Just finishing a body off on a '66 w/ 327/300 and PG. Ready to start but the old vette isn't. No spark - no fire and I'm just about at my wits end and am hoping that some of you experts will be able to help. Here's a recap; All new, Coil, Points, Condenser, Rotor, Plugs, Plug Wires, Dist Cap, Ballast Resistor, and coil primary lead wire. Engine is on top dead center in compression stroke and the distributor/rotor/cap is all set at #1 cylinder. I rewired the entire car with new complete Lectric Limited wiring harness'. All of the electric features work. The starter is a correct rebuilt original. Engine turns over, but no spark. I tested the cranking voltage with my multimeter and am getting around 11 -12 volts on the positive terminal of the coil - the service manual says this is good. Then I checked the ignition switch voltage (same way as the cranking voltage check, but only with the key on and not turning the starter). I was getting a voltage of 12 - the service manual says that anything more than 5 to 7 volts is no good as the starter solenoid is by-passing the switch and positive terminal of the coil. If I understand correctly, this means that the starter solenoid is out to lunch or I have a ignition switch wiring problem. Ultimatley, I find it hard to belive that I have a wiring problem with the switch because the new harness has the proper terminals and it would be virtually impossible to connect the switch wiring incorrectly. I checked the wiring on the solenoid and it is wired in accordance to the AIM, Service Manual and the Diagram that came with the harness. At any rate, the only thing I can come up with is the solenoid is bad. After such a long post, my question is..... has anyone out there experienced this? I just want to make sure before I pull the starter out and spend the money to replace the solenoid. Thanks in advance for any comments.
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Re: '66 Ignition Issues
Dave,
If you are getting 12 volts at the coil-and no spark when turning over -then you need to look at the coil & distributor. The solenoid could be bad but you should get a spark-and the extra voltage will just eat the points faster.
Good luck-
Richard -
Re: '66 Ignition Issues
Do you have the black ground wire properly connected under the bolt holding the starter into the block (the black wire from the engine harness?)Bill Clupper #618Comment
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Re: '66 Ignition Issues
When you turn the switch to "ON", do you have voltage at the coil side of the ballast resistor? If so, How much, ie full system or some lesser value? When the switch is turned to "start", do you still have voltage at the resistor, and how much? If you have voltage at this point, you should get a spark of some sort unless one of the components you replaced is bad.Comment
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Re: '66 Ignition Issues
During cranking you should see battery voltage (about 9 to 11) at the coil because the ballast is shorted out of the circuit by the "R" terminal on the starter solenoid. After releasing the key from the crank position the "R" terminal voltage drops to zero and voltage is routed through the ignition switch to the ballast so the coil voltage should drop to about 7, and you can check this with the ignition switch on and the points closed. If you are seeing 12 volts then the ballast might be shorted. It should measure about 1.8 ohm.
I take it you have attached a plug wire to an old spark plug and grounded it to see if there is an actual spark when you crank the engine? If there's spark the distributer may not be installed properlty
To properly install the dist. place the balancer notch on the initial timing point on the tab (NOT TDC). To be sure you are on #1 pull the plug and feel for compression as the balancer notch approaches the tab.
Pull the dist and check that the dimple on the drive gear is pointing the same direction as the rotor tip. Once the crankshaft is properly indexed drop in the dist. so the rotor points about 30 degrees to the right of the engine centerline, then rotate the dist housing until the points just open. The window should now be about perpendicular to the crankshaft centerline and the vacuum can about halfway between the manifold and coil bracket interference points.
If there is no spark the circuit is not complete. Check the ballast and coil (both primary and secondary winding) for continuity. Also check that the breaker plate is grounded. It has a dedicated ground wire that attaches to one of the vacuum advance mounting screws. This wire can break from constant breaker plate rotation in response to the vacuum advance. Since they are typically soldered or crimped to the breaker plate, you just buy a new one.
Also check the secondary circuit for continuity - rotor, dist, coil wire, etc. There's always a possibility that one (or more) of the new components is defective.
DukeComment
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Re: '66 Ignition Issues
Bill,
The ground on the starter is connected and making good ground.Comment
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Re: '66 Ignition Issues
Ed,
I'm getting system voltage (12) at the ballast resistor when the switch is in the on position. I haven't tried it durning "start" and can only assume that it would be the same as what I'm getting at the coil during my "cranking" test. I have gone through 4 sets of points and condensors with the thought that I'm getting bunk parts, no change.
ThanksComment
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Re: '66 Ignition Issues
Which side of the ballast resistor are you getting the 12V? It will not be the same on the coil side in the start and on positions, as the voltage should be dropping through the resistor( 7-9V) in the "on" position, and fed at full voltage (12-13V) from the solenoid at the "start" position.Comment
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Re: '66 Ignition Issues
You might try running a test ground lead to the distributor,while someone else cranks the engine,more then once ,I've had a poor running engine,or hard starting,or loading up,and it turned out the distributor and block had to much paint to give any or a proper ground.Comment
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Re: '66 Ignition Issues
Dave If you have voltage to the coil, you should have spark while cranking even if there's a solenoid or ballast resistor problem. If there is a lack of spark, a quick check with a timing light and high voltage coil wire while cranking should help isolate the cause. If there is spark at the coil HV output ,points, condensor are likely good and the problem likely lies with the distributor cap, or rotor. If no spark at coil, then the low voltage circuit becomes suspect. That can be checked with the key ON (not cranking). With voltage to the low tension side of the coil, you should be able to check circuit continuity between coil and the points. Put the multimeter on the +12 at the points with the cap off, and the points closed. You should read 0 or close to it. (If you read 12v instead, the points ground is bad.) If you do read close to 0v, open the points by hand. The voltage should rise to 12. If it doesn't either the circuit is bad (which you can verify with an resistance test), or the condenser is shorted (which you can verify by removing from the circuit and rerunning the test. Good Luck LesComment
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If radio equipped,
and the RF suppression capacitor on the coil is either shorted or BADLY leaking internally, you'll essentially short circuit the primary side of the ignition (points, condensor, coil primary). A quickie way to fault isolate lacking a Digi-Bridge to validate the RF capacitor, is to simply disconnect the RF capacitor at the coil's + terminal and see if that makes a difference....Comment
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Is there a dwell reading while cranking?
Dave
If there is no spark, the first this I check is the dwell while cranking.
The dwell reading while cranking should be from 25 to 35 deg. This should give you some spark for starting. correct reading is between 28-32 deg. If there isn't a dwell reading check to ensure the point are opening and closing while cranking. If they are then you need to dig deeper into an electriacl problem as posted earlier.Comment
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Re: If radio equipped, *NM*
Bill Clupper #618Comment
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Follow Up '66 Ignition Issues
Thanks and Hats Off to everyone for your help. The prize goes to Duke - it was the breaker plate ground. Replaced it, and now have good spark. What a great forum, it really worked fantasticly. I couldn't belive that I had suggestions and ideas within just a few hours. Thanks again to all of you - I hope I can return the favor someday.
Dave SaykerComment
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