Posted by Glen
on 6/25/2009, 5:09 pm, in reply to "Idling/Timing"
98.77.54.237
1- Yes the US spec differs, largely due to emissions regulations. Different applications will have various advance/retard & centrifugal specs.
Since there are just so many variables, inop vacuum units, wear in the distributor, drive gears/chain, engine mods from stock, etc, I make sure all is in the ballpark & then fine tune for best running.
2- dunno
3- You should see a color change when the needle is moved up/down.
Two possibilities are that fuel is bleeding through elsewhere into the throat... or the funky little spring washer that holds the needle & adjuster down could be displaced. Have you removed the piston & confirmed that the needle is moving as the adjustment "screw" is turned?
HTH
Glen
--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 !
:
:
:
:
:
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