High CHT, 470 degrees +.

[ragedracer1977]

On 4/6/2020 at 10:43 PM, MikeOH said:

Do you know you had the issue BEFORE the new mag? How about BEFORE the Surefly?

When you say the timing was checked at 25 degrees, that was only for the mechanical mag, correct?

I'm just suspicious of the electronic mag.  Take a flight, get the #4 CHT temp up and then kill the Surefly mag...see if the CHT drops.  That would at least eliminate the Surefly as a contributor.  Do the same with the mechanical mag.

Quoting this as an update.  @EricJ and I went and flew it today.  Temps were better, 20-30 degrees cooler at full throttle, full rpm.  Much higher (near 18gph) fuel flow. 

But something is wrong with the surefly mag side. We ran it on just the Bendix for a while.  Temps on #4 came down to about 380.  Switched to the surefly, temp nearly immediately jumped to 400 and then a steady climb to 430+.   And then it started stumbling.  We ran it on the surefly mag for a while, a few minutes, and it was very "stumbly".  Rich or lean didn't make much of a difference.  

We were at 5500', 2400rpm, 23 ish inches.  75% power or so.  I haven't downloaded the data yet, but I'm hoping I can see the stumbling in the data.  Besides it *really* advancing the timing, I can't see how it could temps that quickly.  I mean it was nearly an instant jump.  And then the rough running.  Plug going bad? Bad harness? 

But we now have a carburetor providing the correct amount of fuel.  We know the doghouse is good (Bendix cht temps were really good), we know there isn't any intake or exhaust leaks.

So it seems to be narrowed down to an ignition system issue on the surefly side.

[MikeOH]

36 minutes ago, ragedracer1977 said:

Quoting this as an update.  @EricJ and I went and flew it today.  Temps were better, 20-30 degrees cooler at full throttle, full rpm.  Much higher (near 18gph) fuel flow. 

But something is wrong with the surefly mag side. We ran it on just the Bendix for a while.  Temps on #4 came down to about 380.  Switched to the surefly, temp nearly immediately jumped to 400 and then a steady climb to 430+.   And then it started stumbling.  We ran it on the surefly mag for a while, a few minutes, and it was very "stumbly".  Rich or lean didn't make much of a difference.  

We were at 5500', 2400rpm, 23 ish inches.  75% power or so.  I haven't downloaded the data yet, but I'm hoping I can see the stumbling in the data.  Besides it *really* advancing the timing, I can't see how it could temps that quickly.  I mean it was nearly an instant jump.  And then the rough running.  Plug going bad? Bad harness? 

But we now have a carburetor providing the correct amount of fuel.  We know the doghouse is good (Bendix cht temps were really good), we know there isn't any intake or exhaust leaks.

So it seems to be narrowed down to an ignition system issue on the surefly side.

Glad you are narrowing this down.  Have you called Surefly?  Maybe time to pull that Emag and sent it to them.

[ragedracer1977]

32 minutes ago, MikeOH said:

Glad you are narrowing this down.  Have you called Surefly?  Maybe time to pull that Emag and sent it to them.

I'm going to reach out to them tomorrow and see what the heck.  I checked the timing, and it's showing good.  Also, it's the starting magneto.  I would imagine if it was that far off, I'd have starting problems, but it fires right up.  It starts like a modern fuel injected toyota, lol.  

[N201MKTurbo]

I’ve never installed a Sure Fly, are you sure you have timed right?

[ragedracer1977]

1 minute ago, N201MKTurbo said:

I’ve never installed a Sure Fly, are you sure you have timed right?

see above.  I'm pretty sure.  You set the engine to TDC, then the surefly has a light on it, sort of like a magneto timing box.  It shows you when the magneto is also at TDC, and you torque the hold down nuts while watching the light.  

Don't laugh, but I was very very careful to be exactly at TDC.  I used the soup bowl thing on the spinner, the piston stop pin, etc, and then verified I was at TDC with a digital dial indicator.  If its off, it's by 100ths of a degree.  

