lower crankcase

The lower crankcase assembly supported the crankshaft without conventional main bearing caps.

Both gear-driven counterbalancer shafts are installed in the lower crankcase, to the left side of the crankshaft.

The rear shock absorber is unusually placed horizontally under the engine and uses the lower crankcase as a mounting point.

This engine was a Škoda version of the Hispano-Suiza 12Gb, with a new lower crankcase.

Firstly, worries about blow-by, i.e. a sealing problem that leads to a gas leak between the combustion chamber and the lower crankcase.

A helical gear pressed in No. 3 counterweight drives twin contra-rotating balance shafts in the shaft housing within the lower crankcase.

The engine had a cast iron block, a detachable cast iron cylinder head, and an aluminum lower crankcase and oil pan.

A T55 Torx bit and driver for the top engine/crash bar mount bolts, and a T40 to remove the stock lower crankcase bolts.

If my reasoning is correct, this setup would induce a much lower crankcase pressure than with just a PCV in the crankcase breather line.

The cylinder block is an open-deck, midi-skirt type with cast-in iron liners and a die-cast aluminium lower crankcase and a stamped oil pan.

The oil pump assembly then bolts into place in the lower crankcase, making sure it fits flush up to the two "O" rings that seal it against the casing.

As a result, engineers developed a rigid reinforcing brace for the lower crankcase chamber to reduce NVH and at the same time reduce the potential for oil leaks.

This decision also allows further development on parts that were initially planned to be closed off, including the upper and lower crankcase, valve drive, crankshaft, air-valve system and ancillaries drive.

Later production R engines featured sodium-filled exhaust valve stems for improved cooling, while additional modifications included a redesigned lower crankcase casting and the introduction of an oil scraper ring below the piston gudgeon pin; a measure that was carried over to the Merlin engine.

By increasing the number of mounting points between the engine and frame, vibrations and stress can be better dissipated in the frame, typically creating a triangle between the swingarm in the rear, the cylinder head at the top and the lower crankcase area at the front.