In a message dated 97-09-08 22:34:19 EDT, gardner@lwcomm.com writes:
> I
> usually just use the tools at the Hobby shop on base, but for some
> reason, theirs only goes up to forty degrees or so. Is 60 degrees
> really high dwell, or do they just have a cheap meter?
Scott:
The dwell angle depends on the number of cylinders. Remember, each cylinder
fires once for each 369 degree rotation of the distributor. On a four
cylinder, each piston has a maximum of 90 degrees of that rotation, a six
cylinder allows only 60 degrees, an eight cylinder only 45 degrees. (Pity the
sixteen cylinder engines of old - they only had 22.5 degrees. Good thing they
never ran at high RPM). Approximately two thirds of the total angle available
is used to build up the field in the coil, and the other one third is used
for the spark. For a four cylinder, that equates to a dwell angle of about 60
degrees, more or less. 40 degrees for a six, and 30 degrees for an eight.
The dwell meters you have at the hobby shop are evidently designed for six
and eight cylinder engines. I just bought a Sunpro from Sears. It's small,
and shock and water resistant, so I can toss it in the trunk and take it with
me. It's also digital, and has tach, ohms, volts, and amp ranges as well.
Dan Masters,
Alcoa, TN
'71 TR6---------3000mile/year driver, fully restored
'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
http://www.sky.net/~boballen/mg/Masters/
'74 MGBGT---3000mile/year driver, original condition
'68 MGBGT---organ donor for the '74
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