Delivery valve internal leak as a cause of nailing? Yes? No? Maybe??? - Page 11 - PeachParts Mercedes-Benz Forum

OM617YOTA · #**151** 06-19-2017, 05:13 PM

No info from PO's regarding any kind of maintenance at all. Trusting that Bosch wouldn't make such a mistake, I'm certain the "new" IP had at least the scratched DV removed at some point, but that's all the info I have. Maybe the local Bosch service center hired a monkey with a rock to lap their sealing surfaces for them? The scratch was deep enough to catch a fingernail in. I can try to repost the pic once I'm home, or it's posted in my build thread. Actually, I don't think forum software will let me post the same picture twice anyway.

gmog220d · #**152** 09-27-2017, 11:18 PM

Talk about being late to the party! I just got finished catching up on this thread. Between work, family, and other projects on the E300 eating up all my summer free time, I have not been hanging around the forums much until recently.

It’s awesome to see all the progress made by contributors to the thread during my absence. Diseasel300, my hat is off to you for all the persistence and hard work you’ve put into this one. We’ve all learned a lot together and that’s pretty cool.

As for our ’96 E300 and it’s nailing issue on #6, I’ve got a different story to tell. We’ve put about 4500 miles on the car since I last chimed in here (March 31). The persistent nail gradually went away after replacing #6 DV’s spring and seals. I thought it might be due to the warm weather, but now that things are cooling off our car is still running nicely. It’s clattery at something like 1000 RPM and below, but the clatter kicks in across all 6 cylinders about the same time - everything seems evenly distributed. It idles smooth and runs quietly off idle. No one cylinder stands out. I’m pleased.

I believe the #6 DV had a problem, but why I don’t know. It took FOREVER to purge the air out of that injection line after putting it back together post injector rebuild. That would seem consistent with the check valve function of the DV not working well enough to pump the air out - it just kept bouncing against the air pocket, unable to build up the pressure needed to push it through. And now, for whatever reason, the thing seems to be working properly enough.

Because the car’s been running so well and I’ve had a bunch of other projects going on I have not been motivated to get into the DVs. I would like at some point next year pull the IP to fix oil leaks. I’ve been thinking about replacing all the DVs with new ones when I do that, but after reading up on this thread I will hold off on ordering them until I have the IP out and can take a look at what I’ve got. They seem to be working fine as they are but there might be some room for improvement. I’ll report back, but it won’t be until next year when things turn warm again.

Thanks again everyone!

Diseasel300 · #**153** 09-28-2017, 09:42 AM

Fuel quality could be a factor in some of your clatteryness. I know it affects my car's noise levels. Always 1000 RPM or below too, over that it shuts right up.

I'm still running the same 5 polished DV's that I did several months ago. So far they haven't acted back up. Cylinder #3 still has the original un-touched DV in it. If I get a bad batch of fuel, the noise level of the whole engine goes up. #3 really stands out then, it isn't nailing per-se, but a very sharp combustion knock compared to the rest of the cylinders. If cracking #3's injector line, the engine just sounds like a noisy diesel. After Harvey, the diesel quality around here has been highly variable, even at the same station. You know after ~10 miles of driving if the fuel you just bought is good or not. If the noise is irritating, I just dump some Power Services in the tank to get through it and that usually shuts it right up.

At some point in the future, I still need to pull the DV's and do a thorough job of polishing the faces, but the thing's been running well enough that I haven't bothered with it yet. When I finally get around to it, I'll post updates here regarding wear to the faces of the polished DV's, especially compared to #3 which hasn't been touched yet.

Diseasel300 · #**154** 10-27-2017, 02:30 PM

It's been several months since I originally polished and reinstalled the delivery valves in my SDL, so it's time for an update.

Recently I've been getting an intermittent nailing that comes and goes. I can never seem to catch it in the act, but did so the other day. Tracked down my suspect to #6. Checked the D/V and it looked fine, but swapped it anyway. No change. Pulled the injector and did a pop test to find it "peeing" instead of chattering. No good! Swapped out with a different injector and the nailing stopped.

HOWEVER, now that the loud nailer was gone, I could hear light nailing from another cylinder only at idle. I took a mechanic's stethoscope and decided to get scientific on pinpointing which cylinder was making noise. I narrowed it down to #1 based on the different sound it was making. When listening to the injectors, I found it was easiest to place the probe in a position that touched both the injector line nut AND the injector line. Good injectors produced a metallic "tink" noise, while #1 produced a "tikka" noise, very undefined compared to the others. I think this may be a key clue when trying to diagnose a D/V as a nailing suspect.

