In a message dated 11/1/2005 10:25:59 PM Eastern Standard Time,
jmitch@snet.net writes:
> Is the hotter plug called for because
> of the higher compression ratio of the earlier cars
John,
My TR6 engine has been modified (Kent TH5 cam, headers, lightened flywheel,
combustion chamber profiling, 3 carbs, etc.) I'm using N9Y plugs because the
heat range of these plugs (cooler) is a better match with the higher cylinder
compression to prevent detonation and pinging.
Yes....at the end of the driving season, depending on how much of my mileage
was shorter, under 2000 rpm driving, I do see some light soot on the base of
the plugs when I change them for next season; however, the electrodes and
ceramic centers are clean. I'm using Jaguar needles (B1E) in the carbs
because
the stock B1AF needles won't deliver a rich enough mixture under power to "feed
the cam". This is the third season that I've had the car on the road since
the restoration and I think I'm finally finished with fiddling with the mixture
to reach that happy balance between too rich at idle and maximum rich at full
power. On my car, that magic point for needle adjustment seems to be one
full turn lean from full rich for each carb.....fuel mileage is 18 to 20
(driving
in "fun mode") to 22 to 24 on a constant highway trip so I'm pleased!
Hope that helps,
Chip Krout
Delaware Valley Triumphs, Ltd.
Skippack, PA USA
'76 TR6 CF57822U
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