The engine is of monobloc construction, andthe valve are set in line in the cylinder head andare operated by rockers and push rods from thecamshaft in the left hand side of the engine.

The camshaft, running in three steel backedwhitemetal bearings, is chain-driven and has arubber chain tensioner.

The distributor and oil pump are drivenfrom the camshaft.

The pistons are the split skirt type of

aluminum alloy, and carry two compressionrings and a slotted oil control ring.

The piston pins are bolted in connectingrods, which have steel backed lead and copperalloy, changeable big end bearings.

A counter balanced crankshaft is fitted. Theend thrust on this component is taken by specialwashers at the center main bearing. Thecentrifugal water pump and cooling fan aredriven by the generator belt.

Engine type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. J typeNo.. of Cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4Bore (mm) 73 mmStroke 77.6 mmVolume 1.299Max. brake horse power .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 67 HP. at 5200 r. p. m .Torque : 10.6 kg-m at 2800 r.p.m.Firing order 1-3-4-2Valve arrangement Overhead valve, push rod typeCompression pressure 163 lbs.per sq.in. (11.5 kg/cm2) at 350 r.p.m.Compression ratio· , 8.2: 1

DATSUN PICK-UP

THERMOSTATOUT -LET TUBE WATER PUMP

An efficient cooling system is of maj orimportance to ensure the satisfactory runningof the engine and it is therefore necessary topay particular attention to its maintenance.

DescriptionThe cooling system is maintained by water

pump circulation, combined with an efficient fancooled radiator and thermostat.

The system is pressurised and the reliefvalve, incorporated in the radiator filler cap,controls the pressure at approximately 0.4 kg

Ass'y cap, pressure~

per sq. cm. Do not remove the filler cap ifthe temperature of the coolant is above boilingpoint or if the engine is running. Topping-upshould only be required occasionally to replacewater lost through the overflow pipe. Top-upwhen the engine is cold, and if possible useclean soft water.

Fill to within 1/2" of the bottom of the fillerplug well. Overfilling when the engine is coldmay cause water to flow through the overflowpipe. The capacity of the system is approxi-mately 5.2 litres.

Hose radiatorto cylinder head--

, f Bolt ~

Wash l' k~ Ass'y cock,er oc dram

In order to ensure maximum efficiency, itis essential to keep the engine operatingtemperatures within certain limit. To assistthis a pellet type thermostat is fitted, beinglocated in the water outlet at front of thecylinder head.

Pellet type thermostat works by the principleof rapid variation of solution of wax.

The device consists of metalic pellet, filledwith the wax, which controls a mash-room valveby solution of wax.

When the engine is cold this valve is closedand on starting the engine the flow of water tothe radiator is temporarily restricted.

Due this, the temperature of the water in thecylinder head and cylinder jackets will quicklyrise, thus ensuring rapid warming up.

The heat so generated will gradually pressup the piston by shrinkage of synthetic rubbersleeve so opening the valve, and ultimatelypermitting a full flow of water to the radiator.The thermostat itself is detachable; therefore,should be occasion arise, it can be removed

from its housing and the hose reconnected toavoid laying up the car.

The thermostat opening is set by themanufacturer and can not be altered.

During decabonising it is policy to test thisopening by immersing the thermostat in waterraised to requisite temperature. The valveshould open under these conditions, but if itfails to open a new unit should be fitted.

OverheatingOverheating may be caused by a slack fan

belt, excessive carbon deposit in the cylinders,running with the ignition too far retarded,incorrect carburetor adjustment, failure of thewater to circulate or loss of water.

Fan Belt AdjustmentThe fan is driven from the crankshaft by

a "V" belt, this also driving the alternator.A new belt can be fitted by first loosening

the clamp bolts (Fig. 3), which hold the dynamoin position, and moving the dynamo towards ·theengine. Slide the belt over the fan and onto thefan pulley.

Rated Temperature

Open at 76.5 °C ± 1. 5 ° COpen fully at 90 ± 1.5 °cOpen at 82 °C ± 1. 5° COpen fully at 95 ± L 5 °c

Adjustment is then made by bringing thealternator away from the engine. The beltshould be sufficiently tight to prevent slip, yetthe belt should have 10 to 15 mm slack betweenthe generator and crankshaft pulley when themidspan is pushed firmly.

After the correct tension has been obtained,securely lock it in position again.

Freezing may occur first at the bottom ofthe radiator or in the lower hose connections.

Ice in the hose will stop water circulationand may cause boiling. A muff can be used toadvantage, but care must be taken not to runwith the muff fully closed, or boiling will result.When frost is expected or when the car is to beused in a very low temperature, make sure thatthe strength of the solution is, in fact, up to thestrength advised by the manufacturers. Thestrength of the solution must be maintained bytopping-up with anti-freeze solution as neces-sary. Excessive topping-up with water reducesthe degree of protection afforded. Solution mustbe made up in accordance with instructionssupplied with the container.

