Hello TEAM !

I have been thru the ringer with this one. Finally have the upper and lower timing chain guide rail pins out (look for my pictoral on that soon) - and I have all of my head bolts out. Everything is off the head as the FSM has directed, but now I'm down to hopefully the last thing before I can see this swinging from my engine lift;

I have the timing chain sprocket off the cam, but I cannot see how to actually get the sprocket out of the head. The timing chain is too tight. I see down on the passanger side of the head there is what looks like a tensioning bolt (or a pir of them, they're coaxial) - do I loosen that so the chain will be loose, allowing me to remove the sprocket? Then, if the head is actually free to move, the timing chain should slip right thru the head as it is lifted up - right?

Remove chain tensioner and small allen head bolts that go into timing cover. I also remove vac pump.

__________________

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

The upper chain guide should be removed now that you've removed the pins.

Remove the chain tensioner by turning the widest wrench flats; the ones against the head. You'll need a new crush washer. IIRC the FSM has a priming process before reinstalling the tensioner.

As NJ300sdl said, there are two bolts that take a 5- or 6mm hex bit that go into the front cover from the inside forward edge of the head. There's also a couple of small bolts on the head 'annex' by the big fuel filter. IIRC the FSM refers to these bolts as 'a' and 'b' in the head bolt torquing and loosening sequences.

Yeah, just let the chain drop into the abyss. It can't come off any of the other sprockets and it can't fall anywhere you can't retrieve it with a hook. Don't turn the engine while the head's off!

Sixto
87 300D

Howdy Sixto,

Yes, I have the pins out safely, am going to remove the guide next chance I get. I'll look for the crush washer (though the FSM does not mention any of this in the head removal section....I may need to look in other sections).

This may be a bad time to mention this, but I did not position the engine to any particular crank position first (like TDC for cyl #1) - I just took photos of the cam sprocket and made some marks on the chain and sprocket for good measure. Figured since the sprocket can only go on the cam in one position, as long as I have the cam in the right point of rotation, all should be well. Right....? It's not too late, I could still put the sprocket back on and turn the engine if needed.

A few of the head bolts had rust on their tips (towards the back of the engine, the very back) - others were covered in oil, then some were dry....wonder what that means.

Next I'm tackling getting the turbo off and out of the way. Does it ever end ?

Put the sprocket back on the cam and set the engine to #1 TDC before you proceed. The cam tower removal and installation sequence is only valid with the cam at TDC. It wouldn't matter if you were simply lifting the head to replace the gasket, but anything can happen requiring the cam to come off so it's worthwhile insurance. If the cam is off the original position when you set the head on the block, you'll likely bend valves.

Sixto
87 300D

Sir - I will follow this recommendation - I don't want to turn my 300TD into a valve-bender !