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OVERHAULING THE FORD.

2nd January 1923, Page 24
2nd January 1923
Page 24
Page 25
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Page 24, 2nd January 1923 — OVERHAULING THE FORD.
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No. 23.—The Model T and 1-ton Truck. Engine and Transmission Dismantling Rectifying and Reassembling. Useful Tools, Jigs and Appliances.

THE FOLLOWING directions are written for the all-round mechanic, not for the amateur. : Simpler details of the work, therefore, common to all motor engine practice, will not be described here.

Tools.

The tools needed fall into three groups—

A. Those in the standard kit.

B. Simple tools not in the standard kit, but found in most workshops—e.g,, f-in. h-in. bolt pocket wrenches, master wrench for speed work, etc.

C. Tools specially designed for use on Ford work, to the production of which much attention has of late years been devoted. Jigs, speeders, etc.; are now obtainable for nearly every operation on the Ford—e.g., from the Fairbanks Co., Lake and Elliott (Braintree, Essex), and others, perusal of whose lists will be most instructive.

Dismantling the Engine and Transmission.

While dismantling, take note of any defective parts which will call for replacement later Parts of each component should be separately boxed as removed.

If possible, get the motor over a pit, and so work in comfort.

Drain water from radiator, and oil from crankcase : shut off petrol at sediment bulb.

In order to remove the radiator, disconnect water inlet and outlet connections (3,004 and 3,015), remove radiator holding-down bolts and nuts, and radiator stay-rod (3,932), disconnect air-throttle pull-wire from carburetter, and lift radiator away. Disconnect sparking-plug wires, and remove plugs and magneto wire. Turn -out the 15 cylinder-head bolts, and carefully lift up and off cylinder-head. Detach cylinder-head gasket carefully. Examine condition of piston tops and cylinder-head. Remove electric horn from dash, or it will be in the way.

In removing exhaust pipe, first separate it from its manifold by unscrewing its pack-nut. Remove the four inlet and exhaust clamp stud nuts, and detach manifold. Take care not to lose the glands (3,064): some may conic away from the port-holes with the manifold : others may remain in the ports.

Disconnect the control-rod leading from dash to carburetter. Remove petrol pipe. To remove fan assembly, take off belt, remove splitpin from end of fan bracket bolt, then unscrew and lift away.

To remove timer, etc., release case spring (3,163) by unscrewing bolt (3,162), extract split-pin from control rod, and remove loom, after detaching wires at both ends.

In removing generator, detach wire leading from cut-out to ammeter, Take out the three cap-screws securing generator to time-gear cover (3,017). Place the left hand under generator to take its weight and, with a small block of wood, or the end of a hammer shaft, gently tap top of casing, when generator will come away. Do not drive the end of a screwdriver blade carelessly between the faces; or damage may be caused.

Next, remove cylinder front cover (3,009C) and timegear cover (3,017). Still working at front end, remove the crankcase front frame bearing cap (3,076). Dismantle engine pans (3,084, 3,085). Remove all engine and transmission bolts.

c38 Remove the two setecrews and two bolts from universal joint housing. Take off magneto contact assembly (3,260); for, if left in place, it will probably get damaged in subsequent work. .

Remove the transmission cover (3,376). If, however, the engine is of the modern starter type, it is advisable first to remove the starter, though both can be removed together if a small portion of the dash is first cut away. In most cases, it will be considered preferable not to do this.

To remove starter separately, take off Bendix shaft . cover and gasket by removing the four small screws. Turn the shaft until the setrcrew is in a horizontal position. Straighten the lock-washer, one end of which you will find turned against the head of the setscrew, the other end being turned against the collar. Remove setscrew. The Bendix assembly can then be removed from its housing. Take care not to lose the small key, which you can easily do. Go to the front end, and remove the four screws which bold starter housing to transmission cover, and pull out the starter, taking it down under the frame.

To remove transmission cover,catch hold of the pedals and give a sharp pull.

