Bill :
I believe you are correct, the WR7DC is colder than a W8DC. And, my
personal opinion is that the resistor has absolutely no effect on the plug
'loading up'.
However, if you saw black smoke when restarting, you have mixture problems.
Several possibilities come to mind, including leaking float valves,
partially saturated floats, fuel pressure too high, etc. However, my guess
would be that you are having problems with the fuel actually boiling in the
float bowls. Didn't IL recently switch to 'reformulated' gasoline ? As a
temporary solution, try wrapping the carbs loosely with aluminum foil (like
an upside down scarf), to form a heatshield, then go find some traffic to
sit in (<g>). If that solves the problem, there are several more elegant
solutions.
BTW, I use WR7BP in my 4-banger. Seems to work quite well.
Randall
On Monday, August 14, 2000 3:52 PM, Bill Elliott
[SMTP:wcelliot@concentric.net] wrote:
>
> I have a '71 TR6 running a Pertronix Ignitor, Lucas Sport Coil, 7mm
> silicone wires, new cap/rotor. Otherwise dead stock.
>
> In a recent parade, the car never overheated, but appeared to be loading
> up the plugs. Miss, hesitation, stall, and restart with black smoke. I
> got caught in heavy construction traffic today with it and it did the
> same thing. (It was about 90 degrees and sunny.)
>
> So I stopped at the local autoparts place and asked for a set of plugs
> one heat range hotter than the Bosch W8DC that are in it. They gave me
> WR7DC, telling me that the resistor plugs did a better job of not
> loading up due to a sharper "edge" on the spark.
>
> I just pulled the old plugs and they look great. Nice and clean, no
> signs of being fouled.
>
> Now my questions:
>
> 1. Isn't a Bosch WR7DC one range _colder_ than a W8AC? (I know Bosch
> and NGK have opposite numbering schemes but I can never recall which is
> which.)
>
> 2. Anyone successfully using the WR7DC on a stock engine?
>
> 3. What else should I be looking at that would cause the "plug loading"
> symptoms I described?
>
> Thanks!
>
> Bill Elliott
> Lake Barrington, IL
>
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