I have only 25 hours on the unit, but so far I am very happy with it. Starts seem quicker.

Michael Z Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

Right now Ive only got about 10 hours on it since install. At this time I am very happy, as soon as the engine starts it is smooth running unlike before where I had to wait a few minutes before everything started to settle down, seems to have more power though Im not seeing the fuel savings many have talked about. The install was painless and not as complicated as expected.

Randall A Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

Since acquiring/installing/flying 10 hours with the Surefly magneto in my PA38 112 Piper Tomahawk O-235 Lycoming engine. Ive seen smoother performance levels in EGT and CHT as per my JPI700. Now saving 1.5 GPH in Fuel flow with leaning properly on average. Im using fine wire plugs all around, which are recommended. To achieve the most efficient and effective use of the technology that Surefly magneto brings to the table.

Very happy so far. Relatively easy install, easier starts and much easier hot starts. I’m also seeing about .5-.8 GPH better in a Mooney M20E with an IO-360 at cruise. Also cooler CHTs.

Kirk A Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

The Surefly SIM4P is a great way to upgrade to electronic ignition without the fuss of using automotive spark plugs and having to replace your harnesses. Ive been so impressed with my SIM 4N on the right side, Ive decided to upgrade to dual EI with the SIM 4P on the left side. Dont forget to order a standard magneto gear as you wont be needing the Impulse Coupling for this installation.

Mike E Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

The future!

Jacques H Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

Installed a 24 volt Surefly on an 0-235-L2C on the right side of the engine. During unboxing of the componets, I was unimpressed with the 14GA wire and $1.99 fuse holder with a 10 amp fuse that was Critical to the operation of the Magneto. So, I am going to be dependent on a 10 amp fuse between me an a critical component required to keep my engine running. Not to mention a 1 amp continues drain on the battey while parked. Surfly recommends a battery minder to maintain the battery while not in use, other wise you have about 30 days till the battery is dead. The Surefly was installed as per their instructions, then test run. During the test run the Surefly Stumbled, then during the mag check it was found that the Slick Mag was not working, we shut down the engine, changed the bad slick mag with a brand new one. During second runup/test the Surefly mag tested bad and the engine was running on the slick mag. We shut down the engine, checked the fuse on the Surfly to find it blown, we changed the fuse on the Surfly and retested. During retesting the Surfly was dead and the Slick mag was functioning normaly. The SureFly was removed, boxed in orginal boxing and sent back. To date Aircraft Spruce has refused to issue a refund since it was installed, the Surefly was not working is clearly defective however, they have refused to process a refund.

Marvin M Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

Easy install. Great engine starts. Very smooth engine now. Will see if the fuel burn improves.

Norman S Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

If you have a fuel injected engine and it is hard to start, this will fix the issue! The prop only makes 2 revolutions and engine is running. Burns 1/2 gallon hour less at same power setting. Best money I have spent on my Arrow.

Scott S Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

Im extremely happy with the performance improvement from the SureFly ignition. Startup is a dream. IT will pay for itself by keeping me from replacing starters so often. This unit is installed on a Piper Cherokee with 0-320 and is used in a flight school. I was replacing starters too often during the cold weather. Startups are fast and easy now. This is the second one I have installed on an aircraft and happy with both of them.

Datchair L Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

Installed on O-200 engine. runs smoother, climbs better and there is about 50 rpm gain at full power. K. Petrov

Konstantin P Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

Impressed with the completeness of the kit. Everything needed for a straight swap from the old magneto is in the box, including screws, washers, 20g wire, crimp terminals, placards etc. Even more impressed with the performance of the Surefly ignition. Cold or hot, my 0-320 now starts like a car. Subjectively, it seems smoother with a little more power, even on the fixed timing setting. Looking forward to using the variable timing option in due course. Very happy.

Malcolm K Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

Been having problems staring the plane. The new magneto works perfectly and plane starts easily.

Richard D Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

We are phasing in these units in our club airplanes and are exceptionally impressed with them. All units so far are Impulse Coupled units. Starts are great and we are seeing notable fuel consumption reductions.

Pugetsoundflyers, I Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

Magneto was very easy to time and install. No time yet to run engine.

