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Surefly electronic ignition

I changed my SIM timing from Advanced, 30*, to fixed, 25* with the dip switch selections. After getting it all internally timed, then timed to the engine at TDC, and torqued in place (150-160 in/lbs!) you are supposed to check the LED flash pattern to make sure you have it set correctly. Well, my flash pattern indicated that I had set 25*, but it was still Advanced. I must have checked my dip switch setting 4 or 5 times. I didn’t want to pull the mag for access to the dip switch plug so I spent an hour getting that little bugger out while still mounted on the engine. With a mirror I was able to determine, for the 6th time, that I had my dip switches in the correct positions for Fixed, 25* timing. So - off came the mag. On my work bench, I checked a few different engine timing settings, and they all worked as far as the timing number goes (20*, 25*, 30*, etc), but all of them indicated Advanced. The #1 dip switch controls the Fixed/advanced functionality, and it is apparently stuck in the open (OFF) position. The SureFly tech rep talked me through this. Whenever you changed one of those dip switch settings, you have to flash power on the timing terminal in order for it to take effect, which I had done. The tech rep told me that without a manifold pressure line attached, it would just default to fixed timing. That didn’t make sense to me, especially since they want you to leave the MAP port uncapped when in Fixed timing. The mag advances the timing based on RPM & MP that it sees on that port, like the others do, and it just seems like I would now be sensing ambient under the cowl pressure. As I climb and the ambient pressure dropped below 25”, there should be some advance. The mag is still indicating, via the LED flash pattern, that it is electronically operating in the Advanced mode. If I changed the #1 dip switch to OFF, I still got the same flash pattern.
Anyway - sorry for the long description, I’m just trying to get this straight in my feeble mind. The mag is on it’s way to Granbury, TX for repair. If you make changes on yours, make sure you flash that timing terminal with the mag grounded. You can use your main power lead for this, or an external battery. Taking the threaded cap plug out to access the dip switches while mounted on the engine wasn’t worth it for me. It is made out of nickel plated brass with a too wide slot that is easily damaged, especially if you are removing it after use. The thread locker they recommend using makes it difficult.
 
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The tech rep told me that without a manifold pressure line attached, it would just default to fixed timing. That didn’t make sense to me, especially since they want you to leave the MAP port uncapped when in Fixed timing. The mag advances the timing based on RPM & MP that it sees on that port, like the others do, and it just seems like I would now be sensing ambient under the cowl pressure. As I climb and the ambient pressure dropped below 25”, there should be some advance.

Scott,
Your understanding it correct. If the unit is set for variable timing, with the MP line exposed to ambient pressure, it will advance when that pressure drops below 25".

Also, the manual states that when you install the unit on the engine, the timing post must be engergized to set the timing. This will take care of "flashing" the unit to the new DIP settings.

The DIP switches are potted in epoxy pretty and very durable if not abused. The bench test units have been switched hundreds of times. The only time they have seen them fail is when a user is trying to change the settings with the SIM still installed on the engine. This is usually tried with a metal pick and a mirror, sometimes resulting in damage to the switch cluster. It's pretty obvious when the unit is inspected upon return.

$$
 
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By “flashing” I meant energizing the timing terminal as you stated, and that’s what I did, and also what the tech rep said to do. The only time I changed dip switch settings was with the mag off the engine and I had only done that once when trying to switch from advanced to fixed, and that was done on my workbench. The only reason I took a look while still mounted on the engine was to see if I had my settings right. It would have been impossible to change those switches while mounted in my installation. Plus, I’m pretty sure I wouldn’t have been able to get that threaded plug reinstalled correctly. All switches performed they way they are supposed to, except dip switch #1. I guess I got the one in a thousand that is faulty. The SureFly rep gave me an RMA# and said to send it in
 
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Yep..... I had the 1 in a thousand with a bad switch. SureFly called me today to say that the #1 switch was indeed bad. I think this was a big surprise to them, because maybe they haven’t seen this before. It’s important to them because this is a certified unit. I got STC paperwork with mine, so I assume it is the same as a certified unit. This is a good company. I purchased this SIM in November of 2019, and I’ve been flying it since January 2020. I don’t know what the warranty period is, but they are sending me a new SIM4. The switch is surface mounted on a PCB, and maybe they can’t just replace that board. At any rate, I am happy with the product, and very satisfied with the company support.
 
50hr report, 3 out of 5 stars.

O-360A1A Surefly right side, 25d BTDC fixed timing, Left side a Bendix with impulse coupling.

Likes- avoid the hassle and cost of the 500hr mag IRAN, install was simple, the SIM allows a smidge more leaning.

Dislikes- the install and ops manuals left out two important points. #1 the vacuum port cap problem, don't plug it off, and #2 Inflight mag checks can abuse your exhaust system. #1 I found out when talking to the factory about another matter, and #2 was discovered when doing high power inflight mag tests. The SIM takes a split second to boot up when the P-lead goes from grounded to open. 1/10 of a second doesn't seem long, but it is long enough to push combustible mix into the exhaust, and then when the SIM does wake up. BOOM! Last July, Bill from Surefly reported there was a fix in the works to make the boot up 2 milliseconds. That would be similar to a magneto.
# 3 dislike, kickbacks, so I'm back to starting on the left mag only (impulse coupling). After changing my routine to both, I had a few kickbacks, probably associated with a weak battery at the time, but the impulse coupling with the 25d lag has never done that. Why? Maybe the effective timing is moved forward with both mags firing or a maybe a more powerful spark from the SIM. The starting TDC problem is discussed in another thread. Short version- a few degrees after TDC minimizes the risk of kickback and doesn't seem to have any downside. A workaround to get later timing is described in the other thread. However, it would be better if the ATDC starting timing were baked in. The workaround to get ATDC timing is not in the certified aircraft installation instructions so it is really only available to experimental aircraft.

