tillison GAV setting

T

TMarsh

Senior Member
I have a 30 coupe bored .80 over with Tillison X carb, otherwise stock. Had problem with high speed miss. Ended up turning the GAV two full turns and just added a tad of advance. I know all these cars are different but does that sound correct. Timed and set points to a knats a---. Runs like a spotted a-- ape with the setting as such, is this acceptable.
 
What ever it takes. When you say added a tad of advance, your advance should probably be at about 1/2 the quadrant at high speeds, or more if you have a standard head. So what is the reference to adding a "tad"? Also it sounds like the GAV is doing its designed thing, although 2 full turns suggests that maybe your main jet could be clogged, needing the GAV to give more fuel.
 
After researching this for almost 2 hours, i found this scale:
1 tad = 2 smidges
1 bit = 2 tads
1 “some” = 2 bits
1 “lot” = 2 “some”
 
I find that Tillotsons usually need the GAV opened about 1 full turn ( which is more than is normally quoted for Zeniths). They are all slightly different, so T Marsh back to your original post ...... if your car is running well don't look for trouble by furkling any more !
 
I usually have a Tillotson open 1/4-1/2 turn.
When using a Marvel 1/4 turn. Starting or warm it doesn't really matter that much.
I do run high compression heads. Also no air filter or thermostat.
 
I adjust the Tillotson X for best running at speed. If you want to save some fuel then start closing it while still maintaining some running performance. Adjusting for best performance usually sacrifices some fuel economy so it can start to suffer a bit but they sure run good when adjusted to run well.
 
I also run a tillotson carburetor. When it's cold outside I run 1 turn open for starting and then 1⁄4 turn open once warmed up and normal driving around.
 
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