The lugs are to locate the bearing fore and aft. Crush is what prevents the bearing from spinning. When everything is correct the split bearings are tight in the parent bore much like a cam bearing.

We get this question all the time at Clevite (engine bearing mfgr) as many thrust (flange) bearings have no lug. In that instance the flange locates the bearing in the block.

The lugs will not prevent you from rolling in new bearing, just make sure you roll out the old one starting at the opposite end (without the lug).

There are some performance rod bearings that are doweled and those do help keep the bearing place due to extreme bore distortion at high RPM's. Those are likely to changed after just a few runs though.

I'm not familiar with any doweled upper mains? There may be some??

I think you rotate the crank in the opposite direction of normal rotation. You put a special tool in the crank oil hole or make one out of a cotter pin bent to the shape of a lazy T. The cotter pin pushes against the upper bearing shell and it pops out. I guess the Volvo has tangs on both sides vice one.

Here is a representative procedure:


Engine in the Car

With the oil pan, oil pump and spark plugs removed, remove the cap from the main bearing needing replacement and remove the bearing from the cap.

Make a bearing roll-out pin, using a bent cotter pin as shown in the illustration. Install the end of the pin in the oil hole in the crankshaft journal.

Rotate the crankshaft CLOCKWISE as viewed from the front of the engine. This will roll the upper bearing out of the block.

Lube the new upper bearing with clean engine oil and insert the plain (unnotched) end between the crankshaft and the indented or notched side of the block. Roll the bearing into place, making sure that the oil holes are aligned. Remove the roll pin from the oil hole.

Lube the new lower bearing and install it in the main bearing cap. Install the main bearing cap onto the block, making sure it is positioned in proper direction with the matchmarks in alignment.

Tighten the main bearing cap to specification.