At 5:17 PM -0400 8/20/96, Jon Moody (BME) wrote:
>How does one use the the 12v light bulb and clips i.e. how do you know
>when you're at 10 degrees BTDC. Hope this doesn't rquire too long of an
>answer!! Thanks.
Hi,
The main thing to keep in mind about static timing with a bulb and wire is
that since the engine isn't running the vacuum advance (or retard, on some
newer cars) isn't active. So you need to figure out whether the timing
specified by the manufacturer is with or without the vacuum advance. If it
says "static timing" or the timing procedure it gives includes
disconnecting the vacuum lines from the distributor, you're OK. Otherwise,
it's hard to tell, and you're probably best off using a strobe if that's
what the book calls for.
Here's what I'd do to time an ignition with bulb and wire:
First, set the ignition point gap to the manufacturer's specs using a
feeler guage, or set the dwell using an electronic meter. The feeler guage
only works with new points; if the points are at all pitted or worn the
feeler guage will give the wrong reading. You'll need to either get new
points, clean up the old ones with an ignition file, or use the dwell meter.
Then, turn the engine by hand in the direction it normally runs until the
timing marks are lined up correctly for the setting you want. Hook a small
12v (assuming a 12v electrical system) lightbulb, such as a panel light or
a 12v flashlight bulb, across the ignition points - one wire to ground, the
other wire to the connection between the distributor and the ignition coil.
Then, turn the distributor, or do whatever you do to adjust the timing on
your engine, until the bulb just barely comes on. Tighten up the
distributor mounting if you loosened it to adjust the timing, disconnect
everything, and you're done.
-john
jtw@lcs.mit.edu
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