350/350 Timing
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Instructor
Joined: Jan 2007
Posts: 207
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From: Key Largo Florida
350/350 Timing
I just purchased a 69, 350/350 manual. Timing is set to 4 degress BTDC. Obviously gasoline octanes are not what they were in 69. The engine tends to "run" after the ignition is turned off. Dwel is at 31degrees with a stock distributer. Any suggestions as to how I should modify the timing for performance w/o and have the engine shut down after I turn it off?Thanks
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Is the engine pinging under heavy acceleration? How high is your idle? The most frequent cause of run on is an idle that is set too high. Just thinking out loud. Do you have the correct vacuum advance can in the car?
Le Mans Master
Joined: Jul 1999
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From: Sewell NJ
Your idle is too high. This was a common problem that caused a run on condition in the earlier cars. It was solved by the use of an Idle Stop Solenoid in later years. My 74 had one until I changed carbs. The solenoid is engaged when the ignition is turned on and idle is set by turning the stop on the solenoid. When the engine is shut down the solenoid disengaged causing the carb to shut completely and therefore preventing run on. If you have a q-jet you can get the bracket and solenoid aftermarket. If you don't have a q-jet you can build a bracket and mount the solenoid so it works the same way. Look at my sig pic to see an example. The solenoid in the picture is mounted to a bracket that I fabricated for my Edelbrock carb. Good luck.
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Joined: Oct 2004
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From: Cape Cod, Mass.
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Tech Contributor
Joined: Aug 1999
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From: At my Bar drinking and wrenching in Lafayette Colorado
You're not running nearly enough timing. Set it up for 36 degrees total and disregard initial.
Timing does not affect run-on after shut-down. Run-on is affected by idle speed. Drop idle speed to 650 and run-on will stop.
Timing does not affect run-on after shut-down. Run-on is affected by idle speed. Drop idle speed to 650 and run-on will stop.
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Thread Starter
Instructor
Joined: Jan 2007
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From: Key Largo Florida
I just have a basic knowlede of what you mean by total timing. My advance is vacuum operated. I set the 4 deg. BTDC with the vacuum advance disconnected and plugged. Are you saying that I should be looking at 36 beg BTDC w/ the vacuum connected? And if so, I what engine rpm?
Sorry if the question is dumb.
Thanks.
Sorry if the question is dumb.
Thanks.
Tech Contributor
Joined: Aug 1999
Posts: 14,379
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From: At my Bar drinking and wrenching in Lafayette Colorado
Your advance is centrifugal with a vacuum advance assist. You need 36 degrees total timing with vacuum advance disconnected and the centrifugal advance pegged out - usually about 3500 rpm-or-so. If you don't have a copy of my timing paper, let me know so I can send you one.
Le Mans Master
Joined: Apr 2001
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From: Was New Orleans but swam to Baton Rouge LA
Cruise-In IX Veteran
Your advance is centrifugal with a vacuum advance assist. You need 36 degrees total timing with vacuum advance disconnected and the centrifugal advance pegged out - usually about 3500 rpm-or-so. If you don't have a copy of my timing paper, let me know so I can send you one.
just what I was going to recommend.
Le Mans Master
Joined: May 2006
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From: League City Tx
Your idle is too high. This was a common problem that caused a run on condition in the earlier cars. It was solved by the use of an Idle Stop Solenoid in later years. My 74 had one until I changed carbs. The solenoid is engaged when the ignition is turned on and idle is set by turning the stop on the solenoid. When the engine is shut down the solenoid disengaged causing the carb to shut completely and therefore preventing run on. If you have a q-jet you can get the bracket and solenoid aftermarket. If you don't have a q-jet you can build a bracket and mount the solenoid so it works the same way. Look at my sig pic to see an example. The solenoid in the picture is mounted to a bracket that I fabricated for my Edelbrock carb. Good luck.
I don't have a run on problem on my low compression, wore out stocker but I do like having everything work as it should.
Did those solinoids come on BBs also? we do have a run on problem with our 69' 427, but I don't see a solinoid or even the wires for it.
Race Director
Joined: Mar 2006
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From: Florida
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
Hmmm thats good info. I always thought that solinoid was intended to kick up the idle speed when the AC was turned on..LOL My solinoid clicks in and out some but does not even touch the lever on the carb. So if you use the solinoid to adjust idle speed, then I assume you back the idle speed screw on the carb all the way out so it doesn't contact the lever letting the throttles close all the way off. That sound right?
I don't have a run on problem on my low compression, wore out stocker but I do like having everything work as it should.
Did those solinoids come on BBs also? we do have a run on problem with our 69' 427, but I don't see a solinoid or even the wires for it.
I don't have a run on problem on my low compression, wore out stocker but I do like having everything work as it should.
Did those solinoids come on BBs also? we do have a run on problem with our 69' 427, but I don't see a solinoid or even the wires for it.
Le Mans Master
Joined: Jul 1999
Posts: 9,206
Likes: 17
From: Sewell NJ
Hmmm thats good info. I always thought that solinoid was intended to kick up the idle speed when the AC was turned on..LOL My solinoid clicks in and out some but does not even touch the lever on the carb. So if you use the solinoid to adjust idle speed, then I assume you back the idle speed screw on the carb all the way out so it doesn't contact the lever letting the throttles close all the way off. That sound right?
I don't have a run on problem on my low compression, wore out stocker but I do like having everything work as it should.
Did those solinoids come on BBs also? we do have a run on problem with our 69' 427, but I don't see a solinoid or even the wires for it.
I don't have a run on problem on my low compression, wore out stocker but I do like having everything work as it should.
Did those solinoids come on BBs also? we do have a run on problem with our 69' 427, but I don't see a solinoid or even the wires for it.
