220D Nailing - PeachParts Mercedes-Benz Forum

Zeppo2K2 · #1 11-12-2009, 07:00 PM

I've been reading all the posts related to nailing in this thread and the diesel thread, but I thought I'd try to post here in desperation. I have a '71 220D that I purchased from the original owner 2.5 years ago. It had 103K miles then, and 136K miles now. I use it as a daily driver, 32 miles a day, highway, with city mix for 1/4 of the trip. It has always nailed when cold, light throttle. Warmed up, or heavy on the throttle, it will not nail. I have not been able to tell which cylinder is the one nailing, if that is so. Nailing was at first, once a week or so, now most days for first 10 minutes of driving. It'll sound like a machine gun at the worst times.

I've done many things, but last June I was determined to fix it, and still did not find the problem. I'll list the items done, and a * means it did NOT nail for about 200 miles or few days, then started again.

1. replaced all rubber fuel lines.

2. replaced all fuel filters (3). Main filter will stop nailing for one trip.

3. replaced the 4 copper washers and 4 o rings in IP. * (best results of any attempt to fix the problem)

4. rotated in set of used injectors *

5. rotated in set of Bosch shop rebuilt and calibrated injectors *

6. swapped primary fuel pressure regulator from 220D that runs fine

7. drained tank (clean)

8. diesel centane booster, and bio diesel gave no effects

It runs better with all that done, but nailing has just gotten progressively worse. I have not checked the IP timing, or swapped the IP pump, nor the lift pump. There seems to be no air bubbles in the 3 clear lines, especially the one into the IP.

Any ideas?

Thanks in advance,

Ron

79Mercy · #2 11-12-2009, 07:03 PM

Sounds like there is water in the system.

Run the tank low and drain it again and look for water.

Tomguy · #3 11-12-2009, 07:10 PM

From my knowledge. timing chain stretch can affect IP timing so you may want to check that out. I'd also look into perhaps replacing the chain as well, but I don't know if Diesels need it as much as the V8 gassers do.

79Mercy · #4 11-12-2009, 07:17 PM

on diesels most of the time we measure chain stretch and install woodruff keys to correct the timing.

But when the mileage is over 250K replace the chain.

Kpmurphy · #5 11-12-2009, 08:45 PM

Quote:

Originally Posted by 79Mercy

on diesels most of the time we measure chain stretch and install woodruff keys to correct the timing.

But when the mileage is over 250K replace the chain.

I would think you only replace the chain if there was to much stretch in it.
I could be wrong

My 70 220D has never had the chain replaced in it and it has over 250K on her, Pierre has never told me it needs to be replaced. The older cars may of had stronger chains in them.

My car nails only when i have the idel turned all the way down and taking off.

79Mercy · #6 11-12-2009, 09:00 PM

Hey Kevin how you doing? Your right but in my opinion with a chain with so many miles its best to replace it. You can install woodruff keys to correct the timing but the chain is still stretched out and one day it break due to it being so stretched, as it stretches it gets weaker.

But if your timing is still well within spec don't bother.

pch2021 · #7 11-13-2009, 11:44 PM

1. I checked Kevins chain, and its perfect. the way he keeps up the car, it will never need it.
2. change the oil in the injection pump on your 1971 220D.

Skippy · #8 11-19-2009, 11:03 PM

Do like Pierre said. Also check your chain stretch at your next valve adjustment, just because it's a good idea to keep tabs on that.

If it continues nailing, you have a couple of options:

1. Keep driving it. This is the one I would take with my 240D if it were nailing, since it's achieved beater status and I'm not going to throw a whole lot of time or money into it.

2. Replace/rebuild your injector pump. You've already done injectors and it sounds like you've eliminated air intrusion. You could check injection timing, but if the timing chain hasn't elongated much, then it shouldn't have changed much from what was set at the factory. That doesn't leave much else to cause nailing.

