Soooo...Do I line up the camshaft mark, then check the RIV tang positioning? or line up the crankshaft timing mark then check, or try one then the other?
I guess I'm kind of fuzzy on the exact procedure.
Sorry if I'm an idiot. Your pic is very helpful.
Thanks for the help.

I'm sure I could find more info if I took the time to do a search

The spec for the RIV tang to be centered in the inspection hole is something like 14.5* ATDC so there's no point in aligning the cam marks or even removing the valve cover. There isn't much of a procedure. Remove the plug using a 17mm wrench then turn the engine until you see the RIV tang. Nudge the engine to center the tang then read the crank pulley indicator.

Sixto
87 300D

The Timing for the RIV is on your Emission Sticker.

There is a device called a Timing Locking Pin. And, there used to be a few to rent on our Tool Rental Program.
Tool Rental List
Tool Rental Master Member List - PeachParts Mercedes ShopForum

The Locking Pin is actually made for when you off the Fuel Injection Pump you remove a plug on the Govern Housing and properly orient and screw in the Locking Pin and then rotate the Fuel Injection Pump and that Tang everyone is speaking about centering locks onto the Pin and holds the Fuel Injection Pump Camshaft in the proper place.

Then you would set the Engine at the proper degrees after top dead center on the compression Stroke and insert the Fuel Injection Pump; tighten the Fuel Injection Pump down, remove the Timing Pin and re-install the Plug and your timing is done.

In your particular case where you suspect your Fuel Injection Pump timing is late/retarded. I don't see why you could not line the crank to the proper degrees after top dead center of the Compression stroke. Loosen the Fuel Injection Pump Mounting Bolts sufficiently to use the Fuel Injection Pump rotation Screw/Bolt and install the Timing Pin and use that Rotation Screw/Bolt to rotate the fuel Injection Pump till it locks.

Tighten the Fuel Injection Pump Bolts and remove the Pin and re-install the Plug and you are done.

I don't think trying to center the Tang by Eye in the Hole is going to get you an accurate timing.

__________________
84 300D, 82 Volvo 244Gl Diesel

Sixto....I thought about it last night after I posted that last post. And kind of figured out myself, Duh.. It's like a distributer on a V-8 gas engine, line up the pointer, then see where the timing is at by consulting the degrees on the crank damper.
I didn't have time to do it last night, but I will this weekend just for kicks and grins.
I think it really doesn't matter at this point as a new more severe problem has come into existence and confirmed last night. See my other post on my other thread about using a block sealer on a #14 head. The head is cracked or head gasket didn't seal at #4 cylinder or something is wrong. So the whole timing thing is now of no consequence.

Thanks for the help anyway, I still have another 300d so I'm sure I will need more help someday.

1998.5 Dodge Ram-Cummins 376k
1987 300SDL 253k-broke and now for parts
1987 300D-T-76k 'Crème Puff'
2013 Jetta TDI-6k
1993 Mustang LX-5.0 convertible-91k (just for fun)

I did have a chance to line up timing marks this weekend. The emissions label under the hood says timing should be -15. So I set the crankshaft damper at -15 and took off the port plug on the IP and the tang is dead nuts in the center of the hole.
I turned the engine over a couple more times to confirm. So, I guess that checks out.
I have posted the car on craigslist, and under the 'Cars for Sale' in this forum, if it doesn't sell I may get interested in trying to find or fix the problem later on this winter. If it doesn't sell fairly soon, I may take the IP off and take it to a shop, have them check it out.

I am going to order the injection pump, timing locking tool thingy. I figure I have 2 of these engines around, I will eventually need it on one or the other. The car is for sale, but if no one comes forth as an interested buyer I am going to take the pump off sometime next week and get it to a authorized shop and have them take a look at it.

Also, when I took the nut off the timing port of look at the RIV tang position I noticed there was a lot of engine oil in there. it was almost so black with oil I had a hard time making out the tang. I have been doing more research on this forum and others, the pics I have seen show it pretty clean inside the port, unless they sprayed it out to get a better pic.

Just wondering if this could be a sign something is not right with my pump?

I know the pump has an oil feed to it, just not sure oil is supposed to be in that section of the pump.

Oily is normal.

Sixto
87 300D