Edited April 16, 2020 by ragedracer1977

[MikeOH]

Just now, ragedracer1977 said:

I'm going to reach out to them tomorrow and see what the heck.  I checked the timing, and it's showing good.  Also, it's the starting magneto.  I would imagine if it was that far off, I'd have starting problems, but it fires right up.  It starts like a modern fuel injected toyota, lol.  

My suspicion is that an electronic mag does NOT have a fixed timing; rather, its advantage over a conventional mag is its ability to vary the timing.  I have no doubt the timing is perfect for starting....it's during climb/cruise that I suspect the timing is out of wack.

[ragedracer1977]

Just now, MikeOH said:

My suspicion is that an electronic mag does NOT have a fixed timing; rather, its advantage over a conventional mag is its ability to vary the timing.  I have no doubt the timing is perfect for starting....it's during climb/cruise that I suspect the timing is out of wack.

agreed.  In theory, it shouldn't be advancing the timing at takeoff, but it could be if something's wrong.  If I capped off the MAP line to it, would it not advance at all, because it's not seeing a MAP decrease?  This is an advance schedule I found, but I don't know the accuracy

.

[MikeOH]

You could be right, but at this point, it seems the Surefly has provided sufficient evidence that it should be sent to the manufacturer.  The damming result was the drop in CHTs when you turned it off.

[ragedracer1977]

2 minutes ago, MikeOH said:

You could be right, but at this point, it seems the Surefly has provided sufficient evidence that it should be sent to the manufacturer.  The damming result was the drop in CHTs when you turned it off.

That and as @EricJ can testify, if my engine started running like it did on just the surefly, I'd be looking for a place to land, right now.  I think we both expected it to quit any moment.

back to both and as smooth as it could be.  

Edited April 16, 2020 by ragedracer1977

[EricJ]

15 minutes ago, ragedracer1977 said:

That and as @EricJ can testify, if my engine started running like it did on just the surefly, I'd be looking for a place to land, right now.  I think we both expected it to quit any moment.

back to both and as smooth as it could be.  

Yeah, it was an unhappy motor running just on the surefly.   It seems like it had multiple issues:   it would randomly sputter and run rough, then smooth out again, and the CHTs and EGTs went way up, especially the #4 problem child.   Running on just the Bendix magneto it was very smooth, and the CHTs and EGTs all tamed down very nicely and were nicely even across cylinders.   While the new carb obviously helped and was a step in the right direction, somethin' ain't right with the surefly.

It was a very useful test flight.  With luck maybe something will be obvious or definitive in the download data.

[ragedracer1977]

6 minutes ago, EricJ said:

Yeah, it was an unhappy motor running just on the surefly.   It seems like it had multiple issues:   it would randomly sputter and run rough, then smooth out again, and the CHTs and EGTs went way up, especially the #4 problem child.   Running on just the Bendix magneto it was very smooth, and the CHTs and EGTs all tamed down very nicely and were nicely even across cylinders.   While the new carb obviously helped and was a step in the right direction, somethin' ain't right with the surefly.

It was a very useful test flight.  With luck maybe something will be obvious or definitive in the download data.

I didn't see anything specific, but I have no idea what I'm looking for.  Hopefully @kortopates can give some insight when it comes across his 'desk'

[takair]

You can switch the surefly to fixed timing to see if it changes things.  Unfortunately, you likely need to pull it to do that.  Be sure the timing sequence is right.  I had one SureFly with failed dip switch and the sequence was wrong, meaning the advance was wrong.  I had to do it a number of times to believe my eyes.   At first glance, the pulse looked close enough....but was not...

[Shadrach]

8 hours ago, MikeOH said:

You could be right, but at this point, it seems the Surefly has provided sufficient evidence that it should be sent to the manufacturer.  The damming result was the drop in CHTs when you turned it off.

The damning result was when he ran the Surefly alone and it ran rough.   When running conventional mags, CHTs always drop when running on a single mag. Not so with variable timing mag.  The Surefly advances timing and should be expected to generate higher CHTs as the whole point of the damn thing is to better synchronize the combustion (pressure) event with the piston power stroke.  If it acted like a conventional mag, there would little point to the installation. 

