My son's '87 190D is REALLY noisy when started cold. It's that usual diesel "ping" only very noisy. I replaced the timing chain to no avail. I probably wouldn't have bought the car if I had heard it start, but the crafty seller already had it warmed up and running when we got there to test drive it. Any ideas??

My guesses, in order...
Glow plug(s) not functioning
Glow plug timer not functioning properly
Injectors dirty, leaking, or incorrect/inconsistent 'pop' pressure
Injector timing incorrect

I do not have manuals for your car..

but for our 123's ... and I think particularly on the NA engines.... the FSM mentions startup noises... so you might check for that book reference...
Also, does your chain use a ratcheting slack taker upper (LOL) ?
Did you renew or adjust that at the time of the chain renew?
If you have that ..but it is working slowly... then the chain slaps around until the slack is taken up...
Did you renew the items in contact with the chain , if any, like rails and slides ?
Also, have you checked your oil pump pressure relief ( if you have one )... that is mentioned as causing noise I think on our 615,616.677 engines... and at least THREE different psi models have been substituted over the years...

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html