20 Engine 5-2 General Information, Diagnosing Malfunctions Model 2120 Tractor TM-4252 (Dec-70) Group 5 GENERAL INFORMATION, DIAGNOSING MALFUNCTIONS GENERAL INFORMATION The tractor is equipped with a 4-cylinder vertical in-line, valve-in-head, 4-cycle Diesel engine with direct fuel injection. The engine is our own design. The "wet" cylinder liners can be replaced one at a time. The pistons are of forged aluminium alloy and cam-ground. Each piston has two single, cast-iron compression rings and one oil control ring. All ring grooves are above the piston pin. The case-hardened piston pins are full floating and are held in place by two snap rings each.
A camshaft supported in the cylinder block con¬ trols the valves and drives the fuel transfer pump. The intake and outlet valves are supported in the cylinder head. The valve stems slide in bores in the cylinder head. The rocker arm shaft assembly is fitted on top of the cylinder head. The engine is supplied with lubricating oil by a gear pump. The lubricating oil passes through a full-flow oil filter in the main oil circuit. To ensure engine lubrication, the oil filter is provided with a by-pass valve which opens when the filter element is clogged. The crankshaft is a one-piece, heat-treated, steel forging.
It is supported in five replaceable two-piece main bearings machined to close toleran¬ ces. The engine has a pressure cooling system consisting of the radiator, water pump, multi-blade fan and thermostat. The connecting rods are provided with a bronze bushing and a two-piece, replaceable bearing cap each.
DIAGNOSING MALFUNCTIONS ENGINE WILL NOT CRANK Water, dirt or air in fuel system Dead batteries Fuel filter clogged Bad battery connections Stuck shut-off knob Defective main switch or starter safety switch Dirty or faulty fuel injectors Starter solenoid defective Defective injection pump Starter defective Defective fuel transfer pump ENGINE HARD TO START OR WILL NOT START Shut-off valve at fuel tank closed Injection pump out of time Loose or corroded battery connections Low battery output ENGINE RUNS IRREGULARLY OR STALLS FREQUENTLY Excessive resistance in starter circuit Coolant temperature too low Too high viscosity crankcase oil Insufficient fuel supply Printed in Germany