Now prepare to remove engine. Take out the bolts and nuts which pass through the aide engine hangers and frame, and between which there are two wooden blocks. These removed, the engine can be pulled for.; ward until the hangers reach the dash, after the front end has been lifted out of the frame bearing, the object being to clear the end of the universal joint. Place a length of stout rope, or engine-lifting appliance, through opening between Nos. 2 and 3 cylinders, and lift from chassis. Get a man to lift also • at the transmission end, seeing that the magneto coil assembly is not dragged along the case and thus damaged. Removal of engine. This is obvious, and need not be described, if the caution given as to protecting the magneto coil assembly be observed,' Take engine to work bench, and lay on its side, Do not rest it on the magneto coil assembly. Separate transmission from engine. Remove the four cap-screws from flywheel : the transmission assembly (3,300) will then come away as a unit, 'and can be taken to bench for necessary work. The transmission can, however, also be removed piecemeal without dismantling flywheel from crankcase, as follows :—

Dismantling Transmission Unit in. Position.

Remove `split-pins from clutch-fingers (3,337), and let out adjustment. Remove the six setscrews from driving-plate assembly (3,321),• and lift away. The clutch-plates can now be removed from inside of brake drum assembly. Remove split-pin from clutch disc drum setscrew'. unscrew, and extract disc with the transmission dutch puller (3Z, 614). The rest of the transmission will now come away Ill the form of the three drum assemblies (slow speed, reverse and brake), and the triple gears will slip off their three shafts. The clutch shaft and flywheel can then be removed.

When laying flywheel on bench, set it with magnets uppermost, and bridge them with small bolts or odd pieces of metal as " keepers " of the magnetism.

If any of the thr-e drum assemblies (3,301, 3,306, 3,311), or any part of them needs replacement, it will be necessary to remove the transmission-driven gear (3,317). This is done with a puller. . Remove the two small keys, and the drum assembly will separate.

Now turn to the engine again. Remove connectingrods and pistons. Note position of clamp-screw (3,029), and you will see that the connecting-rod assembly is fitted on the same side ae the camshaft. It must be so fitted in later replacement. Remove pistons by means of three tin slips. First push ring into groove to full depth. This will give a gap on the opposite side of the piston, and into this you can push your first slip. Slide round a little way, and insert second slip : slide again, and insert third slip. Space the slips e eerily, and you will'be able to remove the rings easily. Remove crankshaft. Before disturbing main bearing caps, mark with figures, so that you. may be able to re-assemble them later in their original positions. Remove pins from castle-nuts, and dismantle. Remove valves, and examine push-rods. If badly worn, the push-rods must be removed, and this necessitates previous removal of the camshaft. Unscrew the two small setscrews from the front and centre bearing, give a gentle tap on end of camshaft, and it can easily be removed. Detach oil pipe and magneto-coil assembly.

Engine Replacements and Re-assembling.

The following instructions are much condensed, to save space. We presume a general knowledge of motor engine work.

Cylinder block (3,0000). Examine carefully, and see that valve seatings are not worn or pitted. If they are, make good. Inspect cylinders : if scored, they must be re-bored. Test babbit in main bearings : if badly burnt, cracked, or loose in housings, get the bearings re-metalled. Gently tap webs of castings to see that they are sound. If the block is sound and serviceable, you can re-bore or re-metal by using service equipment ; or you can send the block to a service station, where the cylinders can be re-bored, and the main bearings re-metalled, within a few hours. Never re-bore individual cylinders; if you re-bore any, rebore all, or you get uneven power from the different cylinders.

If these operations are unnecessary, you can at once proceed to re-assemble. (See later). Test crankshaft, etc., for truth. The maximum error allowable in length of shaft is .002 in., and in the diameter of any pin or journal :0015 in. Tools are now obtainable for the truing of journals or pins. A shaft that is bent can be straightened under a press. Its accuracy can be tested by means of a surface indicator.

Fit crankshaft to main bearings. Test caps and see that their surfaces are true. Assemble them without the crankshaft, and see that when one bolt is tightened the other end does -not spring away from its surface. This can be tested by use of feelers. To ensure bearing fitting properly, it is essential that " capping " should be absolutely true.

Fit main bearings. Smear crank journals with Prussian blue. Turn crankshaft with sufficient pressure on the journals to keep them in position. Lift crankshaft and examine markings. Get things right (usual method). Assemble rear cap, and tighten up ; if unable to turn the shaft, insert shims (3,039) till crank will turn with due ease, and by scraping show a good marking. Proceed with other two bearings similarly. If end play is excessive, make up end of cap, or fit a new one: Back off all bearings at mud .grooves ; this will allow for any displacement of babbit that may occur if bearings at any time run hot.

