Bench rigging solid state ignition
I'm trying to start my 1966 427 engine on a "bench". I've wired the starter on a separate circuit so I can turn it off when the engine starts. I have a new ignition wiring harness and have hooked that up to the distributor, amplifier and coil per the wiring diagrams other than hooking up the 18 Pink wire to the starter. When I apply +12 voltage to the white wire that ends up going to the ignition switch I hear a buzzing noise that I'm not happy with. Do I need a resistor in the ignition wire line or am I screwing something else up? Thanks
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Re: Bench rigging solid state ignition
It's not totally clear what you are trying to do, but you can test a TI system on the bench by applying 12V and ground from a battery or power supply.
Install the coil center wire and attach a spark plug that's grounded to the power source.
You should be able to tell from the wiring diagram which wire on the harness you energize with the power source. I think the TI amp also needs to be grounded.
Spin the distributor shaft with an electric drill, and if you see a spark at the plug, the system works.
Duke -
Re: Bench rigging solid state ignition
Thanks Duke. I've done what you've suggested and the TI amplifier is grounded to the power source as you said. The obvious choice to power the system up is the white wire labeled the Ignition Wire on the diagram. I've done that and got the nasty buzzing sound. If I trace that wire back to the ignition switch I can see a resistor in the line but it's not labeled. A resistor in series drops voltage so I'm not too anxious to power the system up at 12Volts and blow something. Again thanks for the help.Comment
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Re: Bench rigging solid state ignition
Like Duke, I am not sure what or how you have it wired so far. By "bench" start your engine, I assume an engine stand designed to test or break-in an engine-I have one with a dash board, ignition switch, regulator, etc. The TI harness has 2 power source leads as part of the harness. The pink wire from the switch (run position voltage) goes to the male connector of a white cloth wire in the harness (this is a resistor wire and therefore, the system requires no ballast resistor). Then a normally purple or pink wire from the solinoid/starter plugs into a female pink wire connector (coming off the distributor connector plug) of the harness (this will provide a full 12v at crank only)-(since you are bench starting, just make sure you choose the terminal that has voltage during crank only). The forked terminal white cloth wire goes to the positive of the coil and the black forked terminal goes to the negative. Obviously, the 2 wire plug goes to the distributor. This system is critical to have a good proper ground, so do not forget to ground the amp. Caution: do not pull the center coil wire to cap to see if there is spark-this could cause damage to the amp., rather check it at one of the plug wires. If you wire it this way-it will run. If not we can assist to determine what ain't working (have all the individual parts been rebuilt, new or somehow tested to assure they will work within the system??????????).
Good luck,
MikeComment
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Re: Bench rigging solid state ignition
Thanks Mike: The engine is in the chassis without any of the dashboard components you mentioned (including the ignition switch). I've wired the starter to a power supply with a switch so I can crank the engine over. I've wired the TI system with a new harness just as you described and grounded the amp to the chassis ( chassis is grounded to the power supply). I have not connected the pink wire with female connector coming off the distributor to the starter/solenoid as you mentioned, I just let hang. I did put +12V on it as my fist attempt but got that buzzing sound. I then put +12V on the white cloth which would normally hook to the pink wire from the switch - same buzz noise. My thought was to keep the two systems - Ignition and Starter separate so when the engine fired up I could simply switch power off to the starter and disengage the pinion and solenoid? Are you suggesting I should hook both the white cloth ignition wire and the pink starter/Solenoid wire to +12V and then turn the 12V off to the pink wire when the engine starts? Components are new/rebuilt and were run when the engine was dyno'ed a number of years ago. Thanks again.Comment
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Re: Bench rigging solid state ignition
The system is designed to introduce a full 12v to the amp during start for easier starts, but I would not recommend a full 12v for any length of time, i.e. during run; as this could cause damage to the power transistor. The system should however, start and run with just the power source to the white cloth wire, which is the resistor lead-the M&H aftermarket board eliminates the solenoid lead and just runs the one source (I believe this is what you explained you have now). FYI: the Delco line of reproduction modules, uses both leads, just like the OEM board.
Guess my big question is: where is the buzzing coming from? Let's make sure of what you have: if you have a multi-meter, pull the plug at the amp and check the amount of voltage at the black wire (this is the lead that the white cloth wire turns into at the end of the harness). You should be seeing 7-8 volts max.; if so, you have the proper voltage and will not hurt the amp.
