Hot rodding the HEI distributor
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===Pick-up coil assembly=== | ===Pick-up coil assembly=== | ||
[[File:HEI pick up coil assy.jpg|thumb|left|300px|HEI pick-up coil assembly.]] The pick-up assembly doesn't often fail internally, however the small gauge wires that connect to the end of the 4-pin module get flexed each and every time the vacuum advance retracts or extends- in other words, millions of times during its lifetime. Because of the flexing and the stiffening of the insulation from heat over time, the wires inside the insulation can break. This will often manifest itself as a sporadic, transient miss or stall condition that might seem unrelated to the ignition system. | [[File:HEI pick up coil assy.jpg|thumb|left|300px|HEI pick-up coil assembly.]] The pick-up assembly doesn't often fail internally, however the small gauge wires that connect to the end of the 4-pin module get flexed each and every time the vacuum advance retracts or extends- in other words, millions of times during its lifetime. Because of the flexing and the stiffening of the insulation from heat over time, the wires inside the insulation can break. This will often manifest itself as a sporadic, transient miss or stall condition that might seem unrelated to the ignition system. | ||
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| − | The way to test the pick-up coil assembly and its wires is to use an ohm meter and measure the resistance between the two wires at the terminal (unplug the pickup from the module). The resistance should be | + | ===Testing the HEI components=== |
| + | ;Pick-up coil<nowiki>:</nowiki> | ||
| + | The way to test the pick-up coil assembly and its wires is to use an ohm meter and measure the resistance between the two wires at the terminal (unplug the pickup from the module). The resistance should be somewhere around 600Ω to 1000Ω. There's a fairly wide tolerance, but it should '''not''' be infinite and it should not vary as the wires are flexed and moved around to simulate it in use. | ||
| − | If the meter jumps around as the wires are flexed, or if the resistance is drastically higher or lower than | + | If the meter jumps around as the wires are flexed, or if the resistance is drastically higher or lower than 600Ω-1000Ω (or is infinite), or if there is a reading between either wire and the metal case of the pick-up coil, it's bad. |
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| + | ;Coil (from [http://www.hotrodders.com/forum/testing-hei-coil-module-103662.html#post727460 docvette])<nowiki>:</nowiki> | ||
| + | *Remove and invert the cap. | ||
| + | *Measure between the TACH and BATT terminals, using a DVOM, set to OHMS scale, RX1 and calibrated to 000Ω. | ||
| + | *It should read less than 1Ω, but more than 000Ω. If not it's bad. | ||
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| + | Next measure the secondary side of the coil: | ||
| + | *Set your DVOM scale to RX10K or higher. | ||
| + | *Put the probes between the BATT terminal of the coil and the carbon pickup inside the distributor cap. It should read between 6000Ω and 30,000Ω. Outside of that range toss the coil and get a new one. | ||
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| + | [[File:HEI cap.jpg]] | ||
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| + | ;Module<nowiki>:</nowiki> | ||
| + | Many parts stores can test the HEI ignition module at no charge. If that isn't possible, another way is to replace the module ith a known good module. | ||
==Installation tips== | ==Installation tips== | ||
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