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Massey Ferguson 230, 235, 240, 245, 250 - Diesel engine cylinder head and pistons

MF 230, 235, 240, 245, 250 Tractors Repair Operations

Cylinder head

Remove and reinstall - Remove cylinder head, first drain cooling system. Remove hood and instrument panel cover. Disconnect battery cables and remove battery. Shut off fuel, disconnect fuel gage sending unit wire, disconnect fuel supply and return lines, and remove fuel tank and mounting brackets. Disconnect radiator top bose and thermostat bypass hose. Disconnect breather pipe and remove rocker arm cover. Remove retaining nuts and lift off rocker shaft assembly. Remove intake manifold and exhaust manifold. Remove high pressure fuel lines, then remove injector nozzles and sealing washers from cylinder head. Remove stabilizer bar from thermostat housing. Disconnect external oil supply line from cylinder head. Loosen cylinder head mounting stud nuts or cap screws in reverse order of tightening sequence, then lift cylinder head from the Massey Ferguson 230, 235, 240, 245, 250 engine. Clean gasket surface of cylinder head and check for warpage or other damage. Cylinder head can be surfaced and a maximum of 0.30 mm (0.012 inch) material may be removed provided injector nozzles do not protrude more than 4.67 rom (0.184 inch). Do not attempt to use additional injector sealing washers to reduce nozzle protrusion. Determine whether valves must be resealed to provide proper recession after cylinder head is resurfaced. When reinstalling cylinder head, make certain all sealing surfaces and cap screw holes are clean and dry. Lightly oil threads of cylinder head stud nuts and cap screws. Tighten nuts and cap screws in three equal stages to a final torque of 95 Nm (70 ft-lbs.). Tighten rocker bracket cap screws to a torque of 30 Nm. Adljust valve clearance. Complete installation by reversing the removal procedure. Operate engine until normal operating temperature is reached, then retorque cylinder head and readjust valves.

Valve clearance - The recommended cold valve clearance is 0.30 mm (0.012 inch) for both the intake and exhaust valves. Hot valve clearance, engine at normal operating temperature, should be 0.25 rnm (0.010 inch) for all valves. Static setting of all valves can be made from just two crankshaft positions using the following procedure. Remove timing window plug from left side of flywheel adapter housing. Turn crankshaft until TDC timing mark on flywheel is aligned with punch mark and No. 1 piston is on compression stroke (both valves closed). Adjust clearances on No.1,2,3 and 5 valves. Turn crankshaft one complete turn until TDC mark is again aligned with punch mark, then adjust remaining two valves.

Valves and seats - When disassembling cylinder head, keep valves in order so they can be installed in their original positions if reused. On MF 230, 235, 240, 245, 250 some engines, valve heads and seat locations are numbered consecutively from front to rear. Any replacement valves should be marked prior to installation. Intake and exhaust valves seat directly in cylinder head. Valve seat inserts are available for service installation on exhaust valves only on some models. Cylinder head must be machined for installation of valve seat inserts. Chill insert in dry ice prior to installation, then press insert squarely into cylinder head counterbore using the valve guide as a pilot. Grind seat insert as necessary to recess valve the recommended distance from head gasket surface. Valve face and seat angle is 35 degrees for both intake and exhaust of engines with letter S or F in serial number suffix. Engines without letter S or F in serial number suffix are equipped with intake and exhaust valves with 45 degrees face angle. Original production valve seat angle on these engines is 46 degrees, but seats can be refaced to 45 degrees when servicing valves. On all models, desired seal contact width is 1.6 mm (1116 inch) for intake and 2.4 mm (3/32 inch) for exhaust. Valve head should be recessed a specified amount below face of cylinder head. Clearance can be measured with a straightedge and feeler gage. Refer to the following specifications:

With S or F Serial Number Suffix: Valve Face and Seat Angle - Intake and Exhaust - 35 degrees, Valve Head Recession - Intake 1.32-1.63 mm (0.054·0.064 in.) / Exhaust 1 .60-1.92 mm (0.063 0.075 in.), Valve Stem Diameter - Intake and Exhaust - 7.90-7.92 mm (0.311-0.312 in.), Wear Limit - 7.87 mm (0.310 in.), Stem to Guide Clearance - Intake and Exhaust - 0.06-0.11 mm (0.0025-0.0045 in.). Without S or F serial Number Suffix: Valve Face and Seat Angle - Intake and Exhaust - 45 degrees, Valve Head Recession - Intake and Exhaust - 1.50-2.13 mm (0.059-0.084 in), Valve Stem Diameter - Intake and Exhaust - 7.90-7.92 mm (0.311-0.312 in.), Wear Limit - 7.87 mm (0.310 in.), Stem to Guide Clearance - Intake and Exhaust - 0.06.0.11 mm (0.0025-0.0045 in.).

