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Old 01-01-2007, 06:42 AM   #1
67comet
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little or no spark

I just completed a complete engine rebuild 289 on a 1967 comet capri. I did some modifications, .030 bore, crank ground, rebuilt heads, 4 barrel intake, headers, and an MDS coil. When I first turned the engine over for the first time I had lots of spark. The timming was out 180 so I disconectes the coil wires, and pulled the distributor to corrected it. When I turned the engine over there was no spark. Since then I have replaced the coil with a stock coil, points and condenser. Still no spark. I tested my ignition wire, it is at 12 volts on the positive side of the coil. I also have 12 volts at the negative post of the coil. There is also 12 volts at the wire that connects to the points. I have checked the grounds to the block and firewall, they are fine. Now I seem to have a very weak spark sometimes and no spark other times. I have started to pull what little hair I have left so any help would be greatly appreciated. One other thing I'm worried about is I've turned the engine over for a total of about 4 or 5 minutes trying to fix this problem, my concern is my cam and lifter break in, am I still ok? HELP!!!
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Old 01-01-2007, 07:40 AM   #2
azkid110
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Check everything (power to the coil, power to the distributor (if applicable), check the coil to the distributor wire, etc etc), rebuild the system if you have to, if it worked 180 out, it should work when properly adjusted. maybe taking a break for awile will help you out.

follow the power i.e. If you have power to the coil, do you have power after it? If not your problem is the coil. If you have power to the distributor, and no power after it, your problem is in the distributor whether it be the rotar not hitting the points totally, the points themselves, the plug wires, just follow until it ends, and your problem will be right there infront of you.

I had the same sort of problem but my ignition is HEI, I was going back and fourth on that system for over an hour, and I finally found that I didn't plug the distributor/coil in.

If you have good oil pressure when cranking it and you lubed everything when putting it togather, your valvetrain should be safe, just break it in properly when you get it running.

Happy new year.
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Old 01-01-2007, 05:57 PM   #3
67Coronet383
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To make that coil produce juice to get a good spark at the plugs you're going to need the correct power getting to it, a working condenser, the points gapped correctly, & good ground on the motor.

Make sure you're getting good voltage at the positive terminal of the coil from there to ground. With the points open, disconnect the negative lead off the coil terminal and make sure you get an open circuit. With them shut, make sure you're getting good ground. If this checks out, the next step would be to make sure the points are gapped correctly. To gap the points correctly it should be done with the distributor out of the engine and with you making 100% sure the gap you measure is on the distributor cam's highest point. Make sure the points are clean and have good contact surfaces, too. Now once that's all done and if it checks out, put your distributor back in, and make 100% sure you set the timing correctly. TDC on the compression stroke, rotor pointing dead center on #1 tower.

Give it a shot and if you still have no spark, replace the condensor because that's the only thing after those things that would cause a problem (unless your coil is bad but you've tried 2 different ones). Check and recheck everything and make sure its all set up right. That's pretty much all there is to it.
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Old 01-03-2007, 02:33 PM   #4
Wally
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Quote:
Originally Posted by 67comet
I just completed a complete engine rebuild 289 on a 1967 comet capri. I did some modifications, .030 bore, crank ground, rebuilt heads, 4 barrel intake, headers, and an MDS coil. When I first turned the engine over for the first time I had lots of spark. The timming was out 180 so I disconectes the coil wires, and pulled the distributor to corrected it. When I turned the engine over there was no spark. Since then I have replaced the coil with a stock coil, points and condenser. Still no spark. I tested my ignition wire, it is at 12 volts on the positive side of the coil. I also have 12 volts at the negative post of the coil. There is also 12 volts at the wire that connects to the points. I have checked the grounds to the block and firewall, they are fine. Now I seem to have a very weak spark sometimes and no spark other times. I have started to pull what little hair I have left so any help would be greatly appreciated. One other thing I'm worried about is I've turned the engine over for a total of about 4 or 5 minutes trying to fix this problem, my concern is my cam and lifter break in, am I still ok? HELP!!!

OK diagnostics 101:

remove a plug and rest it on the engine. Take HT lead from coil and connect it to the plug. Remove -ve wiring from coil. Prepare a piece of wire to connect to the -ve of coil the other end bare. Turn ignition to on. Ground bare end of wire to chassis or engine by hand for a second or two. Lift wire and look for spark from plug.

Got spark? Reconnect -ve wires to the coil, make sure the points are closed. Turn ignition to on. Rotate engine by hand until points open. Please note the HT lead is still connected between the coil and the sparkplug resting on the engine or chassis.

Got spark?

When you installed the cam, did you prelube the lobes with a high pressure grease like moly? If so you will be more than ok. If you just used normal oil you'll be ok too... cranking revs are pretty low and shouldn't generate enough friction to cause a problem. Just make sure you get the revs up once it starts to allow the springs to dampen the contact stress on the cam nose.
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