617 Missing on a cylinder and other issues

[pawoSD]

My dad's '83 300SD with 301k on it is having some weird engine issues. Firstly, its always been a "gruff" engine, with a somewhat harsh idle etc, but runs smooth and delivers great power/economy. It also has essentially no blowby at all. Yesterday I did a valve adjustment on it, and it developed a bad injector knock on the #1 cylinder, still ran ok, but had a metallic knock.

So I pulled the cover and rechecked the valves, turns out I had over loosened the intake valves because two of my feeler gauge's had stuck together! The "over loosening" was maybe 3/4 turn of adjustment, not huge. I probably set them to like .20ish mm instead of .10mm....I adjusted them all properly at this point. Put it back together, still knocking on cyl #1......sounded a lot like injector knock. (All valves had been quite tight prior to adjustment) Timing chain appears to have about 1.5 degrees of stretch or so. BUT, it doesn't seem to "ride the rail" all the way, the tensioner is crooked, and doesn't like up with the pressure pin, its offset. Thus, the chain's forward-most edge (to front of motor) rides out in space, hanging off the guide rail. Is this right or is something real wrong here? The rest of the chain rides on the guide and it doesn't seem to have any wear or grooves in it.

When loosening injector #1 hard line, the clack/nailing went away. So we swapped out injector one with a spare. Upon install and running, it would not run on that cylinder, it was shaking and loping along on 4....even with the hard line bled properly and checked for fuel. So we tried yet another injector.....this time it decided to run on it....but missed occassionally...and still has a slight clacking sound. It runs ok and he's been driving it, but he said it still shakes a bit sometimes and has the knock/nailing sound.

Any ideas?!

To top it off, the new starter I put in our 300D is skipping, at this point I think there might be damaged teeth on the flywheel. Perhaps caused by the old starter that didn't always engage right.

Not a good week.

Any ideas on the knocking?

[DeliveryValve]

Try swapping an injector from one of the good cyllinders.
Make sure the crush washer is seated propertly with no debris in the area.
And shine a flashlight look down the prechamber to make sure it has not self destructed.

[pawoSD]

Originally Posted by DeliveryValve

Try swapping an injector from one of the good cyllinders.
Make sure the crush washer is seated propertly with no debris in the area.
And shine a flashlight look down the prechamber to make sure it has not self destructed.

Already checked the prechamber last night, looks fine. I've swapped injectors many times, its surely seated properly....I tried two different good injectors with similar results. Low compression possibly? Valve problem? I think we might get a tester and check the compression levels....

Biggest question is why would this have happened after a valve adjustment? Perhaps having the valves in spec made a pre-existing issue worse?

[DeliveryValve]

Yes compression check is in order for all cylinders. A leak down would be next if there is a variation between them and to see if it is a head problem.

If all checks out, then it could lead to IP issues... bad IP, timing, etc.

[pawoSD]

Originally Posted by DeliveryValve

Yes compression check is in order for all cylinders. A leak down would be next if there is a variation between them and to see if it is a head problem.

If all checks out, then it could lead to IP issues... bad IP, timing, etc.

It was running ok prior to the valve adjustment though, it ran rough at idle, but ran ok all the same.

Think the adjustment brought out a pre-existing problem?

[DeliveryValve]

That is the possibility. But you won't know until you perform a compression check and then a leak down to determine if it is a head issue. Until then, it is all speculation.

One more question, I hope you did your adjustment while the engine is dead cold.... Both the initial adjustment and the second adjustment.
I like to do it 12 hours after it last ran..

[rrgrassi]

It's possible. A valve that is too loose has a shorter lift and duration which does have an effect on fuel/air mixture or expelling of exhaust gasses after combustion. I would think valves too tight can cause more damage than too loose.

[pawoSD]

Inital adjustment was dead cold, re-check and adjustment was after the engine had been idling for 3-4 mins, then shut down for 2 hours (but in the very cold garage), it certainly wasn't warm when I re-checked it.

It seems to be doing a bit better, we're starting to think possible water in the fuel or some other issue. He put in a fresh tank of fuel + a bottle of RedLine Diesel Catalyst, we'll see how it goes. Essentially the only issue it has now is a bit of nailing (but not much)....way less than before. It runs well and does not smoke or miss. We'll check the injectors again this weekend to see if we can narrow down any more of the nailing. Might just be a couple bad injector nozzles.

From what I've read on adjustments, its better to err on the side of too loose than too tight for the valves. I checked and re-checked them, and they seem to be right in spec.