D-245 diesel power units, whose valve adjustment will be discussed below, are four-stroke piston engines with four cylinders. Internal combustion engines of this type have in-line vertical arrangement of cylinders, are equipped with direct fuel injection and combustion of the fuel mixture as a result of compression. Additionally, the parameters of the unit are improved by turbine charging with intermediate cooling of the incoming air. Consider the characteristics of the engine, as well as the possibility of adjusting the valves.
D-245: general information
The use of a variable air flow turbine compressor makes it possible to create optimal throttle response in the engine. This indicator is provided by an increased torque parameter with a minimum crankshaft speed. At the same time, the exhaust gases meet the required standards.
All motors of this series are designed for normal operation in temperature conditions from -45 to +40 degrees Celsius. The main scope of the considered diesel engines is power plants for road, construction equipment and wheeled tractors.
Beforestudy the valve adjustment on the D-245 engine, consider its technical parameters:
- Manufacturer - MMZ (Minsk).
- Type - four-stroke in-line diesel engine with in-line arrangement of 4 cylinders.
- Fuel mixture delivery - direct injection.
- Compression – 15, 1.
- Piston travel - 125mm.
- Cylinder in diameter - 110 mm.
- Working volume – 4, 75 l.
- Cooling - liquid system.
- RPM - 2200 rotations per minute.
- Average fuel consumption is 236 g/kWh.
- Power indicator - 77 kW.
- Camshaft gear.
- Intermediate gear.
- Crankshaft gear element.
- VT drive wheel.
The procedure for adjusting D-245 valves is identical for all modifications of this series. Among them:
- D-245-06. This engine has a power rating of 105 horsepower, four cylinders, in-line, liquid cooling and free atmospheric intake. The model is mounted on MTZ 100/102 tractors. As standard, the motor is equipped with a ST-142N starter, a G-9635 generator, as well as a pneumatic compressor, a gear-type pump, an oil pump and a paired disc clutch.
- D-245. 9-336. This diesel power plant has an in-line arrangement of four cylinders and turbine supercharging. The motor is installed on MAZ-4370 machines, equipped with a 7402.3708 starter for 24 volts, a compressor with a turbine TKR 6.1=03-05,fuel, water, oil and gear pumps. Clutch - single disc without crankcase.
- D-245. 12C-231. The modification has a capacity of 108 "horses", an in-line arrangement of cylinders, turbocharging. Diesel is mounted on ZIL 130/131. The motor is equipped with a PP4V101F-3486 fuel pump, a turbine and pneumatic compressor, a single-plate clutch with a crankcase.
The timing package also includes various fasteners, washers, nuts, rocker arms, tappets, camshafts, crackers, disc retainers.
Valve adjustment D-245
Before you start setting up the valves, you need to study the device and the features of this node. The camshaft has five bearings, driven by a crankshaft and distribution gear. Five bushings are used as bearings, which are placed in the bores of the block by pressing.
The front bushing is made of aluminum, placed in the area of the fan, equipped with a thrust shoulder that fixes the camshaft from axial shifts, other bushings are made of cast iron. The steel valve tappets are welded with special cast iron, the spherical surface has a radius of 750 mm. The camshaft cams are slightly inclined.
For proper adjustment of valves D-245 ("Euro-2"), it must be taken into account that the pusher rods are made of steel bar, have a spherical part that goes inside the pusher. Rocker arms are made of steel, oscillate on axles,fixed with 4 posts. The axis of these elements is hollow, equipped with eight radial holes that serve to deliver oil, the movement of the rocker arms is stopped by spacers in the form of springs.
Inlet and outlet valves D-245, the adjustment of which we will consider later, are made of heat-resistant steel. They are located in the guide bushings, which are pressed into the cylinder head. A pair of springs acts on each element, ensuring its closure with the help of plates and crackers. The ingress of oil into the cylinders is excluded thanks to the sealing cuffs that are on the valve guides. Also, the design prevents the exhaust manifold from flooding, preventing oil from passing through the gaps of the valve stems and guide bushings.
Adjustment of valves D-245 ("Euro-3") is carried out according to the following scheme:
- The nuts fixing the racks of the rocker axles are unscrewed, the axle itself is removed along with the springs and rocker arms.
- The fastening of the head is unscrewed, after which it is dismantled. The valve should be dry, remove its plate, springs and washers, and remove the seal from the guide sleeve.
- Adjustment of valves D-245 (lapping) is carried out on special machines or stands. Lapping paste with the addition of stearic fatty acid is applied to the chamfers of the elements.
- Lapping of parts should continue until the chamfers of the valve and itsthe saddle does not form a continuous matte edging with a width of at least 1.5 mm. In this case, breaking the belts is not allowed. Deviation in width in different areas - no more than 0.5 mm.
- After adjustment, it is recommended to flush the block head and valves, then lubricate the operating rod with engine oil. Alternatively, lapping can be done by hand using bench tools. However, adjustment time and labor intensity are significantly increased.
Checking and adjusting clearances
It is advisable to check and adjust the valves of the D-245 ("Euro-2") engine in terms of gaps every 20 thousand kilometers. Also, this procedure is carried out after removing the cylinder head, tightening the cylinder head fixing bolts, or when there is a knock in the valve compartment. The clearance between the rocker arm and the end of the valve stem on a cold diesel engine should be 0.25 mm at the intake and 0.45 mm at the exhaust valve.
To adjust the clearances, loosen the adjustable valve rocker screw locknut. Then, by turning the screw, the required value is set, which is measured with a probe between the striker and the end of the rod. At the end of the process, tighten the lock nut, install the cylinder head cover cap in place. The tightening of the mounting bolts is checked after running in and every 40 thousand kilometers on a warm power unit. After checking, it is necessary to adjust the gap between the rocker arm and the valve, then tightenlatches.