Top-up when the system is cold.If the cooling system has to be drained, run

the mixture into a clear container and use again.

Protection by DrainingOn cars where anti-freeze is not used the

following precautions must be taken duringfrosty weather to obviate any damage due tofreezing of the cooling system.

When heavy frost is imminent, the coolingsystem must be completely drained. It is notsufficient merely to cover the radiator andengine with rugs and masks. There are twodrain cocks one on the Ieft- hand side of thecylinder block and the other at the base of theradiator block. Both taps must be opened todrain the system and the car must be on levelground while draining.

The drain taps should be tested at frequentintervals by inserting a piece of wire to ensurethat they are clear. This should be doneimmediately the taps are opened, so that any,obstruction freed by the wire may be flushed outby the water. The draining should be carriedout when the engine is hot.

When completely drained the engine shouldbe run for a timed minute to ensure that allwater has been cleaned from the system.

A suitable notice should be then affixed tothe radiator, indicating that the water has beendrained.

Flushing the RadiatorTo ensure efficient circulation of the coolant

and to reduce the formation of scale andsediment in the radiator, the system should beperiodically flushed with clear running water,preferably before putting in anti-freeze in thewinter and again when taking it out in the spring.The water should be allowed to run through untilit comes out clear from the drain taps. Atintervals a stiff piece of wire should be insertedinto the taps during draining to ensure that theyare not becoming clogged with sediment.

This method of radiator flushing may servewell, but in cases where the "furring" up isexcessive the operator will find it more efficientpractice to remove the radiator completely andflush in the reverse way to the flow, turn theradiator upside down and let the water flow inthrough the bottom hose connection and out ofthe top connection.

Water PumpAfter draining the water from the radiator,

remove the pump unit from the cylinder blockby taking off the fan belt and releasing thesetbolts with spring washers and hinge boltsto dynamo.

DATSUN PICK-UP

Pulley fan andwater pump

Hub waterpump pulley

Belt fan

~ "~'h."OOkBolt Gasket water

pump coverblock side

Removing the Pump Shaft AssemblyDisconnect the fan blades, pulley and cover.The shaft and ball bearings is combined with

one unit.Put the pulley hub on the bench.First, press or knock the shaft end with a

drift (hard bar) and draw out the pulley hub onthe U type bench.

Fig. 5 Example of the Bench forPump Body

Take out the set pin from the slit whichlocked the shaft assembly to the pump body.(See Fig. 6)

Next, turn the body upside down and pressout the shaft assembly from the vane side on theU type bench.

The shaft and ball bearing assembly can bedrew out from the body.

Thus take out the vane, floating seal and sealwhich remained the pump body.

90S + 0.2- 21 + 0.3

Shaft withbearings

\

The reassembling of the pump is a reversalof the disassembly procedure, but a care shouldbe taken to ensure that the shaft assembly isfitted correctly for a slit (a hole of set ring) witha groove of shaft so as to insert and set the saidring correctly.

Adjusting Clearance the VaneEnd and Body

First, press down the shaft fitting with agroove line to insert the set pin.

Inserting thickness gauge (Thickness 0.4-0.5 mm) between the vane end on the U blockbench. Take out the thickness gauge and findout good condition. Screw up with the cover andcork washer.

Pressure lubrication is used throughout theunit and is provided by an ecentric non-drainingoil pump. The oil pump is bolted into the left-hand side of the crankcase, and is driven fromthe camshaft gear by a short vertical shaft.

The oil is dr:awn into the pump via the filterand is delivered through internal oilways to therelief valve. which is situated at the cover ofoil pump.

Fig. 1From the relief valve the oil passes into the

main oil gallery on the right-hand side of theengine. The flow then passes via connectingojlways to the main, big end and camshaftbearings through drillings in the crankshaft.The connecting ends are drilling in the cylinderblock and the rear rocker shaft bracket, tolubricate the rockers, and then drains back intothe oil pan via the push rod apertures. The oilfrom the center camshaft bearing enters agallery on the left-hand side of the engine andlubricates the tappets through individual drill-ings. As the camshaft rotates, two grooves inthe front journal register with a small hole inthe camshaft thrust plate thus allOWing a smallamount of oil to pass into the timing case twiceduring case revolution ofthe camshaft to providelubrication for the timing chain and gears.From the timing case the oil returns via a drainhole abck to the oil pan. The filter thereforeforms part ofthe main oil gallery and as such isfilled with oil under pressure.

The full of the oil enters the element throughholes in the cartridge, and passes through theelement into the annular space round the centerpipe.

