[Torque454]

At nearly 400,000 miles, is it possible that a 6.5 could reuse the original pistons and only hone the cylinder walls before Installing new rings? 400k is nothing for a heavy duty diesel like in a semi truck, and they can usually be overhauled "in frame" without being bored out and having to have oversized pistons and rings - but would o be lucky enough to get away with that on a 6.5? Id like to put in new rings, gaskets, bearings, oil pump, etc... But without the expense and time associated with new pistons and having the cylinders bored out. Something is up with my 6.5 and it won't make a full revolution anymore even with the glow plugs out and the torque converter unbolted - if you spin it all the way around either direction, it stops in the same spot every time. This is while turning the engine over with a 24" breaker bar using the crank pulley bolt. It has 3 or 4 tight spots on the way around, but this one spot it just won't rotate through - ive pushed and pulled so hard that I though I was going to snap the breaker bar or the enormous crank pulley bolt. Anyway, its probably going to have to be taken apart but I sure don't want, nor do i have, thousands of dollars to spend completely rebuilding this thing. I love the truck and I've had it for about 15 years now so I really hate to get rid of it. But, its got a decent amount of blow-by now and since it's going to need work internally now, now is gonna be the best time to do an overhaul if i can in fact get away with that. If not, I may have to get something else unfortunately. Anytime the word "diesel" is involved, even if it isnt an especially popular like the 6.5, the price of a replacement engine goes up. A lot. Looks like about $4,000 USD for a reman 6.5 and that's just ridiculous.

Anyway sorry for the rant - but what do you all think about a re-ring "overhaul" of a high mileage 6.5. Is it possible that it would work and be worth the cost and effort?

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[tnDan]

I always say do not order ANY parts until AFTER the tear down and machine shop has inspected the parts.

If the engine will not turn one full revolution then you have some form of mechanical failure. Could be broken piston with piece hitting the cylinder head, broken connecting rod or even a broken crankshaft. Your cheapest option would to find (try) a running used engine that passes compression test and hot idle oil pressure specs.

You can't compare this engine to medium, let alone heavy duty, diesel engines. The in frame overhauls you mention many times includes new cylinder liners and pistons. They are wet sleeved engines so they don't get bored out.

A reman 6.5 with a warranty for $4k isn't ridiculous considering how hard it is to find good buildable cores. A brand new GEP Optimizer 6500 is probably around $8k these days.

 

[Torque454]

I always say do not order ANY parts until AFTER the tear down and machine shop has inspected the parts.

If the engine will not turn one full revolution then you have some form of mechanical failure. Could be broken piston with piece hitting the cylinder head, broken connecting rod or even a broken crankshaft. Your cheapest option would to find (try) a running used engine that passes compression test and hot idle oil pressure specs.

You can't compare this engine to medium, let alone heavy duty, diesel engines. The in frame overhauls you mention many times includes new cylinder liners and pistons. They are wet sleeved engines so they don't get bored out.

A reman 6.5 with a warranty for $4k isn't ridiculous considering how hard it is to find good buildable cores. A brand new GEP Optimizer 6500 is probably around $8k these days.

The odd thing about this is that the engine ran fine last time I shut it off - the starter had broken its aluminum housing for the 2nd time in a week. The flexplate was pretty worn on the ring gear and had slowly gotten worse over the years. So after that I pulled the transmission and replaced the flexplate - id been pretty busy so it took me 5 or 6 months, and when I finally got ready to bolt the torque converter to the new flexplate, i was only able to get 5 of the 6 bolts in it - the engine wouldn't turn far enough to get to the 6th bolt. I took all the bolts back out thinking maybe the converter or transmission was hung up somehow but that wasn't the problem. The only thing I can think of is that maybe moisture from this humid climate condensed in one of the cylinders and rusted the cylinder wall enough to prevent it from being able to make a full revolution.

It had to turn a full 360 degrees when I took it apart because I removed all the torque converter bolts and pushed the converter as far back into the transmission as it would go before unbolting the transmission from the engine. So whatever the problem is, it occurred during the 5 or 6 months that it was sitting. I'm really disappointed, I was looking forward to having my suburban back. I've had it for about 15 years now and despite the fact that it has nearly 400,000 miles on it, it was still running great.

