LT engine codes
I am grateful to Steven Wood for this chart and
explanatory note.
Notes to Accompany Chart 0308 – Vehicle Engine,
Fuel Pump and Diff Ratio
This table provides details of engine codes used
for the RT through to the DMS class.
The LT chassis code is set out in the first column
with the LT engine code for each chassis sub type is given in the second column
and corresponding manufacturers engine code included in the third column.
What is notable is the number of engine variants
for RM vehicles. There are 7 LT codes
for RM engines and these can be summarised as follows:
EN45 – AV590 (early type with thick lead bronze
bearings)
EN52 – Leyland 0600
EN54 – AV590 (later type with thin reticular tin
bearings)
EN55 – AV690 (fitted originally to RM’s but
subsequently converted back to 9.6 litre 590).
EN60 – AV690 (as fitted to RCL)
EN61 – AV690 (as fitted to BEA coaches rated at
175bhp @2200 rpm)
EN62 – AV590 (later type with thin reticular tin
bearings and DPA fuel pump and fitted to the very last batch of RML’s)
To complicate things further, there are about 10
manufacture variants of the standard AV590 engine. Variant AV590/1AG onwards appears to be of
the later type with reticular tin rather than lead bronze bearings.
A further batch of AV590 engines were manufactured
after the main Routemaster production run, although neither the LT or
manufacturers code for these is included on the chart.