Surefly SIM4N install in an M20C PIREP

[DXB]

My left Bendix mag failed in flight when I was far from home, leaving me to fly home commercial. Rather than replace it with a conventional mag, I got it swapped it for a Surefly, which I had planned to do at annual in couple weeks anyway.  Here's a PIREP:

Install:

- 4 hours labor seems pretty reasonable for just the mag alone (I paid more because of issues noted below)

- It can go on either side, but put it on the left to derive the potential starting benefits.

- It needs a manifold pressure input if you want variable advance timing - closest MAP input for me was from #4 cylinder head. 

- It needs a power input – taking it directly from the battery positive terminal itself was easiest for me, since it is right next to the left mag in the C model.

- There is a fuse in the power lead provided with the mag. 

- Note there is a very slight continuous current draw from the Surefly even with the master off – they recommend a battery tender if the plane is sitting, so it’s perhaps not a good option for aircraft living on the ramp.

-Bendix mag harness had to be changed to a Slick harness on the relevant side (extra $300 for parts and +2hrs labor)

-Pitfall – NOBODY stocks half harnesses (for just one side), so order well in advance if you need to change a harness or you will have to pay for a full harness. 

-Pitfall – Know how your existing harness is routed before the install starts (mine weirdly had all the bottom plugs running off the left mag and all top plugs of the right). I would have left it the same way had I known, but the installer ended up rerouting the right harness to create the “correct” harness installation on both sides (another 2+ hours labor).

Performance:

-My first startup at about 50F temp without preheat on my carb’d engine was a snap. Temps <=50F usually take a bit more effort for me.

-My mag drop at ground runup on left is slightly less than before, suggesting improved ignition on the left.

-My first flight was at 7500 ft, WOT (MAP 22.7), 2500rpm.  There should be some extra timing advance at this power.  I did notice that I could lean to 8.5gph easily without roughness, whereas I can usually only go down to about 9gph under these conditions.

The only problem I see so far:

When switching from right (conventional mag) to left (Surefly) during a mag check, there is a slight but perceptible lag between turning the ignition key and the Surefly generating spark. This lag did not create an issue during standard ground runup. However, it caused a definite backfire during a subsequent in-flight mag check at the cruise power settings noted above with the engine maximally leaned out.  I suspect this issue will preclude me from doing in flight mag checks, or at least force me to do them at lower power to avoid beating up my exhaust.

[mooniacX]

Thanks for the Pirep DBX. Did you notice any difference on the CHT's during climb? I have been hearing that they run hotter on the C's. Did you notice anything?

[jamesm]

Great report.

Boy now there is going to be a influx left side S200 Bendix magneto's on the market for sale :-O...

I just installed a Surefly in the left position as well  while I had the plane in for annual. 

I think biggest obstacle was in getting Magneto gear in the correct position while keeping the LED out once we figured it  it when pretty smooth,

except  the typically  no room to work.  I had purchased my slick Harness  from Aircraft  Ignition Services, Honey Grove  TX.

My left side routing made it a little short but functional. I have not gotten a chance to really check it out. The weather up here is being a stinker and I have work schedule that isn't cooperating other than the 0.2 hr flight back to my home airport.  

It did seem weird to me on climb out I typically pull the throttle back to 24" or 25" and then the prop to 2400 or 2500 rpm  when I looked at MAP it was at 23" I don't remember pulling it back that much but could have. I wasn't  me since I had been messing with lelft side P-Lead dropping resistor value and the Manifold pressure line spark adviance.   I will have to wait for more predictable weather with higher cloud bases which could be awhile.

 

 

James '67C

 

[J0nathan225]

@DXB what plugs are you running and do you know their gap by chance? 

[DXB]

2 hours ago, mooniacX said:

Thanks for the Pirep DBX. Did you notice any difference on the CHT's during climb? I have been hearing that they run hotter on the C's. Did you notice anything?

I did not notice anything unusual.  I can’t say for sure since I did a couple of full power high speed taxis before takeoff because of the invasive maintenance, so I was starting from a hotter baseline. However I don’t see why it should be hotter at low altitudes in climb - it does not provide any additional timing advance at high MAPs

[DXB]

18 minutes ago, J0nathan225 said:

@DXB what plugs are you running and do you know their gap by chance? 

