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  #61  
Old 11-14-2014, 05:06 PM
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Quote:
Originally Posted by Maxbumpo View Post
In an OM617.9xx, the turbo-charger ensures that if there is play in the valve stems, air flows UP the stem, and oil does NOT flow down into the intake side. Both the intake manifold and the exhaust manifold are constantly pressurized, so forget about oil flowing down the valve stems........
Really ? That is going to surprise a lot of guys with real world experience .....
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  #62  
Old 11-17-2014, 01:35 PM
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Quote:
Originally Posted by leathermang View Post
Really ? That is going to surprise a lot of guys with real world experience .....
Let me correct that: Minimal oil will flow down the stem/guide to keep it lubricated, but oil consumption via play in the valve guides is not a major concern. This would be a concern in a typical gasser car, which will have vacuum on the intake side, but not for a turbo-diesel. Vacuum on the intake side will try to pull oil down into the intake manifold. Simple physics, not really that hard to understand.
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'87 124.193 (300TD) "White Whale", ~380k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 379k miles
'73 Balboa 20 "Sanctification"
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  #63  
Old 11-17-2014, 01:55 PM
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Quote:
Originally Posted by Maxbumpo View Post
Let me correct that: Minimal oil will flow down the stem/guide to keep it lubricated, but oil consumption via play in the valve guides is not a major concern. This would be a concern in a typical gasser car, which will have vacuum on the intake side, but not for a turbo-diesel. Vacuum on the intake side will try to pull oil down into the intake manifold. Simple physics, not really that hard to understand.

What about when you are idling and not boosting? All my guide wear is on the exhaust side. Serious question...


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  #64  
Old 11-17-2014, 04:47 PM
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Quote:
Originally Posted by Maxbumpo View Post
..... Simple physics, not really that hard to understand.
Sometimes a DYNAMIC system is not as simple to mentally visualize as it might seem.....

I have painted a few cars in my life.... and I know that in order to set the minimum pressure for the particular spray gun you need a pressure gauge near the gun... typically a three foot whip on the gun attaches to a gauge clipped to your belt and then that attaches to the air hose to the air compressor... I know that when you pull that trigger... that the pressure at the gun falls significantly due to the time it takes for the air to come from the compressor ... this is affected by the friction encountered by the air inside the hose...
But I have had people argue that it did not decrease.

I have had people on this forum who did not believe that an AC system which has had a leak must be considered compromised because they know that both sides are under pressure... thus can not draw in moisture laden air from the outside as a result. Even though the MB FSM on AC says that... they did not believe me when I said it....

Here is the problem with ' simple physics '......in a dynamic system...with pulses of air flow... pulses of pressure... gravity.... differences in temperature...
Sometimes they are not simple and it is easy to miss the interactions present without way more gauges and knowledge of the physics theories involved.
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  #65  
Old 11-18-2014, 04:13 PM
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Quote:
Originally Posted by Lucas View Post
What about when you are idling and not boosting? All my guide wear is on the exhaust side. Serious question...
Check to see how much vacuum is produced in the intake manifold at idle. Install a gauge that reads both pressure and vacuum, and you'll have your answer.
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'87 124.193 (300TD) "White Whale", ~380k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 379k miles
'73 Balboa 20 "Sanctification"
Charleston SC
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  #66  
Old 11-18-2014, 04:19 PM
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Quote:
Originally Posted by leathermang View Post
Sometimes a DYNAMIC system is not as simple to mentally visualize as it might seem.....



Here is the problem with ' simple physics '......in a dynamic system...with pulses of air flow... pulses of pressure... gravity.... differences in temperature...
Sometimes they are not simple and it is easy to miss the interactions present without way more gauges and knowledge of the physics theories involved.
Fair enough, but my point is that unlike a typical gasser, which uses vacuum to get the air/fuel charge into the cylinder, a turbo-charged engine is different. Common knowledge of gassers, which is what many of us start with, would tell us that worn valve guides will cause increased oil consumption. I'm arguing that such knowledge doesn't apply in this case. I had to "un-learn" many things in order to properly diagnose and repair the MB diesel engines I've owned.
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M. Dillon
'87 124.193 (300TD) "White Whale", ~380k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 379k miles
'73 Balboa 20 "Sanctification"
Charleston SC
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  #67  
Old 11-18-2014, 05:02 PM
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Originally Posted by Maxbumpo View Post
Check to see how much vacuum is produced in the intake manifold at idle. Install a gauge that reads both pressure and vacuum, and you'll have your answer.

This is the answer to the argument. I don't have a 617 turbo. If your car has a boost gauge, doesn't that tell you there's no pressure at idle? If there's vacuum, well, it's gonna pull oil through the guides.


