Old Crow wrote:
Even then. I used to have a boat with a Volvo diesel that could be hand
started. To start it you flipped off the compression lever, which held the
intake (IIRC) valve open, spun it up with the crank, then hit the
compression and the inertia of the flywheel took it through a compression
stroke. After it fired once it was running.

They stop instantly enough that there is no reasonable predictability of
where they would stop. The topic is an assertioin that the flywheel will
stop so that the starter can regularly hit the same 4-inch section of gears.
I say that the starter might roll over the gears, but not make its initial
contact on the same section of gear.




"Bob Noble" <bnoble (AT) sonic (DOT) net> wrote

Hi Jeff,
I've had it happen to an old chevy, I and other people here have told
you it happens and why. If you care to spend some time with google, or
some time talking with the grey haired mechanics, they will tell you it
happens that way. Some time you should like pull the coil wire on a
running engine and estimate how many revs it takes to stop, also note
the occasional reverse rotation when stopping. Mark the timing pully and
do some tests. BTW, earlier I said 2 in 8 deliberatly since there is two
revs for a complete engine cycle.
--
jeff

Jeff Strickland wrote:

Old Crow wrote:
The flywheel will attempt to keep the crank spinning, but the crank
weighs a lot more than the flywheel, plus the crank has to try to push
those pistons up and down against the air column in the cylinder. The
flywheel tends to lose this argument quickly. Dont even recall seeing
dyno engines tending to stop at any set point as an individual piston
tries to move upward against a closed valve.

It is Murphy that dictates that once you have a marginal starter bendix,
it will continue to chew at one single spot in the flywheel until it
removes that tooth, then move on.

Had a mopar 318 with a chewed spot on the flywheel, it would start just
about every time unless on very rare occasion it actually stopped where
the [replaced by that time] bendix just happened to hit the chewed spot.
Luckily was a stick so you could just bump it a good one and drive
away. Ran that way for several months until could get around to
replacing the flywheel. Didnt even hurt the new starter, although I
wouldnt recommend a lot of experimentation.

Not really. The weight of the crank has nothing to do with it. It will act
more like the fly wheel, spinning a weight around it's center. It's on
bearing. If anything, it will help it maintain it's spin. Now, the pistons
and valve drives do have something to do with what you are saying.

--
Bob Noble
http://www.sonic.net/bnoble

"Lon" <lon.stowell (AT) comcast (DOT) net> wrote in message

Bob Noble wrote:
Yep, the crank is balanced so it's just the piston compression strokes.

Either way I've noticed (especially with the chevy 305) that the
harmonic balancer usually stopped in one location (conveniently
grove down so I could chalk it for timing) Cyl 4 and 8 had low
compression.