Unshielded wires

Vanspeed

Vanspeed

Well-known member
While I am problem solving my cooling issues there is another thing I want to ask about. I have lacquer covered cloth wires on my Flathead. I believe they are non shielded. When I first installed the engine I could not get readings on my multimeter, it would just go nuts. I bought a laser temp gun to pinpoint on my engine what temps it is at and that thing goes nuts too. I imagine I am getting all these wacky readings on my equipment because of the wires correct?
 
If the readings you're referring to are being made with a digital multimeter and are being made with the engine running, these erratic readings are due to interference from the high voltage ignition circuit. This would apply to the laser temp gun as well if being used when the engine is running. The only shielded wire that I know of used in these old cars of ours is the radio antenna wire. Unshielded wires are not the cause of what you are experiencing. Get yourself an analog multimeter for measurements being made with the engine running. As for the laser temp gun, turn the engine off and then take your measurement....
 
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Yes with the engine running. What is so special about my ignition? If I use the same tools on my 100% stock 1960 F-100, all my tools read normal. It has the same voltage regulator, basically the same generator......

petehoovie said:
If the readings you're referring to are being made with a digital multimeter and are being made with the engine running, these erratic readings are due to interference from the high voltage ignition circuit. This would apply to the laser temp gun as well if being used when the engine is running. The only shielded wire that I know of used in these old cars of ours is the radio antenna wire. Unshielded wires are not the cause of what you are experiencing. Get yourself an analog multimeter for measurements being made with the engine running. As for the laser temp gun, turn the engine off and then take your measurement....
Click to expand...
 
On your '60 F1 - Probably condensers/capacitors installed at strategic locations and improved design of components to suppress noise. Let me correct my previous statement and say that solid core spark plug wires are probably contributing to your problem. Carbon core spark plug wires may be of help to you but I doubt they will eliminate the problem.....
 
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Carbon core ignition wires can be unreliable if not terminated and handled with care. Solid core ignition wires are more original and very reliable, but will cause electromagnetic interference. I run Pertronix electronics in my crab distributor and they recommend spiral wound core ignition wires, which I did. Very reliable so far and no radio interference. My el-cheapo temperature gun works fine with the engine running, as does my digital volt meter.
 
When running a more powerful ignition...lets say 12v and a can coil togetter with solidcore wires the transmitted interference get´s real bad...
As soon as you leave the original system with a low "reserve" you can run supression wires...why would they be unreliable...all later cars ain´t sitting by the roadside broken down constantly ?
 
Yeah, those EMF's are powerful...I asked a sparkie at work to help me diagnose some issue I was having with my 35. He approached it whilst engine was merely idling and 'blew' his flash Fluke meter. He still cries about that.....
 
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