Page 97 - Vauxhall 20-60 H.P. (R Type) Chassis Shop Manual

VAUXHALL 20-60 SHOP MANUAL

are not fitted to the gudgeon pin bearings of the pistons in any car bearing chassis
number prior to R 3061, they should be fitted in accordance with Service Bulletin
entitled ‘Engine Idling Knocks’.

CONNECTING RODS AND PISTONS —

TO REMOVE

SECTION – Remove engine undershield.
436 – Remove engine sump.
– Remove pan filter from oil pump.
– Remove nuts from big end bearing bolts, remove big end bearing cap,
and push connecting rod and piston upwards to clear crank journal. Turn
crankshaft into a convenient position and withdraw piston and rod.

It is not necessary to remove any oil pipes to withdraw pistons, except on
cars bearing chassis numbers prior to R 1833, where the oil supply pipe to
the timing chain is connected to the crankcase, below the oil relief valve,
when it will be necessary to disconnect this pipe.
CONNECTING RODS AND PISTONS

( After R 3060 )

SECTION Description — On cars bearing chassis number R 3061 and onwards the
437 connecting rods are a high tenstile steel stamping, the small end of which is
split in order to clamp the gudgeon pin in position. The big end bearings are
of white metal. Pistons are of aluminium alloy.

PISTONS ( After R 3060 ) —

TO REMOVE FROM CONNECTING RODS

SECTION On cars bearing chassis number R 3061 and onwards, the gudgeon pins are
438 clamped in the small end of the connecting rods. To remove pistons, slacken
clamping bolt in small end of rods and press out gudgeon pins.

INSPECTION ( Before R3061 )

SECTION – Examine fit of pistons in cylinder bore. Piston clearance should be 002”.
.
439 If clearance is excessive, oversize pistons should be fitted.

– Examine cylinder bores for wear and check for being oval or taper, in which
cases it will be necessary to re-grind the cylinder bores and fit oversize
pistons.

The following oversize pistons are available for Service purposes:—
.
.
.
. 002”, 004”, o10”, 020”, 030” The gudgeon pins should be free from ridges
.
and must be free to slide in the small end of the connecting rod and piston.
The total clearance between either end of the gudgeon pin and the circlips
fitted in the gudgeon pin bearings of the piston must not exceed 030’.
– Check connecting rod alignment.

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