S

Steve Brown

Well Known Member
I'm trying to perform the check on my E/P mags in the least invasive way and hopefully without breaking anything. Check this link for background:
Bulletin 09/12/08
I've got 113s
The concepts of what I am trying to do are perfectly clear to me, but due to my wrenching lameness, I'm having some difficulty with the actual doing.

Questions for those who have done this:
Am I going to have to pull the mags out to do this check?
What optical tool, if any, am I going to need to look through the slit and see the mechanics?
If I need to pull the mags, any precautions to keep from screwing up the timing?
Any other words of wisdom?
 
Steve,

If you haven't had your 113's back for service since last fall you will probably need the updates.

For $25 it is well worth it to remove them and send them in for the update.

BTW, it shouldn't take long, Emag Air turns them around quickly.
 
Steve
its not clear from your post why you would need to check the mags to see if the service bulletin was done - did you recently purchase the plane and are unsure if the previous owner had it done? If so, it may be as easy as getting the serial numbers of the units and calling emag to see if they have a record of it.

If you still need to do the check, removal of the units is not too difficult - loosen up the two mounting nuts, and they will come right out. Be careful to have enough slack in the wires for handling when you pull them off - you can then remove the wires either individually with their individual clamping screws or as a group by unscrewing the receptacle where they enter the unit.

You will need to retime them when you replace them, but thats very easy with the blow-in-the- tube method, following the instructions in the manual, which I believe is available on their website.

Buckle down and do it if you need to - you will learn how, and next time you wont think twice about it. Get Brad at Emag to talk you through it if necessary

erich
 
Thanks guys & more questions

As suggested, I bit the bullet and just pulled the mags to send them in.

They are held in with a bracket, I'm guessing that has some springiness.

How many ft/# do I torque them back down?
Any special precautions?

I noticed that unlike every other important bolt/nut in the airplane, there is no safety wire or cotter pin, only a wimpy lock washer.

Is this normal?

Other words of wisdom?
 
Steve,

Those are 5/16" 18 TPI studs. The nut gets torqued to 204 In lbs / 17 Ft lbs.

The stud should be torqued to 25 Ft lbs, if it comes out.

No safety wire required but I do replace the internal star washer every time I pull mine.
 
Consider using an all-metal lock nut instead of the standard issue for peace of mind. Do not use a Nylok - no good for high heat areas.

erich
 
Assuming the PMags use the same engine studs as a standard magneto, you should NOT use metal self-locking nuts. Just use standard hardware with lock washers, and use some torque seal. If you use self-locking nuts, there is the potential for the studs to back out when loosening the nuts.

Vic
 
Thanks again & more questions

17 ft/lbs, replace washers, use torque seal. Assume "star" refers to toothed washers.

Any preference between internal verses external teeth?

One mag has bolts, the other has studs and nuts. I didn't notice any way to get hold of the studs to tighten them. Maybe I missed it.

I have no reason to believe they are loose, but how do I get hold of the studs to check torque?

What flavor of torque seal is recommended?

More ignorance on my part, but I was shocked at the seemingly haphazard way these guys attach to the block. I've never heard of a mag falling off a motor, so I guess its more robust than it looks.

Thanks again!
 
torque for hold down nuts

Those are 5/16" 18 TPI studs. The nut gets torqued to 204 In lbs / 17 Ft lbs.
Click to expand...

I use 150 in-lbs based on following:

The hold down studs for E/P-Mag are same as used for standard mag installation. Lycoming overhaul manual has 150 in-lbs as torque limit for 5/16 nuts, which is consistent with article posted on Sacramento Sky Ranch article on mag installation that states "....tighten the magneto hold-down nuts firmly (maximum torque is 150 inch/lbs., minimum is 110 inch/lbs.) "
 
OneCharlieKilo said:
I use 150 in-lbs based on following:

The hold down studs for E/P-Mag are same as used for standard mag installation. Lycoming overhaul manual has 150 in-lbs as torque limit for 5/16 nuts, which is consistent with article posted on Sacramento Sky Ranch article on mag installation that states "....tighten the magneto hold-down nuts firmly (maximum torque is 150 inch/lbs., minimum is 110 inch/lbs.) "
Click to expand...

