The cylinder crankcase assembly consists of aluminum alloy upper and lower crankcases. The upper crankcase contains six cast-iron cylinder liners, and houses the crankshaft, which is supported by four cast iron main bearing caps. The upper crankcase contains the chain-driven oil pump drive and driven gears. The oil pump body is a machined portion of the upper crankcase. The lower crankcase provides side-engine mount locations and completes the crankcase assembly. The aluminum oil pan, which houses the oil splash shield and oil pickup assembly, is secured to the lower crankcase.
The aluminum alloy cross-flow cylinder heads have hemispherical chambers and individual intake and exhaust ports for each cylinder. Both the intake and exhaust valve guides are pressed into the cylinder head. The steel valve seats are fitted to the cylinder head.
Each cylinder has a chain-driven overhead cam shaft. The camshaft operates both intake and exhaust valves on each bank by adjustable rocker arms mounted on a single common rocker shaft. The rocker arms are positioned and held in place by two spacers and one thrust spring per cylinder. The hollow rocker arm shaft, which also distributes oil through calibrated holes to the valve train and camshaft, is mounted and secured to each cylinder head with four rocker shaft supports.
Camshaft and Drive
Each chain-driven cast-iron camshaft is supported at four contact areas. Steel crankshaft sprockets drive the two timing chains; the timing chains drive the camshaft sprockets.
Pistons and Connecting Rods
Each aluminum alloy piston uses two compression rings and one oil ring. The steel piston pin has a floating fit in the piston. The pins are retained by a "hot" press fit. The connecting rod bearings are lubricated via drilled oil passages in the crankshaft journals.
The cast-iron crankshaft is supported with four main bearings and main bearing caps. It has three connecting rod journals, lubricated via drilled oil passages in the crankshaft, crankshaft main bearings, and main bearing journals. The crankshaft is sealed at each end with a lip seal.
There are three steel drive sprockets mounted on the rear of the cranshaft. These three chain-drive sprockets drive the camshaft sprockets and oil pump sprocket. The drive chains and sprockets are covered by a timing chain cover which is secured to the upper and lower crankshaft assembly.
The DeLorean DMC-12 has two electric fans for radiator cooling mounted at the front of the vehicle. These fans are activated when the engine coolant exceeds 97°C (206°F) and deactivated at 91°C (195°F). Operation of these fans is controlled by a temperature switch ocated on the coolant return pipe in the engine compartment.
The water pump, located at the rear of the engine, is belt-driven (by the crankshaft pulley). The thermostat is housed in the top of the water pump under the thermostat housing cover. The thermostat housing cover is equipped with an air bleed screw (used to purge air from the coolant system when refilling).
Coolant leaving the engine is directed (through a series of pipes and hose couplings along the left side of the vehicle center tunnel) to the radiator. Coolant leaving the radiator is directed (through a series of pipes and hose couplings along the right side of the vehicle center tunnel) to the engine.
The coolant expansion tank, located on the right side of the engine compartment, is connected to the coolant return pipe by a hose.