Barry,

Thanks for your response - I tried all afternoon (literally) to use the dial gauge w/o success. I just couldn't figure it out and a 1 inch lift dial gauge really doesn't help. Frustrating, but I think my problem was I couldn't keep the gauge perfectly still and tight in position - I think it was moving just a bit.

Anyway, I lined up the marks on the cam tower - did this several times and each time it comes out 5, 5.5 degrees of stretch. Before I drove the car to Ohio, it consistently measured 3 degrees... I just thought of something - I rotated the engine using the power steering pump???

I have no idea if there is a woodruff key in or not, I am thinking of just rolling in a new chain - and replacing the tensioner. I have looked over this chain and I think it's the original- I see no riveted link anywhere.

As to the smoke, if it results from timing being retarded, then I need to move the pump CLOSER to the engine as I didn't advance it far enough, right?

ryan

I am planning on driving this car over 3000 miles in the next month - so I am just trying to get things lined out much as possible.

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

On reviewing your posts you have taken the top of the pump closer to the block and the pinging has stopped. Do I have this right? I find this the exact reverse of what I would have expected. Both from the pinging perspective and the black smoke on reflection.

Trying that intermediate setting between the two still applies. If the smoke goes away and the pinging is not present leave it there. . There is some kind of issue hiding here somewhere in my humble opinion. Should not impact reliability in my opinion either and you are driving three thousand miles soon.

Normally I would have thought you would have smoked more in your former setting. For some reason that was not the case. Thats the primary reason I am suggesting the intermediate setting. It is still more advanced than your original setting was. Again if there are no negative effects at that point stay there.
I am not sure what is really giong on. You did not loosen the two nuts on the nipple flange where the injection line for #1 screws on the pump did you?

One last thought for now. Your air filter is in reasonable shape? If really obstructive car will not burn all it's fuel. Again though it is probably just fine as the smoking started with the timing change.

Yes, if his timing chain is 6 degrees off of TDC he can restore all or part of the Chamshaft timing with an offset Key (if they make them for his engine) or as he said replace the chain. If he dose either of these he will need to retime his IP again as it is driven by the same chain.

But I think that the question is: What would cause is car to smoke at idle and not when he accelerates?

__________________
84 300D, 82 Volvo 244Gl Diesel

Dose your Fuel Injection Pump Have a Pneumatic Governor or a Mechanical Govenor?

If you have a Pneumatic Governor your Fuel Injection Pump will have a linkage going to a butterfly valve in your Air Intake Manifold and I believe tubing or hose going fromt he Governor to the Air Intake Manifold.

__________________
84 300D, 82 Volvo 244Gl Diesel

I had a non-Mercedes fuel injection pump with retarded/late timing and it put out a lot of billowing white smoke.
When the pump was timed OK the white smoke went away.
Oddly I am having a similar problem to yours but not nearly as bad. When I first start up and let it idle I am getting some hazy smoke for about 1 minute or so. Maybe my pump is a litte too advanced also.

__________________
84 300D, 82 Volvo 244Gl Diesel

The smoke is not that bad and I do notice some on acceleration - I think it's a little worse than before...I'm not too worried about the smoke at this point - except as to what it tells me about the injection pump timing. I'm sure I had smoke before, just didn't pay much attention...

This car has the MW injection pump with the mechanical governor.

I really went to timing this thing because of new injector nozzles, sluggish starts from stop, and then the engine pinging - which was VERY noticeable on the way home from Ohio. Advancing the timing (moving the pump CLOSER to the engine has helped the pinging especially)...And I didn't touch the nuts on the pump flange and I have a new air filter.

Now, I am more concerned about the timing chain and if I need to change it out before I leave...

I have read thru all posts regarding replacement vs. key, and I don't really see the benefit in putting in a key, especially since I suspect this is the original chain (I have maintenance records going back years and I see where changing the chain was recommended, but I don't think it was ever done). If I decide to replace the chain, I am going to replace the tensioner as well. Has anyone done this? Do you really have to remove the AC and bracket, as well as the fan and water pump pulley?

I will experiment with the timing issue AFTER I sort out the chain issue...

ryan

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

A lot of members have changed their chains. Locating a proper tool locally to deal with the chain link peening is probably the biggest problem. The other problem with keeping an older stretched chain is it slowly damages the sprockets the longer it gets.