This space is sealed top and bottom so thatthe oil can only escape through a small hole intothe hollow center pipe and from this point backinto the oil pan.

Draining the OilThe oil on new and reconditioned engines

must be drained and then filled with new oilafter first 2000 miles (3000 km) and at intervalsof every 3000 miles (5000 km). The drain plugis at the oil pan. The oil should be drainedwhen the engine is hot as the oil will flow morereadily.

Before filling the oil pan with new oil dis-connect and change the oil cartridge.

Oil PressureThe oil pressure. should not drop below 30

lb./sq.in. (2.1 kg/cm2) on the gauge at normalro'ad speeds, whilst approximately 10 lb./sq.in.(0. 7 kg/ cm2) should be shown when the engine isidling. New engines with new oil will giveconsiderably higher readings at low speedsshould there be a noticeable drop in pressure,the following points should be checked:a) That there is a good supply of the correct

grade of oil in the oil pan.b) That the strainer in the oil pan is clean and

not choked with sludge.c) That the bearings, to which oil is fed under

pressure, have the correct working clear-ances excessive the oil will escape morereadily from the sides of the bearings, par-ticularly whElDthe oil is warm and becomesmore fluid.This will cause a drop in pressure on the

gauge as compared with that shown when thebearings are in good order. The relief valve inthe lubrication system deals with any excessiveoil pressure when starting from cold. When hotthe pressure drops as the oil becomes morefluid.

Check for Low Oil PressureCheck the level of oil in the engine sump by

means of the dip-stick and top up if necessary.If the warning light is still on after refilling thesump, switch off and ascertain that the gaugestrainer in the sump is clean and not chockedwith sludge, sale that no air leakage exists atthe strainer union on the suction side of the oilpump being defective, remove the unit andrectify the fault.

Removing the FilterA new filter cartridge should be changed

after first 2, 000 miles (3, 000 km) and then every10,000 km after this.

The filter forms part of the main oil galleryof the engine. The element of oil filter issealed in the container as a unit, it can easilyremoved by hand. Take care not to lose therubber sealing ring.

The filtered oil in the element of filtercartridge is sent to the oil passage in thecylinder block, delivered to all the lubricationsystem ,crankshaft journal, crank pin, cylinder

- bore, locker arm, camshaft journal and chaintensioner, and finally returned to the oil pan.

The oil filter is provided with a relief valve.If the temperature of lublicant oil is low atstarting, oil viscosity is high, or if the filtration

lement assembly

(oil filter cartridge)

Element

resistance of the oil filter element is largecaused by its choke up, the relief valve will beopened with pressure difference to bypass oil.

Removing the Oil PanThe sump capacity is 3.1 litres. Drain the

oil and replace the drain plug.Remove the set screw bolts which are

inserted from the underside of the s~curingflange, and the lower bolts from the bottom edgeof the bell housing. Lower the oil pan from theengine, taking care not to damage the jointwashers in the process.

Removing the StrainerWith the snup lowered it is, possible to

remove the oil strainer through which oil isdrawn into the oil pump. To remove the strainerunto the union connecting the oil pick-up to thepump and unscrew the securing bolts.

The strainer may be dismantled for cleaningpurpose by removing the delivery pipe flangebolts.

Notice that there are the dowel pins to thecover which must be positioned correctly whenrefitting.

DATSUN PICK-UP

Removing the Oil PumpRemove the oil pan and pick-up strainer.

Three of the five bolts securing the oil pumpbottom cover are long enough to secure thepump to the crankcase. Fig. 3 illustrates thepump in explosed form. Unscrew the long boltsand remove the pump with its drive shaft.

Dismantling the Oil PumpRemove the setscrews and spring washers

which secure the cover to the body and take offthe cover. On tilting the body upside down theinner rotor with its drive shaft, and the outerrotor with slide out.

Washer- plainoil pump---@

Washer lock~Nut~

Valve oilregulator

Spring valve ioil regUlato~y

Washer oil ~regulator~ap ~. ~

~

utNut cap "valve,pnng(t~

fiB

oltWasher

~lOCk

r

Ass'y spindledriving oil pump

Gasket oil pumpto cylinder block

}-Kit gear drive(; driven

!J--- Pin dowel bodyto cover

@--Washer plain oil pump@---Washer lock

Refitting the PumpClean out the sump by washing it in paraffin,

the care to remove any traces of the paraffinbefore refitting the oil pan to the engine. Payparticular attention to the oil pan and crankcasejoint faces, and remove any traces of oil jointingmaterial. Examine the joint washer and renewit if necessary. The oil joint washer can beused again if it is sound, but it is advisable tofit a new one. Smear the faces of the joint withgrease and fit the joint washer. Lift the oil pan

into position and insert the setscrews into theflange tighting them up evenly.