James R Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

Finally, a system that gives modern reliability to older engines. Swapped out my left coupled on my 65 Cherokee and the performance increase is very noticeable. Can not say enough good about how easy the install was or how well it runs. Also, it starts before the prop even makes one full rotation. I will not have another plane with a Surefly on it

Clifford M Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

This is the second Surefly Mag that I have installed. The first went on my own 150 and I used fixed timing. The second went on a PA28-180 and was set up for variable timing. In both cases the installation was straight forward. The engines, especially the PA28, start up quickly and run smoother than before the change. I can not attest to fuel savings for the variable timing install because we have not flown the plane much. The mag on the 150 has been on for a few hundred gourds without a problem. We are very happy with the improvement in engine performance, smoothness and quick starts. I can not think of a good reason not to switch one mag to electronic.

Chris G Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

My I A had issues with this I might have gotten a defective part we have another one on the way so hopefully it’ll work I’m excited to see if it’ll make my io360 perform even better than it already does

William D Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

Fitted the SureFly after having a Magneto issue ! Early days yet but starts easier and runs smoother.

Mark F Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

installed recently on a 172 . super easy start. a slight increase in climb performance not sure how much we save on fuel at cruise . no regret so far

Kootenay L Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

It’s as close to magic as you can get in aviation. Hot starts not a problem. Smooth at idle. I get about 500 rpm more at takeoff.

Mark S Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

PA 30C Twin Comanche (fuel injected, non turbo not CR props). SIM4P configured for variable timing installed on left engine (critical), left magneto. Before fitting the eMag TAS indicated on the Aspen PFD had been 187 mph for many years, FL 080, 2,200 rpm full throttle, peak EGT, OAT 10C, MT three bladed props. First two sectors with SIM4P eMag TAS now 192 mph. (Plugs not touched during installation). Installation and timing procedure accurate and straight forward.

Game changing device. This unit is super simple reliable total solution for a direct magneto replacement. Simple installation Easy configuration. Minimal tool requited Outstanding performance. Really makes great difference. From start to flight level. All the way... Better star Better temperatures Better fuel efficiency Better performance. Using your existing slick harness and sparkplugs.

Texas S Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement

Installed the SIM4P on my 1946 Cessna 140 with new ACS ignition harness from Spruce....initially had issues at high RPM when the ignition was isolated on the SIM4p...after fully troubleshooting the system it turned out to be the brand new ignition harness....put the old one on and was good to go. Starts are great. Engine runs strong and smooth. Talked to the surefly support person several times and got good solid information. Seems like a worthy upgrade. Talking to the tech after we isolated the issue it sounds like they have a fist full of new ACS harnesses that did not work out of the box. The tech says they have had the best luck with Champion and and Kelly Harnesses.

*not paid by surefly at all, but rave to everyone about this. 10 Stars! Surefly will put slick and bendix out of business. Have a well kept Cherokee 180 had a hard time starting hot. Mags only had 200hrs, replaced left with this one and BAM! starts every time very easy! No matter how hot it is. Runs smoother, gets better fuel economy and has more power. Cruises about 5kts faster at a lower fuel burn. ~115kts @ 7.5gph now vs 110kts @8.5gph Best money Ive ever spent on the plane.

I like it! Ran rough in the beginning because harness Springs needed a little stretching to make contact with the Sim, but once everything is working as it should it’s a great product,, the plane runs as good on it alone as it does on both regular mags 👍👍👍

I’ve flown with electric ignition in a Long-EZ for years and was wondering when it would show up for certified aircraft? Had a mag fail it’s 500 hour inspection and it was less expensive to go this route rather than repair. Surefly is super easy to install, about as simple as a traditional mag. I have an EI tach and it required removing the current resistor and replacing it with an 18 ohm version. Tech support was friendly and helpful! No wonder Lycoming is picking up this product.

Well made product, simple to install and easy to set the engine timing. Engine performance seems to be better and smoother. Like the feature to use the existing ignition harness and spark plugs.

Installation took some additional time as we had to use the alternate positioning of the gear onto the SIM shaft to enable engine timing. Initial starting was about one full turn of the propeller. Fastest start in over 10 years of ownership!

