Nerves and Torque settings, 220D from 1973

[skalie]

I'm changing a head gasket on my 220D from 1973 tomorrow, (in about 14 hours), and I'm still not totally sure on the torque settings. The only book I've been able to find is for models from 1976 on.

This.......


......Tightening stages, tightening torques in mkp. The first three stages
are with engine cold, and the last is with the engine warmed up and run
for 5 minutes at operating temperature of 80 degrees C. First stage=4,
second = 6, third = 9, and fourth = 9.


Note that these are straight torque figures, and don't use degrees of
rotation like later ones.


You should retighten again after 300-1000km. This should be done even
though the unscrewing torque might be more than the tightening torque,
so it might appear that the screws are tight enough. "Each screw should
be slightly loosened in the sequence laid down in the screw schedule and
should then be retightened to the prescribed tightening torque. Under
no circumstances should all screws be unscrewed in one operation then
tightened."


.......is what I'm going to go on.

Just to complicate matters a new engine was thrown in in 1992, brand new, from Germany like. On the front is stamped 615 015 1101.

The guy from the local Mercedes garage says that those numbers are worthless, but then he was expecting to see number stamped on the block by the pump.

Any comment, or directions towards technical specs on line would be HUGHLY appreciated.

Thank you in advance,

Richard.

[gdaley]

I can't say for certain on the Benz, but on the cars I have a lot of experience on, I've seen changes in the torque specifications for the cylinder head evolve over time with changes in the technology used in the head gasket. Most head gaskets come with specific instructions from the manufacturer of the gasket and they are what I follow. Few require retorquing after run-in and most use protractor torquing for the final stage. One caveat is that most of the engines using protractor torquing are using stretch bolts so it's conceivable that you would need to change the bolts to obtain the best results.

[Stan Pittman]

I have never read a repair manual that gives the correct toruqe. In my experience if you go by the manual you'll be replaceing the head gasket again. My way is torque the head to the specified torque and then (2) 90 degree turns. Its going to feel like the bolts are going to break but they will be tight.

[skalie]

Originally posted by Stan Pittman
My way is torque the head to the specified torque and then (2) 90 degree turns.

Those are the instructions my book gives for allen bolts with 12 sides. For the 6 sided they give only torque settings, not angles.

I'll be finding out in a couple of hours which I'm dealing with, hopefully the 12 sided as there is less chance of them needing replacement.

Thank you everyone for your prompt replies.

[skalie]

Update.......

.......head off in two hours, wrong head gasket, seems the number on the front of the block doesn't mean anything, they expected to see a serial number next to the injection pump, and even taking in the old head gasket to the Merc garage didn't help them with their somewhat confusing data base.

Now a wait to see if the next one to arrive is the good one, dammit.

Inspected the head, and there's a hairline crack between one of the valves, and one other one radiating out form one of the valves.

Invest in another head? It was running fine before the operation, except for blowing steam out the exhaust due the cracked head.

Does anyone know if the head of a 200D will fit on a 220D block? The 200D head is from about 1978.