Thank you for all of your insight. I am going to do the vacuum check on the carb/dist. and manifold as a possibility. I will get back with what I find out. 
engine won't idle right
Thread Starter
Heel & Toe
Joined: Sep 2008
Posts: 24
Likes: 0
From: Olsburg Kansas
engine won't idle right
I have a 327 that during idle and after I jazz it, the idle speeds up as if the vacuum advance is working. I had been using a old Holley when the problem occurred. I bought a new Edelbrock 1411 and the problem still exists. There are two vacuum ports on the carb and I am hooked to the one for non emissions vehicles. What might be some options to consider for mixing my idle problem?
Team Owner
Joined: Aug 2007
Posts: 58,061
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Army
Well I would have said it was a carb problem (perhaps fast idle linkage set wrong or sticking). That leaves ignition. You want non-ported vacuum for your vacuum advance can.
I'd "T" off that line and put a vacuum gauge on the car and note the readings. Some valve/valve seal problems can create sort of the condition you describe (note indicators at end of this page): http://www.secondchancegarage.com/public/186.cfm
Especially if the engine is "hunting"...creeping up in speed and then settling down briefly -- then it repeats.
And yes, I know who clyde crashcup is !
I'd "T" off that line and put a vacuum gauge on the car and note the readings. Some valve/valve seal problems can create sort of the condition you describe (note indicators at end of this page): http://www.secondchancegarage.com/public/186.cfm
Especially if the engine is "hunting"...creeping up in speed and then settling down briefly -- then it repeats.
And yes, I know who clyde crashcup is !
Last edited by Frankie the Fink; Feb 17, 2011 at 07:38 AM.
Safety Car
Joined: Jun 2003
Posts: 3,596
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From: Grosse Ile MI
Addvance should be connected to manifold vacuum, which should be the non-emissions port on you carb. Sound like your engine isn't pulling much vacuum at idle, or you have the wrong vacuum advance can for your engine's calibration. Check you initial timing. Can't tell you what it is supposed to be since you didn't mention what version of a 327 you have, but 10 degrees BTDC is a good starting point.
Instructor
Joined: Sep 2002
Posts: 227
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From: Barnstable Mass
Check Mechanical Advance Springs
If the springs are too weak, the advance starts too early and then as the ignition advances, the rpms increase which further advance the timing etc., etc. You'll never get a stable idle if the advance is coming in too early.
Instructor
Joined: Sep 2002
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From: Barnstable Mass
While You're at It
Also check the simple things like the throttle linkage right from the pedal to the carb. Any interference with plug wires or other items under hood. Any rusted pivot points. How's the throttle return spring (or springs).
Thread Starter
Heel & Toe
Joined: Sep 2008
Posts: 24
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From: Olsburg Kansas
I finally got the engine to idle correctly. The timing is set at 10 degrees. I take the car out for a test drive and when I step on the gas the car has a tendencie to backfire or nose over (not power).
Safety Car
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From: Grosse Ile MI
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Race Director
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From: Central Arkansas
It may be carb tuning - accelerator pump not adjusted correctly (timing or not a big enough shot). Or if the motor wasn't completely warmed up at the time, it could be choke adjustment - if it goes away when completely warmed up. You could probably help it some if you can use a little more initial advance - but that is probbably just masking a carb problem.
Thread Starter
Heel & Toe
Joined: Sep 2008
Posts: 24
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From: Olsburg Kansas
The vacuum was put on the side of that Edelbrock said was for emissions engines. I had the vacuum on the non emissions and the engine wouldn't idle. A friend that was helping me said "Let's try it on the other vacuum location" and the engine idles. Not I just have to work on getting the backfire issue under power corrected.
Safety Car
Joined: Jun 2003
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From: Grosse Ile MI
When you checked the timing was the vacuum line to the advance can disconnected and plugged??
Melting Slicks
Joined: May 2007
Posts: 3,461
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From: cooper city florida
If it's backfiring out of the carb at takeoff, that's usually too lean of a fuel mixture. I'm not familiar with an Edlebrock but find the idle mixture screws and turn each of them out( or which ever direction to rich up the mixture), about 1/2 a turn each and see if backfire disappears. Check your timing at idle with the vacuum line plugged going toward carb. Lets say you have 10* at idle. When you connect the vacuum advance line you should hear the engine rpm rise a couple hundred rpm......also, if you check your timing now, you should have 26 degrees of timing at idle.....your initial 10* plus the 16* of advance your can should of added. A dial back timing light , a vacuum gauge, and a dwell meter are very valuable tools to have to check your problem. Good luck
