On Tue, 16 Mar 2004 bigfred@unm.edu wrote:
> I thought the distributor on a 4 stroke spins at 1/2 the rate of the
> crank since the cam gear is 2x as large as the crank gear. If the
> distributor is spinning at 1/2 the rate of the crank, it seems like
> there would be a spark (at a specific cylinder) every 2 rotations of
> the crank. Where is the hole in my a**-backwords thinking?
> This means the coil would send a spark every 1/8 of a rotation of the
> distributor = 1/16 of a rotation of the crank (if you use my mixed up
> reasoning above).
> ... I now see why there is a setting for # of cylinders.
>
> What your saying makes sense though, because when I've got my
> distributor in 180 degrees (like I did last month when I was putting in
> an HEI), the motor will back fire. This means it's trying to ignite on
> the exhaust stroke, right?
Not trying to confuse anyone. But basically the spark fires every time the
piston approaches TDC. It does this on both the compression stroke and the
exhaust stroke. This is why you experience the backfire when you put your
distributor in 180 degreees off. It was easier to design the iginition do
this than to make it skip every other rotation.
--
Scott H. Zekanis
zman@kungfumonkey.com
http://www.rod-o-rama.com
http://www.thehellbenders.com
1957 Buick Riviera Hardtop (2 dr., 364" Nailhead)
1959 GMC in Chevy Sheetmetal 1/2 Ton (235" Inline 6)
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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