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160 or 140 Thermostat?
On 25 Feb 2004 07:39:44 -0800,
(modervador) wrote:
Short Wave Sportfishing wrote in message . ..
It is my understanding that a "hot" plug is aimed more towards keeping
heat available to burn off deposits quicker
as in, burn the deposits off the plug itself so the plug stays clean.
and help with a cleaner,
quicker burn when the fuel/air mixture is ignited.
Once ignition has taken place, the spark is no longer a positive
influence to enhance the burn, the ball is rolling, the cat is out of
the bag, Elvis has left the building.
A dirty plug will not give a consistent spark on every compression
stroke, so poor running will result. A plug too hot will pre-ignite.
In between is a plug that stays hot enough to stay clean but cool
enough not to pre-ignite. The penalty for getting too hot a plug may
be the purchase of a new piston.
It is also my
understanding that engine manufacturers allow for a range of types of
hot to cold plugs to adjust for varying conditions like altitude,
emissions requirements and other issues.
I have adjusted plugs for hot/cold on high performance engines because
of the varying temperatures in different cylinders - all within a
range of course but all on the same engine.
That's an interesting idea. Assuming there isn't a problem of uneven
ring wear or uneven carburetion, or uneven crankcase condensate drain
(on a 2-stroke), then you may be left with a slight unevenness of head
temp from one cylinder to the next. In that context it makes perfect
sense to run a hotter plug on a cold cylinder, or vise versa, to
lessen fouling of the plug in the cold cylinder or lessen pre-ignition
in the hot cylinder. What you're doing is getting the plugs to be at
about the same temperature despite the uneven head temp.
I came across this idea from talking with Chuck Etchells at a
basketball game (our kids know each other pretty well) who ran (or
maybe still does) NHRA funny cars for many years. I tried it on a 440
hemi and I gained about 10% more horse power on a dyno.
Again, it's anecdotal evidence, but it made sense to me at the time
and thinking back on it, still makes sense.
Later,
Tom
S. Woodstock, CT
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Basic Fishing Program:
10 - Fish
20 - Eat
30 - Sleep
40 - Goto 10
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