Most service stations are to-day equipped with burning-in machines, which fit crankshaft to main bearings much more satisfactorily than hand-work can do.

Test timing gear for clearance. (This is a convenient point for this job.) See that gears aie not bottoming, but have a clearance of at least .001 in. If gears are worn, there will be excessive clearance, resulting in a rattle when engine is running light, said rattle being caused by thrust of valve springs through the push-rods on to camshaft. This backlash will also disturb the valve timing. If the gears, on the other hand, are fitted with no clearance, they will make a weird grinding noise when engine runs.

Fit connecting-rod assemblies. You have already examined the connecting rods and passed them for condition, or have had them remetalled. You next test the " capping " in the way described as applicable to main 'hearings. Many mechanics at this point assemble one end of the crankshaft between wooden bearings on the bench near the vice, propping up the other end. They then "swing the rods" —that is, fit them till they will drop from horizontal position by their own weight.

All the connecting rods should be tested on an alignment jig before and after fitting. In the absence of such a jig, the best way is to test on the bench, with pistons, rods, etc., in working positions, thus : Examine the piston pins (gudgeon pins 3,022), and fit to pistons (already verified as serviceable). If new bushes are needed, fit and reamer out 'with standard reamer. Fit clamp screw and then split-pin in Such a way as to prevent working loose. Next assemble the crankshaft in the bearings just fitted. Assemble pistons without rings in. the cylinders, and fit the connecting rods in working position ; this will ensure the correct bearing surfaces of the big-ends. Having fitted all four bearings, remove crankshaft and connecting rod assemblies and fit piston rinks. Test for gap. When assembled in the cylinders, the maximum gap should be .0013 in. Assemble the pistons, having, of course, cleared away all carbon deposit from the grooveS. To get rings into position, use the slips already described.

Work on valves, etc. Thoroughly clear away all carbon from stein and head. Examine seating ; if burnt or badly pitted, replace. If stem is much worn, fit a new valve. Examine also seating in cylinder block: if worn, pitted, or burnt, recut with tool

' 817A. The reseating. of the valves can be done with resenting tool or in a lathe. Grind valves in usual way. Before assembling the -valves, examine the pushrods carefully (3,058). If only slightly worn, grind ends, and reassemble; if badly worn, fit new parts.

Test camshaft for truth. if any earn shows slight wear it can be stoned down ;. if badly ridged, shaft must be replaced. See that the two split bearings (3,042, 3,043) fit properly when assembled. The phosphor-bronze bearing (3,044) must also be a working. fit on the end of the shaft, and a driving fit in the cylinder block. These being O.K., .fit to'cylinder block. Reassemble camshaft and bearings, and test clearance between valves and 'push-rods. Correct clearance is between 1:32 in. • and 1-61 in. ; neither limit should be exceeded.

Timing. Inlet opens in. late (i.e., after piston

has. passed top centre), and closes ?sin. after bottom centre. Exhaust opens when piston is Ain. above bottom centre on downward travel, and closes on top centre.

Examine valve springs and seatings. Replace weak springs or damaged Beatings. Assemble.

When fitting timing wheel, see that the zero marks (0) coincide, and the timing will be correct. (The first cam points in a direction opposite to the 0 on large timing gearwheel). The keys should be an excellent fit-i.e., a push fit in keyways, with .0015 in. clearance at top. Clean out oil-pipe, and fit.

Testing and Reassembling Magneto.

Test magneto coil assembly on bench by means of an accumulator and two test wires. (Current from district main service can be used for this purpose.) Jr any of the spools are damaged, or show a short, unsolder the copper ribbon which connects faulty spool to adjacent spool, and press off support core ; then either rewind and insulate or fit new spool and re-connect. If this job is beyond you, give it out to a service station. if several of the spools are damaged, better fit a new 'assembly. When assembling, tighten and wire the four security screws. Clean magnets as assembled on flywheel. If it is necessary to remove them, test their polarity when reassembling. Remember, north pole must always lie next to north pole, and south to south.

Examine tranmission gearshaft and see that there is no undue wear on bearing surface ; also see that keyway is sound.

Fit with flywheel to crankshaft and test clearance between magnet clamps (3,277R) and surface of coil spools ; it should be 1-32 in. See that the coil assembly is in perfect alignment with flywheel, and shim until clearance is correct. Having tightened the flywheel nuts, secure them with a stout wire guard.