Would I buy another? Probably. Bill was helpful and honest about the SIM, but even with great customer service, a mag overhaul would have been less hassle. So, to tip the scales in favor, we've got to avoid future magneto IRAN's.
Surefly will likely improve their product if they can work the changes through the certification system. If they can do that, there is even more to like, it goes from a 3 star review to 4 or 5.
 
...Inflight mag checks can abuse your exhaust system......The SIM takes a split second to boot up when the P-lead goes from grounded to open. 1/10 of a second doesn't seem long, but it is long enough to push combustible mix into the exhaust, and then when the SIM does wake up. BOOM! Last July, Bill from Surefly reported there was a fix in the works to make the boot up 2 milliseconds. That would be similar to a magneto.

This inflight test was a full ignition shutdown, i.e. the magneto was grounded prior to switching the Surefly off, then on?

Or are you using a left-right-both key switch?
 
Yep..... I had the 1 in a thousand with a bad switch. SureFly called me today to say that the #1 switch was indeed bad. I think this was a big surprise to them, because maybe they haven’t seen this before. It’s important to them because this is a certified unit. I got STC paperwork with mine, so I assume it is the same as a certified unit. This is a good company. I purchased this SIM in November of 2019, and I’ve been flying it since January 2020. I don’t know what the warranty period is, but they are sending me a new SIM4. The switch is surface mounted on a PCB, and maybe they can’t just replace that board. At any rate, I am happy with the product, and very satisfied with the company support.

Good to hear they were able to replace the unit under warranty. Regardless of experimental or certified, everyone gets an STC'd unit. No differences in the product. The warranty is for two years.

Because the life of the product is relatively young, Surefly is not rebuilding or overhauling units. So, if you have a warranty issue, they will typically send you a new unit. This will eventually change as the product ages.

Happy flying!

$$
 
O-360A1A Surefly right side, 25d BTDC fixed timing, Left side a Bendix with impulse coupling.

Likes- avoid the hassle and cost of the 500hr mag IRAN, install was simple, the SIM allows a smidge more leaning.

Dislikes- the install and ops manuals left out two important points. #1 the vacuum port cap problem, don't plug it off, and #2 Inflight mag checks can abuse your exhaust system. #1 I found out when talking to the factory about another matter, and #2 was discovered when doing high power inflight mag tests. The SIM takes a split second to boot up when the P-lead goes from grounded to open. 1/10 of a second doesn't seem long, but it is long enough to push combustible mix into the exhaust, and then when the SIM does wake up. BOOM! Last July, Bill from Surefly reported there was a fix in the works to make the boot up 2 milliseconds. That would be similar to a magneto.
# 3 dislike, kickbacks, so I'm back to starting on the left mag only (impulse coupling). After changing my routine to both, I had a few kickbacks, probably associated with a weak battery at the time, but the impulse coupling with the 25d lag has never done that. Why? Maybe the effective timing is moved forward with both mags firing or a maybe a more powerful spark from the SIM. The starting TDC problem is discussed in another thread. Short version- a few degrees after TDC minimizes the risk of kickback and doesn't seem to have any downside. A workaround to get later timing is described in the other thread. However, it would be better if the ATDC starting timing were baked in. The workaround to get ATDC timing is not in the certified aircraft installation instructions so it is really only available to experimental aircraft.

Would I buy another? Probably. Bill was helpful and honest about the SIM, but even with great customer service, a mag overhaul would have been less hassle. So, to tip the scales in favor, we've got to avoid future magneto IRAN's.
Surefly will likely improve their product if they can work the changes through the certification system. If they can do that, there is even more to like, it goes from a 3 star review to 4 or 5.

#2 Mag check backfires are mentioned in the FAQ of the Surefly website. The issue is with Bendix style ignition swiches that are positioned "OFF-R-L-BOTH-START(may or may not). Whether new or old, some of these switches will ground both ignitions momentarily as there are switched between Right and Left. This is a defect in the switch. From the Surefly website:

"Why does the engine stumble during mag check?

On some aircraft there is a slight engine stumble when doing a mag check. We have discovered that some mag switches actually ground both ignition systems in the transition between Left and Right positions. The SureFly Ignition Module requires a few milliseconds to power up after being tuned on. This only occurs on a small percentage of aircraft. If you are one of the lucky ones, stay tuned as we are working on a solution.

We have found that turning the ignition switch slowly between positions masks this issue on most aircraft. (edit: This worked for me and most I've talked to with this issue)

Another remedy to mask the issue is to reduced power to idle before returing to "Both". Sequence as follows - Both, Left, Right, reduce power to idle and move back to Both.

Please make sure your ACS aircraft ignition switch is in compliance with AD 93-05-06."

#3 If you have a weak battery, poorly grounded engine or starter, or corrosion in the starter relay or cable terminals, you can get a backfire during the start. It has nothing to do with the accuracy of the SIM timing during start, and will not be corrected by timing several degrees after TDC. There fix is usually to check the health of your electrical system (weak battery in your case).

It has to do with the system voltage dropping below the required voltage (8.5VDC) for the SIM to operate. I believe the SIM charges the coils as the engine approaches TDC on compression. If the system voltage drops below the operating voltage of the SIM, it will shut down and it is possible for the field to collapse and a spark to be released before TDC. You will see this as the starter struggles to get the blade over compression, and the engine kicks back. Check the voltage at the starter teminal when the starter is engaged to check the health of your electrical system.
 
I have toggle mag switches and have never seen the "backfire or stumble" issue during run-up or inflight mag tests. Either the mag or SureFly is firing at all times. My SureFly is static timed at 0* TDC, fixed timing @ 25*, the remaining Slick mag is non-impulse.
 
