This thread seems to have opened up a hornet's nest of variable opinion!
Let's try and get things in perspective? Discounting later OHC engines, the
rest are cast iron block and head, so likely to be more tolerant of *abuse*
than alloy?
During engine assembly at Coventry, the finished power unit was 'motored over'
on a test rig. This is where the rig was the power source and the engine had
oil in it it and coolant being externally pumped through it. The whole
objective was to initially bed things in and find out where anything fell off
- inside or outside. After this exercise (which lasted about 30 mins) the
power unit was transferred to a run dyno where it ran itself for another hour
at pre-set loads and speeds - including maximum. By the end of this cycle, it
was very hot and all external fasteners were air-torqued to prescribed
settings as shown in the manuals.
LATER factory procedure was to re-torque the head with the engine cold and
usually at the first 1000 mile service - or 1000 miles after an engine
rebuild. Then at 12,000 mile intervals thereafter. Then, they introduced a
revised head gasket which required to re-torque with the engine hot. All the
(now old) men I know in the UK who worked on the engines way back when - and
regardless of the older or later gasket type, claim hot or cold torquing after
500/1000 miles is irrelevant. The key issue is to very slightly slacken each
nut and then check tightness. Just don't forget to reset valve clearances
afterwards as well.
Jonmac
/// triumphs@autox.team.net mailing list
/// or try http://www.team.net/cgi-bin/majorcool
/// Archives at http://www.team.net/archive
|