Chris,

Check Table I on the Service Table of Limits, Standard Torque in the Direct Drive Engine Overhaul Manual, page 1-37 in my manual.

It lists the torque for 5/16 threads as 204 in-lbs/17 ft-lbs and Table V lists the minimum driving torque for the studs as 25 ft-lbs.

In checking the Lycoming manual again, I could find no reference to 150 in-lbs.
 
Check Table I on the Service Table of Limits, Standard Torque in the Direct Drive Engine Overhaul Manual, page 1-37 in my manual.

It lists the torque for 5/16 threads as 204 in-lbs/17 ft-lbs and Table V lists the minimum driving torque for the studs as 25 ft-lbs.

In checking the Lycoming manual again, I could find no reference to 150 in-lbs.
Click to expand...


I think we're just looking at manuals for different engines Bill. I see you have an O-290 and I'm looking at the Lycoming manual for O-360 and O-540 series engines. Section 10 "Torque Limits" in my manual lists 150 in-lbs as max torque for 5/16" nuts and capscrews. The 110-150 range I mentioned is in Sacramento Sky Ranch's article on Slick mag installations using same nuts on same studs as for P-Mag installation.

Does seem odd to me that different size engine manuals would have different torque limits for same size stud/nut....maybe somebody else out there can explain that.

In any case Steve, I'd probably take a look and see what the O-320 manual says for your setup.
 
OneCharlieKilo said:
I think we're just looking at manuals for different engines Bill. I see you have an O-290 and I'm looking at the Lycoming manual for O-360 and O-540 series engines. Section 10 "Torque Limits" in my manual lists 150 in-lbs as max torque for 5/16" nuts and capscrews. The 110-150 range I mentioned is in Sacramento Sky Ranch's article on Slick mag installations using same nuts on same studs as for P-Mag installation.

Does seem odd to me that different size engine manuals would have different torque limits for same size stud/nut....maybe somebody else out there can explain that.

In any case Steve, I'd probably take a look and see what the O-320 manual says for your setup.
Click to expand...

Chris,

They are the same manual, or should be.

The Lycoming Direct Drive Engine Overhaul Manual applies to all direct drive engins, from the O-235 up to the IO-720. There is a Parts Catalog that is unique to each engine, in my case that is for the O-290-D Series engine. However, the torque values I listed came from the Overhaul Manual and applies to all engines. Which manual are you using and how current is it?

After checking the manual again I found a torque values for the "Magneto Nut (To attach drive member ot magneto) - ..."

These torque values were in the range you mentioned but are for attaching the drive gear to the magneto shaft, not to attach the magneto body to the accessory case.

The 204 In-lb / 17 Ft-lb torque value for securing the magnetos looks to be correct.
 
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Thanks for the clarification Bill. It seems that there are multiple versions of overhaul manuals with some slightly different numbers. 150 in-lbs vs 207 in-lbs on a 5/16 stud doesn't seem all that significant so maybe more recent versions have updated numbers.
The overhaul manual I have has a pretty old publishing date (Lycoming approval signature page was signed in 1960) and is specific to O-360 and O-540 series. It shows 150 in-lbs as max torque for 5/16 nut.
As you mentioned, there is a range listed in same torque limits table for the 3/8" gear attach nut but that's not the range I mentioned in earlier post - the range I mentioned is the range specified by the Sacramento Sky Ranch article that is consistent with a max torque of 150 in-lb for the mag hold down nuts. That's a pretty reputable knowledge resource and they state:

quoted from article at:
http://www.sacskyranch.com/faqslickmagneto.htm

".....tighten the magneto hold-down nuts firmly (maximum torque is 150 inch/lbs., minimum is 110 inch/lbs.)."
Click to expand...

Side note on the gear nut torque; my overhaul manual table of limits has range of 180 to 300 in-lbs listed while the spec sheet that comes with the Slick mag I recently installed lists a wider range of about 110 to 330 if I recall correctly. It's secured by cotter pin so the wide range lets you get the hole lined up, but the 1960's era o/h manual I have does appear to be more conservative than what Unison recommends on their product.
 
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