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Inflight mag check

This inflight test was a full ignition shutdown, i.e. the magneto was grounded prior to switching the Surefly off, then on?

Or are you using a left-right-both key switch?

The off-RIGHT-left-both switch. I think what is happening is when I turn from both to Right, the switch is Left only (right grounded) long enough that the Sim has to reboot by the time I get to right. I admit, I am not quick on the switch, as years ago I made the rookie mistake, going too far, all the way to off.

I’m glad to hear the literature or at least the FAQ has been updated to include the warning. Last summer when I discovered this, I encouraged Bill to communicate a warning to customers. I also wrote Mike Busch, as he is the advocate of mag stress tests that convinced me years ago to make the inflight tests routine.

Yes, separate p-lead switches would make this a none issue.

My method now is switch to the SIM with the power pulled back. Might add 5 seconds to the test, which isn’t a big deal, but it is a quirk and in that regard, it is different than running a mag. I don’t think I’d put one on the right side of a rental airplane until the sim bootup is quicker. Installed on the left side might not be an issue at all given the switch design.

Last summer Bill reported the units had a 1/10 second boot. He said they were getting 2/1000 sec bootup in the pipeline. It sounded like a FAA hurdle. I don’t know what they’re shipping now. If the offered a firmware update, I’d do it.

I looked at the FAQ.... at least in my configuration, that isn’t helpful, they have it backwards. Power needs to be low before going to right only, since I’m turning through left only which has shut the SIM down. Once I’ve brought power back on and tested the SIM, going to left or both ungrounds the bendix which comes on line immediately so I do that without reducing power.
 
Low voltage pre-ignition?

#3 If you have a weak battery, poorly grounded engine or starter, or corrosion in the starter relay or cable terminals, you can get a backfire during the start. It has nothing to do with the accuracy of the SIM timing during start, and will not be corrected by timing several degrees after TDC. There fix is usually to check the health of your electrical system (weak battery in your case).

It has to do with the system voltage dropping below the required voltage (8.5VDC) for the SIM to operate. I believe the SIM charges the coils as the engine approaches TDC on compression. If the system voltage drops below the operating voltage of the SIM, it will shut down and it is possible for the field to collapse and a spark to be released before TDC. You will see this as the starter struggles to get the blade over compression, and the engine kicks back. Check the voltage at the starter teminal when the starter is engaged to check the health of your electrical system.

Earlier in this thread, starting timing is covered nicely IMO, so I'm not going to rehash that. However, the low voltage- lets take that one head on. I hope this is wrong. If you right, that is a major design failure. A good design doesn't risk grenading the system when a failure mode that has a 100% chance of occurring occurs. Cold happens, weak batteries happen, masters get left on, etc. Please tell me a spark doesn't get triggered by an event (low voltage) unrelated to piston position.

** another thought. If for some reason power dips when you are 50 degrees BTDC, and you are WOT, full power. (you win the bad luck lottery)

Update- I've heard back from Bill. He insists a low voltage will not cause a firing event. But also says that if the prop stalls (before TDC) the pre-charged coil pack can't hold it forever. It could fire substantially before TDC. In this edge case I prefer the impulse coupling. Preignition event at WOT? Clearly, one can shut off the SIM (ground the P-Lead), WOT, full power and the code manages to shut down each cylinder appropriately. It has been done many times. However, what is the timing behavior if voltage is removed, WOT, full power? Is it a lottery or a safe shutdown?
 
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Any electronic system operated or installed outside its design parameters, has the potential to operate improperly. Not a design fault.
 
Design

Hang with me a moment, it is on topic. Good friends of ours purchased a car, based somewhat on our good experiences with Subaru Outbacks. They got the new model at the time, a 2018, fully loaded- every option. They park in a locked and attached garage. Several times, they found the car with a drained battery. It could happen in a couple days. Turns out, the modern key fob and the car would have a battery depleting conversation. And yes, after a few of these, the dealer points out somewhere, in the 400 page manual, one is instructed to not leave the keys in the car or near the car. In fact, take them out, and even better, drop them in a faraday cage (coffee can) so these battery depleting conversations don't occur.
I tell this story to make a point about good design. Yes, it was mentioned in the manual, and perhaps it behaved as expected according to the engineering specifications, yet for those of us who park in a garage, camp next to the car, the only benefit this behavior has is it makes a great case study in stupid design. Those designers get an F. In the same fashion, if an aircraft electronic ignition system doesn't safely handle low or no voltage situations, another F, whether or not it is behaving as expected.
 
As the poster mentioned in his update, Surefly Tech Supported confirmed the hypothetical would not happen after engine start. The poster who mentioned a backfire on start stated it was due to a weak battery.

Bottom line is that if you are going to have an electronic ignition, then you need a dependable electrical system. The ignition coil is magnetized by current flow. When you remove the current flow, this magnetic field collapses and a surge of current is able to jump the gap in the spark plug. A magneto does this with points that open the magnetic circuit, allowing the field to collapse, creating a spark. An electronic ignition does this with a solid state circuit board. If you remove power from that circuit board when the coil is charged, you may have enough energy to get a spark. This is common with all electronic ignitions.

A weak battery, bad starter, corroded electrical connections etc. will cause the starter to hang as the piston compresses the cylinder. The voltage will drop dramatically. If the voltage drops below the operating limit of the any EIS, it may spark. But, we are talking about just a few degrees BTDC, extremely slow rotation of the engine, hence the back spin of the engine.

I suspect the reason that SF told you it’s a non-issue after start is because the system is designed to only charge the coil while the engine is in a safe zone for a spark? I would guess the FAA testing would have addressed this scenario.

