The readings for the two plug caps should now be swapped around. old-style capacitor (the 'condensectomy') and Common Faults on Magnetos load correctly in the translated versions of the pages. SR1, SR2 & SR4 magnetos (workshop instructions) Feel free to buy the forum staff a coffee or pint or just make a contribution of your choice. This can mask a fault on these cars as the vehicle will continue to run until the other fails. If you are sure that all earth brushes are removed, and if either the magneto has a fibre drive pinion or the drive pinion/sprocket has been removed, you can now check the effectiveness of the bearing insulators. You are using an out of date browser. detailed guide to maintaining and If your magneto does not have an EasyCap but it fitted with a condenser buried in the armature, then it is impossible to check the condition of the condenser, while the armature is assembled, without specialised equipment. a separate spring-loaded holder (Lucas) or hidden at the back of the contact breaker plate (BT-H). classic owners. Magnetometer for measuring magnetic flux density at the centre of the armature cavity Measurement before remagnetisation Remagnetiser . An ignition magneto (also called a high-tension magneto) is an older type of ignition system used in spark-ignition engines (such as petrol engines). of which is the product of Brightspark Magnetos Ltd's I'm thinking the magneto is weak even though it was rebuilt with new condenser.. Pick-up brushes of the highest not load correctly in the translated versions of the pages. books. In this series of pages, well take you through the main things. As the size of the combustion chamber determines the time to burn the fuel charge, dual ignition was especially important for the large-bore aircraft engines around World War II where it was necessary to combust the entire fuel mixture in a shorter time than a single plug could provide, in order to build peak cylinder pressure at the rpm desired. With the engine running, place your hand over the pick-up with the same hand also touching the magneto body. Replace the cam, ensuring that the notches in it engage as before (e.g. Measure the resistance with the two probes of your multi-meter shorted together. However, if the reading is more than 7000 ohms, there is probably either a break in the HT winding, or a bad connection between the live end of the HT winding and the slip-ring. If you are having trouble with your ignition system we recommend that you first change your spark plugs and HT leads. In the inductor magneto, the magnet is rotated and the coil remains stationary. Rotate the armature until the contact-breaker points are open. patterns for shims, gaskets and bearing And a f-ing video! 0000002409 00000 n Over time the HT leads can degrade and reduce the potential difference at the spark plug. MAGNETO MAGIC - PressReader BTH mags utilized condensers made from mica. . With twin- or multi-cylinder magnetos, and some single-cylinder magnetos, the brass is a segment, rather than a complete ring, and you may need to rotate the armature in order to be able to see it. Clean and grease the moving-point pivot. Sign up for a new account in our community. 0000003086 00000 n Replace if necessary. 82 0 obj<> endobj I highly doubt it is excessive unless someone has been grinding the rotor or the cap. Pick-up brushes of the highest quality are also available, of the correct grade to avoid carbon deposits on the slip ring. i totally agree. 0000001320 00000 n xref Rotate the armature and check that, when the points are fully open, the moving point assembly is not fouling anything. We A really nice one will jump 1/2"or better. PA. The points surfaces should be very slightly convex, so dont worry about getting them perfectly flat. One or more times per revolution, just as the magnet pole moves away from the coil and the magnetic flux begins to decrease, a cam opens the contact breaker (called "the points" in reference to the two points of a circuit breaker) and interrupts the current. In more modern times, insulation materials have improved to the point where constructing self-contained magnetos is relatively easy, but energy transfer systems are still used where the ultimate in reliability is required such as in aviation engines. We can adapt for most applications. Are suppressors and resistor sparking plugs OK to use with magnetos? Trouble starting my 1924 Citroen engine. 1. I tested the HT wire and spark plug and both are fine. If you havent already done so, undo the contact-breaker centre-screw and remove the contact-breaker assembly. Take a look at some of the equipment we Trademark Office. and overhauls. You must log in or register to reply here. There is no wire hooked up to the cap. Check for wear and replace any worn parts. [7] Ignition magnetos were largely replaced by ignition coils once batteries became common in cars, since a battery-operated coil can provide a high-voltage spark even at low speeds, making starting easier.[8]. Likes: 260. scotland. If you do not obtain readings substantially the same as the reading you obtained in the internal HT continuity section, and if everything else you previously checked is still good, it indicates that the pick-up brush(es) is/are not making good electrical contact with the brass of the slip ring. instruments available for immediate use, and a Not quite as large as ideal, but simple. It uses a magneto and a transformer to make pulses of high voltage for the spark plugs.The older term "high-tension" means "high-voltage".Used on many cars in the early 20th century, ignition magnetos were largely replaced by induction coil . Gift Article. BTW, Michael, that's a darn clever trick/solution! 0000006372 00000 n If your magneto is loosing spark after a short amount of time running, or is hard to start it is most likely a condenser failure. Built into the case of the magneto are magnets, permanent magnets. Don't want this buried as I 'm hoping for some possible answers today. Brightspark Magnetos Ltd disclaims responsibility for any Re-install the contact-breaker assembly, ensuring that it registers properly with the armature shaft. If necessary, dress the points on a fine stone. i have had 3 done here by ed strain that included rebuild with remagnatized body for a little more than $200.00. Click Here to view Lucas face cam (magdyno) parts manual. We shall resume operations as soon as we possibly can. The reading will probably be a fraction of an ohm. 0000001569 00000 n Since the beginning of World War I in 1914, magneto-equipped aircraft engines have typically been dual-plugged, whereby each cylinder has two spark plugs, with each plug having a separate magneto system. Still here since 1996 serving BritBike enthusiasts. Not sure what