Reassembling the Oil PumpThe outer rotor has a chamfered edge. It is

of great important that this chamber be towardsthe base of the body, failure to assemble in thisway will result in the cover is tightened down.Insert the slotted end of the drive shaft into thebody and bring the rotors into mesh.

SERVICE OPERATION WITHENGINE IN POSITION

Remove the radiator. Slacken the dynamoattachment bolts and remove the fan belt.

Bend back the tab on the nut locking washer.Unscrew the bolt by using Heavy duty "Shocktype" Spanner.

A few sharp blows in an anti-clockwise di-rection will slacken the nut.

Pull off the crankshaft pulley.

Removing the Timing CoverThe timing cover is secured by set-screw

bolts, each having a shakeproof washer and aspecial plain-washer. Note that the specialwasher is of elongated shape and is fitted nextto the timing cover flange.

The spring washers are immediately belowthe bolt heads.

Take out the set-screw bolts, remove thecover and its joint washer. Care should be takennot to damage the washer when breaking thejoint. If damage does occur fit a new washer,cleaning of the faces of the joint surfacesbeforehand.

The timing chain is endless, and it isnecessary to remove both the crankshaft andcamshaft gears together. Before doing this,notice the timing marks on both gears and theirrelationship to each other.

Draw off both the gears a little at a time,first removing the crankshaft gear retaining nut.

As the gears are withdrawn care must betaken not to lose the packing washers frombehind the crankshaft gear. Between the cam-shaft gear teeth, is a rubber ring which acts asa tensioner, and ensures silent operation of thechain drive. Examine the felt washer andrenew it if oil has been lost be seepage.

Replacing the components of the timing gearis largely a reversal of the dismantling process,but special attention should be paid to the

-followingpoints.

Fit the crankshaft and camshaft gears intotheir respective shafts. Ensure the timingmarks are opposite and in line.

Turn the engine crankshaft until the keywayis at T.D.C. and the camshaft with its keywayin approximately the one o'clock position.

Place the gears into position, ensuring thatthe keys are present in keyways on the shaft.Ensure that the timing marks on the gears areopposite to each other and in line. Drive thegears home.

The same number of packing washers takenfrom behind the crankshaft gear must bereplaced unless a new crank or camshaft hasbeen fitted. In this case the alignment of thegear faces and measuring the alignment with afeeler gauge. To adjust the alignment it willbe necessary to vary the number of packingwash

Fit the oil thrower behind the crankshaftgear so that its concave face it towards thefront of the car, and check that the felt washeris in position.

Valve Rocker Cover RemovalRemove the air .cleaner. Unscrew the cap

nuts securing the engine lifting brackets.Remove the rocker cover and the cork jointwasher.

Removing the Rocker AssemblyDrain the cooling system. If anti -freeze is

in use, use a clean container for the fluid if it

It is necessary to drain the system andslacken the cylinder head nuts, because four ofthe rocker shaft fiXing nuts also secure thecylinder head.

If the cylinder head nust are not slackeneddistonation may result and allow water to findits way from the cooling system into thecylinders and pump.

Notice that under the right-hand rear rockerstud nut is a special locking plate. Completelyunscrew the rocker-shaft blacket nuts andremove the rocker assembly. Complete withbrackets and rockers.

Dismantling the Rocker ShaftAssembly

To dismantle the rocker shaft assemblyfirst remove the grub screw and locking platefrom the rear rocker bracket.

Remove the split pins, flat washers andspring washers from each end of the shaft.Slide the rockers, brackets and springs fromthe shaft. Unscrew the plug from the end of theshaft and clean out the oil way.

The two end rockers may be dismantledwithout the whole rocker assembly being drawnout. This may be achived by turning the engineby hand until No.1 push rod reacher its lowestposition:

Unlock the tappet adjusting screw and screwit back as far as it will go.

Withdraw the split pin, flat and springwasher and slide the rocker off the shaft.

Sometimes the valve spring will have to beslightly compressed by levering a screwdriverunder No.'2 rocker, thus allowing the end rocker

to slide off the shaft easily.procedure for No.8 rocker.

On reassembly tighten the pedestal bracketsecuring nuts a little at a time workingdiagonally from nut to nut, left nut of No.1pedestal bracket, right nut of No.2, left ofNo.3 and so on returning from the left nut ofNo.4 bracket and repeating the process untilthey are all tight. If the rocker assembly hasbeen completely stripped down and rebushed,the oil holes will have to be redrilled and thebushes reamed down to size before assemblyon the shaft.

The rockers and spring must be replaced intheir original position on the ends of the shaft.Remember to replace the rocker shaft locating

screw and lock plate.Replace the spring and flat washers with the

split pins on the ends of the shaft. Replace therocker cover and gasket.