MikeComment
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Re: Bench rigging solid state ignition
Thanks Mike: I understand you on the higher voltage at starting/cranking and a lower voltage for running when the ignition switch is released into the run position. I just checked my grounding and it's good. I'll check the voltage at the Amp with +12V on the white cloth wire resistor lead wire. I do have a Delco repro amp and if the lower voltage checks out then I'll hook both leads up. Again many thanks you guys have been a big help.Comment
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Re: Bench rigging solid state ignition
Mike: Well I pulled the amp plug and did the tests you recommended. My wiring diagram shows the white cloth wire that goes to the ignition switch hooks into the pink wire terminal on the amplifier plug as well as the pink wire to the starter solenoid and the white wire to the distributor. The black amp plug wire hooks up to another white cloth wire which then goes to the +'ve terminal of the coil. I hooked +12V to the white cloth ignition wire and got the following: black plug terminal to ground zero Volts, pink plug terminal to ground 12 Volts and the gray plug terminal which connects to the white/green wire from the distributor also had 12 Volts on it. I checked to make sure there was no short between the two wires from the distributor so the voltage on the gray plug terminal appears to be coming from a connection being made in the distributor? I tried measuring the resistance on the white cloth wires and if there's any there it's too low for my meter. No buzzing with the amplifier plug removed. ThanksComment
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Re: Bench rigging solid state ignition
I believe you are correct, sort of. I am a bit confused on some of what you say, so to make sure I have checked my actual car (running), and the pink from the switch goes to the m/f connector white cloth wire of the harness. Yes, there is another white cloth wire, but it has a forked term connector and goes to the coil. On your harness (if correct), you will see a short pink wire split/joined with the pink wire connected to white wire term of the distributor (low side of the coil P/U)-this short pink wire plugs to the solenoid wire for the 12v during crank.
I have to confess to you; I restore these amps as one of the specialties of my restoration shop, and leave on one of my 66 BB cars an amp laying on the fender over the headlight without the backing plate (plugged into the harness and properly grounded) for testing (removed for driving), as well as another in the factory mounted position for driving. I test every repaired board in this backless amp, so I am constantly removing and installing boards to check them. I just verified what I expected to see: with the key on the run position, I measure right at 6.9v DC on both the black and the pink wire at the amp. Pink wire lead is providing power source to the amp circuit, therefore, the voltage at the black terminal that goes to the coil, gets it's power from within the amp circuit. Because the pulse to the coil is via another white cloth resistor wire, which further reduces the voltage seen at the amp, I read 2.7vdc at the coil.
So, in your comment "white cloth that goes to the ignition switch hooks into the pink wire term on the amp plug" is not wholly true. This white cloth wire ends up as the pink wire at the amp, correct. But the pink wire at the distributor end, is also the pink at the amp. Let's go one step further: the split pink wire provides DC voltage to the coil P/U, so during run, it is receiving it's source from within the amp through the circuit, which due to a resistor white cloth wire, is reduced from 12v. from the switch to 7v. at the amp, the primary source of DC voltage. However, during crank when 12 v. is introduced to the system at the split pink wire via the short pink wire-the coil P/U sees a full 12v-you indicated you had yours "dangling". The coil P/U in theory is a generator, which converts the DC power and generates AC voltage which is feed back to the amp via the white/green to the gray wire in the harness-this is AC voltage, which is necessary to "excite" the transistors to "trigger" the pulses to the coil. Remember, the high voltage generated by the coil is also AC voltage, which is converted from DC within the coil itself. This trigger is handled in DCv. at the positive side of the coil (forked white cloth wire). The trigger handled by the transistors in this system are accomplishing the job that point did on a conventional system-it's just that the transistors are working in ACv and directing DC voltage to the coil primary circuit. As a point of interest: on my Sun machine, I can test the amount of ACv generated from the electro-magnetic coil P/U. I test at a baseline 1000RPM, simply because the OEM/NOS typically do not "strobe" the machine much lower and many older ones require even more RPM (due to the magnets lose power over time). I typically see about 2.7vac., which increases to a high of about 4.8vac from OEM/NOS units. For performance applications where originality is not the major concern; I install the latest Delco reproduction coil P/U. In the repro unit the magnet is 40% stronger and the "bobbin" has more windings; resulting in a little more than twice as much ACv across the RPM range. This additional "excitement" to the transistors, should result in a more stable and precious "trigger". The beauty of transistors is they do not vary, fluctuate, or deteriate like points do. Yes, transistor do fail, and the original germanium versions did quite often-this was the weak link in the system. However; today, we have silicon equivalents that we can replace them with, which we do routinely at our shop. The silicon versions are damn near indestructible.
