At 05:14 PM 30/10/98 -0000, Mike Stevenson wrote:
> Some time ago on the Stag list, I asked a general question about
> 'blipping' the throttle just before switching off the ignition. I
> would be interested in the wider classics view. Briefly, since I was
> a kid, I was told to blip the throttle at shutdown so that the
> bearings would be primed for the next start and the float chambers
> would be full if a mechanical fuel pump were fitted. The opposite
> view is that the extra fuel entering the cylinders at shutdown would
> wash the thin film of oil lubrication from the walls and lead to
> excessive friction and wear.
Any "priming" of the bearings will be lost quickly as excess oil drains
down out of the bearings and the oil passages. You'll be starting up on
residual oil film whether you blip the throttle at shutdown or not.
A mechanical fuel pump will keep the float bowls full at any engine speed,
from idle through full throttle, so they will not be any more full if you
blip the throttle at shutdown. If the chambers are less than full at
startup, it is due to evaporation.
Blipping the throttle at shutdown does leave unburned fuel in the
combustion chambers and on the cylinder walls that will wash off (or at
least thin) the film of lubricant on the cylinder walls. That will do
more harm at startup than any of the questionable benefits of blipping the
throttle.
-----------------------------------------------------------------------
Chip Old 1948 M.G. TC TC6710 NEMGTR #2271
Cub Hill, Maryland 1962 Triumph TR4 CT3154LO
fold@bcpl.net
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