Generator Decarb / Overhaul

 

Generator.

Cylinder head

1.
FIRST OF ALL, REMOVE THE SPLIT COTTER AND SPRINGS.
2.
 TAKE OUT THE INLET AND OUTLET VALVES.
3.
 CLEAN THE CYLINDER HEAD THOROUGHLY IN CHEMICAL TO REMOVED
ALL CARBON. DRAIN THE CHEMICAL AND BLOW AIR.
4.
WHEN CYLINDER HEAD IS DRY THEN INSPECT THE CYLINDER HEAD FOR
ANY DAMAGED IN SEAT. DAMAGED SEAT TO BE REMOVED AND NEW
SEAT TO BE INSTALLED.
5.
INLET AND EXHAUST VALES ARE ALSO INSPECTED AFTER CLEANING
FOR ANY CRACK AND PITTING AND SIGNS OF CUT MARK. IF  CUT MARK
IS THERE THAN NEW VALVE SHOULD BE USED.
6.
THE VALVE GUIDE TO BE INSPECTED FOR CLEARANCE. IF CLEARANCE IS
MORE THAN VALVE GUIDE TO BE REMOVED.
7.
 SPRINGS SHOULD BE INSPECTED FOR SPRIING ACTION.
8.
 VALVE ROTATOR TO BE OPENED. BALLS TO BE CHECKED FOR FLATNESS
AND BELEVELLE WASHER TO BE CHECKED FOR DEEP BALL MARKING IN
WASHER AS IT WILL RESTRICT THE MOTION OF THE VALVE ROTATOR.
RENEW BALL AND WASHER FOR EFFICIENT OPERATION.
9.
 IN CASE PITTING IS PRESENCE IN SEAT AND VALVE THEN LAPPING IS
CARRIED OUT. BUT CARE TO BE TAKEN THAT THE VALVE AND SEAT
ANGLE DOESNOT EXCEED THE VALVE IN THE MANUAL AS IT WILL LEAD
TO SHROUDING.
10.
 NEW SEAT AND VALVE GUIDE SHOULD BE FIRST COOLED INREFRIGERATION ROOM AND THEN SHRUNK FIT ON ITS PLACE.
11.
FUEL VALVE AREA TO BE THOROUGHLY CLEANED.
12.
PRESSURE TESTING OF CYLINDER HEAD IS CARRIED OUT TO INSPECT
THAT CYLINDER HEAD DOESNOT LEAK WATER WHEN FITTED IN PLACE.

PRESSURE TESTING OF CYLINDER HEAD :-

ALL THE OPENING UNDERSIDE OF HEAD IS BLANKED. ON THE TOP OF

THE HEAD ALL OPENING EXCEPT ONE IS BLANKED. NOW POUR

WATER INSIDE THE HEAD TILL IT FILLS UP COMPLETELY. NOW

CONNECT THE HAND PUMP ON THE OPENING AND PUMP WATER

INSIDE THE HEAD TILL PRESSURE IN PRESSURE GAUGE SHOWS 4-6

BAR PRESSURE. LET IT HOLD FOR 30 MINUTES. CHECK FOR SIGNS OF

WATER LEAKAGE FROM ALL THE OPENING AND TIGHT IT IF LEAKAGE

IS THERE, AGAIN RAISE THE PRESSURE IF PRESSURE HAD DROP DUE

TO LEAKAGE FROM OPENINGS BLANKED. ALSO CHECK FOR LEAKAGE

FROM ANY OTHER AREA SPECIALLY EXHAUST VALVE SEAT, FUEL

VALVE AREA , SIDE COVERS OF JACKET AND UNDER SIDE OF JACKET. IF

LEAKAGE FROM CYLINDER JACKET IS THERE THAN OPEN THE JACKET

AND RENEW THE ORING. AGAIN DO PRESSURE TESTING TO CHECK THE

LEAKAGE.

Removal of piston and connecting rod:-

After lifting the head, check the liner surface for score marks, blow past etc.

Crack remove the ridges or deposits if any on the top surface to avoid the

lifting of

liner along with the piston and breakage of piston rings while lifting piston

Open the crank case door and remove the bottom end bearing bolts after

removing the lock arrangement and the remove the bolts

Remove the bottom half of the bottom end bearing

Bring the piston to TDC. Make sure the bolt holes on the piston top; lifting tool

holes must be cleared from carbon deposits. Threads should also be checked

and cleared

Put the piston lifting tools and tighten the bolts

Lift the piston and remove top shell of bottom end bearingPlace the piston on the piston stand and cover the crankcase pin to avoid the

foreign material damaging the crank pin.