The vent pipe should be at the front of theengine. Secure the cover by means of the twocap nuts, ensuring that the rubber bushed andengine lifting plates are in position. If therocker cover gasket or the rubber bushes arefound to be faulty, they must be renewed other-wise oil leaks will result.

If the valve rocker assembly has alreadybeen removed all that remains is for the pushrods to be lifted out. They may on the otherhand be taken out without detaching the rockerassembly.

Remove the air cleaner and rocker cover.Slacken all the tappet adjusting screw to

their full extent; then using a screwdriver, withthe rocker shaft as a fulcrum, depress the valvespring, slide the rocker side ways and lift outthe push rod.

All but the end push rods can be withdrawnin this way. These will have to be withdrawnafter the· removal of the two end rockers fromthe shaft. When replacing push rods ensure thatthe ball ends register in the tappet cups. Fromhere onwards, reassembly is a straight forwardreversal of the dismantling process.

Remove the air cleaner and rocker cover.There should be a clearance of 0.014 in.

(0.35 mm) between the face of the rocker andthe base of the valve stem. Whilst checking theclearances it is important to maintain pressurewith a screw-driver on the tappet adjustingscrew to disperse the film of oil from the pushrod cup. Failure to follow this procedure willresult in a wrong reading being taken.

Turn the engine over by hand (startinghandle) until the push rod stops falling, thevalve is fully closed.

To adjust (Fig. 9) insert a screw driver inthe adjusting screw slot and slaken the lock nut.Then insert 0.014 in. feeler gauge between theface of the rocker and the valve stem. Raiseor lower the adjusting screw until the correctclearance is obtained.

Tighten the lock nut and recheck theclearance.

It is important to note that while theclearance is being set, the tappet of the valvebeing adjusted must be on the back of the c am,opposite to its peak.

Rocker shaft-Length-Outer diameter

356.415.85~15.88 mm

Rocker arm bush-Outer diameter(before mounting)

-Inner diameter(Reamer-finisheddimension aftermounting)

-Clearance

Rocker arm-Bore-Lever ratio

19.012-19.037 mm1.43

Removing the Cylinder HeadDrain water from the cooling system by

opening the radiator and cylinder block draincocks.

One is situated inlet tube at the backside ofthe radiator and other at the rear right-handside of the engine. If anti -freeze mixture is inuse it should be drained into a suitable containerand retained for future use.

Disconnect the negative cable from thebattery be extracting the terminal screw andremoving the lug from the battery terminal post.

Slacken both the retaining clips on the hoseconnecting the radiator to the thermostat hous-ing and remove the hose.

Extract the thermostat housing securing nutsand remove the housing and thermostat.

Remove the aircleaner, carburetor, rockercover and the inlet and exhaust manifolds.

Detach the high tension cables and removethe sparking plugs, also disconnect the watertemperature gauge connection from thethermostat housing.

Take off the rocker assembly not forgettingto slacken the external cylinder head nuts at thesame time.

Withdraw the push rods keeping them in theorder of removal.

The cylinder head can now be lifted off thecylinder block. To facilitate breading thecylinder head joint, tap each side of the headwith a hammer using a piece of wood interposedto take the blow. Do not use excessive force.When lifting the head a direct pull should begiven so that the head is pulled evenly up thestuds. Remove the cylinder head gasket.

DecarbonisingRemove the cylinder head. With the valves

still in position remove the carbon from thecombustion chambers and the valve faces.Leaving the valves in position for this operationensures that damage cannot be caused to theseats by the wire brush which should be usedfor the removal of carbon.

If the exhaust valve heads are coated with avery hard deposit this may be removed by usinga chisel shaped piece of hardwood.

Remove the valves, and using the wirebrush clean out the carbon from the inlet andexhaust ports.

Blowout all traces of carbon dust withcompressed air or type pump, and finally cleanthe ports with gasoline and dry them out. Thecarbon should now be removed from the pistoncrowns. Rotate the engine until the piston to beworked on is at T. D. C. Protect the othercylinder bore from the entry of carbon particlesby pushing a non-fluffy rag into them.

Using a chisel shaped piece of hardwood.Carefully remove the carbon from the pistoncrowns. A ring of carbon should be left roundthe periphery of each piston, and the depositround the top of the cylinder bore should not betouched. An indication as to when decarbonisa-tion is require is generally given by an all roundloss of power. Cars used mainly on short runs

will require this attention more often than thoseused for long runs.

Whilst the cylinder head is removed thevalves can be taken out. To do this compressthe valve spring with the special valve springcompressor as shown in Fig. 1.

RemovalRemove the two cap retaining collets.