No system is without compromise. Fortunately, you have a choice. A magneto that has a 500 inspection requirement due to multiple failures. Or an EIS that appears to have solid reliability in the field.
 
SureFly stumble cure

pecanflyboy; said:
We have found that turning the ignition switch slowly between positions masks this issue on most aircraft. (edit: This worked for me and most I've talked to with this issue)

Thanks so much for the tip! I was having to reduce the power on mag check to minimize the SureFly boot-up stumble, but slowly turning my Bendix key switch when switching back to the SureFly completely cured the problem.
 
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where?

Thanks so much for the tip! I was having to reduce the power on mag check to minimize the SureFly boot-up stumble, but slowly turning my Bendix key switch when switching back to the SureFly completely cured the problem.
Is your Surefly installed left or right? And your switch position sequence is off, right, left, both?

thanks
 
Excellent product! I've been running one unit on my RV6 with a high compression IO-360 for two years, and I can't wait to put on the second unit.

This is by far the most tested aircraft electronic ignition ever made. The unit was subjected to much more testing than their certified competitor (by a factor of 7!), tested thoroughly by Lycoming, and has passed with flying colors. The development of this system is a great example of how the FAA bureaucracy can ruin a company, but they persevered.

What it is: This is an easy to install, magneto replacement, that provides altitude compensated ignition advance within the detonation safe zone. In a low altitude, high manifold pressure, high power climb you are going to get 25 degree advance (base timing) just like a magneto. However, it will advance up to 38 degrees once your are in the detonation safe zone below 25" manifold pressure. Installation is just like a magneto with the addition of fused power directly from the battery, and a manifold pressure connection. You use the magneto gear, and the existing spark plug harness. It will last the life of the engine, with no maintenance. Only moving part is the geared shaft on a 50,000 hour bearing that only acts as a trigger. No external boxes or electronics, using existing ignition switch.

What it is not: This is not an electronic ignition for the "hotrodder" that wants to tweak the ignition curve and push the boundaries of detonation with their high dollar engine. Automotive engines have a "knock" sensor that advances the timing until is detonation is sensed and then backs it off. Piston aviation engines have no such system. So the philosophy was to build a KISS principled unit that is easy to install. You cannot adjust the timing curve, which also made the FAA happy during certification.

What it does: No 500 hours inspections, no impulse couplers destroying themselves and falling into the engine, no AD's, plug and play installation. I have easier starts, hot and cold. I can easily run lean of peak, seeing 7.5gph at 10,000' 165knots TAS. It runs so smooth that your mixture essentially becomes a throttle. I even know of carbureted O-360's easily running LOP with this ignition.

What to expect: Any electronic ignition system that burns the mixture more efficiently is going to highlight any deficiencies within your powerplant system. The CHT's will run slightly higher (10 degrees, below 25" MP) as you are extracting more BTU's from the fuel. In my case I found inefficiencies in my baffle that I corrected. I also needed to re-tune my GAMI's as I'd never been able to run this far LOP with mags. Finally, I discovered I had some tired spark plugs that needed replacement.

Bottom line is that I have a engine life span ignition system that costs just a little more than a magneto overhaul, makes my engine happy, and allows me to run more efficiently. I'm going to install my second Surefly SIM as soon as my RV6 comes back from the paint shop. I think you will see further product development from Surefly in the near future.

Who am I: I've been in the homebuilt game since the early 90's. My first project was a Thorp, and I've owned or flown just about every RV. I'm an A&P and an airline pilot. Full disclosure, I live in Granbury and have followed the development of this unit from the start. They are the same group that brought us Skytech and Plane Power, and are well funded. They will be around for a long time. I have no financial connection with them, and had to buy my units just like everyone else. I'm not an ignition expert, and I'm sure that those individuals can pick away at my comments.......but you get the jist.

Fly safe!
Jimmy

I attended SnF 2021. The Lycoming booth had Surefly E-mags re-branded as Lycoming. They even repainted the baby-blue to black which I thought was cool. If Lycoming is putting their name on it...
I did see a recent review on ACS about backfire due to an incompatibility with the key switch that most builders use. Not sure if that's been resolved. Do your homework.
https://www.aircraftspruce.com/pages/ep/ignition_surefly/surefly_08-17076.php
 
I installed a SIM6L on my RV-10. My right mag was originally rough running so I put it on the right side to replace that rough running mechanical mag. The install is straightforward.

Then came the ground runs & test flights. The mag performs fine. During run-up, switching to the e-mag ...the engine will stumble. This is mentioned in the instructions and is expected. In cruise flight if I switch to isolate the emag I'll get a backfire. These are things I can live with.

Then came the time to fly to a local airport for fuel. I set up my 430W direct..then engaged the Trutrak autopilot built in my EFIS and put it into GPSS mode. The airplane started hunting across the magenta track line. Essentially doing aggressive S-turns over the line. It never settled out. It will follow the heading bug smoothly so at least I have that. I don't know if this is being caused by magnetic interference from the mag itself, or if it's from the power wire that I ran from behind the rear bulkhead all the way to the engine compartment. I integrated the wire into the existing wire bundle that runs from the back tot he front. I put a breaker in the back near the battery as per the instructions so I cannot disconnect it from power during flight to debug.....Grrr!


All that said, the install was easy, but you do have to learn to live with having a live wire from the battery to the magneto 100% of the time. The install instructions are adamant about uninterrupted power. When I perform maintenance (i.e oil changes), I'll pull the breaker to cut power so that I can't accidentally arc the magneto power lug to ground.

In my case, the engine didn't run any smoother on the e-mag than when I had the mechanical mag. Still rough so now I will replace the ignition cables and plugs. Sure-fly recommended in the instructions that you change the the ignition harness anyway as it it's starting to appear that plugs/wires are the root cause of rough running.

