Let's say I have 1 foot of wire, and it reads 3.26 Ohms. Should 2 feet of wires be 6.52 Ohms??
Yes.
quote
... the less amount of Ohms the better the wire is...right??
Not necessarily. Electrical resistance is engineered into spark wires for two reasons: 1) to reduce peak spark current, and 2) to damp high frequency resonances and thus reduce radio interference. Consider also that an ignition pulse, which contains many high-frequency AC components in addition to a DC component, is a very different condition than the simple DC resistance test performed by your ohmmeter.
[This message has been edited by Marvin McInnis (edited 01-09-2009).]
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02:36 PM
PaulJK Member
Posts: 6638 From: Los Angeles Registered: Oct 2001
If you look through the spark plug wires in the Summit racing catalog, you'll get an idea of the wide range of resistances the wires can have ....
I can't seem to find the link to see Summit's tech info on aftermarket wires. (MSD, Taylor, etc.)
My understanding is the less resistance, the better the wire is. The less Ohms the better. Can someone explain this more?? Just because of radio interference, and how the wire is insulated isn't what I need to know. I'm useing my Ohms meter, and just want to know what it should read to diognose the condition of used wires.
Thanks,
------------------ fierogt28
88 GT, loaded, 5-speed
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09:25 PM
PaulJK Member
Posts: 6638 From: Los Angeles Registered: Oct 2001
the Summit catalog won't give you any info that would help you do that. i DID see a thread where testing the wires was discussed, but didn't keep it. If you wanna SEARCH the Technical section and Technical archives, you might get some helpful info.
My understanding is the less resistance, the better the wire is. The less Ohms the better. Can someone explain this more?? Just because of radio interference, and how the wire is insulated isn't what I need to know. I'm useing my Ohms meter, and just want to know what it should read to diognose the condition of used wires.
The simple explanation is spark plug wires are not tested with an Ohmeter. They are tested with a Megger. Simple resistance is meaningless.
Megger From Wikipedia, the free encyclopedia Jump to: navigation, search An original "Insulation Tester" dating from World War II
Megger has become the generic description for a high voltage, low current insulation tester. The word is short for megohm-meter. The original Meggers were manufactured by Evershed & Vignoles Ltd., Acton Lane Works, Chiswick since 1889. They were taken over by AVO Ltd. in 1895. The word is now the registered trade mark of Megger Group Ltd. Meggers were also made in the USA by James G. Biddle. Older types have a small built-in generator. The generator is hand-driven, through gearing and a centrifugally controlled clutch slips at a predetermined speed so that a steady test voltage is obtained. Modern types work with batteries and circuitry to generate the voltage required. Both types can output test voltages of 100, 250, 500, 1,000 or 2,500 VDC, depending on model.
Although any Ohmmeter or Multimeter may appear capable of similar measurements, only a Megger type instrument can test the quality of the insulation at or above its operating voltage.
Choice of test voltage is normally determined by the operating voltage of the circuit under test; usually twice the operating voltage is sufficient. Two basic insulation tests are possible: Insulation to ground and insulation between conductors.
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11:53 PM
SCCAFiero Member
Posts: 1144 From: Boca Raton, Fl USA Registered: Apr 2006
And just to make it simpler. The Ohm rating is worthless because if the insulation breaks down, your spark goes through the wire insulator to the closest ground and not to your spark plugs.
Marvin is correct. You do need to know.
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11:57 PM
PFF
System Bot
Jan 10th, 2009
Chris Hodson Member
Posts: 3066 From: Carpentersville Registered: Aug 2006
Im not help to this thread, im just thinking of how much fun this would be... "The generator is hand-driven, through gearing and a centrifugally controlled clutch slips at a predetermined speed so that a steady test voltage is obtained."
Im not help to this thread, im just thinking of how much fun this would be... "The generator is hand-driven, through gearing and a centrifugally controlled clutch slips at a predetermined speed so that a steady test voltage is obtained."
Specially when you hook it to someones chair and start cranking....
Resistace is not worthless. Wikipedia clearly states of the Megger: "It is a high voltage, low current INSUALATION TESTER". Insulation capability is also very important like sccafiero stated. But according to Ohms law the available voltage is proportional to the resistance of the wire. That is why wires are rated in ohms. Is very obvious that big companies like Accel and MSD have meggers to test the insulation capability of their wires.
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01:10 PM
SCCAFiero Member
Posts: 1144 From: Boca Raton, Fl USA Registered: Apr 2006
The original question was focused on testing USED wires to see if they are any good. Not how they compare to other wires. For the original question, all the resistance will tell him is whether the wire is broken. If they are used wires then the odds of the insulation being bad are 99.99% higher than the core being broken and having too high a resistance. In other words, for HIS question, a Ohm reading is worthless.
The reason manufacturers have ratings listed is because it is assumed a NEW set of wires will have good insulation so you can make a comparative analysis, not determine if they are faulty.
Regarding the later question of "are the new wires garbage", that depends on what the application is and what the wire is. A brand new set of cheapo wires can have the perfect Ohm rating and literally lose most of the spark through the insulation from a high powered ignition system. For a stock setup they may be perfectly fine.
Ignition system parts have to be matched, otherwise some new parts can have bad results.
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01:27 PM
La fiera Member
Posts: 2197 From: Mooresville, NC Registered: Jun 2008
IThe reason manufacturers have ratings listed is because it is assumed a NEW set of wires will have good insulation so you can make a comparative analysis, not determine if they are faulty.
Scenario: Manufacturer X rates a foot of wire at 1000kohms, the purchaser tests two - 1 foot lengths to verify. One of them has 1000kohms and the other has 15.500kohms. He has determined that one of the 1 foot lengths is faulty because the specific length exceeds the rated resistance.
Hey guys, can you provide a name of good wire set to get for our 2.8's that possibly are red, good quality, and come in the proper lengths?
I returned the BWD's, the wires ON my car came in at 6k-7k ohms. I megged them at 1000 volts DC and had "infinity" on all of them. I should change them though because the metal connectors on the plug ends are not in the best conditon.
sparx22
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05:27 PM
fierogt28 Member
Posts: 2938 From: New-Brunswick, Canada. Registered: Feb 2005
Hey guys, can you provide a name of good wire set to get for our 2.8's that possibly are red, good quality, and come in the proper lengths?
I returned the BWD's, the wires ON my car came in at 6k-7k ohms. I megged them at 1000 volts DC and had "infinity" on all of them. I should change them though because the metal connectors on the plug ends are not in the best conditon.
sparx22
IMO, the fiero store has wires that are probably the best bang for the buck. They are custom fit, and are red in color.
I bought a set of taylor "thunder-volt" wires and they are a tad too long, plus the coil to distributor wires is too long. That's exactly what I wanna fix.
Those wires I bought were 60$ from Summit.
MSD's are very good wires too, but the taylor wires have a more factory look at the distributor and spark-plugs.
