Remove the whole tensioner.

Crank engine around by hand until none of the rocker arms are under compression. There is a point where this is true, TDC if I remember correctly. Unbolt the rocker arm towers and remove the rocker arm carriers. This will free up the cam and prevent the valves hitting the pistons while you are working.

Crank engine around by hand until TDC is on the mark on the compression stroke on #! cylinder, double check cam -- notch should be to the left of the "pointer" on the cam tower.

Use a large screwdriver to preven the cam from turning and remove the cam sproket bolt. Pull sprocket off cam, and while holding tension on the chain, carefully walk the chain one tooth to the left on the sproket. Don't drop the sproket, it will be oily.

Line the cam back up and install the sprocket and bolt. Rotate engine a couple times, then check the timing. The notch should be just about perfectly centered when the pointer is at TDC on the crank. My new chain was about 2 degrees late, don't expect it to be right on.

If it's now early, it was in the right spot and the chain is worn out, replace it.

Check the injection timting by the drip method (24 degrees BTDC the fuel flow should drop off dramatically).

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!