Bob Smith,
Here are some notes that I collected from this site and talking to Joe A. Good Luck! Bob
Normally the head is tightened and the valves adjusted on these engines at 12,000 mile intervals. If you do not know the service history of the engine, I automatically torque the head first.
Don't forget to loosen the radiator cap first. I do the M130 (280SL) engines at 80 ft. lbs of torque engine warm. Remove all spark plugs also.
Note:
Torque the head when hot but cool enough to handle.
Adjust valves on cool or cold engine.
Let it sit overnight after re-torque of the head. Remove the spark plugs to aid turning engine. Have a new valve cover gasket ready in case yours is stiff and brittle.
Tighten Head Gasket as a first step. Tighten in this order (start in center and work outwards; also loosen hex bolt 1st, then tighten to specified torque):
12, 8, 4, 2, 6, 10, 14
11, 7, 3, 1, 5, 9, 13
Note: see page 37 in the Haynes manual
Use a long 10mm allen
Loosen and re-torque one at a time in correct torque sequence
Don't forget the bolts in the timing chain housing. These are 6mm allen and should be torqued to 2.5kpm (5.5 ft. lbs). These are not under pressure, so can simply adjust by feel.
Adjust Valves:
Adjust via the engine firing order to avoid excess turns of engine…
Adjust 1, then 5, then 3, then 6, then 2
Note: See page 39 in Haynes manual for exhaust vs intake
Feeler gauge should be a tight slide through, some resistance when sliding through, but not loose. Tighten all the way with feeler in place, then loosen.
Exhaust = .007 (7 thousandths)
Intake = .003 (3 thousandths)
Note: My measurement is in inches the one in the BBB is metric. You will find that the conversion from metric to US will give you a slightly higher value than .003" and .007" However these are acceptable values especially on a engine with some miles and wear.
bpossel
Memphis, TN.
1971 280SL
1997 E320
