Timing light and multispark CD ignition ?
Thread Starter
Advanced
Joined: Aug 2006
Posts: 54
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I'm using a Mallory Hyfire 6AL. Have problems confirming 36 deg total @ 2800 rpm. It bounces back and forth between 32-40 deg with my dial back timing light from Craftsman.
And yes, I have checked the distributor gear end play - it's OK.
Do I need to bypass the ignition box to set the timing?
Kind of defeats the purpose...
Any insight in this is appreciated.
/ Mr. Beam
And yes, I have checked the distributor gear end play - it's OK.
Do I need to bypass the ignition box to set the timing?
Kind of defeats the purpose...
Any insight in this is appreciated.
/ Mr. Beam
Burning Brakes
Joined: Aug 2005
Posts: 1,164
Likes: 1
From: Europe, France
I also had a few problems with my timing light and my MSD 6A electronic ignition : the index on the harmonic balancer was always moving by a few degrees, making the reading impossible.
I finally tried this with success : Instead of using the car battery to supply the timing light, I used an external battery ( An external 12V power supply could also be used ) to supply energy to my timing light.
I only used the #1 cylinder ignition wire to give a proper signal to the light and it worked great !
It seems that the CD electronic ignitions create some small perturbations on the electrical systems of the car, and they are sometimes detected as a false signal by the timing lights.
Using a separate supply addresses this issue
I finally tried this with success : Instead of using the car battery to supply the timing light, I used an external battery ( An external 12V power supply could also be used ) to supply energy to my timing light.
I only used the #1 cylinder ignition wire to give a proper signal to the light and it worked great !
It seems that the CD electronic ignitions create some small perturbations on the electrical systems of the car, and they are sometimes detected as a false signal by the timing lights.
Using a separate supply addresses this issue
Racer
Joined: Jan 2005
Posts: 499
Likes: 0
From: Enfield CT
I think the incorrect readings are caused by the multiple sparks that the box puts out per combustion cycle.I am surprised that a separate power source would make the readings correct.I have been told that a electronic dial back timing light will not work but a plain standard light will.
Racer
Joined: May 2008
Posts: 398
Likes: 0
From: Sacramento California
I think the incorrect readings are caused by the multiple sparks that the box puts out per combustion cycle.I am surprised that a separate power source would make the readings correct.I have been told that a electronic dial back timing light will not work but a plain standard light will.
I believe the light is a craftsman.
Burning Brakes
Joined: Aug 2005
Posts: 1,164
Likes: 1
From: Europe, France
The timing light will light at the first discharge of the CD ignition box and the timing light needs some time to reload. Generally, the CD ignition boxes like MSD make multiple sparks in about 2 or 3 crankshaft degrees, no more. I don't think that any timing light can detect and reload so fast, so you will just see the first spark and not the following ones because they are too close from the first.
All what I can say is that the external supply worked for me, and that it doesn't cost much to try
All what I can say is that the external supply worked for me, and that it doesn't cost much to try
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Racer
Joined: Apr 2008
Posts: 254
Likes: 5
From: ingleside illinois
Try another timing light-it shouldnt be bouncing at all.I have seen faulty balancers and plug wires do this.Is the light steady all the way to 2500rpm or does it cut off and on.If its cutting off try a spare #1 wire and recheck.
Le Mans Master
Joined: Mar 2001
Posts: 6,240
Likes: 1,013
From: Watkinsville, GA and Glen Cove, NY
I would think setting total timing at 3000 or so rpm would be fine as by then the MSD is only throwing one big spark. It works OK with my box. I get a little jumping at lower rpms.
Thread Starter
Advanced
Joined: Aug 2006
Posts: 54
Likes: 0
Thanks, a couple of good ideas to try here.
I will try to get hold on another timing light and then also rev it up to ~3500 and see if it stops jumping around. That would shut down the multi spark feature and I still would see 36 deg total if everything is set up right.
BTW. Plugs, wires and balancer - all brand new.
/ Mr. Beam
I will try to get hold on another timing light and then also rev it up to ~3500 and see if it stops jumping around. That would shut down the multi spark feature and I still would see 36 deg total if everything is set up right.
BTW. Plugs, wires and balancer - all brand new.
/ Mr. Beam