Release the valve spring, the valve spring cap,valve oil seal (Inlet valve only) and its retainer.Withdraw the valve from the guide.

Keep the valves in their relative positionswhen removed from the enigne, to ensurereplacement in their original valve guides.

ReplacementNote that the diameter of the exhaust valve

heads are smaller than the inlet valve. Toreplace the valves, insert each valve into itsguide and replace the spring, oil seal andretainer. Fit oil seal chamfered side downwards. The oil seals are more easily fitted ifthey have been soaked in engine oil for a shortperiod before use. The oil seal is used for theintake valve only.

Replace the valve spring and compress thevalve spring.

Refit the cap retainers and secure them bymeans of the valve cotters. Remove thecompressor.

DATSUN PICK-UP

Outer Sp.

52mm38.9mm-±1.5kg

6.54.5

4 mm~25.2 mm~

Free length mmLength in use and

loadedTurning Nos. of coil

. Effective turn of coilDia. of coil wireDiameter of coil

50 mm36.9 mm-±0.7kg

8.56.5

2.8 mm~24 mm~

13204-08100/ (INNER)

0..I,,;;,:,~I'oJ

(OUTER) ~

Valve GrindingBefore replacement of the cylinder head the

valves and their seats should be examined forsigns of pitting or burnt patches and distortion.

If these conditions are present, the valveseats must be recut before attemoting to grindin the valves, whilst distorted valve headsshould be trued or the valve renewed. Onlythe mInImUm amount of metal should beremoved in the turning process.

When grinding a valve onto its sealing, thevalve face should be smeared lightly withgrinding paste and then lapped in with a suctiontype grinding tool. The valve must be groundto its seat with a semi rotary motiron. A lightcoil spring interposed between the valve headand the port will assist considerably when liftingthe valve in order to rotate the face to a differentposition. This should be done frequently tospread the grinding compound evenly.

It is necessary to continue the grindingprocess until an even matt surface is producedon the seating and the valve face.

On completion, the valve seats and portsshould be throughly cleaned with gasoline soakedrag;and dried, and the subjected to a compressedair blast. The valves should be washed ingasoline and all traces of grinding compoundremoved.

Valve head diameterIntake valveExhaust valve

34.9 mm30 mm

1.63 ± 0.015 mm

8.7 mm16(-0.01, -0.02)

Valve stem outer diameter(both intake and ex.)

Overall lengthIntake valveEx. valve

109.54mm108.74 mm

A 40 mm¢

B 34.5 mm¢

C 32.2 mm¢

DO. 2 '" O. 4 mm

A 35 mm¢

B 29.4 mm¢

C 26.8 mm¢

D 1. 0 '" 1. 2 mm

Length Intake valveExhaust valve

Outer diameter (both intakeand exhaust)

Inner diameter (both intakeand exhaust)

Inner diameter at guideinlet to insert (both intakeand exhaust~

Clearance of valve stemand guide (both intake andexhaust)

Height of valve guide (fromface of the spring seat)

47.6 mm56 mm

Refitting the Cylinder HeadEnsure that the cylinder head and cylinder

block joint faces are clean.The cylinder head gasket is marked "Top"

so that it will be placed head in correctly.

Fig. 5 Cylinder Head DistortionMeasurement

Place the gasket into position and lower thecylinder head into place. Fit the cylinder headsecuring nuts finger tight.

Insert the push rods, replacing them in thepositions from which they were taken.

Screw back all the tappet adjusting screws.Replace the rocker assembly and screw downthe securing nuts finger tight. Evenly tightenthe eleven cylinder head nuts a little at a timein the order given in Fig. 6, finally pulling themdown with a torque wrench set to 45 lbs. 1ft.

Fig. 6 The Order of Tighteningthe Cylinder Head Nuts

Reset the valve clearances, and finally checkthem when the engine is not hot or cold. Thecylinder head nuts may pull down slightly moreafter the engine has attained its normal workingtemperature, in which case the valve clearanceswill have to be checked again and reset ifnecessary.

Refit the inlet and exhaust manifolds.Fit the craburetor and reconnect the control

linkage. Refi t the ignition advance suction pipe

to the connection on the carburetter, but do notat this stage refit the air cleaner or it will haveto be removed later to check the valve clear-ances. Replace the rocker cover taking care tofit the cork gasket correctly.

Place the thermostat and its housing inposition and secure with the three nuts.Reconnect the water temperature gauge wireand fit the radiator hose to the thermostat hous-ing. Connect the cables to the battery. Ensurethat the radiator and cylinder block drain tapesare closed, and refill the radiator.

Clean and adjust the sparking plugs and refitthem, clipping on the hightension leads. Thefiring order of the engine is 1-3-4-2. Replacethe clip which secures part of the electricalwiring harness to the side of the head.