Fairly new TEMPEST UREM37BYs at whatever gap they come out of the box, I think 0.018 or so.  I think there was a previous recommendation to use 0.032 but now their website says to use the standard gap

[Ragsf15e]

I also just had one installed at annual, so there’s another ebay left  bendix mag... had same issue getting a new left slick harness.  Ended up buying a new Kelly slick harness for both sides as that was cheaper than a single sided champion harness anyway and as you said, nobody has the single side in stock.  New slick harness from Kelly (total for both sides) was $320 on spruce.  So theres a right slick harness for ebay.  Along with a sos and a vacuum pump, I’m gonna fill up ebay.  

Strangely, my sos came off real easy as it appears to be one of the only firewall items with fixed nutplates.  We did leave the sos wiring in place, just capped it.  I couldn’t justify messing with the switch behind the panel.  Too many wires to mess up.

Ive got an F so had to take apart the interior and route the wire to the battery in the back and then up through the firewall.  That was the hardest part of the whole installation.

[J0nathan225]

10 minutes ago, DXB said:

Fairly new TEMPEST UREM37BYs at whatever gap they come out of the box, I think 0.018 or so.  I think there was a previous recommendation to use 0.032 but now their website says to use the standard gap

Yea I had brand new 37BYs, gapped to .019 and the surefly's stronger spark smoked them (we/they think) This is atleast the primary theory, I'm changing the surefly plugs to fine wires and .036 gap and will see if I get any more issues. I lost 2 plugs in flight on the surefly side within 15 mins. 

[ArtVandelay]

Is there some reason why you must connect directly to battery and not the battery side of the master buss (switch)?


Tom

[Ragsf15e]

2 minutes ago, ArtVandelay said:

Is there some reason why you must connect directly to battery and not the battery side of the master buss (switch)?


Tom

You can connect to the battery or the hot side of the master bus according to the install manual... although I don’t have it in front of me.

[Ragsf15e]

5 minutes ago, J0nathan225 said:

Yea I had brand new 37BYs, gapped to .019 and the surefly's stronger spark smoked them (we/they think) This is atleast the primary theory, I'm changing the surefly plugs to fine wires and .036 gap and will see if I get any more issues. I lost 2 plugs in flight on the surefly side within 15 mins. 

Wow, I’m gonna be bummed if it eats spark plugs like that!  I have fine wires, so fingers crossed!

[DXB]

2 minutes ago, ArtVandelay said:

Is there some reason why you must connect directly to battery and not the battery side of the master buss (switch)?


Tom

I’m not great at stuff that involves electrons, but I’m guessing it creates fewer points of failure for power to the surefly?  Having it draw a little power when the master is off may be an undesirable side effect.

[DXB]

1 hour ago, J0nathan225 said:

Yea I had brand new 37BYs, gapped to .019 and the surefly's stronger spark smoked them (we/they think) This is atleast the primary theory, I'm changing the surefly plugs to fine wires and .036 gap and will see if I get any more issues. I lost 2 plugs in flight on the surefly side within 15 mins. 

Wow that’s crazy!! Are those lead deposits? Were they the 2 bottom plugs? Looks like you were running at a pretty typical power and mixture when it happened. Is that hot fouling or cold fouling? Would a different temp rating plug help?  Did you talk to Surefly tech support?  I’m curious what they’d say- they seem very responsive. Also did you check your non-Surefly driven plugs for deposits?  Were they clean?

[DXB]

27 minutes ago, Ragsf15e said:

You can connect to the battery or the hot side of the master bus according to the install manual... although I don’t have it in front of me.

Says battery pos terminal or positive battery input terminal to to the master solenoid - so both options are on same side?

[DXB]

While we are on the topic, I don't really get why the Surefly would aid leaning on a carb'd engine (maybe I'm imagining the apparent benefit I report above).  My understanding was that on an engine with balanced injectors, the timing advance reduces lean misfires.  But on a carb'd engine, the roughness comes from different power outputs from each cylinder while leaning long before it gets too lean for combustion.  I guess the timing advance could still give a little more power to a carb'd engine?  I didn't see obvious evidence of that  however....

[N201MKTurbo]

A hotter spark will ignite a leaner combustion charge. That’s why you can go leaner before it misfires.

