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Discussion Starter #1
KDP struck me and ever since I’ve been fighting a terrible gear whine. I’ve replaced everything I can think of and am more curious on what the next steps I should take are. I pulled the whole cam not the gear and have had the cam in and out a few times now. Everything goes in by hand smoothly. Motor turns over smooth by hand. So I have the FSM and have the specs for backlash but I honestly do not know how to and can’t find a video. I have tools, dial indicators and what not. Or if anyone has any other ideas. I’m trying to get a video onto YouTube. Sounds like a supercharged Cummins lol I’m at my whits end chasing this noise though
 

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What items were damaged/replaced due to the KDP?
 

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Discussion Starter #3
What items were damaged/replaced due to the KDP?
I replaced the case obviously, but the pin and had just rode around and ended up pressed against the bottom of the case. I looked over all the gears and didn’t see any damage from the pin riding around. I went ahead and put an oil pump in it after the first time I fired it up and opened the cover back up just cause I had an “upgraded” 24 valve one sitting around from another project
 

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How certain are you that there is a noise? Or that it wasn’t there before the incident? Could you be hearing your IP?
 

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How certain are you that there is a noise? Or that it wasn’t there before the incident? Could you be hearing your IP?
I’m fairly certain, it sounds like it has roots blower instead of a turbo lol the thing that gets me the most is, it runs amazing, doesn’t leak any oil but the gear whine is god awful
 

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Got a video you can post up? Does it change with RPM? Whe you changed the oil pump, did you check the oil pick up tube, or drain the oil and check for metal? May be some metal stuck in the pick up tube. Damaged vacuum pump maybe. I’d try to isolate where the sound is coming from.
 

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Got a video you can post up? Does it change with RPM? Whe you changed the oil pump, did you check the oil pick up tube, or drain the oil and check for metal? May be some metal stuck in the pick up tube. Damaged vacuum pump maybe. I’d try to isolate where the sound is coming from.
I will get a video of it later on today, I know it’s not the vacuum pump I capped off the oil line and pulled the pump off for for a few and the noise got substantially louder. I had to pull the pan from a 1/2 dowel breaking on me and dropping a tappet in the pan. When I pulled the pan off for that there was absolutely nothing in there except old oil and the tappet.
 

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Discussion Starter #10
#1 is from about 10 minutes ago, i dont have all the intake hooked up. #2 is from a few months ago but all the boost tubes and everything are hooked up
 

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Please clarify, you capped the oil line to the vacuum pump and pulled it off, and then did what? Block off the accessory drive port?

The only thing I've heard about gear whine is people claim they had gear whine start after the timing gear is removed and then reinstalled out of it's original tooth indexing relative to where it had been. The claim is that the cam and IP gear teeth wear into each other enough that if you disturb that alignment, it will make noise.

Everything I've personally experienced suggests this is SYROTI. I've put two engines together in the last year and a half. The first engine was a rebuild of my original 5.9. It went back together with the original crank gear, a used cam gear not original to that motor, and the original IP gear that was not indexed to the cam gear in any particular way. There was no geartrain noise on this engine. Then, I built my current engine with a new crank gear, the same used cam gear from the rebuilt 5.9, and a brand new IP gear. This engine also has no geartrain noise. I think if the internet claim was true, there would be/have been geartrain noise in at least one of these engines. None of the several dozen engines we've rebuilt in the shop over the last while have had geartrain noise either, and there's plenty of geartrains that go back together not in the exact original configuration for one reason or another.

Still, I would say your geartrain noise is abnormally loud. We put straight-cut gears in the big nasty race truck at work, yours isn't quite that bad but it's way worse than it should be on helical gears. The indexing thing is the only thing I can think of that might explain it, assuming it's not a myth and I just got extraordinarily lucky on my two builds to not have it. Which I doubt, but there you go. The sound is qualitatively wrong for there being some foreign object dragging on the gear teeth. If that were the case, the hardened gear teeth would have figured it out pretty quickly even if it was a bolt head or something like that. Based on my experience, I would recommend you check the geartrain lash with a dial indicator. Assuming it passes that check, you can either live with it or go into your front cover however many times is necessary to restore the indexing between the cam and pump gears.
 

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Discussion Starter #12
Please clarify, you capped the oil line to the vacuum pump and pulled it off, and then did what? Block off the accessory drive port?

The only thing I've heard about gear whine is people claim they had gear whine start after the timing gear is removed and then reinstalled out of it's original tooth indexing relative to where it had been. The claim is that the cam and IP gear teeth wear into each other enough that if you disturb that alignment, it will make noise.

