Help! P-mags makes my engine run rough!

[Steve Sampson]

Originally Posted by lostpilot28

...I did not install any blast tubes yet. Is this required?

Sonny, If you look in the docs you will see blast tubes are required. If you go here, scroll down to the last picture, and double click it so you get a larger view, you can just see the right hand corrugated plastic tube. You must aim it at the thinnest bit of the neck. I spoke to Brad (E-mag ignitions) about this and he emphasised that many of the units that came back with faults had been overheated (They record the hottest temp they have seen in the software.). I also have temperature sensitive stick-ons on mine that should go off at 93C. They havnt gone off and have worked superbly, but then I only have 16 hours on the aircraft.

AFS have indicated they will implement the EICAD software on their unit. It will be great if they do because then those of us with P-mags and the AFS 3x00 can read the P-mag temps, presumably, in flight. I think that will really show the faulty units as being subject to higher than normal temps, but it is just a guess.

I also am concerned that they must get quite hot when the engine is shut down.

[Davepar]

I'm guessing this was already discussed, but why point the tubing at the thinnest part of the neck instead of the little screen area?

[N941WR]

Alf,

Great news on your first flight, congratulations!

After one of your flights, did you check the timing on the left (and right) P-mags while they were still hot? If so, did you notice any problems?

You mentioned that you had them back for "upgrades", did they also do the magnet retention upgrade? The early P-mags had the timing magnet attached with epoxy and they have an upgrade to replace the epoxy with brass retainer and screws. Heat can cause the epoxy to fail, thus this upgraded is also required.

I suspect that when you switched them left and right, you didn't move any of the plug's. But please verify the routing of the plug wires and make sure they are not touching any metal structure.

Are you running auto or aviation plugs?

As the others have mentioned, blast tubes are required. There are pictures of my installation on my third engine page (http://www.repucci.com/bill/engine_pg3.html).

BTW, I'm up to 181 trouble free hours with duel P-mags. BTW, my first flight was August 5, 2007. Like you, I had a problem on my 2nd flight, sent both P-mags off for the upgrades and never looked back.

[N941WR]

Alf,

After re-reading your post, I find it difficult to believe your CHT's and EGT's were "OK". Could you post those numbers?

If a P-mag (or any mag) looses it's timing, the CHT's typically sky rocket.

Is it at all possible that the offending P-mag was not clamped down and moved just enough to through off the timing when it heated up and moved back when it cooled down?

[lostpilot28]

Originally Posted by Steve Sampson

Sonny, If you look in the docs you will see blast tubes are required.

Thanks Steve...your picture was very helpful. I've heard that the P114 series of P-mags have fins on the chassis. I'm not sure why the neck area seems to need more cooling than the rest...any thoughts on this? Is this area where the cooling fins are located on the new 114's?

Makes me wonder if cooling fins could be retro-fitted to a P-113 to assist in cooling.

[Steve Sampson]

Originally Posted by Davepar

I'm guessing this was already discussed, but why point the tubing at the thinnest part of the neck instead of the little screen area?

Dave, for no other reason than Brad at E-mag ignitions is very insistent that it is the correct place; not the screen. It is counter intuitive I know.

If you talk to him, he is concerned that too many owners dont have blast tubes set up as described in the docs.

Steve.

[ao.frog]

Hi again.

Thanks for all the inputs folks!

I'm finally back home after 5 days at work, so it's time to focus on the RV again.

Here's some answers to the questions:

I don't know which upgrade I got when I sent P-mags to Brad in April this year, but at least by that time, they got the latest upgrade. Does anyone know if there is a newer upgrade out?

I've only flown one trip (lasted 2 hrs) so far, and I've not yet swopped P-mags or anything else because I wanted to talk to Brad first.

Tomorrow I'll verify plug routing, wiring and timing.
I'll also check if it's possible for the P-mag to move when it's heated up.

I'm running the autoplugs and wires which the P-mags came with.

Below is two pics taken during the first flight.
The first one is take after 36 minutes and the second after 73 minutes.





You'll see that there's no RPM-indication.
The indication quit showing above approx 2000 RPM during takeoff and showed up again during taxi in.
I had just installed the "RPM-board" from AFS, so I was thinking everything was ok.
I had however, brought along a digital RPM-counter and had taped it on top of the glareshield. So that's what I used during the flight.

The oilpress was at 50-52 for the entire flight, but I was expecting 80-90. This can be an indicator problem. I'll check that out tomorrow too.

The CHT for #1 seems alittle low, but I guess it's too early to start experimenting with alu-tape?

So: any thoughts folks?

PS: I've not yet been able to reach Brad on his cellphone, but I'll keep trying...

[ao.frog]

Hi.

Here's an update on my P-mag problem:

I was finally able to reach Brad on his cellphone (bad cellphone coverage at OSH) and he was VERY helpful, (as always!)

He said that the problem is most probably a faulty circuit board in the left P-mag.
He said my circuit board probably had a problem with it's "power delivery system", since the P-mag is running OK when on it's own power.

Therefore I'll probably send in the P-mag to him for exchange of the circuitboard.

Soooo... it seems like the problem is identified and hopefully solved soon. Stand by for a final update after the swoop.

PS: I'd like to add that the engine is running VERY smooth when both P-mags works ok. It's almost humming! It's no doubt the smoothest engine I've ever flown behind...