P-mag install problem, what to do? (spacer or no spacer?)

Hi P-mag guru's.

Today, it was time to install the new 114 series P-mags in my new Lyc XIO-360 bought from Vans a couple of years ago.

The engine came with Slicks, so I took those out and thought it'd be easy to put the P-mags in, and that was true for the right P-mag: it went right into the hole.
The left P-mag however was a different story, because the left Slick had a spacer-ring installed beetween it and the engine-case.

First we left the spacer-ring in the engine-case and installed the left P-mag "on top" (behind) it, but then I started to think that the spacer-ring might position the P-mag too far aft?

Here's how they look:









You can see that the Slick has a longer "nose" than the P-mag, and I guess that's why it comes with this spacer:





If I install the left P-mag without that spacer, then both mags will go equally far into the engine.

The P-mag install manual doesn't say anything about this spacer, so the big question is: shall the P-mag be installed with or without this spacer?
(my gut feeling is the install it without the spacer, but I need to be sure ofcourse)
I'm planning to contact Brad at E-mag Air on Monday, but maybe someone out there in RV-land knows the correct answer?




Another question:

If the P-mag are to be installed without the spacer, the treaded pins in the engine will be too long so I need some spacers for the pins.
How have you guys solved that?

We testfitted the left P-mag and used a couple of nuts to get and idea how it'd be:





As you can see, those pins-spacers needs to be pretty long.

It's no way we can replace the pins by now (too little room to work with), so the pins needs to be used.


Good ideas appreciated folks.

Thanks!

Hi Alf...

because the left Slick had a spacer-ring installed beetween it and the engine-case

Click to expand...

This is because of the "impulse" unit between the Mag and the gear.

First we left the spacer-ring in the engine-case and installed the left P-mag "on top" (behind) it, but then I started to think that the spacer-ring might position the P-mag too far aft?

Click to expand...

Yes - the P-Mag fits fine like this, but unfortunately does not work Ask me how I know

If the P-mag are to be installed without the spacer, the treaded pins in the engine will be too long so I need some spacers for the pins.
How have you guys solved that?

Click to expand...

Either "bodge" it as you've done with extra nuts as spacers, or replace the studs with the correct ones. Getting the old studs out is an adventure in itself and there are threads on here about it.

The P-Mag manual does make clear not to use the Gear from the Impulse Mag on the P-Mag - just checking you have sourced the gear from somewhere? Brad offers to sell them, but rarely has any.

The P-mag install manual doesn't say anything about this spacer

Click to expand...

The manual I have [v19] does on p13:

Installation and Timing
Note 1: [Lycoming Only] If replacing an impulse magneto, you need to remove the magneto impulse spacer. Impulse magnetos are traditionally installed on the left side. The spacer is a roughly 1? section located between the magneto and the engine case. The studs that hold the spacer to the case will be too long for use with the E-MAG. You?ll need to replace the long studs with shorter ones, or simply use suitable length bolts (not provided).

Click to expand...

Hope that helps

The spacer was under the impulse coupled mag. It is not used for a P-mag.

Sad to say, you need to remove the long studs and install the correct length, as on the other side. Borrow the right tool, a purpose-made stud remover from a mechanic. Double-nutting isn't always enough friction and torque, and you've a higher risk of breaking the stud - that would be really bad news. The correct studs are a Lycoming part number. For that you'll need to do some research.

John Siebold

I?ll do the same in spring when it gets warmer and I already have the parts laying around. According my research all the above said is correct. On my receipt the studs have the P/N 31C-14 (0.3125-18 x 1.75 long).
I did some research on removing the old studs and it is probably best to have the correct stud remover. Also heat should help to get the bond softer.

Hi Alf - I agree with the others - you need to remove the impulse coupler spacer and the longer studs. I did this last year when I upgraded the Val to dual P-Mags, and yes, it took a little extra time to get the correct studs in, but not that long. I was able to borrow the correct Snap-On tool - it is not cheap, but very much worth it to do right.

Paul

At a minimum, I'd suggest you use a lock nut.
Using spacers on the studs is not dangerous, just heavy and unsightly. You could make lighter, more elegant spacers out of pipe cut to length.
Remember, every ounce you remove from the plane is another hamburger you can eat!
No! I was just kidding about the hamburger!
So you could operate with the long studs and adapters until you get the tool, the shorter studs, and some time to do it all, then have at it again.

Ao.frog send me dimensions !

I will make you aluminum spacers in the lathe if you send me dimensions. Or, I can just measure the impulse spacer on my 0320 and make them. Your call !..Larry at [email protected]

Thanks for the replies guys. Ok, it'll be without the spacer then.

Andy: you are absolutely correct: the manual says it on pg 13. STUPID ME who didn't read that far ahead!!! I just read the install-part in the maunual on pg 1 through 3 before we started the P-mag installation.

Regarding the studs: because of the tight space in that area, I can't see how it's possible to remove the studs, (no room for tools anymore) so I guess it'll have to be spacers.
We could ofcourse remove some wiring, oil-and fuel lines, governor bracket etc etc to make room, but I think we'll try the easy route first.

I think we'll take the spacer-ring, cut off the ring itself and make it into two spacers. Then put locknuts or use "teethwashers". Maybe some locktight too. We'll see.

Larry: thanks alot for the offer to make spacers. Very nice of you!
I'll keep that in mind if our attempt to make spacers from the ring doesn't work out.

I wish I had read through the whole P-mag manual before installing the engine!!! To replace that left stud with the engine sitting on the floor would've been a non-event....

Well, I guess that's the punishment for beeing over-confident...

Alf
You may need your spacer ring in future and they are not cheap. A hardware
store should have something you can use that would look and work better. A coupling nut like used to connect pieces of threaded rod is one possibiity. You can also buy ready made spacers that could be modified if necessary.

Alf...

We made a spacer using Al tube slightly drilled out, with (large) nuts outside. The nuts took the load, the Al tube kept it all in place / rigid.

Next time I had some time we got the studs out - but with difficulty. Good luck!

Remove the spacer and replace the studs with smaller ones. I would advise against adding spacers to the longer stud.

To remove the stud, you can use the stud removal tool. As Paul mentioned, SnapOn has one. The other option is to borrow one. Some auto parts stores may lend you one for a fee.

But what I did was to use the double nut method. That is to put two nuts on the stud and, using two wrenches, tighten them against each other. Then by putting the wrench on the nut closest to the engine, remove the stud. This was very easy for me. But some studs have been known to be harder to remove.

You can either order an exhaust stud from spruce or just go to the auto parts store and get a shorter one.

Stud Torque

Anyone have the correct torque when installing the shorter studs?

Thanks,,

About ready to dive into my dual P-Mag install,,