Opening the gap will increase the energy in the spark and help with lean combustion. Our mags don’t have enough power to fire across a big gap, but the Surefly does.

As far as those fouled plugs, I would try standard plugs. The BY plugs might not be hot enough to burn off the deposits.

[Brian E.]

Great PIREP--thanks for sharing.  Keep us up to date on the plug situation.   

All issues considered would you recommend switching to Surefly or staying with the legacy mags? 

[DXB]

1 minute ago, N201MKTurbo said:

A hotter spark will ignite a leaner combustion charge. That’s why you can go leaner before it misfires.

Opening the gap will increase the energy in the spark and help with lean combustion. Our mags don’t have enough power to fire across a big gap, but the Surefly does.

As far as those fouled plugs, I would try standard plugs. The BY plugs might not be hot enough to burn off the deposits.

I'm confused as to what the Surefly really delivers in terms of differences in spark - they claim "higher energy".  This means longer duration I think, which might help starting, or in far LOP operation- but otherwise should have no effect?  The carb'd engines don't really get that lean before the power output among cylinders becomes too unbalanced, so C model owners might realize little benefit on the leaning front. 

What you say about the plug temp makes sense.  If I see the same issue that @J0nathan225 does,  I might try standard hotter (UREM40MRE) plugs at the Surefly positions rather than going to fine wires with a wider gap.   I'm really curious to know how many hours it took for his two plugs to get so badly fouled, and how all his other plugs looked - did the other two Surefly driven plugs also have more deposits?

[DXB]

27 minutes ago, Brian E. said:

All issues considered would you recommend switching to Surefly or staying with the legacy mags? 

No regrets at 4 hours into running the Surefly - too early to tell though. I'll keep this thread updated.  As a natural pessimist, I haven't torn out my SOS system yet .

[Niko182]

Additional note on the backfire. Its normal that it does it with a conventional ignition switch. When you jump from the mag to the EIS, it needs about 20 miliseconds of time to setup and get ready, meaning for those 20 miloseconds, you have no ignition, followed by the EIS starting up. So if you time the switch perfectly, theres a chance of backfire. The reason electro air had those nice ignition switches made was so that when doing the mag tests, you could test one mag, turn both on, and test the eis, and then get both without having to jump from left to right to both.

Edited December 17, 2019 by Niko182

[J0nathan225]

It took 15 mins. After PLing at falcon field the plugs were cleaned and tested well. I took off with GREAT power and at 6500' enroute to 8000' I lost my #3 plug on the surefly side again. I'm switching to the massive 38s for my magneto and going to try running 4 fine wire on my surefly side. The worst plug you saw was from the top of 4. 

[rbridges]

12 hours ago, DXB said:

No regrets at 4 hours into running the Surefly - too early to tell though. I'll keep this thread updated.  As a natural pessimist, I haven't torn out my SOS system yet .

I'm thinking of going down that road with AGL.  I was told people generally keep the SOS b/c it's a pain to remove.

[Immelman]

3 hours ago, J0nathan225 said:

It took 15 mins. After PLing at falcon field the plugs were cleaned and tested well. I took off with GREAT power and at 6500' enroute to 8000' I lost my #3 plug on the surefly side again. I'm switching to the massive 38s for my magneto and going to try running 4 fine wire on my surefly side. The worst plug you saw was from the top of 4. 

Just curious have you contacted surefly on your plug issue?

I may be in the market for one of these soon and yours is the only concerning report, so I'm very curious to hear what the problem might be.

[Marauder]

Says battery pos terminal or positive battery input terminal to to the master solenoid - so both options are on same side?

For those of us with rear batteries, I think the master solenoid is in the avionics bay with the battery.


Sent from my iPad using Tapatalk Pro

[Marauder]

I'm thinking of going down that road with AGL.  I was told people generally keep the SOS b/c it's a pain to remove.

On my F, the SOS is mounted on a plate that is attached to the firewall. It is in one of the most difficult locations under our panels to reach (behind the avionics stack and up high). My mechanic and I had to loosen the plate to get to the nuts on the voltage regulator. There was not much play in the wires and of course over the years, they had mounted other stuff on the panel.




Sent from my iPad using Tapatalk Pro