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I've got an older Morris mag with the kill switch stud that sticks outside of the mag body. I am reading continuity between the kill stud and the mag body. I thought the kill stud was insulated from the mag body by a insulating washer?
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I don't get it: If you look at an exploded view of the stud, it has an insulated washer that keeps the stud from grounding on the mag body? If that's the case, the stud should never contact the mag body unless a kill switch or kill level is engaged, hence continuity, hence that's how the kill switch or lever works?Comment
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don't fight it, just accept it ….
also NEVER EVER connect the magneto to any form of power as it will fuck it up,...
about the only thing to know about them is always use copper core wires, they don't like silicon or modern shit leadsComment
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Try this ....
On the inside of the stud remove the wire (At the points would be easiest) ... Then do your test and see what you get ...
... OR ...
Take the cond. off and let it dangle to the side ... Don't let it ground to the Mag body ...
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Wanna make life easier .. ??
Get yourself one of these ...
Considered a must-have item, easy to use tool to set your timing accurately. Also useful to test your magneto for 'ready to run' by simply connecting the tool any time, then turn the motor. Well constructed from aluminum, and long battery life. You'll love it!
Made to exclusive Morris Magneto specs, this solid state unit detects induction, not "buzz box" continuity. Can be used for for testing other things, like starter relays or standard battery-coil ignition timing (with the power disconnected!).Last edited by Dragstews; 11-21-2019, 2:05 PM.Take my 45 and outrun em all ..Comment
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Driving that train, high on cocaine
Casey Jones you better, watch your speed
Trouble ahead, trouble behind
And you know that notion just crossed my mind​Comment
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Standard aircraft mag tester design. https://www.amazon.com/Magneto-Timin.../dp/B01N7W6NJ1Made to exclusive Morris Magneto specs, this solid state unit detects induction, not "buzz box" continuity.
Of course most mags (including the Fairbanks, Wico and other industrial mags repurposed for motorcycles) were timed by timing mark and refined by ear but aircraft can't afford not restarting in flight or burning holes in pistons so testing by "E-gap" is done
Benchtop aircraft mag testers also allow visual test for spark quality off the aircraft. The Smokstak and other antique engine folks post a variety of mag testers, sources for unusual mag parts and more. HD engine designs date from the same era. This is probably the best general magneto forum:
How a mag tester works (with simple build instructions): https://www.gasenginemagazine.com/ga...-magneto-timer
Variant for two-stroke bike magnetos, chain saws etc:
Morris rebuilds and remagnetizes their and other mags. (I had a Fairbanks redone there.) Older mags can lose magnetism but you can have a local auto electrical shop (if they work on old stuff which most do) remagnetize a mag or send it off.
If you have ever needed to set the ignition timing on a 2-stroke magneto engine, you may have had difficulty knowing exactly when the points open. It’s not something that you can easily measure, because the resistance of the coil in the magneto is quite low and there is very little difference in the resistance across the points when the points are open as compared to when they are closed.
This handy device, known as a “Squarker,” solves that problem, because it is able to detect very slight changes in resistance, down to less than 1 ohm. I constructed my first Squarker around 40 years ago, when I was working as a motorcycle mechanic. I still have this original unit and I have used it from time to time over the years since leaving the motorcycle trade. So, why is it called a Squarker, you ask? Just listen to it in operation and you will have the answer.
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Typical HD mags fire pole-to-pole so I use two spark plugs tack welded (worm drive hose clamps work fine too) at the shells to test them and any dual fire ignition coil on HDs, rice etc. No need to ground the plugs to the engine or awkwardness maintaining contact when kick starting.
There must be sufficient continuity and both spark plugs connected to the coil for those mags to fire.
If you suspect a kill stud is ALSO grounded to the body AT the body instead of getting a continuity reading through the magneto system you can simply un-ground the condenser by removing the screw and supporting it in space away from the mag body, but it's unlikely to be a problem and if you get spark that kill stud is correctly wired.
Does your mag produce spark? If it does it's likely fine, but you can install a fresh condenser and points for a fresh start. As with any points ignition it's wise to have spares and you ain't gonna find magneto points anywhere but a very old tractor supply store, good indy bike shop, or online. They are very simple systems still firing industrial engines on farms out in Bumfuck, Idaho.
