1976 300d Question

"..repair bill from 1994 in the glovebox with timing chain, valve guides, etc done at 92000 miles. I purchased it with 99500 on the odometer."

So it must have run after the timing chain was replaced.

Yes, there should be some suction at the intake. There's probably a crank case breather hose connected to the intake that will relieve some of the suction.

Since you have the valve cover off:

Suggest you crack open the high pressure line to the injector for #1 cylinder (at the pump) and turn the engine by hand so you see (i) if there's fuel being sent to the injector and (ii) when that occurs, if both valves for #1 are shut (cam lobes at 1 o'clock as viewed from the front).

Then you can also check the synchronization of the cam to the crank. Just aft of the cam's chain sprocket is a collar which has a notch. Mid point on the driver's side of the front camshaft support is a cut groove. Turn the motor (not by the cam) to align the notch with the cut groove - that's TDC for the cam. Then read the scale on the crank's harmonic balancer - should be less than 5 degrees ATDC given the chain replacement job.

If you find all this to be OK then I suggest you check if the glow plugs are working and, if so, suggest you prime the fuel system again to ensure all the air has been expelled.

Thanks T.G. for the response! This has me puzzled and makes me think that it is a timing issue and I will definately check on the suggestions that you mentioned. It especially worries me when it won't even fire on starting fluid (with the glow plugs inactivated) as well. Either it is way off on timing or there are all of a sudden issues with the bottom end. Thanks again!

Holy cow TG! We all should pay you a salary! :-)

cp

done at 92000 miles. I purchased it with 99500 on

breather hose connected to the intake that will

(at the pump) and turn the engine by hand so you see

both valves for #1 are shut (cam lobes at 1 o'clock

of the cam's chain sprocket is a collar which has a

groove. Turn the motor (not by the cam) to align the

crank's harmonic balancer - should be less than 5

working and, if so, suggest you prime the fuel system

Starting fluid is BIG no-no on Mercedes engines. It washes the oil off the cylinder walls and you loose compression. The engine needs all the compression it can get to fire.

When this happens, we have to resort to 24V to get them started.

I'd think that the stress to the connecting rods and crankshaft from the starting fluid's lighting off so early before the pistons reached top dead center would be a bigger concern with a diesel. (Especially in the case of a 350SDL.)

But setting that aside for a moment, wouldn't the engine have enough rotational momentum, after the starting fluid had been consumed, to get oil flowing onto the cylinder walls again while fuel was still being injected into the cylinders?

Simply cranking the engine with 12V (and without starting fluid) wouldn't restore oil to the cylinder walls adequately?

Geoff

Starting fluid is dangerous in a diesel that uses glow-plugs, which Benz does. Some large trucks have a provision to mount a can of ether with dedicated in-cab control.

Talk about a dedication to maintenance..

Okay all Update on the unit! It looks like all is in order with the valve train, and the timing on the timing chain as well. It would turn over fine but wouldn't start. I seen on another group that even though it is an automatic, it will start if pulled over 30 and then slipped into S. Well that worked well, and the engine would purr like a kitten. I had it running for about 10 minutes then decided to shut it off and restart. Once again, it will turn over but would not fire off. How fast are these engines supposed to turn over with the starter? It doesn't seem to turn over as fast as my powerstroke, but seems to be spinning faster than some of my diesel tractors, so that shouldn't be the problem, or is it? I do not have a tach so it is hard to know exactly how fast it is turning. Most folks say their engine is running with only one or two spins so I definately have an issue there. (I also loosened all the fuel lines and it is pumping fuel out on all the injectors, no air bubbles.) When it was running it seemed like it was not as responsive, so maybe the inj pump needs to be timed. HELP! Tim

Definately. This guy had a few cars that were his reason to live. Nice fellow with lots of friends as well. His vehicles were very nice!

On 22 Nov 2005 06:02:37 -0800, against all advice, something compelled "TimmyD" , to say:

I'd replace the glow plugs. I had a roommate (from hell, but that's a different forum) with a diesel car. He needed a push start on a not infrequent basis. I suggested he change the glow plugs, and it started normally after that. The nice part is that they don't cost much, and you should probably swap them out anyway.