Thorp Air Command - T18.net

David, what's your service record on the 18 mm threaded plugs, I see the ones that summit are carrying look like they are not plated, this can make them stick to alum threads if you don't use high temp never sneeze but I always use that anyway. In your 800 hrs have you had any glitches with the 2.00 18MM plugs by chance? Dan

Hi Bernie , thanks for the input, it sounds like you are happy with the E-Mag install, this is good. How long have you had your install, and, have you had any Glitches at all? I will Cal the guys at e mag tomarrow and ask about the plug adapters and there reasoning and I am sure they will have a plausible answer, I will report my findings so that all may join in on the info receiving. Are the bushings used to adapt the auto plugs a pain to use or anything of that nature? Thanks Bernie. Dan

I have had the P-mag for about 6 years. Have had it back to the factory about 6 times. Quite a few issues with going off of timing and intermittent operation. Last time I sent it back was about 1.5 years ago for intermittent operation. They could not duplicate problem but replaced one coil and that fixed it. Only have about 25 hours on it since then and no problems. I think they have got them pretty reliable by now. Not so much in the early days. They have always been nice to deal with on repairs. Guess they felt sorry for me always being broken down or stuck away from home with a bad ignition.

I had the aircraft plugs and harness till 25 hours ago. When I put in a new engine, I switched to auto harness and plugs. The adapters work fine. The instructions say "do not torque just the adapters". You put the plug in the adapter and then tighten both together using the socket only on the spark plug. No problems with the adapters as far as I know.

Same P-mag on new and old engine. Only difference is old engine had aircraft plugs and new has auto plugs (just talking about p-mag). I get more rpm drop during the ignition check now (when mag is off and running just on p-mag) than I used to when running aircraft plugs. Don't know if it has anything to do with the plugs, just an observation.

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Bernie Fried
N18XS

Scott, Have you any troubles with the P-mag or the 18 MM Plugs, what is your history with this setup would you say it has been a good experience? Thanks Scott, Dan

Scott, Have you any troubles with the P-mag or the 18 MM Plugs, what is your history with this setup would you say it has been a good experience? Thanks Scott, Dan

Is anyone using auto fuel with this setup by the way??? Dan

I usually run the plugs for 100-125 hours or so. If I think I have a problem I have replaced them sooner because they are so cheap but I have run them for a year at a time more than once. I always use antisieze on the threads and make sure the screw on tops at tight, then torque the plugs at 25 ft-lbs. I have been running 91 octane auto fuel for years now, I only burn 100LL away from home. FWIW I dump a bit of MMO in the fuel every time as well. Who knows, maybe I have just been lucky. DR

'Feisty' has an O-290G conversion. with 7:1 O-290D pistons. It runs fine on 87 octane ethanol free mogas, as it did for the previous owners.
I think the 18mm Autolite 385 plugs I installed with the Pmag are doing fine, however, they are on the hot side, and are clean and white when I pull & inspect them. They seem to be OK in a 125 HP O-290 with 7:1 compression, but I've read about problems when used in an O-360 with higher compression, so I use adapters and NGK BR8ES plugs in the O-360 on my RV-8.
The T-18 does run on the cool side, with CHT around 320, but it used to be about 20 degrees cooler when I was running 2 magnetos.
I don't have much mogas experience with the Pmag. I've been using mostly 100LL lately.

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Scott Emery
EAA Chapter 326
T-18 N18TE

Good Info Guys all the way around thanks much. This will be my 4th year running auto fuel, I run the mid grade and when it gets cheap then I run the Premium, 4 OZ of MMO per 10 gal of fuel when I fill up at home, 100LL when away from the house, all seems to be well and no fouled plugs. Well, I called Brad Yesterday and asked about the 18MM Plug anomalies, he just stated that they had a few reports from a few customers that had some bad luck with them. The conversation did not get real detailed but I said I would report what was said. I then went ahead and ordered a new P- Mag, so I should see it arrive here in the next 4-5 days or so. The last time I had spoken with them was in 2009 and it was still on there records. I will do the Install before long and give a results report when finished, In the meantime I will probably Pester the snot out of all that run electronic so be prepared for what could possibly be some of the dumbest questions you have ever heard........Dan

Good information for sure.

One question, since each P-mag can and does have its own alternator. Can any of that electrical output be tapped into in order to run say a GPS or other electronic instrements?

I'm sure that is not what it was designed to do. But to keep something like a GPS or an ipad running in the event of electrical failure as a back up redundant system would be a reassuring feeling. I don't think a GPS/ipad have a huge power drap per say.

I run one Pmag and one magneto on both my T-18 and my RV-8.
I'm not on their payroll, but I do like and use their product. I think you will like it.
When setting it up, use the less advance option which is controlled by whether a jumper wire is installed or not. You can change that later, but for now you want to be conservative.
Even in the 'less advance' mode, there will be more advance than the magneto at full RPM & power. The Pmag will give near Zero advance for starting, and add advance with RPM so the engine can idle more smoothly, even if there is still one magneto. I replaced the Impulse Coupled magneto, so the magneto adapter ring is removed and long studs removed or spacers made for under the nuts.
Pmags require hold down clamps, my oldBendix mags have mount ears, so I made new clamps, but Emagair sells these now.
'Feisty' picked up about 20 RPM top speed with the addition of the Pmag, and at higher altitudes or reduced throttle, the Pmag adds some advance where the increased fuel economy is realized.
Pmag internal alternators are sized to meet their load and remain isolated from the rest of the aircraft for obvious reliability reasons.
If you want a back up alternator, B&C makes a nice unit that is driven from the Vacuum pump pad.

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Scott Emery
EAA Chapter 326
T-18 N18TE

More good advice thanks Scott......The alt in the p mag will power the mag and nothing else, I use a DC Charger hooked up the the AC elec system. The I pad stays fully charged when in use, this will allow to kiliing the panel and having a fully charged GPS........not much of a plan but at least will allow some Before the batts gone.....Dan

I got my P-Mag in week before last and finally got it installed, the install was uneventful and very straight forward, simple and the instructions were very clear and left nothing to the imagination. The folks at P-mag are the best and I cant say enough good about them. Anyway, Got it all hooked up and timed( the timing is so simple it is really ridiculous)and rolled it out of the Hanger. One shot on the throttle, cleared the Prop and it lit right up and ran smooth as silk. I ran it for a bit on the ground, I have a switch that powers it up so I ran my Idle at about 750 rpm( by my tach anyways) and I cut its 12V juice from the AC electrical system, it just kept right on running smooth as silk. I did go for a short flight but I ran outta time and had to cut my morning short so my observations for this short flight were: Smoother Idle, super easy start up, a little more static Rpm which makes for some faster acceleration, and it really makes a difference in smoothness when you pop the throttle to it. I am going to try to fly some at altitude this weekend and will report again what I find or at least offer up my opinion of this rig. I can say in short at this point, I like it!! I can just Imagine what 2 of the little devils would do for the Lycoming....... Dan