Mechanics

WHAT IS THE ENGINE OIL CLEARANCE OF THE CONNECTING ROD BEARING AND ITS CAP BOLT.NIT TIGHTENING TORQUE?

1987 Mercedes Benz 260e • 33,400 miles

The connecting rod bearings are due for replacement
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Edgyona10
September 14, 2011.




The bearings shouldn't need replaced at 33K miles. Are you getting a knocking from the engine? Has the oil been changed on a regular basis?

The engine oil pressure was such too low. Zero reading as engine warms up. An oil change is not followed at its regular changing intervals.

Tiny
Edgyona10
Sep 15, 2011.
Can you hear the rod bearings knocking? My concern is that it may just be a bad oil sending unit. You may want to check oil pressure with a mechanical gauge to confirm the pressure is very low. As far as clearance between the bearings and crank, you are looking at thousands of an inch. You need plasta-gauge to check if they are bad.

There's no knocking noise whatsoever. Since we've got to change the conrod bearing, we will be using plasti-gauge to initially check the clearances. May we please know the oil clearance tolerance and the tightening torque of the conrod bolts. Thanks.

Tiny
Edgyona10
Sep 16, 2011.
By the way, what is the specific lenght measurement of the oil pump relief valve spring. Sorry for the mis typing of mileage run, it should be 68,912.

Tiny
Edgyona10
Sep 16, 2011.
Connecting rod journals diameter 1.8880 - 1.8884 inches or 47.955 - 47.965mm

Torque: Step 1. 22 ft lbs
Step 2. Angle tighten 90 degrees

I don't have the length of the relief spring. All I can find on that is it is set to release at 71 psi

Thanks for the info, it will best serve us if the measurement has to be taken on the flattened plasti-gauge rather than taking the difference between the diameter of the big end bore against the diameter of the crankpin journal. I reasoned out that I dont have caliper and bore measuring tools. May I please know the oil clearance dara, your help is so much appreciated. Thanks.

Tiny
Edgyona10
Sep 16, 2011.
Oil clearance? I'm not sure I understand.
AD

Means the required clearance between the connecting rod bearing and its corresponding crankpin journal.

Tiny
Edgyona10
Sep 17, 2011.
That would be the tolerance of the bearing. It should be.010


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