When installing a new timing chain, does the cam tower marks/degree wheel line at TDC or elsewhere? I thought I saw + (or -) 2 degrees somewhere in the archives of this here message board.

The second owner relaced the short block back in 1979 and I'm trying to determine if it was set correctly.

After adjusting the IP to get one drip/second at 24 degrees BTC, the car is now harder to start and bellows gray smoke at idle. Acceleration smoke is also more gray than black now. . Car still hits 80+mph and acceleration is 0-70 in 30 seconds, according to the likely inaccurate speedo.

This was after about a 2mm bump towards the engine, fwiw.

I thought the IP adjustment was to compensate for timing chain stretch. But could it be so far gone that, at 170k, adjusting the IP makes matters worse?

Regardless, after having the injectors rebuilt, I'm washing my hands of it and make the trek to the "local" specialist, some 90 miles away.

I'm trying to learn something of timing chains in the meantime in case it needs replaced.

Danka.

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1974 240D "Boldie" 170K.- New timing chain/freshly rebuilt IP/replaced valve seals/injectors/upgraded stereo/new Bilsteins with Yokohamas/fresh paint and rocker panels plus lots of welds.

I can only speak in general. When the Engine was new; when the Camshaft Gear and Tower Timing marks were lined up it was supposed to point at TDC (OT).
However, if when the rebuilt the Engine they reused the Crankshaft Gear and/or the Camshaft Drive Gear I would suspect that those gears have some wear on them and that you would not get exactly TDC; even with a new Timing chain.
Also there is no Woodruff Key to correct it if it is a few degrees off.

The Crankshaft Timing Gear is the smallest and is the one that pulls the Chain. It must be the most stressed of the Gears.

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84 300D, 82 Volvo 244Gl Diesel