INTERNAL AND EXTERNAL MAGNETO TIMING
Introduction
For an engine to work correctly, many processes should be followed sequentially. The engine has a cylinder that should be close at the top of its compression to enable it to fire. Both the intake and the exhaust valve have to be closed. In the magneto part, there should be an E-gap. For the engine to function fully selected wires from the magneto distributor, have to be connected to the cylinder in the engine and a fresh air charge. Magneto timing is mostly done internally in the magneto and then set to the engine. Some things are set or installed for the timing process to be successful — this includes; distributor alignment, rotor cam, and the E-gap adjusting the points to just open. Magneto timing can either be internally or externally.
Internal magneto timing:
In an engine, when replacing or fixing the magneto for the first time, some things have to be considered for the internal timing of magneto. The operator has to ensure that an E-gap is placed correctly which is acquired when the magneto rotor at the E-gap position are fully aligned when the break contacts begin to open. In aircraft, there are three main processes where you can place the magneto fully to enable it aligning with the timing mark (Sterling & Moore, 2001). There are different forms of magneto models, but for each model, the manufacturer determines the central position where the rotor will attain the strongest spark at the pointy of a breakpoint separation.
In one of the models, a step is set at the break came to enable the internal timing. A straight hedge is laid on the cut, and it meets with the breaker housing timing marks. This places the magneto rotor at the E-Gap which in turn makes the contact points of the break to just open.
In model two, the timing mark is placed alongside the chamfered tooth, and this makes the breaking points to start opening, therefore, checking the E-gap (Shiao & Cheng, (2016).
In another model, the rotor and E-gap are considered fully functional when there is a timing pin in place, and red marks are seen through a vent-hole.
External magneto timing:
When the E-gap is correctly placed and fully functional an external timing is done. The external timing is done when the magnetos are placed on the engine, and the ignition timing is set correctly. Mostly external timing is checked using schedule light. External timing is very crucial to engine performance as well as its operation. Monitoring of the timing should be done after every 100 hours (Mehnert, Hossain & Steinmann, 2017).
The criteria involved are;
First, there is the establishment of the top-dead-center position (TDC). This is achieved when a spark plug in the first cylinder is removed, and the crankshaft is rotated to attain the specified position and in this case the TDC. The crankshaft is then rotated to the desired firing position which is 20% before TDC (John Pons, Douglas Pons & Jasper Pons, 2014). Lastly, using the ignition timing light as mentioned earlier the magneto is functional making the breaking points open at the expected firing position. Rotating the entire magneto on the mounting pod until the breaking contacts start to open creates a full adjustment of the magnetos.
The main purpose of both internal and external timing is to ensure that the engine and the magnetos are fully functional. Magnetos may be a part that is mostly ignored but can lead to engine breakdown. According to an article on the Avweb website, improper application of this timing may lead to engine failures such as loss in power and rough running or even total breakdown.
References
Mehnert, M., Hossain, M., & Steinmann, P. (2017). Towards a thermo-magneto-mechanical coupling framework for magneto-rheological elastomers. International Journal of Solids and Structures, 128, 117-132.
John Pons, D., Douglas Pons, A., & Jasper Pons, A. (2014). Differentiation of Matter and Antimatter by Hand: Internal and external structures of the electron and antielectron. Physics Essays, 27(1), 26-35.
Shiao, Y., & Cheng, W. H. (2016). PERFORMANCE INVESTIGATION OF AN SI ENGINE WITH VARIABLE VALVE TIMING AND LIFT BASED ON A MAGNETO-RHEOLOGICAL VALVE. Transactions of the Canadian Society for Mechanical Engineering, 40(5), 749-760.
Sterling, A. C., & Moore, R. L. (2001). Internal and external reconnection in a series of homologous solar flares. Journal of Geophysical Research: Space Physics, 106(A11), 25227-25238.