Posted by mark radz
on 7/13/2009, 7:01 pm, in reply to "Re: Idling/Timing"
72.231.172.199
--Previous Message--
: The choke plates on the side of the carbs
: are known leakers making you run rich.
: to check it (or pass smog) take them
: off and reassemble with a piece of
: aluminum foil sandwiched between the
: choke and the carb body effectively
: sealing that fuel source.
:
: --Previous Message--
: Hello !
:
: If anyone could shed some light over
: this, id'be much appreciated:
:
: Haynes book specs indicates 4 ATDC
: degrees for idle timing on GT6 engines
: (USA cars).
:
: UK's specs is 13 BTDC for 100 octane
: gas (!) and 7 BTDC degrees for 97
: octane.
:
: My '68 GT6 was shipped from the factory
: to Canada so I'm guessing it's a USA
: spec car, so idle timing should be 4
: ATDC (the engine is original).
:
: Now my questions:
:
: 1-Is there a different spec for USA
: cars depending on the octane rating
: used ?
:
: 2-I add a bottle of STP booster to
: every fill of 91 gas (best I can find
: around here). Now how does that excatly
: affect the octane level in the thank ?
:
: 3-Tried a Colortune plug and find out
: that the mixture is too rich, wich I
: suspected since all the plugs where
: fooled with black powder. Got that
: special tool to adjust the needle but
: turning it CCW doesn't change a thing.
: Any clues ?
:
: Thanks !
:
:
:
:
: im no expert here, ive owned two and i did all the work, but your exact problem im unsure of. i do have the original maual for my 69, i believe it called for 103 octane, minimum. that was no problem in the day, because sunoco 260 was 105 octane.youll foul the plugs rinning 92 or so, i would not only add octane boost, and plenty of it, id use a hot plug like the (old) AC super spark. im not sure whats available today.i think it had a gold contact. i never timed according to the book, (imtalking about 1973-1975), i first sound tuned the carbs, just putting my ear to each stromberg, and adjusting until i got an equal hiss, then i turned the distributor until i was idling fairly smoothly at about 1000 rpm. never could get one running good at a lower rpm. my guess is that you will be advancing the timing some to try to get a jump on burning that crappy gas. you risk burning the valves if you dont add octane. hope i helped. im no pro, but i kept two on the road many years, and they never went into a shop. i couldnt afford it.i love and hate these cars, im actually looking for another one, guess ive forgotton all those hours under the hood. good luck.mark
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