It went on easily, the extra spark really made a difference in starting on my IO-390 with fine wire plugs. Maybe its a bad thing to not have to learn the most perfect possible way to set up a hot start, but I sure like the fact that it will just start now. Like learning to do rolls in a Pitts, vs. a Citabria…..you learn more technique and theory with the Citabria, but the Pitts is just easy and fun. I have it in fixed timing mode, but will try the advanced (variable) timing when I figure out how much the proprietary algorithm changes the timing. Im a bit paranoid about getting the CHTs up on climb out or high cruise. I think its an awesome replacement for an impulse coupled mag that is almost due for inspection/rebuild.

Read somewhere this mag wont work with horizon tachs there is a reverse polarity issue, also need a cylinder head temp guage per the stc if you want to take advantage of the advance timing feature. Still looks to be better then standard slick mags though at this time.

Long story, so here goes: My plane has a 24V battery in the tailcone, and the Surefly has to be connected to the battery side of the battery contactor for the STC to be valid for the installation. (This is because if the battery contactor fails and you lose the power bus, the Surefly still runs the engine off the battery) As 24V AGM batteries are in the $700 class nowadays and there is a (albeit small) leakage current on the Surefly when the engine isnt running, and leaking current kills batteries, I heeded the advice from Skip Koss from Concorde and put in a fuse holder in the instrument panel that would let me disconnect the Surefly power from within the cabin to shut off the power when I wasnt flying. The trouble is that would leave an unfused length of wire from the battery to the instrument panel. So to ameliorate that, I put a 15 A fuse in the fuse holder in the tail and left the 10A fuse in the panel. The Surefly was then installed at the annual, and I left in the original plugs and harness, even though Surefly recommends replacing both the plugs and harness when installing the Surefly.. Ran great, seemed to climb better, and I definitely got book speeds in no-wind conditions in cruise. But there was an oddity: during climb between 8500 to 10,500 the engine would balk unless I used full rich mixture. Huh. Weird. Well, they DID say to change the plugs and the harness. So I changed the plugs to an New-Old-Stock of Autolite UREM38Es I bought 16 years ago when they were $9 each. Well, that made matters worse. Now the engine was skipping randomly, losing 100 to 150 RPM, then surging. Happened in climb, cruise, and descent, once even when I was on takeoff and only 50 feet off the ground. Very sphincter-puckering moment, there. Egads, was it the plugs? Harness? I thought maybe there was some momentary bridging of the electrode gap, so I widened the plug gap. For one flight that seemed to work fine, but the intermittency came back a week later. Gads. So I changed the harness with a new Champion (the old one was the Aero-Lite that I put on 9 years ago) Nope, same problem where a full-power runup on the Surefly magneto alone would have a 200 to 300 RPM drop in the runup, then seem to work fine, and Id see 100 RPM drops in cruise when both mags were on, then surge again when the ignition kicked back on. An in-flight mag check saw a 200 to 300 RPM drop on the Surefly alone, and running fine (no RPM drop) on the right magneto. On two flights I had 6 misfires between initial climb and turning to the downwind leg, so I just came back to the airport on the right mag. While all this was going on I called the Surefly tech line many times, and Bill and Tom were paragons of patience and good advice. I was all set to pull the mag and send it back to verify it was working, and Bill convinced me to do a pull test on all the electrical connections from the battery to the Surefly, check the engine ground strap, and to check the P-lead grounding on all ignition switch positions with an ohmmeter. (The Surefly installation LED blinks the code for the advance timing settings whenever power is interrupted, so if an intermittent occurs in the power wire, it would show up on the LED). So I removed the 10A fuse from the instrument panel, moved it to the fuse in the tail cone, and re-did all the crimp connections for the power wire, then yanked each lead while watching the LED. Another odd thing happened when I pulled the 15A fuse out of the inline fuse holder in the tail cone, namely, the fuse just dribbled out, Normally theres a spring that holds a small preload force on the fuse to ensure contact, but it seemed like there was little or no force on the fuse when I pulled the 15A fuse out. There WAS spring force on it when I reinstalled the 10A fuse, so its possible the brad inside the fuse holder cocked a bit when I put in the 15A fuse just enough to keep the preload off of the fuse, thus making and intermittent/poor electrical connection. Subsequent pull test on the wires never got the LED to blink, so that confirmed the power was rock-solid to the Surefly. The first runup had a bit of a stumble, but seemed to clear up with a high speed runup (like a typical fouled plug) and next test flight ran perfectly. The hiccup where I needed full rich mixture from 8500 to 10,500 was now gone. and I got up to 12,500 with relative ease. So, upshot after this long story: Yes, it works. According to Bill at Surefly, the spark advance starts when manifold pressure falls below 24 inches of MP, so power wont fall off with altitude as much as it does with the constant-timed magnetos, so rate-of-climb will be improved and, in my case, I get actual published book speeds even though my plane was in a major accident in its youth. BUT: make sure you get it installed right! Sometimes even the little things can bite you on the rump and affect how it all works. Mine seems to be running fine so far. Hopefully your installation will learn form mine and will go a lot smoother. Best of luck to all. Happy flying.