Your mag is likely good so test it before disturbing anything. You can clamp it to your bench and spin it with a hand drill (manual or electric) or whatever ya care to crank it with. Connect plugs, spin that bitch, note results. Remember mags rotate at 1/4 engine speed so slow is fine.Last edited by farmall; 11-20-2019, 11:16 PM.Comment
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Farmall,
Didn't have time to read the whole thing yet but I have mentioned the fact that antique plane guys are probably the best people to go to about information and rebuilding of mags. Those old bi-planes were the first to have dual mag set-ups. Who knows better than the people whose lives depend on it.
I have never ran a mag but now have an old 57 Pan that came with a Joe Hunt . If I have any issues when It's time to start it I have an 2 old customers ( both ex-fighter pilots , British and New Zealamd respectively ) who belong to an antique Aeroplane club who's hangers are 25 minutes away. Both contribute to restorations in their own way and have access to a wealth of information within' the club.
Have told friends in the past to seek them out but have been ignored.
As an afterthought. Before the radial bi-planes take off they test the mags on the ground individually. They start the motor on both I believe than they have a way to isolate each individual mag ( ground one out maybe ?) to make sure they are both firing correctly. If all systems are a go they than bring it back to full power and take off.
Why two mags ? Cause if one fails they can still fly .Comment
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Like farmall said above, I got a buzzbox with leads for two mags for about 30$ cheaper than the morris unit. I think the website was aircraftpruce.com or something to that effect. It looks exactly the same with an extra lead and light. Also has different buzzer sounds for each mag. Same construction so i'd bet it came from the same place. I'm not usually one to buy cheap tools, but it's simple piece and had to come from the same factory. Funny that an aircraft supply store had a better deal than a motorcycle place.Comment
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Those testers are so simple the labor to assemble them probably costs more than the parts.
Magneto theory of operation and troubleshooting: https://www.youtube.com/watch?v=cOr3b10zmrQ
Many non-radials use dual mags too. https://www.qaa.com/products/aircraf.../dual-magnetosThey start the motor on both I believe than they have a way to isolate each individual mag ( ground one out maybe ?) to make sure they are both firing correctly. If all systems are a go they than bring it back to full power and take off.
All these designs are older than dirt and highly refined from the same ancestors which is why the aircraft mags look a lot like industrial and bike mags. The impulse coupling used on more expensive motorcycle mags was first used on ground equipment mags.
Aircraft Spruce also have aircraft fuel tank sealant which is the goo of the gods for sealing gasoline, diesel hydraulic, and other tank, cover and panel joints, panel faying sealant, canopy and window sealing, and more.
I don't use it often but every mechanic should try a kit. Before the Air Force cared about expired kits the tool crib would give leftovers away and we had to share fairly since all the car and bike mechs wanted some. You can also find kits on Ebay and for personal ground use expired is fine. The fuel shop and structural folks taught me a great cure check trick. Save a blob from the kit you use, and when cure time is up cut the blob in half with a knife. If blob is cured so is your work. Applies to any cured sealant or epoxy.
https://www.aircraftspruce.com/pages...09-04493-4.php is my favorite. Insert plunger to spew dark into light goo, grab upper area with visegrip then turn clockwise and stroke. (Fuel shop had the cool mixer but on the line it's been done this way since at least the F4 Phantom era.)
If you clean a holed tank and its patch to clean,dry bare metal (they can be dissimilar metals in ground use since there's no contact) the stuff will reliably patch fuel tanks. ABDR (Aircraft Battle Damage Repair) teams keep lots of it handy.Last edited by farmall; 11-21-2019, 9:36 AM.Comment
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if ya have any problems contact Dave at Morris Magneto 973-540-9171
or email him at ….. [email protected]
well worth a visit to his shop,... he's been building and fixing them for close to 45years now,... great fella.
As ya only on Long Island its only in Morristown NJ,.... which is about 30 minutes in from Hoboken once ya on the mainland ….,...Comment
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Aircraft have two mags to combat detonation, which would blow a head or cylinder apart quickly. the fact that it has some redudency is a slight convience. Aircraft cylinders are rarely bored out, but chromed back to size or replaced.Comment
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You can have expensive bike cylinder bores replated/recoated and ground to size too.
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