If pistons have not already been assembled to eons' necting rods, assemble them now. Use a piston 'clamp jig to prevent distortion of pistons when fitting gudgeon pin. See that gaps in rings are not in line. Use piston ring squeezer (3Z 652) to enter them into cylinders. —Smear cylinder walls and pistons with oil, and assemble. Smear crankpins and big-end bearings with oil, and tighten up and splitspin all nuts.

Fit timing dove!' with new felt and gasket. Shellac or gold-size to make joint oil-tight. Reassemble fan drive pulley. See that the pin is a, driving fit in crankshaft and pulley ; split-pin..

Replace timer on end of camshaft. Turn engine over until No. 1 piston is on top esistre end of compression stroke (both valves being alert closed).' Then place brush roller 45 degrees past top centre, to left of perpendicular, and insert pin: (Reeent models have brush assemblycamshaft so drilled that wrong assembling' is mpossible.)

Overhauling and Reassembling of Transmission.

Examine triple-gear assemblies (3,313). These are held together by rivets, which sometimes work loose: See that new rivets, are fitted, if needed, and that the assemblies are otherwise in satisfactory condition. The gear bushing (3,3144) should be a nice' working fit on .shaft (3,315), and • pressed into the gear assemblies.

Examine slow-speed, reverse, andbrake-dram assemblies. The rivets must he tight, and the bushes a good working fit. Do not use any doubtful material in this important part of the mechanism. See that the driven gear (3,317) and keys are properly fitted.

• Place the three triple gears in mesh with the driven gear according to punch marks. If there are no punch marks, set them at equal centres. You can now either tie them in position with string, or hold

them with the hand, and so assemble on flywheel. This may seem a difficult job, and often proves so, but it is really quite easy, and an be done at the first attempt, if you see that the centres of the triple gears are equally spaced out before trying to assemble.

Assemble thrust-plates. •(In old models a thrustbush was fitted. Fit clutch disc drum key to shaft and press drum (3,332) into position, inserting security screw (3,334) and pin, so as to prevent its unscrewing when transmission is in operation. Fit large clutch-plate (3,329), after smearing with thin oil ; then small plate (3,328). Continue in same order with the 13 large and 12 small plates, ending up with a large plate. (The reason for ending up with a large plate is that if a small plate were fitted at the end it would be liable to drop over the clutch drum when changing from high to slow speed, and so, prevent changing back into high.) Examine push-ring (2,336) and, if good, fit into position with the pins facing you.

Assemble the driving-plate (3,321). Before doing so, however, carefully examine the three fingers, pins, and adjusting screws. Clean off any burrs from the face which fits on to drum assembly. Now assemble so that the adjusting screws, when adjusted, press against the push-ring pins. Tighten all setscrews, and wire together in pairs. You can now test correct assembly by turning. If it revolves truly, it is quite correct. Assemble dutch shaft (3,344), with small end rest • ing•on clutch fingers ; then the spring, with support • (3,341). Compress and insert security pin, which fits through the hole in driving plate hub. Evenly adjust clutch and screws so that spring is compressed to within a space of 2 ins.

Examine transmission bands, If badly worn, renew linings, using brass. copper, or aluminium rivets. (Iron or steel rivets must not be used, as they cut the drums to pieces.)

Examine crankcase (3,100). If serviceable, clean thoroughly.and assemble.

Lift engine into position ; fit new gaskets, and bolt up. Thoroughly clean carbon from 'cylinder head and holes in block ; fit new gasket. Tighten bolts up gradually and evenly all round. Fit bolts to engine hangers, and secure.

Assemble transmission cover. Pass the •three bands in turn over the triple gears and turn until opening is at top. Assemble each on its proper drum. Compress and tie lugs of each together. Examine the cover and see that spindles and bushings are all good—that there is no movement between the pedals and their shafts through badly fitting pins, and that the band springs are good.

Gold-size or shellac the gaskets and place in position, not forgetting the cross-over felt. In assembling the 'cover, see that the clutch release ring (3,400) is fitted into the rear groove of the clutch shaft and the band springs between the lugs of the bands. Remove string ; adjust bands ; fit inspection plate ; fit magneto contact assembly. Some important points omitted in foregoing treatment will be dealt with in a later article.

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