First things first, I need to isolate to see if the new e-mag is confusing the GPSS mode steering of my auto-pilot or if maybe it's my physical wire run, etc. Once I resolve that, then I'll focus on smoothing out my engine.

If anyone has any experience with e-mags causing this weird interference, please speak up.
 
Having problem with Surefly

Just installed a Surefly SIM4P on my Lyc I/O-390, left side, replaced impulse mag, and am having some problems with it that maybe someone here with experience has some insight to, since the Surefly tech support folks are confused so far.

To start with, before the install, the engine was running and starting great (usually half a prop rotation to start) with the recently overhauled Slicks and SlickStart. Mag check (at 1800) RPM drop 50 to 60 both mags.

Now, with the Surefly it takes a good 2 to 4 prop rotations to start, and Surefly
left side mag check drops 90 to 100 RPM, and not particularly smooth at that.

Timing set for 20 degree engine and timed properly to TDC, and checked 3 times. Fixed timing code dot-dash-dash-dot verified 3 times!

SO, not getting the heralded "much better starting" and at 1800 RPM and fixed 20 degree advance, the Surefly left mag check drop should be the identical -50 or 60 RPM. So I can only conclude it isn't actually providing the 20 degree advance, and associated low RPM retard isn't right either.

I followed Surefly suggestions for a new harness and cleaned / gaped the plugs and no change. Double checked power and grounding, and all good.

Any suggestions?
 
Mag check

I’m not familiar with the slick start system, perhaps educate us, before the sure-fly, did that start on both mags or just one slick mag? I have noticed that even with two healthy mags, if the timing is not exactly the same, you won’t have equal mag drop from side to side, so you might double check your slick timing on the right side.
 
Just installed a Surefly SIM4P on my Lyc I/O-390, left side, replaced impulse mag, and am having some problems with it that maybe someone here with experience has some insight to, since the Surefly tech support folks are confused so far.

To start with, before the install, the engine was running and starting great (usually half a prop rotation to start) with the recently overhauled Slicks and SlickStart. Mag check (at 1800) RPM drop 50 to 60 both mags.

Now, with the Surefly it takes a good 2 to 4 prop rotations to start, and Surefly
left side mag check drops 90 to 100 RPM, and not particularly smooth at that.

Timing set for 20 degree engine and timed properly to TDC, and checked 3 times. Fixed timing code dot-dash-dash-dot verified 3 times!

SO, not getting the heralded "much better starting" and at 1800 RPM and fixed 20 degree advance, the Surefly left mag check drop should be the identical -50 or 60 RPM. So I can only conclude it isn't actually providing the 20 degree advance, and associated low RPM retard isn't right either.

I followed Surefly suggestions for a new harness and cleaned / gaped the plugs and no change. Double checked power and grounding, and all good.

Any suggestions?

RPM drops should be similar if both timing advances are equal. Therefore, with a 50 RPM spread between the mag and the surefly, I would speculate that they are not the same. Have you checked the mag timing also? Best way to confirm what is really happening with both of the ignitions, is to use an automotive timing light, You can then swap the pickup from the top to bottom on #1 to see both of their actual timing; at least at idle. Also, I believe the top plug produces a slightly faster burn, so I get a 10-20 RPM variation across ignitions eventhough they are exactly the same timing. You should not be looking for EXACTLY the same RPM drop.

Many EI systems (those with missing tooth arrangements) require 1.5 - 2 complete crank revolutions of the engine before they "acquire" TDC and can then start sparking. If the starter is slow to ramp up speed, then it could take 3 or more revolutions for the software to figure things out. A mag does not need to do this as everything is fixed/mechanical. I think the SDS system uses a secondary sense pulse at half rotation and can therefore acquire sooner. Not sure if the SF does that. Most use missing tooth arrangement as that software is plentiful and easy to copy.

Larry
 
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Shipped instructions?

What does the current instructions say about the vacuum port when using fixed timing? When I installed, the instructions said use the provided cap, and tech support said, no, leave un-ported. I slid on a short piece of hose and let it hang to make the opening point down. Apparently, installing the cap leads to dodgy behavior when in fixed timing mode.
 
Problem with Surefly

Thanks for the inputs. I will go back and check the right mag timing, but suspect it is close to the 20 degrees, as the drop is 50 or 60 on that side, which is about as good as it gets when mags are in good condition and timed right. It still seems to me that if the Surefly were to be firing at the advertised 20 degrees, the drop should be the same as the mag. So a timing check with an auto timing light may be in order. Not sure how to attach it to plane plugs and how I will feel checking the timing with the prop rotating....

Today I did a flight and graphed the EGTs, and during the steady state portion of the flight, they were pretty ragged on two cylinders, not a good thing. Pulled up the data from the last flight with both mags, and the EGTs were flat rock solid. Ugh, to quote Rosanna Danna Danna (for those old enough to remember!), there's always something! Back to talking to the Surefly folks...

Regarding the comment about EI needing a revolution or 2 to find TDC, that's very interesting and makes sense. It raises the question though of how it is that everyone with Surefly SIMs talks about how much better their engines start - Does that mean their engines start with 2 or 3 revolutions all the time now and are happy with that/and previously starts were worse than that? Am I disillusioned because before with the mags and SlickStart shower of sparks it always started in under a revolution?
 
Thanks for the inputs. I will go back and check the right mag timing, but suspect it is close to the 20 degrees, as the drop is 50 or 60 on that side, which is about as good as it gets when mags are in good condition and timed right. It still seems to me that if the Surefly were to be firing at the advertised 20 degrees, the drop should be the same as the mag. So a timing check with an auto timing light may be in order. Not sure how to attach it to plane plugs and how I will feel checking the timing with the prop rotating....