The ignition can now be switched on and theengine started. When the normal operatingtemperature has been reached switch off andremove the rocker cover so that the valveclearances may be rechecked. Replace therocker cover and fit the air cleaner when thefinal check has been made.

Whilst the engine is running check that thewater hose connections and fuel line unions donot leak. Tighten them if necessary.

L_(_) _:_» ) _

Fig. 9 Location of Valve Guideto be Fixed

Remove the cylinder head.Remove the appropriate valve and spring.

Rest the cylinder head with its machined facedownwards on a clean surface and drive theguide downward into the combustion space witha drift.

• This should take the from of hardened steelpunch. (See Fig. 8)

When fitting new valve guides, these shouldbe driven in from the top of the cylinder head.

,Removing a Valve Spring in Position

In an emergency a new valve spring can befitted without removing the cylinder head. Whendoing this, the applicable piston must be broughtto its T .D.C. position to eliminate anypossibility of the valve falling into the cylinder.

Remove the spark plug from the cylinderconcerned. Hold the valve onto its sealing withthe aid of a suitable tool such as a bent screw-

driver which will pass through the sparking plugorifice, and locate on the valve head. By usingthe rocker shaft, as a fulcrum point, the springcan be compressed with two screwdrivers or afork ended bar.

Withdraw the valve cotters and renew thevalve spring.

;;

Nut Cotter Pin~Washer Washer

Adjust screw nut \ VL t" S " ~ "-oca mg pnng"""" "-Valve rocker~ ~ plate (out Sid~©© l

Bracket g/~crew ~Jvalve rocker shaft ~ Bush1 ~ ~ ~

SPring; ~ •• ~ ~~I ~ ~ I I "" Valve

~ ~ ~ ~valve rocker shaft

~ "~~ Rocker shaft bracket

Collet -----------:~

Spring retainer~~ ~~ -Tappet adjusting screw

Rubber ring ~~ ~--Push rodOuter spring -~ ~ ~ lnner spring

(

Chain tension Intake valve 1 ~Valve lifter

Bolt /

Lock w,"h" Ed,,~'volye-! ~..-~~ ~\"-.

Carn shaft gear, ' ~ ~ ~ -

''fi/if; . ~~ Carn shaft

::~ ~t~ \ """"""-LOM'O' pI".

~\~~ ~"'" ~LOCk washer

Carn shaft' Bolt, wasther

Gear bolt Tirning chain

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Q.Washer joint water

.l>::O& outlet e~

"'" '.'....ther~~~iat~

9~NutWasher jointthermostat @--Washer

Nut~Washer----@)

"",/Screwywasher lock

A~S'Y covervalve rocker Packing

rocker cover

\Gasket cylinder head

Removing and Replacing the TappetsRemove the carburetor and the rocker

cover, then take off the manifolds.Disconnect the high -tension leads from the

sprking plugs, remove the rocker assembly andwithdraw the push rods, keeping them in theirrespective positions so that they will be replacedonto the same tappets.

Remove the tappet covers and lift out thetappets, also keeping them in same locations(Fig. 13).

New tappet should be fitted by selectiveassembly so that they fall into the guides undertheir own weight when lubricated.

Assembly is a reversal of the above pro-cedure, but car should be taken to see thattappet cover, joints are oil tight, and that the

rockers are adjusted to give the correct valveclearance.

Dia. of tappet 22.48~22.49 mm~Dia. of cyl. side hole 22. 50~ 22. 52 mm~Clearance of the hole 0.01-0.04 mm

Piston and Connecting Rod RemovalDrain the cooling water from the engine

and radiator. Drain and remove the sump fromthe engine, then disconnect and remove the oilstrainer. Take out the setscrews and rockwashers from the big-ends and withdraw thecaps. It will be noted that the caps are off-set;When used parts are replaced after dismantlingit is essential they are fitted into their originalpositions. To ensure correct refitting mark thecaps and connecting rods on the sides to identifythem together. The piston and connecting rodsmust be with drawn upwards through the cylinderbores.

Fig. 14 Removing Connecting Rodwith Piston

Release the connecting rod from the crank-shaft and slowly push the piston and rod upwardsthrough the cylinder bore.

It may be necessary to remove the ring ofcarbon or lip from the top of the cylinder borewith a hand scraper to avoid risk of piston ringbreakage.

Remove the assembly from the top of thecylinder block.

Check the crankpins for oval with a pairof micro meter calipers, and examine the bear-ing surface for scoring, either defect willnecessitate the removal of the crankshaft forregrinding.

