Correct distributor dwell angle
Thread Starter
Pro
Joined: Dec 2009
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From: Flakewood Wrench, FL
Correct distributor dwell angle
I need to replace the distributor cam on my 66 327/300hp coupe. The car is a stock survivor with a -153 cast iron distributor. The underside of the weight plate is stamped 530 CCW. I understand that means 30° of advance. I've been told it's 24° or 26°. Which is correct?
Pro
Joined: May 2012
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From: Portland Oregon
Centrifugal advance
Randy
Safety Car
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My 67 used the same #530 part and it allows 30* centrifugal advance. You can play with the slot length to limit total centrifugal advance but if your motor is stock and you are so inclined all you need to do is TRY different springs to bring the advance all in by 3000rpm's.
Remember to keep you original parts because you can't find these anymore.
Thread Starter
Pro
Joined: Dec 2009
Posts: 635
Likes: 108
From: Flakewood Wrench, FL
What's the matter with the distributor weight base/cam assembly on your distributor? Don't be so fast changing anything.
My 67 used the same #530 part and it allows 30* centrifugal advance. You can play with the slot length to limit total centrifugal advance but if your motor is stock and you are so inclined all you need to do is TRY different springs to bring the advance all in by 3000rpm's.
Remember to keep you original parts because you can't find these anymore.
My 67 used the same #530 part and it allows 30* centrifugal advance. You can play with the slot length to limit total centrifugal advance but if your motor is stock and you are so inclined all you need to do is TRY different springs to bring the advance all in by 3000rpm's.
Remember to keep you original parts because you can't find these anymore.
Safety Car
Joined: May 2014
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The cam lobes look worn. While I agree to keep in as stock as possible, I also try to keep it running as well as possible. Sometimes those two intersect, still. I found and nos 1967002 cam in the unopened Delco can cheaper than a reproduction. It's stamped 530 CCW which is the exact stamp on mine. 30° advance. I'm happy. Thanks for the help on this one.
Team Owner
Joined: Oct 2000
Posts: 38,897
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From: Washington Michigan
Somebody's confused between dwell angle and centrifugal advance, which are unrelated and totally separate functions. Dwell angle is set with a dwell meter, and is always 30* (it's the number of degrees of distributor shaft rotation during which the points are closed). 
Race Director
Joined: Nov 2000
Posts: 10,340
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From: Beverly Hills (Pine Ridge) Florida
The Breakerless SE does not include any timing advance system (see below link):
http://www.breakerless.com/features.htm
Plasticman
Last edited by Plasticman; Jul 13, 2014 at 02:07 PM.
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Brett Foote
Le Mans Master
Joined: Oct 2000
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From: Santa Ana CA
The dual point distributor was designed to further extend the dwell angle but electronic ignition put an end to this crutch. IIFC my Mallory HyFire automatically sets the dwell at 42 degrees regardless of what the points are doing.
And that makes the Mallory an ideal situation for a distributor with a worn point block. Put is a good set of Accel points and as long as you can get them to trigger, the Mallory will take care of the rest. The points no longer carry current so don't burn out of adjustment over time.
Safety Car
Joined: May 2014
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I think you are confused. The Breakerless SE is just an electronic points replacement conversion. It still requires the mechanical cam / advance ststem of the distributor to advance the timing.
The Breakerless SE does not include any timing advance system (see below link):
http://www.breakerless.com/features.htm
Plasticman
The Breakerless SE does not include any timing advance system (see below link):
http://www.breakerless.com/features.htm
Plasticman
Race Director
Joined: Jul 2001
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Maybe I did not phrase my response correctly. If I understand his concern, the cam lobes that open/close the points look worn to him. The breakerless SE installed on his worn part will function fine. I simply stated his #530 weight base/cam (the worn part) allows for 30* centrifugal timing advance. The electronic switch will take care of the coil dwell time.
Race Director
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From: Beverly Hills (Pine Ridge) Florida
Safety Car
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From: AUSTIN Tx
John is right, dwell is simply a measurement of how many degrees of rotation that the points are closed. Too short of a dwell, and the coil will not reach saturation of the magnetic field, and the spark will be weak. Dwell has absolutely nothing to do with advance of timing. Point gap and cam profile are the only two things that affect dwell, and point gap is driving the bus.
There is a limitation to how fast a coil can build and collapse lines of flux to make a spark, and this is one reason why every car built today has a dedicated coil for each sparkplug. Dwell is not a problem when you have 8 coils!
Regards, John McGraw
There is a limitation to how fast a coil can build and collapse lines of flux to make a spark, and this is one reason why every car built today has a dedicated coil for each sparkplug. Dwell is not a problem when you have 8 coils!
Regards, John McGraw