Today I did a flight and graphed the EGTs, and during the steady state portion of the flight, they were pretty ragged on two cylinders, not a good thing. Pulled up the data from the last flight with both mags, and the EGTs were flat rock solid. Ugh, to quote Rosanna Danna Danna (for those old enough to remember!), there's always something! Back to talking to the Surefly folks...

Regarding the comment about EI needing a revolution or 2 to find TDC, that's very interesting and makes sense. It raises the question though of how it is that everyone with Surefly SIMs talks about how much better their engines start - Does that mean their engines start with 2 or 3 revolutions all the time now and are happy with that/and previously starts were worse than that? Am I disillusioned because before with the mags and SlickStart shower of sparks it always started in under a revolution?

re-read your original post and missed a couple things. If you get stumbles or backfires, something is wrong and likely beyond basic timing. If it is just timing issues causing backfires, it will be seriously retarded and to the point where RPM drops would be very large. More likely they are afterfires, due to intermittent misfires (which could explain the "ragged" EGTs), which also could feel like a stumble. It seems quite plausible there is some problem with your unit.

When you drop one ignition and the RPM drop is low, the ignition still running has more advance than the one shut off. If the drop is high, the running ignition has a lower advance than the shut off one. At idle RPMs, as well as run up RPMs, more advance=more RPM at least to a point.

Most modern timing lights have a clamp that goes over the plug wire.

I would not expect any EI system to start better or faster than a shower of sparks system. Your buddies probably had regular mags and their weak spark requires a relatively tight range of mixture to be able to light it. The stronger spark on the EI's are more tolerant of mixture variance and therefore appear to start better as they can ignite mixtures richer or leaner than an impulse mag can.

Larry
 
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Having problem with Surefly

When you drop one ignition and the RPM drop is low, the ignition still running has more advance than the one shut off. If the drop is high, the running ignition has a lower advance than the shut off one. At idle RPMs, as well as run up RPMs, more advance=more RPM at least to a point.

Most modern timing lights have a clamp that goes over the plug wire.

I would not expect any EI system to start better or faster than a shower of sparks system. Your buddies probably had regular mags and their weak spark requires a relatively tight range of mixture to be able to light it. The stronger spark on the EI's are more tolerant of mixture variance and therefore appear to start better as they can ignite mixtures richer or leaner than an impulse mag can.

Larry

Thanks Larry! Very helpful comments! So it appears the Surefly is exhibiting less advance than the mag, re-assuring in terms of engine safety. I suspect the lateness may be significant as in flight the performance is also a bit off - a good 5 knots slower.

I've flown it several times now, and the EGTs continue to be consistently ragged, at least on one cylinder. Next I am going to do some in flight mag checks to see whether it is the mag or the Surefly responsible for the ragged EGTs. It likely is, as the plugs are in good shape, the wires are new (though it behaved the same with the old wires - it's just that Surefly suggested new wires), and the mags used to deliver perfectly flat EGTs in cruise.

I'll have to go and get a new timing light - I guess I revealed my age given my old timing light, that never gets used anymore, but hooks in series with a car plug wire! It's been a long time since it got used, distributors got turned just like mags, capacitors got replaced etc.! Every 10K miles!

Reinhard
 
Clamp-on timing light

Does anyone know if an inductive pickup timing light work on shielded spark plug wires? I've often wondered if there is enough image current in the shield to trigger.
 
starting questions

Regarding the comment about EI needing a revolution or 2 to find TDC, that's very interesting and makes sense. It raises the question though of how it is that everyone with Surefly SIMs talks about how much better their engines start - Does that mean their engines start with 2 or 3 revolutions all the time now and are happy with that/and previously starts were worse than that?

Great question. Back in February of 2021, I complained to Surefly about exhaust system combustion events during in flight mag checks. Bill from Surefly explained the boot up delay as 1/10 of a second. This was enough time to put combustionable mixtures into the exhaust, that were then subsequently lit when the SIM started firing again. He reported they had new software that would shorten boot to 0.002 a second, but were waiting on FAA approval. I had assumed at the time, that it had to do simple OS boot up, but maybe it has to do with a certain number of engine revolutions so the SIM calculates crank position. The 0.002 second fix might have been to have the unit keep track of crankshaft position regardless of p-lead switch position, then when spark is called for it already knows position. Doing a little math, 1/10 of a second is 2.25 mag rotations, 4.5 engine rotations at 2700 rpm. Keeping track of crank position is likely easy to do during a inflight mag check, but will the SIM know position after sitting for a week, and the prop was fiddled with? Doubtful.

How long does the SIM keep track of crankshaft position? Does anyone starting on the SIM only start before 1 or 2 blades? SIM only, since we know impulse couplings are ready to go immediately.
 
One thing I believe I was told by surefly's tech support, way back when I installed mine in the 2 planes, is that they purposely have the mag drop higher than what they could have it. My lightspeed barely drops at all, maybe 20rpm. The surefly is more near 100 I think. They said that they have it tuned to drop that much because people who are upgrading from standard mags would be confused if it didn't provide the expected mag drop that they're used to.
While I don't agree that they took the right path on that, if they indeed did what they told me, it would explain the large drop.

Also, another surefly user told me the mag checks better with that system if you do it over 2000rpm. So I started doing that myself. I don't know that it matters if you choose 1800, 1900, 2000, or whatever number, as long as you develop a routine so that you know when it's varied from what you're used to.

The slow bootup is a little painful, so don't ever expect that with the older software you won't get that boot delay on mag check. I'll be interested to hear what they do for people as far as getting software/firmware upgraded. Would not be fun to have to ship them in, but I bet that's the only solution.
 
Does anyone know if an inductive pickup timing light work on shielded spark plug wires? I've often wondered if there is enough image current in the shield to trigger.

