I am doing the head gasket on my '78 240d. A huge undertaking for the beginner I am, but a very interesting experience. NO problems so far. ( I am halfway, at the part where the cyl head is already off...)

BUT, one thing has me really scared. I am not sure that I've kept the timing chain always tight, though I tried to..and I might have perhaps rotated the crank pulley backwards a little removing the pressure of the cam lobes from the rocker assemblies etc. etc., I don't remember entirely.

SO, how to be sure that the timing chain will align the crank pulley and pump timing gear (the big one behind the vacuum pump) -- to the tooth=18 degrees?--, with the camshaft gear, so it doesn't end up smacking a piston into a valve or whatever happens when it is incorrectly timed?

Hoping for some help before I start back into it on friday...

I had this same very problem, i lost the timing on my 1981 240d entirely. my crankshaft and IP were both in time but i lost the cam timing. So what i did was look at the pointer where it says TDC on the harmonic balancer, that means either, cylinders 1 and 4 are TDC (Top Dead Center meaning pistions at the top) But i still didnt know if i was correct on my IP timing (Injection pump timing) So what i did was blow out the number 1 port for the injector line. and put a peice of towel in there. i rotated the engine to TDC and it didnt shoot from injector 1. so i continued to rotate until it welled up. then i knew that i went too far and the last TDC i went by was the correct one. and how i checked if 1 and 4 were TDC i pushed down on the valve it should hit the top of the pistion. (You want 1 and 4 to be at TDC) After that i put the cam on, now i lost the position of the cam i so reset it to where the intake valve on cylinder number 1 is JUST ABOUT to open, that means the lobe is allmost touching the valve. AFter that throw the timing gear on there and rotate the engine to make sure that not only are your clearances correct with pistion and valves, but the timing of the injection pump. (Its really not possible to break anything by hand you would have to be really wrenching it) if nothing hits and everything is in time, Proceed!

Im sorry for the run on sentences and tons of commas, im quite tired right now lol. have fun.

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Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac?

As long as they would add one additional commandment for you to keep thy religion to thyself.
George Carlin (Wonder where he is now..)

1981 240d (engine donor 1983 240d) recently rebuilt engine hurray! - No more.. fought a tree and the tree won.

pearl black 1983 240d 4speed (Converted!@$$%) atleast the tranny was rebuilt.