Need help with engine
Thread Starter
Instructor
Joined: Dec 2005
Posts: 100
Likes: 0
From: Syracuse, New York
Need help with engine
I am having trouble with my 327 in my '66. It has a "flat spot" when I step on the accelerator. I took it to the Carb Shop in Denver, and after they re-jetted and adjusted, and dyno-ed it, it came back with the same problem. They offered to take another look at it when it warms up around here, but I was wondering if anybody has any ideas before I bring it back in. Is anyone familiar with this type of problem? What usually causes it? Is it the Carb or maybe something else? I'm getting to the point of real frustration with this.
Thanks
Thanks
Safety Car
Joined: Jun 2003
Posts: 3,596
Likes: 8
From: Grosse Ile MI
Ignition may be the problem
Originally Posted by Mike'sincorrect66
I am having trouble with my 327 in my '66. It has a "flat spot" when I step on the accelerator. I took it to the Carb Shop in Denver, and after they re-jetted and adjusted, and dyno-ed it, it came back with the same problem. They offered to take another look at it when it warms up around here, but I was wondering if anybody has any ideas before I bring it back in. Is anyone familiar with this type of problem? What usually causes it? Is it the Carb or maybe something else? I'm getting to the point of real frustration with this.
Thanks
Thanks
Mike,
Go through the ignition system and make sure timing and dwell are set to spec. Also, check the centrifugal advance to see if it is operating properly and that you have the correct vacuum advance canister connected to manifold vacuum.
Instructor
Joined: Jan 2005
Posts: 171
Likes: 19
Originally Posted by mgsouthard
You said they re-jetted and adjusted...no rebuild????
If that's the case....your problem sounds like a typical accelerator pump gone bad.
r/ Mike
If that's the case....your problem sounds like a typical accelerator pump gone bad.
r/ Mike
Would be fastest and easiest to check also.Don
Melting Slicks
Joined: Nov 2002
Posts: 2,460
Likes: 5
From: Wheaton IL
Originally Posted by stingrayl76
Mike,
Go through the ignition system and make sure timing and dwell are set to spec. Also, check the centrifugal advance to see if it is operating properly and that you have the correct vacuum advance canister connected to manifold vacuum.
Go through the ignition system and make sure timing and dwell are set to spec. Also, check the centrifugal advance to see if it is operating properly and that you have the correct vacuum advance canister connected to manifold vacuum.
Make sure the entire timing CURVE is correct before contacting the carb guys. Your advance might not be coming in until late in the RPM band.
brian
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,927
From: Washington Michigan
A "flat spot" (or hesitation, or "bog") is almost always a temporary lean condition during the transition from the idle system to the main metering system; this is supposed to be covered by the accelerator pump shot. Make sure the pump adjustment is correct (properly set at the WOT linkage position, not at the idle position), you have the proper pump cam installed, the proper shooter, the check ball installed under the shooter, and the pump diaphragm isn't ruptured. 
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