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  #68  
Old 11-18-2014, 05:06 PM
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I had to unlearn a bunch of stuff also.... so I got the paper MB manuals and read them...

but worn valve guides and worn out valve stem seals can cause oil burning.... amply evidenced by people who have fixed that complaint by renewing those items... that is bottom line... with no theory thrown in which may or may not fit the physics of the situation....
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  #69  
Old 11-19-2014, 05:05 PM
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Mechanic had to reschedule, will be beginning of next week.
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  #70  
Old 11-27-2014, 06:22 PM
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Mechanic got stuck at his main shop in Cali, now it's turkey day, we'll be figuring this out later.

I did some poking around with a mechanic's stethoscope(much more refined than a large screwdriver). I have a pretty serious knocking noise coming from the area of the intermediate shaft - the noise is pretty loud from the vaccum pump, which has been gutted.

I've done the intermediate shaft bushing already. Could I have damaged the timing device? Does the timing device require pressure from the vacuum pump to hold it in correct position?

Happy Thanksgiving, everyone. Off to finish up cooking and dive in.
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  #71  
Old 11-27-2014, 06:22 PM
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Oh, and just a heads-up. There's an om617yota username on a couple other forums. That is NOT me.
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  #72  
Old 11-28-2014, 04:11 AM
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Quote:
Originally Posted by OM617YOTA View Post
...
I've done the intermediate shaft bushing already. Could I have damaged the timing device? Does the timing device require pressure from the vacuum pump to hold it in correct position?

Happy Thanksgiving, everyone. Off to finish up cooking and dive in.
The timing device is bolted onto the intermediate shaft but it does break down to smaller parts =>

OM617 timing device - advice required

Worth checking it out considering what a pain in the arse this has been so far
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  #73  
Old 11-28-2014, 11:25 AM
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Originally Posted by Stretch View Post
The timing device is bolted onto the intermediate shaft but it does break down to smaller parts =>

OM617 timing device - advice required

Worth checking it out considering what a pain in the arse this has been so far
Thank you! Pain in the arse is right.

My timing device rattled when I had it out and searching the forum back then for timing device rattle brought me to exactly your thread! Mine has the heat treat bluing as well. It's definitely a knock, instead of a rattle.

Update thus far(wordy, my apologies):

Found the power steering pump was tapping the hood. Engine flexes the motor mounts to the passenger side when I'm applying throttle, and the opposite direction when coasting down. Some fine adjusting to the inside of the hood with a hammer gave some clearance, and coast-down noise was greatly reduced.

I now have a steady stream of bubbles through my prefilter. Something in my fuel system is letting air in while under vacuum but not leaking fuel out when resting. Back to the plan to replace all the fuel lines, and I think this will cure the first start roughness and miss.

Lastly, I'm going to yank the gutted vacuum pump housing and poke around. Hopefully there'll be something incredibly obvious and easy to fix, but the way this project is going I'm expecting the demon Murphy to raise his head.

Thanks again everyone.
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  #74  
Old 11-28-2014, 12:39 PM
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617 weird behavior diagnoses

Lol. Loved the fine adjustment with a hammer to the hood. "This device needs calibration, let me get my 5lb sledge."

Noises can travel through the block in weird ways. Not that's it's not accurate, but not 100% definitive.

If it were a crawler I would say bolt that motor down solid with no rubber. Adds to the manly effect. Brappppp.

I've said this a few times here, but I replace the fuel lines with clear. Summit sells the type, PCV or something like that, but a local brewery or winery supply store or has it way cheaper. My brother in law has a brewery and I steal it from him.

If you look up the type and diameters online you'll know what to get.

It's also helpful to blow through all your lines with your air nozzle at like 90 psi. I had a new tractor with a service plan, and the mechanic would do it every service. The breathers too.

Easy trick is taking your fuel cap off and see if the bubbles go away.

I once chased demons for hours to find sludge in the bolt for a banjo fitting. After that I put on clear. Blockage can cause the system to pull air through the crush washers on a properly fitted banjo fitting. It's always the next fitting after the problem.

If you end up needing a timing device I have an extra from a 615. Not sure if that fits.
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  #75  
Old 11-28-2014, 02:41 PM
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Thank you!

I agree on the clear fuel lines. The stock fuel line from the tank to the engine compartment is the only part of the fuel system that is original to the truck, and is a mix of EFI parts originally meant to handle pressurized gasoline. It's a mix of compression fittings, rubber hose, steel line, rubber hose and hose clamps where the EFI filter used to be, more steel line, another compression fitting, the original rubber EFI hose, and then the Gates Barricade hose I've used. I've already learned the hard way that gasoline resistant fuel line isn't necessarily biodiesel resistant, so I think that's the next step.
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