High CHT, 470 degrees +.

[carusoam]

I bet the Surefly guys are interested in that...

 

Trying to relate that back to the wasted spark comment as well...

A standard mag unknowingly sparks on the top of each upstroke of each cylinder....

On the exhaust stroke, the spark goes off and nobody notices it... there is no fuel left to burn...

It would take a logic snafu for the Surefly to send a spark on the exhaust stroke...

Logic or a funky install error out of sync by 180°...

Thanks for sharing the details.

Best regards,

-a-

[Shadrach]

1 hour ago, ragedracer1977 said:

I'm not sure if the wasted spark system is why, but they for sure said that the way the surefly works, it's not possible for it to fail in such a way that only effects one cylinder.  If there's something wrong with it, by design, it has to effect both cylinders on that side.  

I'm not sure, but assume, the 6 cylinder version functions the same way

Indeed it does. All cylinders indexed 180° Out of sync fire at the same time. Spark fires on both compression and exhaust strokes. It’s a simpler design.

[ragedracer1977]

1 hour ago, carusoam said:

I bet the Surefly guys are interested in that...

 

Trying to relate that back to the wasted spark comment as well...

A standard mag unknowingly sparks on the top of each upstroke of each cylinder....

On the exhaust stroke, the spark goes off and nobody notices it... there is no fuel left to burn...

It would take a logic snafu for the Surefly to send a spark on the exhaust stroke...

Logic or a funky install error out of sync by 180°...

Thanks for sharing the details.

Best regards,

-a-

I don't think it would be possible to install it 180 out.  Well, I guess you could, but I don't know that it would work at all.  If it was installed 180 out, then the Bendix mag would be as well.  

[ragedracer1977]

Surefly is on its way back to them today.  Spoke to tech support and they asked a bunch of questions, I'd already done everything they would have suggested, and with the savvy data showing its misfiring alot on a cylinder pair, they're ready to take a look at it

[ragedracer1977]

Bendix mag installed in the left.  

To say things improved is an understatement.

[orionflt]

glad you got to the bottom of the issue.

Brian

[HRM]

So we're done here. Bendix mag to the rescue. Who would have thought...

[ragedracer1977]

12 minutes ago, HRM said:

So we're done here. Bendix mag to the rescue. Who would have thought...

Now I'm curious to see what surefly has to say about whats wrong with it

[Ragsf15e]

Ok, stupid (very stupid) question... are you sure which mag is “hot” and which is grounded in each key position.  And if you have a good way to remember that, please tell me.  I.e. - is the left position on the key running on the left mag or grounding the left mag?

 I also have a SF.  I had an ignition issue after annual (not a SF issue).  Only way I could get it straight in my mind was that the engine has a slight miss when cycling from the mag to the SF due to the SF “boot up” time.  I had to cylinder through a few times, listening for the miss and then consider which mag was running in which position.

My problem was loose ignition leads causing radio noise, so clearly not the same.  Just wanted to make sure you thought it through.

 

[ragedracer1977]

Yes.  When the key is on R, the right mag is working.  When it's on L, the left mag is working.  

 

[carusoam]

Typically the key position is a bit mis-leading...

the left most position is for the R mag.

they are marked.... off, R, L, B, Start...

Most likely, the only way to know this is testing the P wires for continuity with each switch position...

I currently, am going on the faith of the people that assembled my ignition system...   

Both of my mags are near identical... one isn’t preferred for any reason... or is it?

PP thoughts as usual...

Best regards,

-a-

[Ragsf15e]

20 minutes ago, carusoam said:

Typically the key position is a bit mis-leading...

the left most position is for the R mag.

they are marked.... off, R, L, B, Start...

Most likely, the only way to know this is testing the P wires for continuity with each switch position...

I currently, am going on the faith of the people that assembled my ignition system...   

Both of my mags are near identical... one isn’t preferred for any reason... or is it?

PP thoughts as usual...

Best regards,

-a-

Checking the P leads to confirm ground in different key positions is probably a good idea... the wires come through the firewall together and look the same.  My airplane is 52 years old.  How many times have they been disconnected/reconnected?

 

Edit: but now that I think about it, you’d have significant starting issues if it was wired backwards.  

[DXB]

Boy this is a spectacularly interesting thread for a fellow Surefly early adopter and C model owner. I have a left Surefly, and I've had much higher #4 temps on takeoff whose cause still eludes me - though it's not as terrible as for @ragedracer1977.  It ain't the fuel flow (always 17-18 gph at takeoff). It ain't the baffling - I've meticulously brought mine up to snuff over years. It ain't the timing - I was sure that was it because it coincided with the #4 problem appearing (overhauled R bendix mag was installed a couple months after the Surefly), but I had the R side tuned up to no effect.  Oddly the hot #4 problem is there only during climb and low altitude cruise and goes away in high altitude cruise, where #2 goes back to being the problem child, like it's always been.   It's like the Surefly is advancing at low altitude and high power, when it shouldn't.  Mine doesn't run rough on the left side though.  Maybe I have a minor version of the same problem?

