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 Intake / Carb and Fuel Delivery Tech
 Ethanol does it effect how timing/carb
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Buckethead
Tribal Scout

USA
11 Posts

Posted - 13 Jan 2017 :  1:23:01 PM  Show Profile  Reply with Quote
Does using ethanol effect gas effect how the timing and carb should be adjusted for a stock 67 2bbl 326. The booki have says 6 derees of timing. But the engine seems to like 13 better.

cortcomp
Coyote

USA
5335 Posts

Posted - 13 Jan 2017 :  1:43:20 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
12-15 is very common, not really ethanol, just better timing for most of the recipes most guys build by anyways. Even on the smog engines that wanted like 8, i've found they run better up near 15. My sbcs that speced 10 per the book, when rebuilt to factory specs/cams/compression, still ended up running well closer to 15. 15 is my new rule of thumb unless i'm dealing with like a straight 8 or something a lot older than your 50s/60s v8s.
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Buckethead
Tribal Scout

USA
11 Posts

Posted - 13 Jan 2017 :  6:09:14 PM  Show Profile  Reply with Quote
That's good to know. I was kinda worried that it may be way out. Not really use to the pontiacs yet. I always had chevy small blocks as a kid but now I can "afford" the Pontiac that I couldn't back then. I have been concerned that the ethanol might be an issue. I had a boat with a chevy v-6 and it burnt a hole in the piston due to the combination of to much timing and ethanol. Or so I was told by the machine shop. The motor is all stock never been apart, 49k original miles. It seems to run great but a little rich I think. The exhaust stinks and smokes a little till it warms up. I was planning draining and putting fresh gas in it just to make sure its not just old fuel stinking us out. The smoke I would think is normal for a fifty year motor. But it does run very smooth even at 500 rpm idle.
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Blued and Painted
Chief PONTIAC

USA
3406 Posts

Posted - 13 Jan 2017 :  7:35:16 PM  Show Profile  Reply with Quote
How much ethanol? Running E=85 would warrant a re-jet.. 10% ethanol pump gas probably would not need a re-jet.
Black smoke cold-- I would check for a blown choke pull-off diaphragm or the pull-off adjustment. What type carburetor?


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.

Edited by - Blued and Painted on 13 Jan 2017 7:36:47 PM
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Buckethead
Tribal Scout

USA
11 Posts

Posted - 14 Jan 2017 :  11:10:53 AM  Show Profile  Reply with Quote
Just plain ol 93 pump gas up to 10% ethanol. 2bbl qet with vacuum choke. The choke is indexed to the full rich. It also won't activate all the time either. Im figuring it needs to be rebuilt or just replaced. More grayish smoke when cold but goes away when hot. Reminds me of my old 283 when the valve seals were just old and leeking
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cortcomp
Coyote

USA
5335 Posts

Posted - 14 Jan 2017 :  2:44:31 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
If it's valve seals you'll notice it more on decel as vacuum sucks the oil from the covers through the seals into the motor.
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Blued and Painted
Chief PONTIAC

USA
3406 Posts

Posted - 15 Jan 2017 :  12:31:21 PM  Show Profile  Reply with Quote
Its much better to build an original carb than buy some parts store junk thats been thru the the re-builder butcher mill over and over. Miss-match internal parts is the norm.
The dual jet is a rock solid daily driver carb and fairly easy to build.


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.
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Buckethead
Tribal Scout

USA
11 Posts

Posted - 15 Jan 2017 :  2:11:46 PM  Show Profile  Reply with Quote
the rebuilt kits are cheap to. I ordered the pertronic conversion for the points today with all new wires coil and plugs. so with that and rebuilding the carb I hope for it to be real reliable and get rid of the dead spot where it wants to spudder on acceleration. feather the pedal a little to get past the dead spot and it keeps on going just fine but its a bad spot that effects take off. thinking it may be a combination of things and possibly a bad accelerator pump in the carb.
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cortcomp
Coyote

USA
5335 Posts

Posted - 15 Jan 2017 :  5:45:33 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
Most likely that accel pump. When i've bought cars that haven't run for a long time or carbs that have been rebuilt and sat, in a couple weeks the accel pump goes from the newer fuel. Basic rebuild from a carb shop with alcohol compatible kit and good as new.
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Buckethead
Tribal Scout

USA
11 Posts

Posted - 16 Jan 2017 :  4:36:08 PM  Show Profile  Reply with Quote
I've rebuilt several of the older quadrajet 4bbls years ago hopefully the 2bbl 2g is a snap. hopefully this will solve all my issues between the igniton upgrades and the carb rebuild it should be smooth sailing. really wanting to get everything setup for cruising. not looking for the car to be a speed demon just a reliable cruiser. Hopefully there a no secret tricks to these 2bbl carbs.
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