My partner and I recently replaced the Left (Impulse) magneto in our 172N with a 0360 Lycoming and twin Slick magnetos. The installation instructions were clear, accurate, and the results are essentially as advertised: smoother idle, easier starting (especially hot-starts), and a notably smaller drop in rpm during run-up. However, it was during the run-up that an interesting trait of the electronic magneto made itself known: During the run-up, when rotating the ignition switch from R to L, there is a brief but distinct POP apparently from the exhaust, similar to a slight backfire. The POP is considerably more pronounced when performing a magneto check in lean cruise, and probably such checks should be avoided. The POP happens every time the switch rotates from R to L and at no other times. Its obvious the anomaly occurs the instant the L mag is turned on during the R to L motion of the ignition switch. The actual POP, I suspect, is due to the L magneto initially providing a retarded (25 degrees from the normal advanced setting) spark because it doesnt yet realize the engine is running. The retarded spark ignites an overly rich mixture which is still burning by the time the exhaust valve opens, hence the POP. Again, probably not an issue under normal run-ups, but at altitude under load Id have some concern over the exhaust system. I spoke with Bill at SureFly about this and discovered Im not the first to have noted the issue. SureFly suspects the cause is due to the design of the ignition switch along with the 100 milliseconds it takes the SureFly to actually produce a spark after it is ungrounded. Their thought is this delay results in an instant between R and L during which neither magneto is operating, thus causing excess fuel to accumulate in the cylinder. The L magneto then ignites that rich mixture with the POP being the still burning fuel when the exhaust valve opens. SureFly is currently attempting to get FAA approval for shortening that time from 100 milliseconds to 1 millisecond. Perhaps that will address the problem. That said, when rotating a perfectly good ignition switch from R to L, there is no point where both magnetos are grounded. In fact, the L magneto becomes ungrounded (turns on) well before the R magneto is grounded (turned off).

Purchased because there was no Bendix magneto in stock, also had to buy a brand new slick harness for the mag only works with Slick harness. What a nightmare. Installed per the manual run rough right away. Double checked everything and kept running rough. Called Surefly and found out that the installation manual contradicted what support was saying. Why dont they update the manual? Talking about the installation manual, it is a reduced copy and it’s not even stapled to keep the pages together. After talking to four different people at the “support” one guy in the end told me that the mag “likes” the spark plugs as wide open as it can be. 0.036” gap what I was told. Really? Why that info is not written on the installation manual? So now I have to have a “special” gaper to open up 8 brand new spark plugs. The whole thing just didn’t sound right to me. I started to regret big time that I bought this unit. After that the mag keeps playing intermittent game. Smooth, rough, smooth, rough. After two days dealing with the support and having spent lot’s of money for a brand new product that gave me nothing but trouble I decided to send to whole thing back. What a nightmare! Easy just request a return? You wish! I was told I have to call the company first and bunch of nonsense start to pop up, it took me 6 phone calls and three weeks calling everyweek to get my money back. Called a lady at Surefly four times to get the return moving. Spruce send the unit to Surefly the unit got there Trusday. I called Friday the lady said she was going to process Monday. I called Tuesday and she now is saying she ill process “today” on and on. Thanks to a great guy here at Spruce/Chandler AZ the return ended up happening. Surefly, no more.

Lewis M Verified Purchase

Surefly SiM4P 4-Cylinder Impulse Coupled Magneto Replacement