In the case of #1's nailing, I found that I installed the D/V I lapped UPSIDE DOWN! Very much a Mea Culpa moment there. I flipped the D/V over and buttoned it back up and #1 stopped nailing immediately.

There was still some injector knock, nowhere near as pronounced as #6, or even #1, but audible enough to annoy me. I tracked it down to #4 by cracking injector lines to find the culprit. I pulled the injector to pop test and found it also peeing like #6. Swapped in a different injector and I now have an OM603 running as quiet as it can. All you really hear at idle is the D/V's clicking, it doesn't hardly even sound like a diesel.

So for those keeping track, the D/V lapping does seem to be holding up. Other than #1 which some idiot (yours truly) installed upside down.

Somewhat concerning to me is the short duration that the injectors held up. I have Monark injector nozzles and took the time to balance the pop pressures within 25 PSI of each other. The 2 injectors I'm having problems with still pop right at 1950 PSI where I set them, but the pee stream is a bit worrying. I'd have expected them to last longer than that. I'm now running on a mix of 4 Monarks and 2 Bosch nozzles. Car seems to be happy, so I'll leave it like that for the time being.

phlfly · #**155** 11-28-2017, 07:16 PM

Can you please wright how to disassembled and assembled after cleaning. I heard horror stories from mechanics , that if you moved them it will never run a same again.

I changed fuel injector nozzles, and result same as you experienced even louder or same. Than I added 2 -stroke oil, and it's get better sometimes it's so good I can hear soft clucking.

https://youtu.be/maiKdps41i4

Quote:

Originally Posted by Diseasel300

Just a word of advice and caution to anyone willing to be guinea pigs with DV face polishing:

USE THESE INSTRUCTIONS AT YOUR OWN RISK!!! PLEASE BE CAREFUL AND DON'T TRY THIS ON YOUR ONLY MEANS OF TRANSPORTATION!!! EVERYTHING BEING DISCUSSED HERE IS THEORETICAL AND EXPERIMENTAL!

If you do wish to try polishing your DV sealing faces, use common sense and follow the instructions below:

1: Make sure you have your DV oriented correctly. If it has a groove on the barrel, it should be pointing down, away from the plunger part of the DV.

2: Before you do anything to the DV, clean it in solvent, such as lacquer thinner to remove any varnish or contaminants.

3: Dip the entire DV in a thin oil such as sewing machine oil, or even WD-40 as a lubricant.

4: Use Cerium Oxide as your abrasive. It is extremely fine (finer than makeup powder) and is a very "soft" abrasive.

5: Use a battery operated drill and fasten the tip of the plunger part of the DV that the spring attaches to in your drill chuck.

6: Use a toothpick dipped in oil to transfer some of the cerium oxide to the beveled face of the DV. Try not to get it anywhere else. Keep applying until you have a coating of the cerium oxide on the face.

7: Insert the plunger into the barrel and press the two pieces together firmly and run the drill at medium speed for ~15 seconds.

8: Pull the parts apart and clean in your solvent. Inspect the faces and look for a polished appearance. If they need more polishing, repeat 3-7 above until you're satisfied with the final appearance.

9: Use a toothpick dipped in cerium oxide to clean up the entire beveled face of the plunger. I held the drill up and ran the tip of the toothpick back and forth over mine. This will help get any other oxides off and give you a fully polished sealing face.

10: Clean both halves of the DV in CLEAN solvent. Dry and repeat in a new pot of CLEAN solvent. Use a tooth brush or a Q-tip to really scrub everything perfectly clean.

11: Dip the DV in thin oil and reassemble to check fit. It should move freely without dragging. Press the DV halves together and twist. It should not feel "rough".

Keep in mind this process and all of the anecdotes attached to it are theoretical and experimental. If you screw up your IP or break your only car, you have yourself to blame. Not I, Pelican Parts, or anyone else is responsible for you or your engine. As the fine print always claims - "Your results may vary"

Diseasel300 · #**156** 11-28-2017, 07:30 PM

Quote:

Originally Posted by phlfly

Can you please wright how to disassembled and assembled after cleaning. I heard horror stories from mechanics , that if you moved them it will never run a same again.