Valve guides (Massey Ferguson 230, 235, 240, 245, 250) - Intake and exhaust valve guides can be renewed if excessively worn. Using a suitable removal tool, press guides out top of cylinder head. The guides are interchangeable. Note that both ends of guides are chamfered, one end at 45 degrees and the other at 20 degrees. Be sure to insert 20 degrees chamfered end into top of cylinder head (45 degrees chamfered end up). Press into place until top end protrudes 14.83-15.09 mm (0.584-0.594 inch) above spring seat surface of cylinder bead. Replacement valve guides are presized and do not require reaming if carefully installed. After renewing valve guides, reface valve seats to ensure concentricity of seat to guide. Valve guide specifications are as follows: Valve Guide I.D - 7.98-8.01 mm (0.3142-0.3155 in.), Valve Stem O.D - 7.90-7.92 mm (0.311-0.312 in.), Stem-to-Guide Clearance - 0.06-0.11 mm (0.0025-0.0045 in.).

Valve springs - Springs, caps, retainers and locks are interchangeable for intake and exhaust valves. Springs may be installed either end up. Renew springs if discolored, distorted or if they fail to meet the following specifications: Spring free length should be approximately 45.30 mm (1-25/32 inches). Spring pressure should be 93-110 N (21-25 pounds) when compressed to 38.1 mm (1.5 inches). Cam followers - The mushroom type cam followers (tappets) operate directly in machined bores in cylinder head. With cylinder head removed, cam followers can be removed after first removing adjusting screw and locknut from top of cam follower. Identify cam followers as they are removed so they can be reinstalled in their original positions if reused. Always renew cam followers whenever camshaft is renewed. Cam follower diameter is 15.81-15.84 mm (0.6225-0.6237 inch). Diametral clearance in cylinder head bores should be 0.02-0.09 mm (0.0008-0.0035 inch).

Rod and piston units

Connecting rod and piston units are removed from above after removing cylinder head, oil pan and rod bearing caps. Be sure to remove carbon and ring wear ridge (if present) from top of sleeves before pushing pistons out of cylinders. Cylinder numbers are stamped on the connecting rods and caps. When reinstalling rod and piston units, make certain the numbers are in register and face away from camshaft side of Massey Ferguson 230, 235, 240, 245, 250 engine. Connecting rod cap nuts and bolts should be renewed whenever they are removed. Note that two different types of connecting rod nuts, with different tightening torque values, have been used. Early models used cadmium plated (bright finish) nuts while later models use phosphated (dull black finish) nuts. Do not intermix the different types of nuts. Connecting rod nuts should be tightened to the following torque values: 61 Nm (45 ft.-lbs.) for cadmium plated nuts and 81 Nm (60 ft.lbs.) for phosphated nuts.

Pistons, Sleeves and rings - The aluminum alloy, cam ground pistons are supplied in standard size only and are available in a kit consisting of piston, pin and rings for one cylinder. The toroidal combustion chamber is off-set in piston crown and piston should be marked FRONT or F for proper assembly. If FRONT or F marking is not present on piston cmwn, assemble piston to connecting rod with the cavity offset towards side of rod that is stamped with cylinder identification number. Five piston rings are used in engines with serial number suffix D or DL. The first (top) ring is chrome plated, parallel faced and may be installed either side up. The second ring is cast iron, parallel faced and may also be installed either side up. The third compression ring consists of four steel segments. The segments appear practically flat when not under compression, but when compressed the ends will curl up (or down if ring is turned over). Ring ends should curl down on segment installed at bottom of groove, up on second, down on third and up on top segment. Space end gaps of the four segments 180 degrees apart from nearest segment. The fourth ring is chrome plated, laminated, oil control ring. Install, flrst install the internal expander, install the two lower rails, spiral ring, then the top two rails. Stagger the gaps of the ring segments around the piston. The fifth (bottom) oil control ring is nondirectional and may be installed with either side up.

