Mayf,
Like any subject, there are a range of opinions. Here are some I found on
the Web:
http://www.nightrider.com/biketech/tech_spark_plug_gap.htm
http://www.magnecor.com/magnecor1/TECHSAT.HTM
http://www.purehonda.com/cool/spark.html
http://www.extrememotorsports.com/plugfaq.htm
http://www.torontokartclub.com/tt_plugs.html
http://www.xfile.f9.co.uk/spark_plugs.htm
While I don't guarantee the complete veracity of these articles, I have only
picked those that seem to be credible. Taken as a whole, I have the
impression after reading these that I may want to reduce my gap below the
.055" gap I've been using all these years, just to be on the safe side. I
will probably gap them to .050" the next time I install a new set.
I think that gap only matters when you are operating near an extreme. For
example, at very lean conditions, or at idle especially with a high overlap
cam. Your "engine man" probably knows the plugs out of the box come with a
consistent and reasonable, machine-set gap and you are a lot more likely to
screw it up than help it. And even supposing you could get another 1%
horsepower out of the motor by tweaking them, what would that buy you? Your
horsepower requirement goes as the cube of the speed, so an increase of 1%
(.01) will produce an increase in top speed of 0.01^3, or only .0001%. Yes,
I would agree this is "not an issue".
Glad to see you are having fun.
Best regards,
Bob
-----Original Message-----
From: owner-tigers@autox.team.net [mailto:owner-tigers@autox.team.net]On
Behalf Of DrMayf@aol.com
Sent: Saturday, October 07, 2000 9:05 AM
To: rpalmer@ucsd.edu; larry.p@erols.com
Cc: theo.smit@intel.com; tigers@autox.team.net
Subject: Re: Dist. Cap
Interesting discussion, this! The last 2 months it has been my pleasure to
crew on a car driven on the salt flats at Boneville. The car is a 1980
Camaro
(the one that was in Hot Rod Mag a few months ago) and it has a 296 cubic
inch engine. The engine has a static compression ratio on the order of 16 or
17 to one and uses 118 octane race gasoline. It has a full complement of MSD
hardware, primarilly an MSD 6AL. This year we laid on a 200hp shot of
Nitrous
at the top ends of the run. Now the interesting part is that the engine
consultant comes from Conn, the car from Alabama and me from Las Vegas. The
engine man always takes the plugs out and his comments are generally, "gap
is
not an Issue". He reads the plugs looking for bit of aluminum and clean
firing. But he generally just pulls the plugs from the box they came in and
sticks them in. And this is a very knowledgeable engineer who has worked on
many formula 1 cars, top fuel, funny cars, and Bonneville cars. Oh, this car
has about 765hp on the juice, so it has the capability to missfire. But, it
runs very strong at WOT for a full 6 miles! "Gap is not an
issue"...Interesting thoughts...
mayf
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