Samual, John, and all---I have never tried to tune a Triumph PI engine,
so can't comment about their willingness to adjust to a "clean" air/fuel
mixture, necessary for passing the tougher, Ca. emissions test. I did
have the pleasure of trying to get an S2-cammed '73 TR6 passed, by the
test stations here, in 1985. While the engine was in good condition, the
"tail pipe" emissions read too high in both HC and CO, no matter how the
carbs and other parts were adjusted. I finally had to take it to what's
called a "referee station" to get an exemption (necessary to get tag
renewal). Even with the station's sophisticated equipment, including a
gas analyser, they were not able to adjust things (while I cringed) to
get it under the maximum allowable parts-per-million. They then
reluctantly gave me a two year exemption. Rather than to go thru this
experience again (they treat you like an outlaw) I then switched back to
a stock cam. The engine passed the next inspection with flying colors.
This rather windy tale is my experience with a cam with a long overlap.
Tuned as good as could be, ran well, had "nicely colored plugs" and
still apparantly burped out unburned fuel. Or so the tail pipe sniffer
showed...
I would like to hear of the experience of other sixes that had
performance cams, and had to go thru emissions testing such as this.
With or without the PI.
Dick Taylor
L.A.
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