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Surefly revisted

sailvi767

Well Known Member
I am considering a Surefly for my Parallel valve IO540 with 9.5 to 1 pistons. This would be a single installation with a slick on the other side. I have read most of the threads here and on other sites. Overall it appears the Surefly has had a very trouble free rollout in comparison with other EI options. There have been issues but most but not all seem installation related. The reliability at this point seems almost stellar for a new product.
My current setup has the mags timed at 23 degrees. My plan would be to set the base timing on the Surefly at 23 also. This would keep both ignitions at 23 anytime the engine was above 25 inches MAP. Max advance at 2700 RPM would be about 33 degrees. If I understand what I am reading correctly that will give me a effective advance of 30 to 31 degrees with the fixed slick. My CHT’s are currently quite good for a Rocket and rarely exceed 385 even when leaning during climb.
I would appreciate any comments and would like to hear from others especially if your running the 6 cylinder version. The 4 cylinders version also seems to reduce fuel flows. I hope that holds true for the 6.
G
 
Surefly

I tried the Surefly EI and just couldn't make it work the way I wanted. I replaced a Slick MAG with the Surefly to run along side of a Lightspeed EI which was installed from the beginning.

The problem was that no matter what I did I could not get it to run as well as the Lightspeed EI. Several conversations with the Mfg with adjustments of timing etc but to no avail. In the end the Mfg. agreed to give me my money back so that is what I did.

A short time later running the Lightspeed EI with one Mag I decided to give the SDS CPI a try. This decision has turned out to be a good one in that it is running perfectly and almost identical to the Lightspeed EI. During the run-up I typically see a 10-20 RPM drop on both EI's. Testing the ignition system during Cruise flight there is a barely perceptible note change in the engine when one EI is turned off.

From my experience (1400 hrs. in an RV-10) I would definitely recommend both of these EI systems primarily because they are both crank triggered rather than triggered by the gears on the accessory case with ZERO moving parts. I much prefer the SDS EI system because it gives you full control over the advance/retard ramps plus a programmable LOP switch.
 
I tried the Surefly EI and just couldn't make it work the way I wanted. I replaced a Slick MAG with the Surefly to run along side of a Lightspeed EI which was installed from the beginning.

The problem was that no matter what I did I could not get it to run as well as the Lightspeed EI. Several conversations with the Mfg with adjustments of timing etc but to no avail. In the end the Mfg. agreed to give me my money back so that is what I did.

Interested to hear the details of your troubles, if you don't mind.
 
I replaced a new impulse coupled Slick on my 300 hour IO390 with a Surefly SIM4P. It took about 3 hours to R&R the mags, set the dip switch's, connect the vacuum line fittings and install the battery connection. The Surefly customer support was helpful to confirm a couple questions.

Performance on the airplane has been flawless so far. Lean of peak at 10.1 GPH I am getting 2-3 kts more speed at 6500 cruise.

At the mag runup check, the Surefly does have a noticeable sound when switched from R to L. The mag drop is 75 rpm from the slick. I might be able to refine that with the Slick, the Surefly is dead on the setting using the LED and battery installation. Lycoming now offers this mag on new engines.
 
Surefly trouble.

Interested to hear the details of your troubles, if you don't mind.

Had I not had a Lightspeed EI driving the top plugs I might not have know how poorly it compared. My main complaint was that for a EI check (aka mag check) that when the Lightspeed EI was turned off the Surefly would show a 100-150 rpm drop compared to 10 to 20 on the Lightspeed.

Timing, plugs and plug wires as well as all connections were checked and re-checked to no avail.

The SDS CPI system I put in worked perfectly from the start plus it uses automotive plugs @ $10 ea instead of $30.00. Now having said that I should point out that the installation of the SDS CPI is more complex. Not a difficult process but more time consuming, well worth the effort IMO.
 
