Deutz diesel engine FAQ
4. Why does the cylinder bed break?
The main reasons for cylinder breakout are:
(1) The inherent quality of the cylinder bed itself is poor;
(2) The oil pressure is too high;
(3) The cylinder head bolts do not reach the specified tightening torque;
(4) When installing the cylinder head, the cylinder head bolts were not tightened according to the prescribed method;
(5) The lower plane of the cylinder head is deformed due to long use; ( )
(6) In addition, if there are burrs, bosses and grooves on the upper plane of the body and the lower plane of the cylinder head, cylinder punching will also occur;
(7) After the cylinder liner is pressed into the body, its shoulder is higher than the plane size of the body and the height difference on the same body is out of tolerance.
5. Why does the valve leak?
After the valve leaks, a chattering sound will occur in the cylinder, resulting in a decrease in power. The reasons are:
(1) The sealing surfaces of the valve and valve seat are worn, burned, or have pits;
(2) Improper adjustment of valve clearance;
(3) The fuel injection nozzle has poor atomization or insufficient pressure, resulting in excessive carbon in the sealing area of the valve and valve seat and lax closure;
(4) The valve stem is bent and deformed or the valve stem and the guide tube are too tight, causing resistance when running up and down.
(5) The valve spring is broken or the elastic force is weakened, and it is unable to close the valve tightly.
6. Why does the piston hit the valve?
When the piston hits the valve, the engine will produce a heavy impact sound. If it is not eliminated in time, the piston will be damaged and a major accident will occur. The main reasons for this failure are:
(1) The depression depth of the valve does not meet the technical requirements;
(2) The main bearing nut is loose;
(3) The connecting rod tile alloy melts or falls off;
(4) The bolts of the camshaft gear pressure plate are loose and the camshaft gear is moving, causing the valve phase to be out of adjustment;
(5) The piston shaft and connecting rod bushing are severely worn, and the matching gap is too large.
(6) Improper valve clearance;
(7) The timing gear has the wrong marking or is not assembled according to the marking, and the valve phase is incorrect;
(8) The valve spring is broken;
(9) The depression depth of the valve (the plane of the valve big end is lower than the plane of the cylinder head) is out of tolerance.