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[56pan]

Kind of sounds like hydrolock to me. Water or maybe fuel somehow got inside a cylinder when it sat all that time. You could try pulling the glowplugs and turning it over.

 

[Torque454]

Kind of sounds like hydrolock to me. Water or maybe fuel somehow got inside a cylinder when it sat all that time. You could try pulling the glowplugs and turning it over.

Already have the glow plugs out. Still have the same issue. I had wondered about that myself

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[sctrailrider]

Do you have anything bolted to the rear of the crank now? If so remove everything and rotate the crank, you might have a bolt that is too long and touching something on the rear of the block.

 

[56pan]

Already have the glow plugs out. Still have the same issue. I had wondered about that myself

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Yeah, reread you original post and missed that.

 

[paleyjim]

Do you have anything bolted to the rear of the crank now? If so remove everything and rotate the crank, you might have a bolt that is too long and touching something on the rear of the block.

Totally agree. When symptoms appear right after doing work, look very hard at the work you just did and anything that could be related to that work.

 

[Torque454]

Do you have anything bolted to the rear of the crank now? If so remove everything and rotate the crank, you might have a bolt that is too long and touching something on the rear of the block.

Only the flexplate, and I can't remove it without removing the transmission

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[TheJoggernot]

We're the glow plugs removed for the 4 or 5 months ? It's definitely possible there is some corrosion on the cylinder. This happened to me. I remedied it by using on blaster or other agent into the cylinders via the glow plugs holes and just worked the engine back and forth.

It goes without saying but you're going to want to blow all the crap outa the cylinders before you even think of putting those glow plugs back in there unless you want a grenade.

 

[dieselolds]

At nearly 400,000 miles, is it possible that a 6.5 could reuse the original pistons and only hone the cylinder walls before Installing new rings? 400k is nothing for a heavy duty diesel like in a semi truck, and they can usually be overhauled "in frame" without being bored out and having to have oversized pistons and rings - but would o be lucky enough to get away with that on a 6.5? Id like to put in new rings, gaskets, bearings, oil pump, etc... But without the expense and time associated with new pistons and having the cylinders bored out. Something is up with my 6.5 and it won't make a full revolution anymore even with the glow plugs out and the torque converter unbolted - if you spin it all the way around either direction, it stops in the same spot every time. This is while turning the engine over with a 24" breaker bar using the crank pulley bolt. It has 3 or 4 tight spots on the way around, but this one spot it just won't rotate through - ive pushed and pulled so hard that I though I was going to snap the breaker bar or the enormous crank pulley bolt. Anyway, its probably going to have to be taken apart but I sure don't want, nor do i have, thousands of dollars to spend completely rebuilding this thing. I love the truck and I've had it for about 15 years now so I really hate to get rid of it. But, its got a decent amount of blow-by now and since it's going to need work internally now, now is gonna be the best time to do an overhaul if i can in fact get away with that. If not, I may have to get something else unfortunately. Anytime the word "diesel" is involved, even if it isnt an especially popular like the 6.5, the price of a replacement engine goes up. A lot. Looks like about $4,000 USD for a reman 6.5 and that's just ridiculous.

Anyway sorry for the rant - but what do you all think about a re-ring "overhaul" of a high mileage 6.5. Is it possible that it would work and be worth the cost and effort?

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Did you remove the valve covers afterward to find out whether a valve was stuck open?

You could do a rering with the engine still in place to get yourself out of a jam if that’s what you want to do.More than likely it has a cylinder ridge at the top on each bore so using std rings on a bore with a ridge present at the top automatically will tell you the bore is tapered but I have seen engines rebuilt using std rings with a ridge present and it turned out okay but it’s not the proper way to do it in all honesty.

The moment I see a cylinder ridge at the top of a cylinder it automatically means it needs to be bored oversize 9 times out of 10.

 

[Torque454]

Did you remove the valve covers afterward to find out whether a valve was stuck open?

Yep. The only ones that are open are the ones that the cam lobes are on - and they close when i rotate the engine they all seem to work ok. Next step i suppose is to pull the heads. There's nothing else in the way of that now on the passengers side - intake, IP, coolant crossover, exhaust, valve covers etc. And only the ps pump and exhaust manifold on the driver's side.