I changed fuel injector nozzles, and result same as you experienced even louder or same. Than I added 2 -stroke oil, and it's get better sometimes it's so good I can hear soft clucking.

https://youtu.be/maiKdps41i4

On the M pump that the SDL uses, the delivery valves come right out once you take the holder off with the special spline tool. Unlike the MW pump that the 617's use, the Delivery Valves have no bearing on how the engine runs since you are not disturbing the pumping elements.

phlfly · #**157** 11-28-2017, 08:54 PM

Did you ever look at prime pump? May be this nailing sound is coming because the fuel flow is not enough. Just a thought. It came to me after added 2 stroke oil, a "thicker" diesel is creating better flow to pump and fuel nozzles.
Now why is I'm thinking, because before I added 2 cycle oil, my would like fluctuating at stop light, like skipping one cylinder. I know for sure my nozzles are at right pressure, since I change all previously installed spacers, they were all not enough to get right pressure at nozzle.
It's little expensive part , prime pump . But this pump is working all the time, even start up, right ?
I got springs from Pelican and will get kit from Mercedes source.

Quote:

Originally Posted by Diseasel300

On the M pump that the SDL uses, the delivery valves come right out once you take the holder off with the special spline tool. Unlike the MW pump that the 617's use, the Delivery Valves have no bearing on how the engine runs since you are not disturbing the pumping elements.

Diseasel300 · #**158** 11-28-2017, 08:58 PM

The lift pumps move a LOT of diesel. If the engine is rotating, the pump is pumping. You could have air ingress, hook up a piece of clear tubing in place of your return fuel line and see if you have bubbles in it. A very common leak is the fuel preheater thermostat.

Unless you dumped in several gallons of 2-stroke oil, there's not any real thickening of the fuel.

How did you test your injectors? Do you have a pop tester? Did you check pattern and leakdown in addition to just the pop pressure?

phlfly · #**159** 11-28-2017, 09:35 PM

My friends shop has this pump and it worked good since we test on old injector, and playing with washers.

I added just about 200 milliliters, a cup. Well I had air leak engine would run same way as without 2-stroke oil. A 2 stroke oil changed something to better. Did you watch the video, I posted early?

Quote:

Originally Posted by Diseasel300

The lift pumps move a LOT of diesel. If the engine is rotating, the pump is pumping. You could have air ingress, hook up a piece of clear tubing in place of your return fuel line and see if you have bubbles in it. A very common leak is the fuel preheater thermostat.

Unless you dumped in several gallons of 2-stroke oil, there's not any real thickening of the fuel.

How did you test your injectors? Do you have a pop tester? Did you check pattern and leakdown in addition to just the pop pressure?

phlfly · #**160** 11-28-2017, 10:00 PM

What do you mean by that : lapped upside? Piston part or cylinder ?

Quote:

Originally Posted by Diseasel300

In the case of #1's nailing, I found that I installed the D/V I lapped UPSIDE DOWN! Very much a Mea Culpa moment there. I flipped the D/V over and buttoned it back up and #1 stopped nailing immediately.

Diseasel300 · #**161** 11-28-2017, 10:08 PM

2-stroke oil modifies the way the diesel combusts, similar to how cetane boost additives do. It can help mask injection or compression issues.

The Delivery Valve is made up of 2 parts - the piston and the cylinder or barrel. The cylinder has a groove around the bottom for directionality. When I reinstalled the DV, I lapped it correctly, but reassembled it incorrectly (groove up). Engine ran fine, but was always a bit "tappy". Correcting that one DV stopped it nailing on that cylinder.

phlfly · #**162** 11-28-2017, 10:31 PM

Its still nailing sound, so I will try to clean DV parts, and replaced spring copper washer. We shall see it will help.

Diseasel300 · #**163** 11-29-2017, 09:39 AM

If you installed new nozzles with good spray patterns and popping at the correct pressures, try driving the car hard and fast on the interstate to burn the carbon out of the prechambers. You can sometimes get a combustion knock from carbon buildup from a crappy injector. One thing at a time and all...

phlfly · #**164** 11-29-2017, 12:11 PM

what is diameter of the cylinder/barrel ? is it about half of inch?

oilslick · #**165** 11-29-2017, 04:50 PM

I was there to order new DV springs. He informed me that 9/10 times the only thing that needs to be addressed on these M pumps is the delivery valve itself. He said that the “piston” will become pitted and grooved causing a loss of pressure and that the pump will try to compensate for this and it results in knock, rough idle, loping idle, and even smoke at idle. He said they only change springs if they’re broken. He priced me a complete set of DV’s for around $225 with tax. That’s $35 per DV. He said he’d order the springs for me if I really wanted them, but wouldn’t recommend them. The springs are $8/each 😳. This guy is always very helpful and free with sharing info. I’m taking my “vintage” Bosch pop tester to him later this week and he said he would test it for me and see what it needs for me to be able to rebuild my own injectors. He appears to be very helpful. We’ll see. 😁