit, wipe and use the ball end of a ball peen and lightly tap the block if the liners are out and the crack will either appear or "spit" the penetrant out of the crack allowing it to be seen.

The between liner cracking was a manufacturing issue. We saw alot of cracking in things that had extreme duty cycles, busses, trash trucks, yard spotters, the on the throttle hard and stop kind of cycles. That and Cummins engines have.....unique, power delivery. If you have ever driven a perkins powered truck or a DT powered truck you will feel the difference

 

[74M35A2]

Will knows his way around Cummins engines better than any 10 people here. I’d take what he says over the manual.

If you are still in doubt, I can send you this, just send it back when done. Magnaflux crack checker. Or buy it from your local Grainger or online, it is not expensive.

 

[Mos68x]

Thanks Will! Soon as I get back home I’ll be sure to check it. I did use the wire wheel on the deck and still didn’t see a crack. Any quick tips for pulling the liners? I’m hoping piece of bar stock cut to size to fit the liner and a slide hammer or a threaded rod to pull it out. About cracks you mentioned between the liner that were below the deck, how common were they.

 

[Jbulach]

Hey Mos, if your doing a complete overhaul and by some chance you get your liners and a piston out in good condition, let me know, I may be interested in buying them from you. I have an A2 that needs a piston, six liners and rings, plus a head and turbo as well. I’m cheap and not above putting used parts in, unless someone tells me I’m nuts and gives good reason not to.