Distance between center oflarge end and small end

Large end bearingTypeOverall widthThicknessOuter diameter

Width of large endEnd play of large endFinishing dimension of

inner diameter ofsmall end bush Standard

Clevite (F500)22 ± 0.1 mm

1.87~2.34 mm51.35 mm

31 mm0.20-0.31 mm

Clearance of bearingperiphery to cylinderblock hole

Material White metal(Block side)

Clevite metal(Cap side)

Clearance of bearinginner diameter andcrank journal

Diameter of main journalEnd play of crankshaftCrank pin diameter

StandardDifference of crank pin

diameterEnd play, flywheel is

installed

50.813-50.825 mm0.051-0.076 mm

The shell bearing are removable by hand.The bearings are require no "bedding in" it is.being only necessary to ensure that the housingsare scrupulously clean and dry, and to place thebearings into position with the tangs located intheir corresponding slots. Always renew bear-ings if they are scored or damaged in any way,or following the regrinding of the crankshaftbearing surfaces. In the iatter case undersizebearings will be required and the kinds of sizesavailable are -8, -12, -25, -50, -75 and -100(with punched mark).

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Dowel

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Fly wheel Ring gea Iassembly

Replacing Pistons and Connecting RodsInsert each piston and connecting rod

assembly into the cylinder from which it wastaken; it is essential that the split in the skirt ofthe piston is positioned towards the camshaft.

Compress the piston rings with insertingpiston using tool (Fig. 18), and gently tap thecrown of the piston with the wooden end of ahammer handle, until the piston is clear of thepiston ring clamp.

Now push the piston down the cylinder blockuntil the big end of the connecting rod justprotrudes through the bottom of the cylinderbore, then position upper half bearing shells.

Each upper & lower bearing has two oilholes, there by ensuring sufficient and it is ofthe greatest importance that the correspondingoil hole in the bearing shell registers with theoilway to provide an unobstructed passage.

Pull the connecting rod onto the crankpintaking care not to injure the bearing surface.Insert the shell into the connecting rod cap;~oSition the cap and the locking washers.Insert the setscrews and tighten with a torquewrench to 21. 7-24.6 lbs. 1ft.

Fig. 19 Measuring Thrust Clearanceof Connecting Rod

Finally knock back the lock washers.Check the connecting rod big end for side

clearance (7/1000 in.) and see that the shellbearings are not binding on the crankpin whenrotating the crankshaft. If it is difficult toturn, undo the big end and examine the shell andseat for dirt or grit.

Before reassembling always apply a littleclean oil to the piston surfaces and into thecylinder bore. Never file the connecting rodcaps or their mating surfaces as this createsoval in the bearing.

Removing a PistonRemove the clamping bolt from the small

end of the connecting rod and push out the

gudgeon pin. The gudgeon pin is a push fit inpiston at 70° F. (21.1° C.)

When reassembling, ensure the gudgeon pinis positioned in the connecting rod so that itsgroove is in line with the clamp screw hole.Check that the spring washer fitted under thehead of the pitch bolt is not damaged.

Fig. 20 Re-assembling Pistons andConnecting Rods

DiameterOver size· 1

23

17.41 mms60.1250.2500.375

65.3 mmDegree to be able to

push it by finger at20° C.

LengthClearance of pin and

pin hole

Clearance of pin andconnecting rod bushhole

Insert "Feeler gauge", 0.04 mm thick,between cylinder bore and piston, and measureat the lower portion of the cylinder bore at rightangle to the piston pin.

There should be a clearance of 0.015'-'0.030mm.

Pull out with feeler gauge by the springscale and then inspect if the reading is withinregulations (0. 5-1. 5 kg) or not.

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Piston RingsThe piston ring gap should be O.OOS-O.013 in.

(0.203-0.330 mm) when checked in the cylinderbore. The clearance of the compression ringsin their grooves should amount to 0.0015-0.0035in. (0. 03S-0. ()S9 mm) and the oil control ring0.0016-0.0036 in. (0.041-0.092 mm).

Fig. 22 Clearance Between Ringand Groove

Because the piston rings do not travel to theend of the cylinder bores a "lip" is eventuallyformed due to wear.

This may be checked with a dial gauge andmust be removed. If this is not done there willbe a tendency to noisy operation or a fracturedring, caused by the top piston ring striking thelip.

Piston and rings are available in. 0.010 in.(0.254 mm) 0.020 in. (0.50S mm) 0.030 in.(0.762 mm), and 0.040 in. (1. 016 mm) over-sizes. The piston rings should always be fittedfrom the crown of the piston and never pushedupwards over the skirt. Before fitting therings, remove any carbon deposit from thegrooves in the piston. When fitting, note thatthe second compression is tapered type and oilcontrol ring is slat type processed by chromiumplating.

Fig. 23 Measuring Clearance ofRing Joint