Naming Magnetos

Slick Goodlin · Mon Mar 29, 2021 9:16 pm

So here’s the situation: project has an airplane engine that has been physically flipped upside down meaning that what used to be on the left side of the engine is now on the right and vice versa, including the two magnetos. Ignition control is via two toggle switches side by side. Which switch would you wire to which mag?

It’s not necessarily as simple as it sounds. At first blush it should be as easy as left switch to the mag on the left side of the engine. Makes logical sense and a dumb mechanic (like me!) can troubleshoot issues in the run up or whatever. However, only one mag has an impulse coupling which informs certain maintenance and operational procedures so now by going physically left and right I’ve just sabotaged my future wrench-turning self so perhaps I should consider them carb-side and offside then confuse the hell out of myself later when I have to clean or replace one set of plugs.

What are your thoughts?

David MacRay · Mon Mar 29, 2021 9:52 pm

Interesting, I think it is still the same you look up at them instead of down but I kind of get where someone is going to think it needs to be more complicated.

Mag 1 and Mag 2?

You could stamp them if you want to get fancy.

Liquid_Charlie · Tue Mar 30, 2021 2:05 pm

yup numbering is better just like engines, left, right, port ,starboard has always been a poor system.

digits · Tue Mar 30, 2021 3:33 pm

This is a cool question. Could you physically install any engine upside down (with some minor tweaks)? If so, why is that not standard practice for lycomings, so the corrosion prone camshaft would be drenched in oil all the time?

Slick Goodlin · Tue Mar 30, 2021 5:15 pm

digits wrote: Tue Mar 30, 2021 3:33 pm This is a cool question. Could you physically install any engine upside down (with some minor tweaks)?

Of course. The big changes are to the oil system and carb/manifold and generally where you see it most is when a WWII-era inline engine gets flipped over to install in a WWI-era replica. It’s also done a bit on some old race cars.

It would be somewhat silly to turn a horizontally opposed engine over and get stuck with a carburetor and muffler sticking out the top of the cowl but hey, you do you.

digits wrote: Tue Mar 30, 2021 3:33 pm If so, why is that not standard practice for lycomings, so the corrosion prone camshaft would be drenched in oil all the time?

I believe what you want is a Continental. Thread drift, a part of me wants to see if Lycoming cylinders can be adapted to a Continental case to put the intake and exhaust manifolds on top of the engine for a low, low monster engine in my eventual Porsche project. She’d look like a VW but at about 3 times the displacement. Yes, please.