Surefly SIM, Hot Starts, & Kick back

[Bcone1381]

Service Difficulty: My Lycoming IO-360 is very difficult to hot start and (rarely) has kickback during start despite taking precautions to avoid this.

My Goal:

• The SIM delivery of confident Spark every time every cylinder reaches TDC on the start’s compression stroke.
• Eliminate all kickback risk during hot starts.

Relevant Data:

• Mechanical FI, Bendix
• SIM (Surefly Ignition Module) is timed to fire 5 ATDC during start. I deviated from install instructions attempting to avoid kickback during hot starts. It helped 90%.
• EarthX battery
• Voltage during start is satisfactory.
  • measured & graphed at the starter during start
  • V has also been found to be satisfactory on the ships Voltage meter.
  • the starter confidently spins the engine verifies this data.

Data I desire to collect:

• See the ignition system fire trigger timing light during hot starts just to see that power is reaching the spark plug.
  • Can I see the position of the crank during the start anyway?
• Judge if the EarthX Battery paired with the SIM is a factor.
  • Will the engine start better with a separate EarthX battery powering the SIM?
  • Will the engine start better with a lead acid batter powering the SIM?
• Measure the Temperature of the case of the SIM.
  • is the starting problems related to SIM temp?
  • Temperature tolerances exist for the SIM….I wonder what they are and how close I am to them during a challenging het start.
• Data from other SIM/EarthX users.

Kickback Avoidance

• Kickbacks can cause damage. They will cause wear and tear on starter pinions and ring gears
• I will continue Kickback avoidance
  • Keep SIM timed 5 ATDC.
  • Limit start attempts to 10 blades per attempt, and two start attempts per minute.
  • Cool down the engine compartment before starting when possible.

 

[lr172]

• See the ignition system fire trigger timing light during hot starts just to see that power is reaching the spark plug.
  • Can I see the position of the crank during the start anyway?

Yes, you can observe WHERE the spark is firing. Set the timing light up on #1. Set crank to TDC. Make a pointer that attaches to the upper case and terminates near the flywheel. Use a sharpie to mark the flywheel with TDC. Move crank to 25* BTDC and make another mark. Now make some other graduated marks in between. Crank away and observe. You can go to ICO to prevent starting, but do not pull plugs out of cylinders. The lack of compression will cause the RPMs to rise above the starting threshold and the sim will think it is in run mode and advance accordingly. If you don't see any of your marks and the light is flashing, the SIM has likely gone wonky and sparking outside of the range you set up. you can put numbered marks all over the flywheel to pin this done. use laquer thinner to remove when done.

 

[Walt]

Maybe try installing a PC680 just for grins, easy to do and eliminate the EX as a variable.

 

[bjdecker]

also out of curiosity, what is the voltage at the SIM connector during cranking? (Not on the EFIS/EIS screen, or gauge on the panel)...

Which part of the engine case is the ground wire connected -- left half (starter side) lug at bottom motor mount, right half (alternator side) lug at bottom motor mount, accessory case (magnetos, fuel pump, prop governor, etc.), or bottom oil sump/induction, or other?