Edited April 16, 2020 by Shadrach

[DXB]

4 hours ago, Shadrach said:

The damning result was when he ran the Surefly alone and it ran rough.   When running conventional mags, CHTs always drop when running on a single mag. Not so with variable timing mag.  The Surefly advances timing and should be expected to generate higher CHTs as the whole point of the damn thing is to better synchronize the combustion (pressure) event with the piston power stroke.  If it acted like a conventional mag, there would little point to the installation. 

Surefly only advances timing under very specific conditions- It wont do so at anywhere near takeoff power.  Installs where there the STC does not allow advanced timing are still marketed as worthwhile because of the much longer service life and better starting - I can personally attest to the latter being an impressive improvement. Someone here recently mentioned they had bad fouling on the plugs served by the Surefly - the same phenomenon would explain the high EGT and roughness on that side but not the high CHT obviously.  As an early adopter of the Surefly, I'm anxious to hear if it turns out to be a failure of the Surefly unit itself.  

[EricJ]

5 minutes ago, DXB said:

Surefly only advances timing under very specific conditions- It wont do so at anywhere near takeoff power.  Installs where there the STC does not allow advanced timing are still marketed as worthwhile because of the much longer service life and better starting - I can personally attest to the latter being an impressive improvement. Someone here recently mentioned they had bad fouling on the plugs served by the Surefly - the same phenomenon would explain the high EGT and roughness on that side but not the high CHT obviously.  As an early adopter of the Surefly, I'm anxious to hear if it turns out to be a failure of the Surefly unit itself.  

FWIW, the roughness it was exhibiting wasn't normal "rough" operation due to excessive timing or leaning, it was "it's failing" kind of roughness.    To me it seemed like it was either just going totally intermittent or occasionally just dropping a cylinder for a while.   It would do it for a second or two and then be okay for a while, do it again, etc.   Maybe it'll be more evident on the data what it was doing, or at least I'm hoping so.

 

[ShuRugal]

FWIW, the roughness it was exhibiting wasn't normal "rough" operation due to excessive timing or leaning, it was "it's failing" kind of roughness.    To me it seemed like it was either just going totally intermittent or occasionally just dropping a cylinder for a while.   It would do it for a second or two and then be okay for a while, do it again, etc.   Maybe it'll be more evident on the data what it was doing, or at least I'm hoping so.
 

Bad plug? Cracked wire? That sounds like a "spark isn't getting from the mag to the plug" issue, not a "mag isn't sparking" issue

[carusoam]

This morning’s PP summary...
 

1) Nice to see the FF back where it makes sense... matching Brian’s carb (prior data)

2) tough to hear news about the electronic mag...

• Possible timing dip switch challenges noted by Rob...
• Something clearly isn’t working as designed...

3) Looking forward to seeing...

• the JPI data
• Surefly’s response
• Savvy’s response

4) Great MSer Detailed input..!

• @ragedracer1977
• @EricJ

5) Continue to keep both eyes open for other standard challenges as @ShuRugal reminded us...

• plugs
• wires
• or something that could have been affected by the installation of the new mag, or by the new mag’s stronger output...

With all that... the solution is almost here.

Stay the course... 

PP thoughts only, not a mechanic...

Best regards,

-a-

[Shadrach]

16 minutes ago, DXB said:

Surefly only advances timing under very specific conditions- It wont do so at anywhere near takeoff power.  Installs where there the STC does not allow advanced timing are still marketed as worthwhile because of the much longer service life and better starting - I can personally attest to the latter being an impressive improvement. Someone here recently mentioned they had bad fouling on the plugs served by the Surefly - the same phenomenon would explain the high EGT and roughness on that side but not the high CHT obviously.  As an early adopter of the Surefly, I'm anxious to hear if it turns out to be a failure of the Surefly unit itself.  

So in looking at the timing map posted earlier it appears the advance begins at 25inHg.  The map has a base timing of 20BTDC which is 5° retarded of spec.  Do you know if the Surefly base timing is at 25° per Lycoming specs or are they using 20° depicted in their timing MAP?  The DA in Phoenix today is 2218' not hard to imagine that the surefire is starting to advance a minute or so into the climb. Does it use some other parameter other than MP and RPM to determine advance?