Colorado220 · #9 11-20-2009, 12:44 AM

What is nailing?

katja · #10 11-20-2009, 01:20 AM

I need to get a recording of mine as it's definitely nailing now, but I think this is a decent example of the "Nailing" sound:

http://www.youtube.com/watch?v=biiidzR4VnE

Mine does some of this ticking at idle at a cold start and a steady ticking after a hard run. Otherwise, idle is pretty good and sounds fine on heavy acceleration, but light throttle leads to random nailing (periodic, loud "clack" sound, or sometimes several clacks in a row, like a crackle).

I think I just need new injectors but from this post and others that I've read on the Diesel Forum regarding nailing, it sounds like IP problems can be another cause...or worse yet, low compression/worn engine.

For me, Diesel purge eliminated the nailing for about a month the first time, but a second purge yielded no improvements.

gs sparhawk · #11 12-12-2009, 01:31 AM

Nailing is usually an early ignition problem. Maybe you have an excess of carbon build-up in the cylinder. Get a reamer for the purpose and ream out the carbon in the glow plug hole......... As a suggestion, get the compression tested in each cylinder. Then get the injectors pop-tested to insure they are withing a couple to five pounds of each other--one may be early. A clean set of combustion chambers with injectors even on the PSI test and pump timed right will more than likely be smooth.

Zeppo2K2 · #12 12-18-2009, 12:20 AM

It was the injection pump timing. I had the little drip tube ready to time the pump, but was really discouraged getting the third, lower nut loose on the pump flange to rotate it after the test. So I never did the test, 'just marked the original location, then moved the pump about 1mm., advanced. That is I moved the pump towards the block, thinking that the chain may have stretched.

That did the trick, the car no longer nails, just 1mm! BTW does anyone have a tool idea for that bottom nut, mine is not as tight as the top two. I just can't get to it.

Also, someone suggested for pump timing to insert an offset key. I think that is just for the cam (valves), not the IP, correct?

Thanks for all the suggestions.

Ron

strelnik · #13 12-18-2009, 09:56 AM

Quote:

Originally Posted by Zeppo2K2

It was the injection pump timing. I had the little drip tube ready to time the pump, but was really discouraged getting the third, lower nut loose on the pump flange to rotate it after the test. So I never did the test, 'just marked the original location, then moved the pump about 1mm., advanced. That is I moved the pump towards the block, thinking that the chain may have stretched.

That did the trick, the car no longer nails, just 1mm! BTW does anyone have a tool idea for that bottom nut, mine is not as tight as the top two. I just can't get to it.

Also, someone suggested for pump timing to insert an offset key. I think that is just for the cam (valves), not the IP, correct?

Thanks for all the suggestions.

Ron

I believe that it is just for the cam, but someone else can confirm that.

In talking to older drivers of the OM 615, a lot have talked about the nailing and I'm wondering if this wasn't due to four possible causes:

1. timing chain stretch
2. pre combustion chamber build-up
3. injector pump timing out of spec
4. water in fuel

All except #1 seem pretty fast and easy to check.

Regarding #2, I have been told that the so-called " Italian tune-up" , i.e. running the vehicle a little hot by running it in a lower gear, like 45 in third, would do the trick to clean out the combustion chambers if done about once/ week.

If anyone has any other info, please publish it for the benefit of the group.
Thanks

gs sparhawk · #14 12-18-2009, 10:19 AM

I use a long extension & socket to reach behind the pump for the 3rd nut. Chain stretch can be adjusted with the offset key. Use a diesel addative and don't lug the engine. Try Diesel Purge. Take off the cam cover & put the crank pulley on zero and see where the cam timing marks are---early?--late? Probably late. Pump timing is done at the pump as you found. If you have changed the filters you wont get water in the pump. I should show up in the in line filter where you can see it. Otherwise, drain the tank through the big bottom plug. These cars are made to be DRIVEN. Get out on the highway & run it at it's limit now & then. Surely you can find a nice open stretch where you can max it out---all the way to 72 MPH???. Drive it like you stole it. It'll thank you for it.

Sparky

pch2021 · #15 12-18-2009, 02:17 PM

minor chains stretch will cause this, but it is nothing to worry about. pump was probably out for work in the past and was not timed back up properly.