R

roee

Well Known Member
I've never removed or installed a magneto before, so some of these are pretty basic questions...

Looks like each mag is secured to the accessory case with two clamps (top and bottom) that get tightened down on 5/16" studs in the accessory case. Is that all it is? Is there any special procedure to tightening these down, or do just torque them down normally? And if so, what's the torque spec for these? Is it 17 ft-lb like any other 5/16" fastener on the engine?

Now, about why I'm asking. I have P-Mags (already on the engine), which require blast tubes for cooling. But I see no good provision for securing the end of a blast tube to the P-Mag itself. So I'm thinking of using the top magneto clamp stud to also attach an adel clamp to secure a blast tube. Any thoughts on this?

Thanks,
 
For the blast tubes, I simply use some safety wire wrapped around the convoluted tubing and then tied to whatever is convenient to keep it pointed at the circular part of the P-Mag. On one side, that is the upper clamp bolt - no Adel clamp needed.
 
There are a number of ways to secure the blast tubes, including what Paul suggested.

Three other methods that I have seen, include using adel clamps, which is what I did, as can be seen here.

The second method is to wrap a long piece of safety wire around the neck of the P-mag, thread it up through the tubing, into the hot side of the baffles where it is secured to either a screw in plate nut riveted to the back side of the baffle or twisted on a small cross member that keeps it from sliding back down the tube.

The third method is to make a shroud that goes around the P-mag and holds the blast tube.

Pick what you feel is the best.
 
Thanks for the suggestions, Paul and Bill. I'm considering all those ideas, and variations thereof.

In principle, I actually like the shroud idea the best. A shroud that directs the airflow around a major portion of the neck of the P-Mag should, at least in theory, make the most effective and efficient use of cooling air. But the design of the P-Mag again doesn't easily lend itself to that. I'm thinking up different ways of making such a shroud, but I'd love to see some existing examples, if others have already come up with good designs for a shroud that are robust and reasonably easy to fabricate and install. Photos would be great!

BTW, I'd still be interested in the answers to my questions about the mag clamps, even if for nothing else than to satisfy my curiosity and pick up another potentially useful tidbit of knowledge.

Thanks!
 
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