Frequently asked questions
General
What does it weigh?
SIM4P - 4.4 lbs.
SIM4N - 4.0 lbs.
SIM6C - 5.0 lbs.
SIM6L - 5.2 lbs.
How is the SIM turned on and off?
The SIM is turned on and off with the existing ignition switch through the p-lead wire connected to the p-lead terminal of the SIM.
Why is variable timing not available for a turbocharged, turbo-normalized or supercharged engine?
Upon loss of manifold pressure input, a SIM configured for variable timing will calculate advance based upon pressure altitude. In this unlikely scenario, variable timing may result in engine detonation margins too narrow to safely operate a turbocharged aircraft at high altitudes.
Can I use a Bendix harness?
No. The SIM only interfaces with a Slick-type magneto harness. If you are replacing a Bendix magneto, you will also have to replace the Bendix harness with a Slick-type harness.
Can I use automotive spark plugs with a SIM?
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.
Does the SIM output a tachometer signal?
The SIM outputs a 60Vdc spike with a 10Vdc offset on the p-lead (2 pulses per rev for 4 cylinder models & 1.5 pulses per rev for 6 cylinder models).
Will the SIM help my engine start?
Absolutely! Compared to a magneto, the SIM provides a more accurately retarded spark and a more consistent, higher energy spark at low engine RPM. Hot-starts are greatly aided by the installation of a SIM, but keep in mind SureFly can’t remedy fuel system shortcomings!
Should I replace the impulse or non-impulse magneto with a SIM?
SureFly recommends replacing the impulse coupled magneto. This is to reduce the possibility of impulse coupler mechanical failure and also to help the engine start better.
Can I replace both magnetos with SIM’s?
No. At this stage SureFly’s FAA STC only accommodates the replacement of one magneto with a SIM. SureFly intends to certify the replacement of the second magneto in the near-future.
Does SureFly have a SIM replacement for a dual magneto?
Unfortunately not. We expect to work on that after we have certification to replace both magnetos on an engine.
Will the SIM work with Electronics International brand tachometer?
Yes, it is necessary to replace the existing isolator with an inline resistor. Different p-lead wire gages, lengths and ignition switches will require different resistances for the EI tachometer to read the SureFly's p-lead signal. In our experience, most installations require a resistor value from 8K to 18K ohms.
Will the SIM work with Horizon or B&D Industries brand tachometer?
Yes! You will need to install a TACH2 signal converter to make a SIM compatible with a Horizon tachometer. Please call SureFly to discuss the installation.
What are the advantages of a SIM configured for fixed timing over a magneto?
The SIM is a solid-state ignition module with the benefit of improved reliability and zero maintenance (no rebuilds & no overhauls) over the lifetime of the SIM. Another benefit is improved starting.
What is the service life of a SIM?
Return the SIM to SureFly for evaluation after 2400 hours of SIM operation.
Why is variable timing not available for engines that burn less than 100LL fuel?
We have a limitation on our STC because we have only tested the variable timing schedule with 100LL fuel.
What spark energy and voltage does a SureFly output?
We are often asked about how "hot" our spark is. What most people actually mean when they use that term is - "How many volts will your ignition output?"
The truth is, voltage is only half of the equation. The total output energy is measured in millijoules(mJ), and the voltage at the spark plug varies in proportion to the gap of the spark plug. The SIM produces 27mJ of energy at the spark plug (the same as a Slick Mag at 2700 RPM) and 60mJ of energy during start sequence.
Will the SIM work with the tachometers in Garmin and other EFIS and Engine Monitors?
Yes! You will need to have a magnetic pickup installed in the remaining magneto or install a TACH2 signal converter to make a SIM compatible. Please call SureFly to discuss the installation.
What's in the box?
1. SureFly Ignition Module (SIM)
2. Power wire harness (84" long 14ga. wire with inline fuse holder, 10A fuse & ring terminals)
3. Manifold pressure hose (36" long 1/8"ID x 1/4"OD high temp. rubber hose)
4. Engine STC paperwork
5. Airframe STC paperwork
Installation
What is the recommended spark plug gap for the SIM?
SureFly recommends following the spark plug manufacturer's recommendations for plug gap.
Where do I connect the SIM to aircraft electrical power?
SureFly’s STC requires you to connect the SIM directly to the aircraft’s primary battery. You may connect the SIM power wire directly to the battery’s positive terminal or to the battery input terminal of the master solenoid. A power wire harness with terminals is provided with the SIM.
Can I protect the power wire with a breaker instead of a fuse?
Yes, but SureFly advises you to use the provided inline 10A fuse and holder to protect the power wire.
Where is the best place to connect the SIM to manifold pressure?
A 36” long 1/8”ID x 1/4”OD hose is provided with the SIM to connect manifold pressure. The installing mechanic is required to provide appropriate fittings based on the choices below:
Option (a): Tap into existing MAP gauge plumbing with a T-fitting (recommended).
Option (b): Hose barb in threaded port on cylinder head.
Option (c): Hose barb in threaded port along intake track.
What fittings do I need to connect our 1/8” tube to an AN8 hose
Here are a couple fittings that have worked well for other customers:
anhosefittings.com
TR-08-02-A -8AN Male to -8AN Female w/ 1/8” NPT port $15.90
mscdirect.com
MSC Part# 48755003 1/8 NPTF Thread Hose Barb x Male NPT Connector $1.76
Mfr Part# P-201A-2A
Post Installation
What RPM drop should I expect during a Mag check at run up?
You should expect a normal 50-100 RPM drop during a mag check. If the rpm drop is greater on the SureFly, you should verify the remaining magneto is timed correctly - it is not uncommon for the remaining magneto timing to have changed a few degrees from its initial installation.
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.
Another remedy to mask the issue is to reduced power to idle before returning 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.
Can I perform a high voltage lead test?
Yes, but do not perform a high tension lead test with the harness connected to a SureFly. Remove the harness cap from the SIM before testing the leads.
