At 10:45 AM 2/26/2000 -0800, Michael Torrusio wrote:
>....
>Ever since I started driving, I have always stepped upon the clutch before
starting the engine. I was taught, and it makes sense, that the starter
doesn't need the extra work of dragging the transmission gears around, when
it is starting the engine. When I bought my '71 B, my mechanic stopped me
and said that he has always found the engine cranks over faster if the
clutch is NOT depressed. ???!!!
Smart fellow, that mechanic. The friction of the internal gearbox parts
free-wheeling in oil is generally quite small, unless you're using 90W gear
lube in very cold weather, which you shouldn't be doing anyway. When you
depress the clutch it puts an end load on the crankshaft, which in turn
loads up the clutch release bearing and the thrust washers at the center
main bearing. The drag from the thrust washers can be substantial,
probably more than the drag from the gearing in the tranny, and especially
if the engine has sat for a long time and the oil has drained down.
For a few years I ran a MGB competition pressure plate in my MGA, which
resulted in about a 50% increase in pedal force for clutch actuation. This
caused very noticeable slowing of the engine cranking speed. If the
battery was in anything less than perfesct condition, or the engine was
stone cold, or the engine was a little hot after autocrossing, then it
might not turn over at all with the clutch depressed. The competition
pressure plate went to parts heaven a couple years ago, and I'm actually
glad to be rid of it.
Barney Gaylord
1958 MGA with an attitude
http://www.ntsource.com/~barneymg
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