[EricJ]

45 minutes ago, ShuRugal said:

54 minutes ago, EricJ said:

FWIW, the roughness it was exhibiting wasn't normal "rough" operation due to excessive timing or leaning, it was "it's failing" kind of roughness.    To me it seemed like it was either just going totally intermittent or occasionally just dropping a cylinder for a while.   It would do it for a second or two and then be okay for a while, do it again, etc.   Maybe it'll be more evident on the data what it was doing, or at least I'm hoping so.
 

Bad plug? Cracked wire? That sounds like a "spark isn't getting from the mag to the plug" issue, not a "mag isn't sparking" issue

Definitely a possibility.   If a wire or plug is intermittent it would explain the occasional rough running.   The bigger issue was the high temps, which may be timing or something.  It seemed like there were multiple problems.   Fingers crossed that something useful shows up in the data.

 

[DXB]

1 hour ago, Shadrach said:

So in looking at the timing map posted earlier it appears the advance begins at 25inHg.  The map has a base timing of 20BTDC which is 5° retarded of spec.  Do you know if the Surefly base timing is at 25° per Lycoming specs or are they using 20° depicted in their timing MAP?  The DA in Phoenix today is 2218' not hard to imagine that the surefire is starting to advance a minute or so into the climb. Does it use some other parameter other than MP and RPM to determine advance?

I think it's just RPM and MP.  Base timing is set based on the DIP switches in the unit, as per specific STC parameters related to the engine.  Mine is 25BTDC as is OPs, so advance may come at lower MP/RPM combinations.  It's worth noting Surefly stopped publishing advance curves, and this one was meant to be conceptual, not precise for any particular engine.  

[ragedracer1977]

I spoke to surefly this morning, I explained all the issues that I was aware of (hot#4, etc) and they said it sounded like it was mistimed considerably.  They specifically told me that the surefly could not effect only one cylinder, because its a wasted spark system I believe is how they explained it.  They said if it was a problem with the surefly, I would have to see misfiring on a cylinder pair, ie 1/3 or 2/4. 

 

I received my analysis back from Savvy.  They said "pronounced misfire on #2 & 4, weak spark on entire surefly". Looks like we might have confirmation.  

 

We checked the timing, and it is dead on.  If it's off, its way less than 1/2 degree, which could not cause the issues I'm seeing. 

 

I'll be sending the magneto back to them tomorrow, we'll see what they have to say!

 

[carusoam]

Brice,

Does the old link have your latest JPI data associated with it?

Wondering what that looks like now...

Best regards,

-a-

[Shadrach]

29 minutes ago, ragedracer1977 said:

I spoke to surefly this morning, I explained all the issues that I was aware of (hot#4, etc) and they said it sounded like it was mistimed considerably.  They specifically told me that the surefly could not effect only one cylinder, because its a wasted spark system I believe is how they explained it.  They said if it was a problem with the surefly, I would have to see misfiring on a cylinder pair, ie 1/3 or 2/4. 

 

I received my analysis back from Savvy.  They said "pronounced misfire on #2 & 4, weak spark on entire surefly". Looks like we might have confirmation.  

 

We checked the timing, and it is dead on.  If it's off, its way less than 1/2 degree, which could not cause the issues I'm seeing. 

 

I'll be sending the magneto back to them tomorrow, we'll see what they have to say!

 

Wasted spark means that the mag is firing the plug at the top of the exhaust stroke as well as the compression stroke. It’s common on motorcycle ignitions (at least the old ones with which I like to tinker). I am really interested to see how this shakes out.

[ragedracer1977]

33 minutes ago, Shadrach said:

Wasted spark means that the mag is firing the plug at the top of the exhaust stroke as well as the compression stroke. It’s common on motorcycle ignitions (at least the old ones with which I like to tinker). I am really interested to see how this shakes out.

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

Edited April 17, 2020 by ragedracer1977

[ragedracer1977]

1 hour ago, carusoam said:

Brice,

Does the old link have your latest JPI data associated with it?

Wondering what that looks like now...

Best regards,

-a-

Heres the flight where the surefly was acting up big-time.

 

https://apps.savvyaviation.com/flights/3861707/27abca39-3ebf-4d43-836b-08e4b84b39e3