<VV> Plug gap
tony.underwood at cox.net
Sat Nov 6 13:09:33 EDT 2010
At 11:24 PM 11/5/2010, Stephen Upham wrote:
>I decided to look at the plugs because of what seems like excessive
>gas smells while running. There are no detectable gas leaks anywhere
>in the lines.
I seriously doubt that a gas smell could be caused by plugs unless
several were not firing and gasoline fumes were going out the
exhaust. If the engine isn't misfiring, you have another issue
>The gap on the plugs is at .030.
Slightly narrow... the gurus at GM said .035 but it shouldn't make
much difference. Depending on how much spark you have, and the
demands of the engine (compression and cylinder filling capabilities)
you could get away with less gap than that, or more gap, and not
notice a difference in the majority of driving. Some of the smog
years engines were using very hot spark and plug gaps up to .085 in
order to light a miserably lean mixture.
Your plugs at .030 are likely fine as-is.
>I have almost
>everything new(ish) on the rebuild including plugs, distributor cap,
>Seth's plug wires, Pertronix I, Flamethower coil,
You could, just to hedge your bets, open the plug gaps to about .04
or maybe even a little more, and take advantage of that hot coil and
snappy ignition. It could make the engine run smoother in
situations where a stock ignition could misfire. With your ignition
and coil, it wouldn't when used with a wider plug gap that would
light a mixture that the stock ignition might balk from.
Still... I don't think your gas smell is being caused by anything
involved with your plugs.
>and rebuilt carbs.
>The advance is 29 degrees BTDC. I'm using 93 octane. Should I widen
>the gap and/or look elsewhere?
Is that 29 degrees *initial advance*? If so, I think that's too
much unless you're running open-chamber smog heads (which suck, by
the way). Even then, it's pressing the edge to run that much initial
advance. I'm surprised it's not pinging.
Now: WHERE is the gas smell most evident? Is it coming from the
engine exhaust, from inside the car through the heater/air ducts, or
is it coming from outside the vehicle? Is there an electric pump
on this car? If so, is IT leaking? I'm wondering if you have an
unspotted fuel leak someplace instead of an unburned mixture thing
working its way out the exhaust, although that's still possible but
not very probable.
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