One thing that may or may not be important to know is that the passengers side exhaust manifold has been off most of this time and the air intake from the turbo has been uncovered. I didn't stuff rags into the exhaust ports or the upper intake, but I have kept the hood closed - it hasn't been rained on or anything like that.

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[dieselolds]

Yep. The only ones that are open are the ones that the cam lobes are on - and they close when i rotate the engine they all seem to work ok. Next step i suppose is to pull the heads. There's nothing else in the way of that now on the passengers side - intake, IP, coolant crossover, exhaust, valve covers etc. And only the ps pump and exhaust manifold on the driver's side.

One thing that may or may not be important to know is that the passengers side exhaust manifold has been off most of this time and the air intake from the turbo has been uncovered. I didn't stuff rags into the exhaust ports or the upper intake, but I have kept the hood closed - it hasn't been rained on or anything like that.

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It’s Pretty strange this sort of thing has happened.It was okay when you last parked the vehicle and now it can’t be rotated a full rotation.Awfully strange circumstances to say at the very least.

 

[Torque454]

We're the glow plugs removed for the 4 or 5 months ? It's definitely possible there is some corrosion on the cylinder. This happened to me. I remedied it by using on blaster or other agent into the cylinders via the glow plugs holes and just worked the engine back and forth.

It goes without saying but you're going to want to blow all the crap outa the cylinders before you even think of putting those glow plugs back in there unless you want a grenade.

No the glow plugs I just removed a few days ago. The exhaust manifold and turbo has been off the whole time tho. There was potentially one valve open or partially open and exposed to air during that time, but nothing liquid. The hood is on and kept closed when im not actively working on anything.

And yes I always check any openings for contaminants before putting any back together. And I like to keep the area around me clean, so i have rags, an air blow gun and a shop vac (if necessary) handy to clean up the areas that im working in - i used the shop vac to clean around the intake before I pulled it off, and again after it was off ( its amazing all the crap that finds its way into the valley under the intake).

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[Torque454]

It’s Pretty strange this sort of thing has happened.It was okay when you last parked the vehicle and now it can’t be rotated a full rotation.Awfully strange circumstances to say at the very least.

I know. There's got to be an explanation for it though, only disassembly is going to reveal it tho it seems.

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[dieselolds]

I know. There's got to be an explanation for it though, only disassembly is going to reveal it tho it seems.

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Hopefully you’ll find something when the heads are taken off.

 

[Torque454]

Hopefully you’ll find something when the heads are taken off.

Yeah hopefully. If not, it'll be time to pull the entire thing out. It irritates me to know that I put all that effort into reinstalling the transmission only to have to undo everything again because of a serious, unusual and certainly unexpected problem. It's not any fun handling that 4l80e. I can't believe how heavy it is.

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[OkDually]

Yep. The only ones that are open are the ones that the cam lobes are on - and they close when i rotate the engine they all seem to work ok. Next step i suppose is to pull the heads. There's nothing else in the way of that now on the passengers side - intake, IP, coolant crossover, exhaust, valve covers etc. And only the ps pump and exhaust manifold on the driver's side.

One thing that may or may not be important to know is that the passengers side exhaust manifold has been off most of this time and the air intake from the turbo has been uncovered. I didn't stuff rags into the exhaust ports or the upper intake, but I have kept the hood closed - it hasn't been rained on or anything like that.

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Get you one of those cheap bore cams on Amazon that attach to your smartphone. Inspect things through the exhaust and intake

 

[dieselolds]

Yeah hopefully. If not, it'll be time to pull the entire thing out. It irritates me to know that I put all that effort into reinstalling the transmission only to have to undo everything again because of a serious, unusual and certainly unexpected problem. It's not any fun handling that 4l80e. I can't believe how heavy it is.

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Yes those 4L80 units are heavy buggers indeed.I can pick up a 700R4 no problem and carry it around but the 80 is a heavy sucker.

 

[vstech]

I cannot imagine what could be wrong during a flywheel swap… but I would pull it back out if the motor won’t spin over after the change.