In my suggestion of checking voltage previously, was to see if you had voltage to the coil. I was however, mistaken to suggest you would see 12v. at the black-I have corrected this statement above (you would see the 12v only at the coil P/U. Further, because the DC voltage to the coil is delivered via a white cloth resistor wire, the voltage is stepped down again. So, although you should read 7v. at the black term at the amp, you will see about half of that at the coil-I read 2.7v on my car.
I hope I have not made this more complicated than needs to be, but I hope you can identify where you should see voltage and approximately how much. If you do not see voltage at the coil-it ain't gonna start. The buzzing: my guess is you are not feeding voltage in properly and the circuit is revolting. I just hope you have not fried one of the components.
MikeComment
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Re: Bench rigging solid state ignition
i guess you have this wiring diagramComment
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Re: Bench rigging solid state ignition
Mike: Your last message I think pointed out the problem. I've been doing my tests without the engine running so without the distributor spinning there is no exciting voltage to the amp. I never could get a good explanation why the distributor looked like and acted like a "generator" until now. I'll set my next test up with the engine cranking and +12 volts coming from the starter solenoid to the TI circuit from the split pink wire. I won't apply voltage to the white cloth ignition wire since this is the one that through the ignition switch provides RUNNING voltage to the circuit after the cranking circuit is deactivated correct? I'm doing all this without the benefit of the ignition switch which is currently in the my restored instrument panel nicely wrapped and packed away. If I find a problem with this test I'll pull the amp out and send it to you for repair if that's OK. My wiring is as you've described and I tried to describe. I'm using a correct new wiring harness from Lectric Limited and have been applying voltage directly to the white cloth ignition RUN wire or the pink solenoid CRANK wire. CLEM: Thanks for the diagram but I couldn't enlarge it to see details but I do have it wired correctly other than the two wires providing voltage to the TI circuit.Comment
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Re: Bench rigging solid state ignition
Harry-
You should not have to have the engine running to see the measurements I mention. Pull the backing plate off and as long as the housing is grounded, you should see the measurements I indicated. It is not necessary to even hook up the short pink wire to the solenoid, as the system will start and run with just the switched pink wire-I was just laying out how the system is wired and should work, and where and how much the measurements should be. I am concerned of you probing around in the amp if the engine is running, for fear of shorting across two terminals, etc.
If you have it wired correctly, are you still hearing the buzzing? I also am not clear if you have it running or not? Keep us posted. Yes, if you need any repair or restoration to the amp, we do that work-you can check out my e-Bay listing for that service to see further details (michaelz505), and we carry a full line of the Delco reproduction parts in stock. Please note everyone, I am not advertising or soliciting for any of my services, but only trying to help a member.
MikeComment
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Re: Bench rigging solid state ignition
for you tech type guys here is the AMP tester i build back in the 60s when i was repairing amps. it uses double throw double pole relay to fire the amp with wire wound adjustable resistors to control the voltageComment
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Re: Bench rigging solid state ignition
Mike: Sorry I haven't replied earlier. With all due respect to your last message I went ahead and cranked the engine with the short pink Starter solenoid wire hooked to +12V but I set it up so it would only get the +12V when the distributor was turning. No applied voltage on the white cloth ignition wire. I didn't hear a buzz although the cranking may have masked it and I did get a nice spark at my test spark plug - so it's working. Voltage across the coil on cranking was around 2VDC as you said. Next step is to get coolant and fuel into the engine. I'm going to set up the wiring to a 3-way household light switch so I can quickly switch the voltage from the starter solenoid wire to the white cloth ignition wire once the engine catches. If I'm not quick enough I'll have to pull out my ignition switch and wire to it. Again many thanks for your help.Comment
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Re: Bench rigging solid state ignition
Clem: Pretty slick tester. Thanks for sharing.Comment
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