Back fire when cold? Edelbrock carb - Page 2 - Chevelle Tech
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post #16 of 20 (permalink) Old Nov 15th, 19, 9:15 PM Thread Starter
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Re: Back fire when cold? Edelbrock carb

Quote:
Originally Posted by Dave Ray View Post
Please outline these parameters for timing, if you would:

INITIAL timing, with vacuum advance hose disconnected and plugged
Mechanical advance degrees, this specification, added to the INITIAL, will give the total advance (INITIAL and mechanical degrees)
VACUUM ADVANCE degrees of timing the unit will add
What source is the vacuum advance working on, ported, or full manifold vacuum?

What we are attempting to do is form a set of specifications the tmiing is working from

NO OFFENSE INTENDED, but, "36" really doesn't tell us anything.
No offence taken, HEI will only give about 20 mechanical advance, so that should put me in at about 15 initial, I don't recall what the vac advance was at but it starts and runs well when it's more than 80 degrees outside, I plan on checking it tomorrow to give some solid numbers, thanks for the help.

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post #17 of 20 (permalink) Old Nov 15th, 19, 9:17 PM Thread Starter
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Re: Back fire when cold? Edelbrock carb

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Originally Posted by modern malibu View Post
What octane fuel you running? Higher octane fuel burns slower by nature and can cause problems during cooler operating conditions.If the car runs good when warmed up, try changing your fuel grade to a lower octane. Easy and cheap thing to try. If you live up in my part of the country, there are specific warm and cold weather blend fuels. Generally speaking, octane level requirements drop in colder conditions. Cooler intake charge helps to deter detonation.
I think you might have something here, I just use 98 due the the way the engine has been set up.

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post #18 of 20 (permalink) Old Nov 21st, 19, 12:09 AM
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Re: Back fire when cold? Edelbrock carb

X3 on the timing question. Idle numbers. Dave Ray and 4 Speed are thinking you have the timing too retarded at idle. Thus, the "36 degrees doesn't tell us" comment. Retarded timing, sooty plugs, rich idle.

I'm in Houston with an Eddy on an AirGap disaster. Like any disaster, it's cool to look at. No heat spacer, but it would hot start better if I had one. With the mechanical choke adjustment dialed in per the book, mine has started great, comes onto the highest high idle step and warms up fine for the first minute or two. Then when it drops down to second idle step it would die unless I was vigilant and on the pedal. And it was REALLY hard to start because it was lean. Never backfire. Always problem below about 60 degrees. Restart it and let it warm up to a coolant temp of about 160 (vs your 180) and then I could drive it even though the choke wasn't fully open. This is about a 6 minute window, versus your 10 minutes.

I just gave it 3 ticks on the choke dial richer last weekend. Temps were in the 50's so I could play with it. Cold start up high idle was the same, dropping to the second high idle step was better because the choke dial was holding the choke on more. No dying now. More drivable before fully warmed up.

FYI I'm airflow limited on my cooling system and running a 180 stat, so in cool temps I'm never above 180.

Zeke

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post #19 of 20 (permalink) Old Nov 22nd, 19, 1:09 PM Thread Starter
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Re: Back fire when cold? Edelbrock carb

15 int, 20 mech, 12 vac. So 47 total. Full manifold vacuum.

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post #20 of 20 (permalink) Old Nov 23rd, 19, 4:32 AM
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Re: Back fire when cold? Edelbrock carb

Zeke, sounds like you're getting there. don't be concerned about tightening it up a few notches. You can always back it off when the weather warms up.

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