The Surefly is fine with automotive plugs if your certified aircraft has a STC. If it’s a experimental auto plugs are fine. Keep in mind the Surefly is a FAA approved unit so they have to abide by rules light speed and others do not. I currently am running two mags, one with aircraft and one with auto plugs. The aircraft plugs have a bigger mag drop.
From Surefly website:
The SIM is compatible with all automotive and aviation spark plugs. SureFly’s FAA STC’s do not grant permission to use automotive spark plugs in FAA certified engines. You may only use spark plugs FAA-approved for your application.
 
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The reason that Lightspeed has almost no “mag drop” is that it’s running 40* or so of advance at runup rpms. The SureFly will have a similar drop as a standard mag as it’s not running as much advance as Lightspeed at runup.
 
I run Lightspeed & Surefly. Same experience as Ivan. The Surefly doesn't run as smooth as the Lightspeed on runup. Tried it both in fixed or advanced mode.

The advance curve seems to be a bit aggressive with this setup (slightly higher CHTs) so I'm running the SureFly in fixed mode.

I like the redundancy of having a crank mounted trigger on one ignition and a mag gear trigger on the other. A broken alternator belt could theoretically take out both crank mounted triggers. The likelihood of that may be higher with a misaligned alternator belt...
 
I run Lightspeed & Surefly. Same experience as Ivan. The Surefly doesn't run as smooth as the Lightspeed on runup. Tried it both in fixed or advanced mode.

The advance curve seems to be a bit aggressive with this setup (slightly higher CHTs) so I'm running the SureFly in fixed mode.

I like the redundancy of having a crank mounted trigger on one ignition and a mag gear trigger on the other. A broken alternator belt could theoretically take out both crank mounted triggers. The likelihood of that may be higher with a misaligned alternator belt...

Sadly this is not just theoretical. Happened here.

https://www.atsb.gov.au/media/5341498/AO-2013-221 Final.pdf
 
Mag drive gears fail too. I received a report from a friend, also in Australia, of their 540 swallowing mag gears and seizing (on short final fortunately). That's not the only one I've heard of over the years.

There are plenty of single points of failure on single engined aircraft.
 
Mag drive gears fail too. I received a report from a friend, also in Australia, of their 540 swallowing mag gears and seizing (on short final fortunately). That's not the only one I've heard of over the years.

There are plenty of single points of failure on single engined aircraft.

That happened to my hangar mate....
People likely expect that if an idler gear dies then you’re going to be in a paddock. Thankfully that’s pretty rare.
Alternator belts on the other hand you wouldn’t want to trust your life to.
Personally I think trying to mitigate the damage from a flailing alternator belt is risky. Better off not putting both critical components in harms way subject to the same failure mode.
 
That happened to my hangar mate....
People likely expect that if an idler gear dies then you’re going to be in a paddock. Thankfully that’s pretty rare.
Alternator belts on the other hand you wouldn’t want to trust your life to.
Personally I think trying to mitigate the damage from a flailing alternator belt is risky. Better off not putting both critical components in harms way subject to the same failure mode.

This can be worked around. My 540 setup has crank triggers at the flywheel and was able to create a setup that fully shields the sensor and wires from getting hit by a broken fan belt. You could easily lift my engine from the trigger sensor attachment. I have heard too many stories about broken mag drive parts in the accy case on the 540 to consider using a mag drive based pickup, like I did on the 320.

Larry
 
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The older LS crank sensor arrangement is flimsy- just an exposed circuit board and lightweight wires attached by small screws. The SDS bracket is strong enough to lift the whole aircraft up by and there is provision to attach protection brackets for the much more robust 4 conductor shielded and sheathed Mil-Spec cables. Not vulnerable to this type of scenario at all.

Properly maintained belts are very unlikely to break in the first place. Get lazy and leave in on for 10 years and maybe so- just like lots of other bits on your airplane.
 
Agreed that comparing the LS crank trigger to the SDS example is essentially irrelevant. With proper installation, a thrown alternator belt won't take down the SDS trigger or wires. Period. Dot.
 
Properly maintained belts are very unlikely to break in the first place. Get lazy and leave in on for 10 years and maybe so- just like lots of other bits on your airplane.

That got my attention, while I check the belt at condition inspection how often should it be replaced? Mine looked OK but is 10+ years old.
Figs
 
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