Everything I've personally experienced suggests this is SYROTI. I've put two engines together in the last year and a half. The first engine was a rebuild of my original 5.9. It went back together with the original crank gear, a used cam gear not original to that motor, and the original IP gear that was not indexed to the cam gear in any particular way. There was no geartrain noise on this engine. Then, I built my current engine with a new crank gear, the same used cam gear from the rebuilt 5.9, and a brand new IP gear. This engine also has no geartrain noise. I think if the internet claim was true, there would be/have been geartrain noise in at least one of these engines. None of the several dozen engines we've rebuilt in the shop over the last while have had geartrain noise either, and there's plenty of geartrains that go back together not in the exact original configuration for one reason or another.

Still, I would say your geartrain noise is abnormally loud. We put straight-cut gears in the big nasty race truck at work, yours isn't quite that bad but it's way worse than it should be on helical gears. The indexing thing is the only thing I can think of that might explain it, assuming it's not a myth and I just got extraordinarily lucky on my two builds to not have it. Which I doubt, but there you go. The sound is qualitatively wrong for there being some foreign object dragging on the gear teeth. If that were the case, the hardened gear teeth would have figured it out pretty quickly even if it was a bolt head or something like that. Based on my experience, I would recommend you check the geartrain lash with a dial indicator. Assuming it passes that check, you can either live with it or go into your front cover however many times is necessary to restore the indexing between the cam and pump gears.
I capped it off and pulled the vacuum pump off enough to start it without the gears engaging and let it run for about 30 seconds just to see if the noise was coming from the vacuum pump, poor attempt at me trying to pinpoint the problem. I’ve been in the front cover so many times I was debating on taking it to a shop that has a little more knowledge but I don’t want to waste $$ either. Think I could live with it?? I was honestly more worried about something catastrophic happening if I continued to run it
 

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Okay, just wanted to make sure I understood. I know from running these engines on stands that if you have the front cover open, the geartrain noise is abnormally loud. If the accessory drive wasn't blocked off, I wouldn't rule out that the sound was coming from the vacuum pump. To positively rule it out, buy a blockoff plate (Cummins part number 3914868) or make one from a piece of steel using a gasket as a template. Pull the pump, install that, and run the truck.

If the noise persists, check geartrain lash with a dial indicator. You'll need to pull the front cover. Set an indicator up to read circumferential travel of a cam gear tooth. Then, use a prying tool to rock the cam gear back and forth without moving the crank. Repeat the test on the pump gear, this time moving the pump gear without moving the cam. The concern you want to rule out with this test is if the gear lash is too little. The gear teeth binding on each other will cause damage sooner or later, to some unknown degree. If lash is excessive, they will be noisy but it's not really going to hurt anything on a stock engine (stock to me means most engines with original internals, so sub-500hp).

If lash is in spec, and you don't see anything dragging on the teeth, I have no better explanation than the internet claim regarding gear indexing. If that's all that's going on, the noise will gradually lessen over time as the gears wear into each other again.
 

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Myths start from somewhere,usually a distortion of common sense and fact. This is the first time I've heard this one. I've paid absolutely no attention to the placement of the pump gear on any of the engines that I have assembled. That noise would drive me crazy on a long drive, which is what I do.
 

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Discussion Starter #15
Myths start from somewhere,usually a distortion of common sense and fact. This is the first time I've heard this one. I've paid absolutely no attention to the placement of the pump gear on any of the engines that I have assembled. That noise would drive me crazy on a long drive, which is what I do.
I am ready to pull my hair out. I’m fairly mechanically inclined and I’ve done everything 3 or 4 times now and it’s driving me crazy that I cannot figure this out. I am going to put a dial indicator on the gears this evening. If I don’t find anything there I’m just going to start driving it. I hate the noise but I hate not having my truck even more
 

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Myths start from somewhere,usually a distortion of common sense and fact.
Sure, to some degree. Others are based on a complete lack of understanding or knowledge though. The "pulling the plate can cause the rack to stick" or "pulling the plate can break the governor" myths are perfect examples. There will never be a conclusion to the debate on whether using a plate or not is the ultimately superior way to tune a pump (it really depends heavily on the use case and the requirements of individual operators), but big-name pump shops have been building pumps without plates now for about 10 years. Those two specific myths could not be proven wrong any more thoroughly, yet occasionally, you can still find people going full Chicken Little with those beliefs.

Even in those cases, it wouldn't surprise me at all if the rumors ultimately started with some rebuilt pump failing which happened to have the plate deleted by the operator, and the pump shop used the deleted plate to dodge the warranty because it was a convenient excuse, regardless of whether it factually contributed to the failure. Anyway, I digress...
 
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