The other concern is your reading 5-5.5 degrees stretch now. Yet reading only 3 degrees stretch only a month ago. If the additional stretch has really occured it could be signalling something is changing fast. Far too fast.

Most believe the chain fails because of a problem with another component. This may not be totally true in all situations. I find myself wondering if the pinging that became noticeable during the trip but not present during the initial part of the trip. Could that have been because of a sudden elongation of the chain? Moving the pump ahead seems to have gotten rid of it. That almost proves it in my mind.

When stretch is present the chain may side whip a little when running. This produces a lateral force component. If that over time does fatigue the side links the chain is going to let go at some point.

Still something funny here though. Or I should say at least beyond my grasp at the moment. Needless to say if the chain had suddenly elongated it would have retarded the injection pump and cam. That should not have induced the pinging. In effect it was just retarding the pump. I think the cam change was not signifigant enough as well but may be wrong here. Also strange the pinging should lessen when advancing the timing.

Since you are pretty sure your elongation tests where done by the same method. I would change that chain much sooner than later as you are questioning the sudden apparent change. At first I suspected it was just your method for the strange change in the readings. Not sure at all now when thinking this whole thing through.

I am a very slow thinker at times but re reading your posts seems to indicate you probably know what you are doing. Or at least enough to be in control of the situation. Some of the questions you have now seem to possibly add up. Not all mind you but certainly some.

You may also have noticed something almost by accident. Some chains might issue a warning. Most of us will never catch it though if true. A sudden increased of stretch rather than over time. We expect a new chain to stretch a little fairly fast when entering service. Not a well used chain to gain 2-2 1/2 degrees apparent increased stretch in a months use. Almost double of what it initially aquired over a lot of years.

Sorry about some of my earlier questions. There was no intent to question in any form of negative fashion. It was basically because things were not adding up correctly. Still are not totally but the chain has to go. In my opinion it is too risky not to change it. The 5.5 degees of stretch do not disturb me. Its the apparent rapid rate of change that does.

When you get the old chain off clean it in solvent. Examine all the links with a magnifiying glass on both sides. If no cracks are found side load the chain over various areas. See if the chain forms the same side radius over its length. Or are there almost kinks in areas. Post good or bad. It may help others down the road.

There have been recomendations by obscure parties to change chains out at every 150k. You might have discovered the reason it is mentioned here and there from time to time. Hindsight is great but those parties might have experienced or seen evidence of fatigue in some chains. Just a thought at this point.

Barry,

Thank you for your very thoughtful response - I appreciate your help. I am pretty sure that I am dealing with the original chain (I have talked with the last 2 owners), so I am going to change it (275,000 - 300,000 miles on the car).

I am not sure as to the pinging and the advancing/retarding of the timing - and I don't know why it occurred all of a sudden. I thought that it could be related to bad diesel at some point on the trip home to Ohio, but the problem has persisted. The timing chain stretch has DEFINITELY showed some change over that past 2500 miles - again I don't know why, but I do know that I used the same procedure to check (and re-check and re-check) both times.

I am going to change the tensioner - do I need to change the tensioner rail? I have tried to look at mine as best I can (I know it's difficult with the old chain still there) but it looks fine.

ryan

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

If that is the original chain the engine might be in exceptional shape for the milage. The chain is the best indicator of oil changes. It wears fast with dirty contaminated oil. The primary barometer in fact as nothing else in an engine wears as fast with neglect.

If the chain guide looks pretty good and no evidence of loose plastic. It should be good to go. I think at this point I will lay back in the shallows like an old alligator and see how things go for you. Keep posting as you go along. I feel there may be something to learn here.

What we do not know cannot hurt us is an old untrue expression. Had you taken the car in for a pump timing. Chances are the mechanic would have discounted your suspicion of the rapid recent chain elongation. Drip set the timing and further adjusted it a little to get rid of the smoke somewhat at best and that might have been it. The chances of running across a really good mechanic still interested in these older cars is not too good.

Sure enough somewhere far from home the chain might have parted. Had you not been checking the car yourself the sudden elongation would not have even been noticed. There are many other areas on these older cars that require some thought from time to time.

