Mystery #2 solved. Bad ROTOR?
Orig. Posting Date | User Name | Edit Date |
Oct 18, 2017 09:37AM | minimans | Edited: Oct 18, 2017 02:46PM |
Oct 18, 2017 08:16AM | Dan Moffet | |
Oct 18, 2017 08:09AM | dklawson | |
Oct 18, 2017 04:04AM | helpmymini | |
Oct 18, 2017 03:52AM | helpmymini | |
Oct 18, 2017 03:44AM | dklawson | |
Oct 18, 2017 03:16AM | helpmymini | |
Oct 18, 2017 02:55AM | nkerr | |
Oct 18, 2017 02:39AM | helpmymini | Edited: Oct 18, 2017 02:39AM |
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As an aside it's easy to test the rotor by pulling the cap and removing the coil lead from the cap, then have an assistant crank the engine over (Ign. On) and hold the end of the coil lead over the top of the rotor with a small gap, it should not spark. If it does it means the rotor is supplying a ground path to the distributor body and is NFG.
The updated and more costly ones are red in colour.................. Why do they cost more?...........Because they work.......
As an idea of how dangerous this can be, I was pulling out on the main Hwy in my 73 MGB GT when the rotor failed without warning, no splutter just dead. I narrowly avoided disaster because the twin trailer grape hauling truck driver was fully awake and took to the verge to avoid me. His words of advice about my piece of sh*t vintage car still haunt me!
Strange I wrote my reply thinking nobody else had replied as nothing except the original post showed? Now it's all showing I see that the question had already been answered..................................
Mini's are like buses they come along in a bunch
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I still cannot see responses to this thread until I enter edit mode. Very strange.
Mark, the only wires that should be inside the distributor are:
The wire from the moving arm of the points which goes to the coil,
The wire from the moving arm of the points to the condenser, and
The wire from the breaker plate to the distributor housing.
The breaker plate wire is a ground connection. It can touch anywhere inside the distributor housing as long as it does NOT touch the moving arm of the points or anything connected to that arm. If it touches there it provides a short to ground for the points and coil... like a kill switch, and you won't get any spark.
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"Hang on a minute lads....I've got a great idea."
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I still cannot see responses to this thread until I enter edit mode. Very strange.
Mark, the only wires that should be inside the distributor are:
The wire from the moving arm of the points which goes to the coil,
The wire from the moving arm of the points to the condenser, and
The wire from the breaker plate to the distributor housing.
The breaker plate wire is a ground connection. It can touch anywhere inside the distributor housing as long as it does NOT touch the moving arm of the points or anything connected to that arm. If it touches there it provides a short to ground for the points and coil... like a kill switch, and you won't get any spark.
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My friend got an email from Jeff. Here is what he said:
I made the red rotors to eliminate 2 problems: 1. high carbon content of the black rotors was promoting burn-through and arcing to the shaft (ground) 2. the brass rivet was shortening the distance for that arcing to short to ground (and they're typically loose)
As a distributor rebuilder, I simply got tired of answering calls every day about stalled cars that were caused by failed rotors. After selling 60,000+ rotors, I have 3 known failures on my desk. 1 broken in half, two shorted internally from very high voltage systems with failed plug wires. I can live with a failure rate of .005%. Yes, half a thousandth of 1 percent.
You DO NOT need to replace these rotors as periodic maintenance. Just clean the edge with a file, scrape your distributor cap terminals with a pocket knife, and keep driving!!!
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My conclusion to this situation is the wire or wires in the body of the distributor are causing it to short through the rotor with the exposed rivet. It's not one thing, it's a couple combined. I also wonder if there was a plug of material in the bottom of the rotor that degraded or fell out allowing it to short out. My distributor in my mini doesn't have that bad wire and it wouldn't run with the bad rotor? Hmmmmmm. More to learn.
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The typical failure mode is not an "open" as you discuss above but a "short". When the rotor shorts, the electrical path is from that center contact point on the distributor cap right through the rotor to ground via the shaft in the distributor. The electricity is never routed to the plugs... just straight to ground. Fortunately you had an old rotor to experiment with.
The advice given on many threads like this is to either buy replacement rotors from Jeff S. at Advanced Distributors or buy the blue epoxy rotors available from some parts suppliers. As you observed, the rotor is not unique to the Mini so there are several sources for the blue rotors.
Sidebar: In edit mode I see that Norm has responded with almost the same response as mine. Oddly... I cannot see Norm's response when I read Mark's original post. I only see Mark's first post.
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Glad you posted this response. I will log that in my bank of things to look for if my car stops running!
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if it wasn't a red rotor from Advanced Distributors, then the answer is, "they all do that". The black rotors are not trustworthy and have not been for something like 20 years. Countless magazine articles and internet "discoveries" have covered this fact, over and over so much that it is still a surprise to find how many folks still haven't heard about it.
Jeff developed his, with proper quality control and materials used to maintain the quality, made it red and marked it with "AD" (there are some bootleg red ones which should be avoided as much as the black ones, they lack his mark).
N
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URL: https://youtu.be/Y3TQ71jF-00