I did some more research on ignition coils. Wikipedia states older coils are filled with an oil or similar liquid. These are the coils I'm most familiar with and are most likely to leak. (Any coil that is leaking, even if still working, can be considered damaged and should be replaced.)
Wikipedia further stated that modern coils are filled with a solid epoxy-like substance instead of a liquid. Some epoxies can melt or disintegrate if exposed to elevated temperatures and could result in a modern coil leaking. Regardless of whether the coil is leaking or not, prolonged exposure to elevated temperatures could damage the coil.
All things considered, there is a valid argument for replacing a significantly older coil with a modern one of the same physical and operational type. (OEM-equivalent.) However, I see little reason to replace a working older coil, unless you're willing to spend the money to bring your motorhome up to better-than-new condition. (Even then, there's lots of other things I'd spend the money on first.)
1970 Explorer Class A on a 1969 Dodge M300 chassis with 318 cu. in. (split year)
1972 Executive Class A on a Dodge M375 chassis with 413 cu. in.
1973 Explorer Class A on a Dodge RM350 (R4) chassis with 318 engine & tranny from 1970 Explorer Class A
And what about candlepower? I remember the old 1157 bulbs were 3 and 32 CP and 1156 was 32. The manufacturers like to play with CP, the flashlights with 2 bazillion candlepower...lol
The oil (in older coils) and epoxy-like material (in newer coils) serves to isolate and insulate the wires inside the coil. When the oil leaks out, the bare wires are allowed to come in contact, creating an internal short circuit. The same happens, to a lesser extent, when the 'epoxy' melts or disintegrates. In both cases, this is usually due to excessive heat. As you noted. the usual cause is internal heat due to the coil being subjected to extended periods of full battery voltage. Less frequently, this can be due to external heat 'baking' the coil.
You also mentioned the Mopar dual ballast resistor. In Mopars with single ballast resistors, the START circuit bypasses the ballast resistor, feeding full battery voltage to the coil. 0.5 ohms isn't a lot of resistance so there isn't a lot of difference between single and dual resistor systems. People risk damaging their ignition coils with either system when cranking the engine for extended periods. (More than a minute or two and without several minutes pause between starting attempts.)
Note: Until several months ago, I always thought the purpose of the ballast resistor was to save wear and tear on the spark plugs and distributor points. I now know the resistor primarily serves to prevent damage to the coil.
I also appreciate your comparison of GM, Ford, and Chrysler ignition systems. It helped me understand something I've noticed as far back as the early 1970s. Dodge (and International) trucks are notably easier to start in subfreezing and subzero temperatures while GM and Ford vehicles are much more difficult.
My mom used to get frustrated when her relatively new Chevrolet Impala was difficult to start, even though it was in an unheated garage with the block heater plugged in. She tended to get very annoyed when my '49 International Metro van would start right up even though it had no block heater and was parked in the open at the edge of the yard.
This was most notable when northern Minnesota temperatures plunged to minus 30 degrees F. My Metro would fire up on the first attempt, with only a second or two of cranking, while she had to make several attempts, each spanning a minute or more of cranking.
Even at severely subzero temperatures, I'd sit in the Metro while it warmed. I learned I'd have to listen to her pitch a fit if I went inside. (She didn't understand and hated the Metro, often saying, "Nobody would want to steal that thing.")
Candela (the modern term for candlepower) is a base unit of luminous intensity in the International System of Units (SI). (source: Wikipedia Candela article) Lumen is a SI derived unit of luminous flux. There is a direct relationship between candela and lumen: one lumen equals one candela times one steradian. (Steradian is a measurement of a conical section of a sphere.)
Note: 'luminous intensity' versus 'luminous flux.' While candela and lumen both measure visible light, each measures it in distinctly different ways.
Yes, understanding the two units requires a better than average understanding of physics and three-dimensional geometry. Don't let that stop you from exploring the subject on Wikipedia. You're never too old to learn and the best way to learn is to wade into topics, see where things lead, and try to understand.
I am fortunate in having a good understanding of physics and geometry. However, I cannot (in any way, shape, or form) be considered a physicist or mathematician. (I'm a generalist -- sometimes called a 'polymath' -- rather than a specialist.) On the whole, the Wikipedia articles on visible light are well written and lean towards 'plain English' description rather than dense science and mathematics. (The same cannot be said for related articles elsewhere on the Internet.)
I found it interesting to know the history behind the evolution of both units of measurement, which is covered in the Wikipedia. (I believe it's important to know how we got where we are today.)
That being said, lumens are a good means for the average person to make reasonably accurate comparisons about light emitted by light bulbs and fixtures.
As soon as i get all the maintenance done ill be dealing with the house. You guys have been helping a lot. Glad this forum exists.
Youtube has a guy named yankee prepper that has helped me a lot also. he is restoring a 78 dodge MH with a 360.
'73 Concord 20' Class A w/Dodge 440 - see profile for photo
Leeann wrote:
Welcome!
Welcome!
I second the welcome. Be sure to hit us with any questions you might have. You may also want to discuss what you're planning to do in more detail. We may have ideas as to how to do some things better or easier. Likewise, describing your experiences will be helpful to others doing similar things.
But in short, with the help I have already gotten, I am doing some maintenance, making sure the rig is safe and dependable, then comes the house. which I know nothing about lol.
So far I have changed fuel pump, changed oil, replaced booster, master, brake hoses, and pads. Next is tranny fluid and gasket, and ruuber belts and hoses. And im currently looking for some tires.
everything going smooth so far.
* This post was last edited 01/23/18 04:55am by RvFNG76 *
Any thoughts on this cross checked model numbers and its the same one i can get at work for $25 but the ones i use go into travel trailers. Btw im never buying a newer pull behind.