> Quick question - since the crankshaft rotates twice for every full turn
> of the cam, there are two different strokes for every piston. Starting
> from TDC (#1 piston), is the first rotation of the crank the compression
> stroke or is it the second rotation?
Depends on whether you start at TDC after the compression stroke or TDC
after the exhaust stroke. They're both known as TDC ... although TDC after
compression is usually the one you're interested in, since that's the
reference point for ignition timing. And of course it's different for each
piston, although again #1 is usually the one you're interested in (for the
same reason).
> And where is TDC of the
> compression stroke (I know, at top dead center, but before the stroke
> starts or after - basically the first or second TDC)?
Not strictly accurate, but generally when someone says "TDC on compression",
they mean TDC at the end of the compression stroke. That's the only TDC
adjacent to the compression stroke (which technically begins at BDC and ends
at TDC).
> Just want to
> check before I set up the final timing on my new engine.
Good idea ... they don't run worth a cr*p with the timing off by 180 degrees
... and I've got the frostbitten toes to prove it !
Randall (it's a long story)
|