I know first hand the inductive timing light won't work with a Lightspeed system, you'll need to make a a short length "shunt "out of automotive plug wire to go between the spark plug and mag harness plug cigarette.
 
Does anyone know if an inductive pickup timing light work on shielded spark plug wires? I've often wondered if there is enough image current in the shield to trigger.

I have never tried it, but speculate that it may not work. The clamp is measuring inductance from when the energy field collapses. The primary purpose of shielding is to capture this and drain it to a ground. If this is effective enough, there may not be a strong enough field for the sensor to capture.

Larry
 
Great question. Back in February of 2021, I complained to Surefly about exhaust system combustion events during in flight mag checks. Bill from Surefly explained the boot up delay as 1/10 of a second. This was enough time to put combustionable mixtures into the exhaust, that were then subsequently lit when the SIM started firing again. He reported they had new software that would shorten boot to 0.002 a second, but were waiting on FAA approval. I had assumed at the time, that it had to do simple OS boot up, but maybe it has to do with a certain number of engine revolutions so the SIM calculates crank position. The 0.002 second fix might have been to have the unit keep track of crankshaft position regardless of p-lead switch position, then when spark is called for it already knows position. Doing a little math, 1/10 of a second is 2.25 mag rotations, 4.5 engine rotations at 2700 rpm. Keeping track of crank position is likely easy to do during a inflight mag check, but will the SIM know position after sitting for a week, and the prop was fiddled with? Doubtful.

How long does the SIM keep track of crankshaft position? Does anyone starting on the SIM only start before 1 or 2 blades? SIM only, since we know impulse couplings are ready to go immediately.

This would be my guess. As long as power is not cut to the CPU, the s/w should be able to maintain the crank position and a s/w change should shorten ramp up with just a p lead on/off cycle, assuming that originally they just initiated the full start up sequence again.

FYI, the mag on a lycoming rotates at the same speed as the crank, unlike most automotive distibutors. The mag has a 2:1 gear reduction at the rotor, while an EI treats it as a crank sensor instead of a cam sensor; This is why they are all wasted spark-they only know crank position and not cam position. The mags use 1:1 because at 2:1, the mag wouldn't have enough energy to spark at lower RPMs; It is simply a PM generator and they need a decent amount of speed to produce enough power to saturate the primary winding of the coil.

Larry
 
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SureFly installation issues - subsiding

My SureFly issues seem to be subsiding! Since I had seen some ragged EGTs on one cylinder since the installation, I decided to do an altitude cruise mag check as well as fly for 5 minutes each on the mag or SureFly separately. Expecting one or the other to show some roughness, surprise, both ran smooth! Apparently the EGT bobbles are either a failing probe or loose connection. And the plane flew about a knot faster on the SureFly than the mag.

The other discovery was that since SureFly significantly shortened the start up time (from 100mS to 2mS) I get no backfire when switching. And, with much cooler temperatures today, the ground mag check RPM drop was closer to 50 or 60. All good!

Reinhard
 
Reinhard,

What was the turnaround time for the startup time upgrade?

Lenny

The other discovery was that since SureFly significantly shortened the start up time (from 100mS to 2mS) I get no backfire when switching. And, with much cooler temperatures today, the ground mag check RPM drop was closer to 50 or 60. All good!

Reinhard
 
Start up time upgrade

Reinhard,

What was the turnaround time for the startup time upgrade?

Lenny

Mine was a new unit bought a couple weeks ago, so it came with the start up time improvement. I assume you mean sending a unit in to them for the upgrade - unfortunately I don't know if they are actually doing that - if it is only firmware. Sorry, you'll need to ask them. They are very responsive!

Reinhard
 
One thing I believe I was told by surefly's tech support, way back when I installed mine in the 2 planes, is that they purposely have the mag drop higher than what they could have it. My lightspeed barely drops at all, maybe 20rpm. The surefly is more near 100 I think. They said that they have it tuned to drop that much because people who are upgrading from standard mags would be confused if it didn't provide the expected mag drop that they're used to.
While I don't agree that they took the right path on that, if they indeed did what they told me, it would explain the large drop.

Also, another surefly user told me the mag checks better with that system if you do it over 2000rpm. So I started doing that myself. I don't know that it matters if you choose 1800, 1900, 2000, or whatever number, as long as you develop a routine so that you know when it's varied from what you're used to.

The slow bootup is a little painful, so don't ever expect that with the older software you won't get that boot delay on mag check. I'll be interested to hear what they do for people as far as getting software/firmware upgraded. Would not be fun to have to ship them in, but I bet that's the only solution.

There is no "designed" RPM drop during an ignition check. The unit makes a spark....period. If you are having a significant drop during this check, it's probably downline or improper installation.

The boot up issue is only a problem if your Bendix style switch is momentarily grounding the SIM during the ignition check. This is discussed on their website. For some reason, new or old, some of these switches momentarily ground the p-leads during the check as the switch is swiftly turned from both through the ignitions. In my situation, turning the switch slowly and smoothly solved the problem. I now have rocker switches on the ignitions. Even though this is not a Surefly issue, they have tried to minimize it by upgrading the units as they mature and better components come onto the market. This does not solve the problem that lives within the switch, it just minimizes it. Consider replacing your ignition switch.

Surefly does not upgrade units. Like most technologies (think iPhone), as they mature they receive upgrades and improvements. The units cannot be "flashed" to upgrade the software. It is built with modules that cannot be re-programmed (FAA cert issue). Anyway, the upgrades of which you are speaking are typically hardware upgrades. Your only option is to sell your unit and buy a new one.

Either way, call Surefly with questions. 817-373-5161

Jimmy$
Full disclosure: I don't speak for Surefly, as I am only an experienced user. However, I have helped them with Tech Support and installations in the past. These are my opinions based on personal experience.
 