Piston and ring specifications are as follows: Five-Ring Pistons - Piston Skirt Diameter - 91.326-91.351 mm (3.5955-3.5965 in.). Ring Side Clearance in Groove. Top and Second - 0.05-0.10 mm (0.002-0.004 in.). Bottom - 0.05-0.10 mm (0.002-0.004 in.). Ring End Gap - Top - 0.36-0.76 mm (0.014-0.030 in.). Second - 0.28-0.69 mm (0.01 1-0.027 in.). Third (each segment) - 0.25-0.38 mm (0.010-0.015 in.). Fourth (each rail) - 0.46-0.94 mm (0.018-0.037 in.). Bottom - 0.28-0.69 mm (0.011-0.027 in.). Four piston rings are used in engines with serial number suffix DS or DLS. The first (top) ring is chrome plated and may be installed either side up. The second and third rings are alike and are internally stepped. The groove cut into the inner diameter should be toward top. The bottom (fourth) ring is nondirectional with a coil spring expander. Install the expander groove first being sure the latch pin engages both ends of spring, then install the ring over the expander. Piston and ring specifications are as follows: Four-Ring Pistons - Piston Skirt Diameter - 91.336-91.361 mm (3.5959-3.5969 in.). Ring Side Clearance in Groove - Top - 0.05-0.10 mm (0.002-0.004 in.). Second and Third - 0.05-0.10 mm (0.002-0.004 in.). Bottom - 0.05-0.11 mm (0.002-0.0045 in.). Ring End Gap - Top - 0.36-0.69 mm (0.014-0.027 in.). Second and Third - 0.28-0.61 nun (0.011-0.024 in.). Bottom - 0.25-0.74 mm (0.010-0.029 in.).

On all models, check installed piston height at TDC when any new piston is installed. Top of piston must be 0.10 mm (0.004 inch) above to 0.03 mm (0.001 inch) below top surface of cylinder block on Massey Ferguson 230, 235, 240, 245 models. On Model MF 250, piston installed height must be 0.03-0.15 mm (0.001-0.006 inch) below surface of cylinder block. If necessary, machine top of piston to obtain specified installed height. Cylinder sleeves used in original production are 0.03-0.08 mm (0.001-0.003 inch) interference fit in cylinder block bores. Fit of service cylinder sleeves in cylinder block is from 0.03 mm (0.001 inch) tight to 0.03 mm (0.001 inch) loose. Original cylinder sleeve l.D. is 91.48-91.50 mm (3.6015-3.6025 inches). Sleeves should be renewed if cylinder bore taper exceeds 0.15 mm (0.006 inch) or if out-of-round is in excess of 0.10 mm (0.004 inch). A suitable sleeve removal and installing tool is required to renew sleeves. Thoroughly clean and inspect cylinder block bores and sleeves before installing new sleeves, as even the slightest burr or dirt can cause distortion of new sleeve when pressed into the block. Lubricate cylinder bores with a thin lubricant prior to installing sleeves. Press sleeve into cylinder block bore until sleeve flange bottoms in cylinder block counterbore. When correctly installed, top of sleeve should be 0.10 mm (0.004 inch) above to 0.10 mm (0.004 inch) below top surface of block. Allow sleeve to stabilize, then check to be sure sleeve bore is not distorted and is the correct diameter. Service sleeves are prefinished and should not require additional machining after installation. Correct installed cylinder bore diameter is 91.50-91.53 mm (3.6025-3.6035 inches).

Piston pins - The floating type piston pins are retained in piston bosses by snap rings. The piston pins are a transitional fit in piston; heating piston to 38-49C (100-120F) in oil or water will make removal and installation of pin easier. Piston pins are available in standard size only. Outside diameter of pin is 31.744-31.750 mm (1.2498-1.2500 inches). Inside diameter of connecting rod bushing should be 31.76-31.79 mm (1.2505-1.2515 inches). Desired pin to rod bushing diametral clearance is 0.04-0.10 mm (0.0018-0.0039 inch). Piston pin should have transition fit in piston bosses of 0.0 mm (0.0 inch) interference to 0.01 mm (0.0004 inch) clearance. The renewable connecting rod bushing must be final sized after installation to provide recommended piston pin operating clearance. Be sure hole in bushing is properly aligned with oil hole in top of connecting rod when installing new bushing.