[carusoam]

At the ignition switch, things can easily be mis-wired... all the wire ends there... can easily reach the wrong post...

But... the way things need to be wired for a successful start is pretty limited... the Left mag gets the responsibility of adjusted timing for start...

The question I always have... is the Left mag on the pilot side..?
Or is it on the left while standing in front of the engine, co-pilot side?

I always have this question, because I can’t remember the answer... the answer has never been very helpful... 
 

If you only have one good mag... make sure the bad one is getting swapped out no matter what it’s named....  

I always relate the switch position to the mechanic doing the work... my engine stumbled when the switch was in the L position...

I feel better that way...

 

Now for the other topic... carbs with two fuel jets...

We would need a pic to see how these two jets are spraying.... what they are spraying at... and how things change when the secondary jet shuts off...

The spray patterns probably aren’t extremely uniform before getting to the four intake tubes...

But, that is where the fun of adjusting Carb temp and closing the throttle valve some comes into play...

To make any changes to that situation... getting the fuel injector STC probably makes more sense...

PP thoughts only...

Best regards,

-a-

[carusoam]

Brice,

Those CHTs look fantastic!

Any measurable (or seat of the pants) power change come with that?

Best regards,

-a-

[ragedracer1977]

20 minutes ago, DXB said:

Boy this is a spectacularly interesting thread for a fellow Surefly early adopter and C model owner. I have a left Surefly, and I've had much higher #4 temps on takeoff whose cause still eludes me - though it's not as terrible as for @ragedracer1977.  It ain't the fuel flow (always 17-18 gph at takeoff). It ain't the baffling - I've meticulously brought mine up to snuff over years. It ain't the timing - I was sure that was it because it coincided with the #4 problem appearing (overhauled R bendix mag was installed a couple months after the Surefly), but I had the R side tuned up to no effect.  Oddly the hot #4 problem is there only during climb and low altitude cruise and goes away in high altitude cruise, where #2 goes back to being the problem child, like it's always been.   It's like the Surefly is advancing at low altitude and high power, when it shouldn't.  Mine doesn't run rough on the left side though.  Maybe I have a minor version of the same problem?

I think there's been something wonky with mine from the start. I had problems initially with missing and what not, and they convinced me it was timing. So I fixed it, and then put in fine wires.  Still had some random weirdness, and now we're here

[ragedracer1977]

Just now, carusoam said:

Brice,

Those CHTs look fantastic!

Any measurable (or seat of the pants) power change come with that?

Best regards,

-a-

Not that I could tell specifically.  It was a really rough day though.  30+ knot winds at 3000 agl, and they were nasty.

[Guest]

8 hours ago, HRM said:

So we're done here. Bendix mag to the rescue. Who would have thought...

Long live the magneto!

Clarence

[HRM]

54 minutes ago, M20Doc said:

Long live the magneto!

Clarence

Yep! 

[DXB]

3 hours ago, M20Doc said:

Long live the magneto!

Clarence

Can't say I fully share the sentiment, but I did keep my SOS and wiring in place after my Surefly install.  I'm still hoping my humility doesn't pay off 

[Andy95W]

11 hours ago, M20Doc said:

Long live the magneto!

Clarence

Agreed!

(But only until my SOS craps out or my left magneto needs it next 500 hour inspection.  That's the day I order a Surefly.)

[MIm20c]

56 minutes ago, Andy95W said:

Agreed!

(But only until my SOS craps out or my left magneto needs it next 500 hour inspection.  That's the day I order a Surefly.)

I’m sitting here with the plan of sending both off for an iran or buying one of these. This thread has me leaning towards sending them both to a reputable shop. 

[Guest]

There are no options for the IO-720, for me I’ll keep maintaining my trusty Bendix magnetos.

Clarence

[takair]

1 hour ago, M20Doc said:

There are no options for the IO-720, for me I’ll keep maintaining my trusty Bendix magnetos.

Clarence

Those must be massive magnetos!  8 outputs?  Can you still get parts?

[takair]

1 hour ago, MIm20c said:

I’m sitting here with the plan of sending both off for an iran or buying one of these. This thread has me leaning towards sending them both to a reputable shop. 

For what it’s worth, I’m just coming up on 100hours on mine.  Small snafu at initial install, but their support was great and performance has been great.  Will be curious what the outcome of this issue is.