I really enjoy getting my hands dirty. Just not enough time usually. The local service places here are out of the question. I even have to service and source parts for our newer cars starting when the warranty ends. A lot of members talk about being leaned over their fenders. I just refuse to assume that position myself.

I have the same concerns here - I can not find anyone that can, or wants to work on this car - especially when it comes to something like timing the injection pump. I have never had it done and I know this is hard to believe, but I don't know if it's ever been done on this car until I just did it a few days ago.

I do think the engine is in pretty good shape and I know (from PO records) the oil was meticulously changed - I also have real good compression across all 5 cylinders.

Interestingly, I checked the timing chain stretch again last night and noticed only 3-4 degrees this time - again using the lining up cam marks method - which is really tricky getting the marks to line up just perfect. This has led to my trying to measure cam timing using the 2mm method (see my recent thread - really frustrating as I can't figure it out!).

ryan

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

I have been trying to fallow all the problems and have gotten the impression that you are rushing yourself through these jobs. I know that when I rush myself I my thinking becomes reactionary instead of thoughtfull and and inhibits my ability to pay attention to details an sometime causes me to make the wrong decision.

When I drip timed my first Mercedes IP when I worked in a Fuel Injection Shop (my first mechanic job) my Boss checked it and it was not set exactly to spec. My Boss did not expect me to get it right the first time as I was still learning. I did not get it exactly right until the 3rd try. After that I had no problems doing the drip method which by the way at the time was used on most all of the inline type IPs except for CAT IPs which use a timing pin.
My point is that somethings we need to take our time doing things.

__________________
84 300D, 82 Volvo 244Gl Diesel

I don't think it's that I'm rushing - but thanks for the heads up. I have every intention of going back over the drip timing and checking it again. I just got sidetracked, and concerned about, the timing chain.

I really do take my time (I'm a college professor and I have lot's of time in the summer) - actually I obsess over these things really wanting to get things 'right', or as right as I can.

So for the last 2 days I've been studying chain stretch and timing related issues and trying to figure out the 2mm lift method - which if you read my other post, I think I have finally figured out. My chain is currently - with the 2mm method - showing only 1.5 degrees stretch, so I am going to put things back together and revisit the injection pump timing.

Thanks for the help!

ryan

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

I'm sitting here thinking about this mysterious chain enlongation then shrinkage and have an idea. This may be way out there but here's my 'what if'.

What if the chain and sprockets had an uneven wear along the length of the chain and around the cam, crank sprockets???
Since the cam does not run at the same speed as the crank the chances of having both sprocket's teeth mated to the exact same links of the chain the next time it was checked would be vary rare.

It could be the first (and last) time you checked the stretch it was all mated up tight and then, in the loose position the second time.

Just a wild guess.

Advancing the timing causing the pinging to go away does sound backwards to me. Normally, pinging is due to injection timing being too far advanced.

Please do keep posting your findings.
Good luck!

I think my 'erratic' timing chain readings are a "measurement" problem. I have double, and triple checked the timing using the 2mm lift method and got the same 15 degrees consistently (although even that approach is tricky trying to get the dial gauge needle to stop right at 2mm!).

I don't understand the timing advance - no more pinging result either. That is, if everyone is sure that moving the pump CLOSER to the engine does in fact advance the timing?? This is the direct quote from the FSM:

"Swivel direction of injection pump

Toward engine = earlier begin of delivery
Away from engine = later begin of delivery"

I am going to move the pump back just a bit to see what it does for the smoke. I took my car by a local mechanic and when I asked him about the smoke, he looked at it and said "it's a diesel". He said that that amount of smoke wouldn't bother him at all.

Maybe the car is 'supposed' to smoke a little bit...HA! It does run good...

ryan

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

Professor,

Earlier = advance
Later = retard

For example, injection at 20 degrees BTDC is more advanced (and less retarded) than injection at 10 degrees BTDC. But both are advanced relative to TDC.

In reality, setting the timing does not require that you actually know whether you are advancing or retarding the injection timing; you just need to move the pump to the position that yields the specified drip rate.

Now, after all the focus on the pump, are you certain the you had the crankshaft positioned properly?