What does the current instructions say about the vacuum port when using fixed timing? When I installed, the instructions said use the provided cap, and tech support said, no, leave un-ported. I slid on a short piece of hose and let it hang to make the opening point down. Apparently, installing the cap leads to dodgy behavior when in fixed timing mode.

This is the manifold pressure port, which should be left open to atmospheric pressure in fixed timing. If it is capped, it could pressurize the manifold pressure sensor as you climb and cause the unit to throw an error code (rapid flashing LED on the back of the unit).
 
There is no "designed" RPM drop during an ignition check. The unit makes a spark....period. If you are having a significant drop during this check, it's probably downline or improper installation.
.

Sorry, but this is wrong.

The amount of RPM drop during a mag check is directly related to WHERE the spark occurs relative to TDC on the one running ignition compared to where it occurs on both running ignitions, as well as where it occurs on the other ignition. It is NOT a simple binary spark event; That spark event MUST be properly timed to the crankshaft postion. From TDC all the way up to about 40* BTDC, more advance = higher RPM. Therefore, one uses the amount of RPM drop from one ignition to the other to determine the state of advance difference between the two ignitions.

A mag test is designed to determine two different things: 1) that both ignition systems are firing all 4 plugs (noted by not getting a very rough running condition on one or the other individual system, and 2) that one mag is not too far advanced relative to the other as determined by RPM drops across each individual mag relative to both. If one mag goes too far advanced, detonation can occur and this is why the certified airframe designer specifies a max RPM drop as well as a max drop differential. We are experimental and therefore have no such specification. However, large differences in RPM drop are a sign that something is not right and pilots need to heed that warning. Those with only one EI need special guidelines as most EI's produce far more advance at 1800 than the mag and therefore will get different RPM drops on the EI vs the mag. Seems as though surefly intentionally dropped the advance back to 25* at 1800 to avoid alarming users with a large delta and allow those users to follow the airframe guidelines. Not surprising given they are the only ones that sell to the certified market.

Larry
 
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Those with only one EI need special guidelines as most EI's produce far more advance at 1800 than the mag and therefore will get different RPM drops on the EI vs the mag. Seems as though surefly intentionally dropped the advance back to 25* at 1800 to avoid alarming users with a large delta and allow those users to follow the airframe guidelines. Not surprising given they are the only ones that sell to the certified market.

Larry

My SureFly is configured for fixed timing so it is 25* regardless of the rpm. I see 10-15 rpm higher with the SureFly than the mag when doing a 1700 rpm runup, probably due to my mag having a bunch of hours on it.
 
My SureFly is configured for fixed timing so it is 25* regardless of the rpm. I see 10-15 rpm higher with the SureFly than the mag when doing a 1700 rpm runup, probably due to my mag having a bunch of hours on it.

I think there may be some variance in where the top and bottom plugs are. It could also be that the mixture concentrations are different from top to bottom and this causes differences in the flame front travel speed. The Lyc chamber and valve arrangement is not considered state of the art in flow mechanics. I have two EI's and the timing is VERY close between the two and I still see a 10-20 RPM drop difference between them on my 540.

Larry
 
Surefly

The unit makes a spark....period. If you are having a significant drop during this check, it's probably downline or improper installation.

I don't think that's correct. The drop will also depend on the unit's timing. If it's timed correct, then yes. If it is not, the drop can/will change. For example, when regular mags age, their timing can shift due to cam follower wear, and you can tell from the mag drop increase that it may be time for an overhaul.

Reinhard
 
FYI, the current link appears to be: https://www.lycoming.com/sites/defa...20Approved%20Slick%20Magnetos%20and%20EIS.pdf

It appears to be (unless I missed something) that the I/O-390 is still Lycoming's only certified Surefly installation with variable advance.

That said, has anyone been able to either test or find out what that Lycoming approved advance schedule for the 390 is? How close is it to the 20 degree base variable advance schedule in the non-Lyc version of the Surefly? Since the 390's are now so popular in our planes, particularly for RV-14s, this to me seems like some info that would be of great interest. Last I tried to pump Surefly on the subject I couldn't get past "it's Lycomong proprietary".....

Reinhard
 
FYI, the current link appears to be: https://www.lycoming.com/sites/default/files/attachments/SI1443R%20Approved%20Slick%20Magnetos%20and%20EIS.pdf

It appears to be (unless I missed something) that the I/O-390 is still Lycoming's only certified Surefly installation with variable advance.

That said, has anyone been able to either test or find out what that Lycoming approved advance schedule for the 390 is? How close is it to the 20 degree base variable advance schedule in the non-Lyc version of the Surefly? Since the 390's are now so popular in our planes, particularly for RV-14s, this to me seems like some info that would be of great interest. Last I tried to pump Surefly on the subject I couldn't get past "it's Lycomong proprietary".....

Reinhard
That's been the response since Lycoming's introduction at OSH some years ago. I too am curious, given subsequent testing of other EI's among our flock says running an angle valve at more than 30 BTDC is pointless.

Sooner or later someone will simply point a timing light at the Lycoming version.,..
 
That's been the response since Lycoming's introduction at OSH some years ago. I too am curious, given subsequent testing of other EI's among our flock says running an angle valve at more than 30 BTDC is pointless.

Sooner or later someone will simply point a timing light at the Lycoming version.,..
Beyond curiosity, if it turns out Lycoming made sense limiting around 28 to 30 degrees, it would be great to find a way to pressure Surefly to make such a schedule generally available. There should be a way to circumvent any Lycoming claim to the 390 schedule given that it is in the best interest of operating a 390 safely, optimally - Lyc shouldn't be in the business of thwarting that.
 
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