24
Chapter 1/Engine
if you are going to do so anyway it will be simpler to take the
connecting rods off the crankshaft afterwards. Start with No. 1
and, using a socket with an extension, slacken the two connect-
ing rod cap nuts by inserting the extension into the crankcase: It
is important to have the crankshaft positioned so that the socket
spanner fits squarely and completely onto the head of each nut.
2 Once both are loose, carefully undo each one and keep them
captive in the socket when undoing them so as not to drop them
in the crankcase. The cap will be left behind and may be
awkward to retrieve. Tip the engine to shake it out if necessary.
Retrieve both halves of the bearing shells also. Loosely refit the
cap to the connecting rod noting the two matching numbers on
the shoulders of the rod and cap which must line up on
replacement. It is a good idea to note on a piece of paper which
serial number applies to which cylinder number. This avoids the
need to mark the connecting rods further. If the same rods and
pistons are being put back it is very desirable that they should go
back in the same position as they came out.
3 It is unlikely that a connecting rod will be bent except in
cases of severe piston damage and seizure. It is not normally
within the scope of the owner to check the alignment of a
connecting rod with the necessary accuracy so if in doubt have it
checked by someone with the proper facilities. It is in order to
have slightly bent connecting rods straightened - the manufacturers provide special jigs for the purpose. If a rod needs
replacement, care should be taken to ensure that it is within 10
grams in weight of the others. If too heavy, connecting rods may
be lightened by removing metal from the shoulders near the big
end of the wiper parts where the bearing cap mates up to it.
4 The small end bushes are also subject to wear. At a temperature of 70°F the piston (gudgeon) pin should be a push fit. No
axial or rocking movement should be apparent. The fitting of
new bushes is a specialist task and although the bushes
themselves may be easily pressed in it is necessary to ream them
to fit the gudgeon pins. Unless you have reamers readily avail-
able and the knowledge of how to use them this should be
done by a firm (or individual) specialising in engine reconditioning. Remember that if you are fitting new pistons it may
be necessary to fit new connecting rod bushes. If you are lucky
the new gudgeon pins may fit the old bushes properly however.
Make sure that the new bushes have been drilled to match the oil
holes in the connecting rod This should be done before reaming
so that there are no burrs on the bush bore.
5 The shell bearings from the big end are matt grey in colour
when in good condition. If the engine has done a considerable
mileage it is good policy to renew them anyway when the
opportunity presents itself. To make sure you get the correct
replacement size make a note of the numbers on the back of the
bearing shell or take it along to the supplier.
6 If the crankshaft is being reground new bearing shells will be
required anyway and these are normally available from the firm
which does the regrinding and will be matched to the degree of
regrjnding carried out .
15 Camshaft and tappets - removal and renovation
1 The camshaft and tappets can be removed only after splitting
the crankcase and this procedure is described in the section on
crankshaft removal.
2 Having split the crankcase the tappets should be checked in
their respective bores in the crankcase and no excessive side-play
should be apparent. The faces of the tappets which bear against
the camshaft lobes should also have a clear, smooth shiny
surface. If they show signs of pitting or serious wear they should
be renewed. Refacing is possible with proper grinding facilities
but the economics of this need investigating first. The lobes of
the camshaft should be examined for any indications of flat
spots, pitting or extreme wear on the bearing surfaces. Minor
blemishes may be smoothed down with a 120 grain oil stone and
polished with one of 300 grain. The bearing journals also should
be checked in the same way as those on the crankshaft. The
camshaft bearings are renewable.
3 The gear wheel which is riveted to the end of the camshaft
must be perfectly tight and the teeth should be examined for
any signs of breakage or excessive wear. It may be possible to
have a new gear wheel fitted to the existing camshaft - much
depends on the facilities available in your area. It is not a job to
be attempted by the owner.
16 Flywheel - removal and renovation
1 With the engine removed from the car the flywheel may be
removed after the clutch cover has been taken off (as described
in Chapter 5. See Fig. 1.8.
2 The flywheel is held by a single centre bolt which is tightened
up to 253 ft/lbs so do not think you can get it undone just like
that. It was necessary to obtain a piece of angle iron to lock the
flywheel by putting the angle iron across two of the clutch bolts
which were put back into the flywheel. If by yourself the other
end of the angle iron (or flat bar will do) can then be held in the
vice with the engine on the bench.
3 A 36 mm socket is then put on the bolt with the longest
handle from the socket set (do not under any circumstances try
to use anything other than a correct sized socket - you could
easily cause serious damage or even hurt yourself). A piece of
steel pipe is then put over the socket handle and leaned on with
considerable weight. The bolt slackens with no fuss at all. It may
cost you a little money to get the stuff to do this job properly
but we cannot recommend any other way.
4 Remove the bolt and large washer and before going any
further make an identifiable mark on the flywheel hub so that
you can re-locate the flywheel in the same place. The matching
mark on the crankshaft cannot be made until the flywheel is off,
so remember not to move the flywheel when it has come off
until you can make a corresponding line up mark on the crank-
shaft flange. This is important as there may be no other way of
knowing the correct position of balance.
5 The flywheel is now located only by four dowel pegs which
fit into holes in the crankshaft flange and flywheel boss. Put a
piece of wood under the edge of the flywheel starter teeth to
support the weight and then use a soft mallet or block of wood
to tap the edges of the flywheel and draw it off. Do not try and
lever it off with anything against the crankcase or you are likely
to crack the casting and that will be expensive.
6 When the flywheel is free, hold it steady, and remove the
metal or paper gasket fitted over the four dowel pegs in the
flange. Then make the second line-up mark on the crankshaft
referred to in paragraph 4.
7 The dowel pegs are a precision fit into both the flange and
flywheel. If any of these should be a slack fit there is considerable risk of the flywheel working loose, despite the tightness of
the securing bolt. Where a flywheel has worked loose and caused
the holes to become oval a new flywheel will be needed. (The
precision work of boring and fitting oversize dowel pegs would
cost more).
8 Another area of wear is in the starter teeth. These are
machined into the flywheel itself so there is no question of
fitting a new ring gear. If the teeth have become seriously
chewed up it is in order to have up to 2 mm (0.08 inch)
machined off on the clutch side of the teeth. The teeth should
then be chamfered and de-burred. Any good machine shop
should be able to carry out this work.
9 Examine also the land on the flywheel boss where the oil seal
runs. If this is severely ridged it may need cleaning up on a lathe
also. Any such ridging is very exceptional.
17 Crankshaft oil seal - removal
1 The crankshaft oil seal may be removed after taking the
engine from the car and removing the flywheel.
2 The oil seal may be levered out of the crankcase with a
screwdriver or similar but great care must be taken to avoid
damaging the crankcase where the seal seats. This means that the