Putting in a new timing chain in this weekend (feed method). I've read where I should pull the injectors to relieve the cylinder pressure so I can turn the crank, & I know about pulling the glow plugs but some are a bear to access without pulling the intake.

So the idea seems attractive but I don't know what I may be in for. Maybe I should just replace the injectors at the same time. Is it just a swap out? What is to "Pop" the injectors? What else? Or just pull the intake.

What is the opinion of replacing the tensioner? Mine "seems" fine. And yes I would like to pull the cover and replace the rails /guides too but they will have to wait a few more miles.

Thanks!

Heat shields and return hose will be needed if you remove the injectors. Plastic clips on injector lines are subject to breakage when the lines are removed. I have never put a chain on, but would remove the vac pump so it does not fight the rotation.

Good working injectors do not need to be replaced or worked on.

Should be able to continue using present tensioner.

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Present
1987 300SDL
1991 300SL
1990 560SEL
2001 ML320

Past
1969 200D 1979-82
1983 300SD 1984-85
1972 250C 1982-02
1995 S350 2011
1997 S320 2012

Do lots of reading before jumping into a timing chain, if this is your first time.

Ideally 3 people, one person has a tool on the camshaft, another with tool on the crank, and third does the feeding. All roll in unison and each is responsible for not letting there part of the job slip.

Camshaft will jump backwards when spring pressures on the lobes are just right. This can throw a lot of people off if they're just letting the cam free wheel as they roll chain on. A jump back of the cam can hop a tooth or two... and now your timing is lost.

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Cheers!
Scott McPhee

1987 300D

Thanks nj300sdl & Scott. Great tips!

Not my first but first MB by this method. A little nervous.

Any tips on removing the injectors?

Re: Chain draw + skip potential I plan to use lots of multiple zip ties to keep the chain contact tight with the cam sprocket. Go very slow. Plus hope to have a helper.

Also figured out my "pop" & "balance" procedure.

Just thought after 317k the injectors could use replacement. Maybe not?

Nothing special to removing an injector. Get the right deep socket, pull the return hoses off, crack the nut and move the hard line away, slip the socket with breaker bar over the injector to the base and reef (counter clock wise). When you have it loosened off a few turns, use compressed air to blow debris from around the hole, then fully extract.

When injector is out, pull the metal "washer" (injector seat seal) out using a hooked shape tool. Throw them away, use 6 new ones. Note which way those things sit in there.

If you're doing the chain, do a new tensioner. Or at least, you'll have to pull the old one out, reset it and put it back in on the new chain. Otherwise it will be too tight (too much side pressure) on the new chain after it's rolled in.

Lots of zip ties is smart... cheap insurance. People use vise grips, but they can pop off too easily.

New chain, timing set right, plus new injector nozzles, set right pressure right equals amazingly new-like qualities at idle.. less smoke... and it will run with more power for a same given amount of fuel.

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Cheers!
Scott McPhee

1987 300D

If you Cylinder Head is Aluminum removing the Glow Plugs can result one or more of the Hex Heads snapping off.

There is a wiki and a bunch of threads on that and some ways to decrease the chance of it happening.

In the above case plan for the worst and hope for the best.

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84 300D, 82 Volvo 244Gl Diesel

This is primarily the OM606.

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Gone to the dark side

- Jeff

Thanks.

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84 300D, 82 Volvo 244Gl Diesel