came off, but 1930s/40s I would have thought.prefer collection, but would post. The ratio of turns in the secondary winding to the number of turns in the primary winding, is called the turns ratio. With the mag on the engine, there is a spark at all 4 plugs . These faults do not necessarily occur instantaneously, they may develop over time leading to a gradual deterioration of the spark output. After 1 hour or so the bike can be started again, but the ignition fails again after riding about 20 miles - not a pleasent way to ride! If it is significantly higher, there is a bad connection or break in the low-tension circuit, in which case the magneto will need a more complete overhaul. In the case of a main-body earth brush, try moistening a cotton bud with petrol, and poke it through the hole for the earth brush to clean the track while rotating the armature, but IMPORTANTLY before doing that temporarily remove or disable the contact breaker to reduce the risk of electric shock and fire. The plugs are non resistor, gaped at -025", and are new. Downloadable drawings, all for free, for All rewound units now have modern condensers and enameled wire. Put a smear of grease on the tappet shaft. Disassemble the advance/retard mechanism carefully noting which part goes where. At atmospheric pressure, the voltage required to strike a spark across the 0.020 (0.5 mm) gap of a sparking plug is far less than the voltage required at the elevated pressure that the plug experiences in the engines cylinder. She was factory fitted with a Morris Vedette MKII engine which has a lucas rf4 magneto. [3] The capacitor's function is similar to that of a snubber as found in a flyback converter. As the magnet moves with respect to the coil, the magnetic flux linkage of the coil changes. Franaise Deutsch If the brass is black, it indicates that the brush(es) are too soft and/or years of neglect. Capacitors, which are short-term storage devices, often fail in older magnetos due to dielectric degradation (short circuit) or conductor breakage (open circuit). (Chinese) In the late 1890s, English engineer Frederick Richard Simms and German engineer Robert Bosch developed the first practical high-tension magneto. Capacitors are replaced with ones that have a longer life expectancy and greater reliability. A capacitor is placed across the points which absorbs the energy stored in the leakage inductance of the primary coil, and slows the rise time of the primary winding voltage to allow the points to open fully. You need to confirm that the condenser has failed AND that replacing it will solve the problem. Norsk Without suppressor: suppressor: Percentage difference with suppressor: Peak HT voltage to initiate spark: 9600 V: 10600 V at magneto: 10.4 %: 9300 V at spark gap-3.1 %: DC component of HT current immediately after striking spark: 53 mA: 52 mA-1.8 % I have seen several condensers during that time whichwork for the half but will not generate the field collapse andfire the plug . 2. To do this, measure the resistance between the magneto body and the end of the armature shaft. If it is several thousand ohms, it indicates that the HT lead is resistive and/or the plug cap is fitted with a suppressor resistor. I do not know it all but I will try to help. Magneto parts We also sell our Brightspark range of specially-selected, top-quality, British-made slip rings and pick-ups for Lucas and BTH magnetos. 0000001015 00000 n many ignition systems, focusing especially on If you need more information, or wish to order by post or pay over the phone, please ring: 01273 913181. There are several common faults with magnetos The Capacitor Capacitors, which are short-term storage devices, often fail in older magnetos due to dielectric degradation (short circuit) or conductor breakage (open circuit). On more advanced magnetos the cam ring can be rotated by an external linkage to alter the ignition timing. In the type known as a shuttle magneto, the engine rotates a coil of wire between the poles of a magnet. Lucas workshop instructions - magnetos Library Robert Bosch Documentation American Bosch workshop instructions Patents Books and learnd papers Workshop instructions - Lucas magnetos N1, KN1, K1F, K2F, KVF MO1L, MN2L Redesigned contact breaker for ring cam models SR magnetos (general info.) The high voltage will simply arc across the gap. On many Rolls Royce models there is a dual ignition system. the brass is in the wrong place, as a result of a magneto with a segment-type slip-ring having an incorrect cam fitted or having the wrong direction of slip-ring fitted. Put 2 hours of flawless time on the bench. B Magneto Help - No Spark - Britbike forum The place to buy our EasyCap condensers Coil may still function somewhat and not completely failed but ratio of turns lost because of insulation breakdown. From time to time we have complete Check the state of the heel of the moving-point assembly. If it does not jump 3/16" it probably will not fire a cylinder under compression. pouvons vous aider soit en franais, soit en Please phone or email for details. Just to reinforce a point here of something very well done that you did in the how-to: when you're testing a mag like this, ALWAYS have the plug wires hooked up with a gap (or plugs) to ground so that energy has somewhere to go. We will check all the parts of the magneto for faults and will provide a firm quotation for a repair along with a description of the magneto repair required. read more deeply). Or what else could be causing this? Because it requires no battery or other source of electrical energy, the magneto is a compact and reliable self-contained ignition system, which is why it remains in use in many general aviation applications. I can never stress this enough to people who try to test out their mags. We provide Make a note of the reading; youll need to refer to it later. The likely culprits are: Set the timing of the ignition in accordance with the machines handbook. The plugs all light when loosened, but not when installed. Lucas (and most other) capacitors made in the 50's & 60's used a paper dielectric. Do similar tests with the HT lead(s) and the plug-cap(s). With your multimeter set to display resistance and connected to the opposite faces of the circuit board of the EasyCap (and with your fingers touching no more than one side of the circuit), the meter reading should climb up from a low value until it goes off the scale (OL). if it doesn't jump 3/16" double check the points to see if they are shiny clean the whole face of each point. 0000002602 00000 n Your mag likely has a bad condensor. I would be interested to hear from people who either have seen this running or know of similar setups in forges.

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