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Installing SureFly, wierd issue with rough idle and hard starting


msh9

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Hey all, thought I would throw a post out there to see if anyone with experience could help. I just got my IO-360-A1A back from a tear down / IRAN due to a case crack and decided to replace the left mag with a SureFly unit. The issue is that the engine is now incredibly hard to start and runs rough on both mags. Once started it runs happily on the old, existing, right mag. My mechanic and I are pulling our hair out over what's wrong. I'll list the things we've tried,

  • Double checked the engine ground, we're using a new copper braid from the engine to the firewall
  • Double checked that the p-lead is the correct, advance wire, used with the origin SoS system and original left mag
  • Ensured that the SureFly was installed timed to TDC on cylinder #1 with dip switches set to 25 BTDC base timing
  • Bought, installed, and tried in both directions the expensive $300 mag drive gear (I originally had the the single woodruff slot drive gear)
  • Checked for split timing between the two mags. My engine has the older base timing of 25 degrees BTDC.
  • We bought a New Horizons Maggie harness for use with the SureFly and we've checked that the leads are good
  • I am currently using massive spark plugs (will use fine wires in the future, but the current set of plugs all test fine). We also re-gapped them to .032.

The engine is behaving like the surefly is mistimed and firing at the wrong time. We just cannot figure out why though. Any thoughts? I really appreciate the help!

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MSH,

There is plenty of experience written up around here from a certain gear in some mags to electric conditioning….

You might want to find those threads and study what the existing problems have been…. And see if you took care of those…

There is some value of going with the existing experience, than trying to start fresh…. As if everything is going to work out of the box as expected…

Expect there is probably a bad gear that doesn’t allow the timing to be quite right… your mechanic should have found this during the install… If you have the bad gear, a new one is easily available…

How many Sureflys has your mechanic installed?

PP thoughts only, not a mechanic…

Best regards,

-a-

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3 minutes ago, carusoam said:

MSH,

There is plenty of experience written up around here from a certain gear in some mags to electric conditioning….

You might want to find those threads and study what the existing problems have been…. And see if you took care of those…

There is some value of going with the existing experience, than trying to start fresh…. As if everything is going to work out of the box as expected…

Expect there is probably a bad gear that doesn’t allow the timing to be quite right… your mechanic should have found this during the install… If you have the bad gear, a new one is easily available…

PP thoughts only, not a mechanic…

Best regards,

-a-

Yup found those threads and did indeed buy the overpriced gear. Unfortunately that didn't seem to resolve the issue, rotated either direction no less.

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Got an engine monitor?

The run up data can usually shed light on the differences between the mags and their timing…

From your description… it sounds like the timing can be off…

How many sureflys has your mechanic installed?

If you have a JPI, and can down load the data… send it to savvy, click the share button, post the link here…

There are a few MSers that can read the graphs… expect that if you haven’t done this before, there is plenty to know about the run-up to optimize the data you are trying to collect…

Best regards,

-a-

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6 minutes ago, msh9 said:

Yup found those threads and did indeed buy the overpriced gear. Unfortunately that didn't seem to resolve the issue, rotated either direction no less.

Interesting, when you set up the dip switches, did you enable advance timing?  How did you hook up the manifold pressure?

Is this 28v or 14v airplane?

 I would call SF.  They have reasonably good support.  Mine worked perfectly straight out of the box.

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From your description it has to be the Surefly.

1 hour ago, msh9 said:

Checked for split timing between the two mags. My engine has the older base timing of 25 degrees BTDC.

This statement doesn't make a lot of sense, if you're referring to checking timing with the timing light on the Surefly and magneto timing box on the right mag - they should be split by 25 degrees

Since you installed a new maggie harness on the Surefly, I'd double check you have the wires routed properly to the correct cylinders - it may have a couple crossed explaining the roughness and starting difficulty.

Otherwise it seems you have a timing issue and if everything else checks out I'd try with the MAP advance turned off.

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I agree with @Ragsf15e, get in touch with SureFly's support.  They helped me through my initial problems.  Mine were harness related, so it appears that you have covered that issue with the Maggie harness.

One of the first areas we addressed with Surefly support with my issue was power delivery.  Where did you install the tap for your power?  With an E model, your battery is almost certainly behind the luggage compartment.  Did you go back there for your connection?  The closer to the battery the better.   The supplied power wire is too short to get to the battery box.    What kind of connections did you make along the way?  Are you sure they are solid against the rhythmic assault our planes and their components undergo?  Power jumping around can apparently give this problem.  Especially if the power gets above ~32v sometimes (I forget the correct number but somewhere up there) the Surefly will shut off in protection mode and restart, causing late firing, Your E model should be 12v... so the high voltage --shouldn't-- be a problem...but might be worth a check.  But the other side is low voltage dropouts...could also be a symptom of a bad regulator...maybe a bad diode on an alternator would push the voltages to above the cutout threshold...

@kortopates just made an excellent point.  Checking for split timing doesn't make any sense with the surefly.  It is a point of contention in my upkeep of the system.  I really like to hear the buzzers and have the lights turn on together when I time magnetos.  There is no way to do that with a surefly next to a old style mag.  Are you certain that you didn't time it to 25btdc and it's trying to fire @ 50btdc?  As always, check your timing marks, too.  But make certain that the light is turning off at the 0 deg mark, not the 25btdc mark.

Hope that's helpful.  I love mine.  I had to put it on standard timing at this recent annual due to the engine running a little hot, but I love how there is virtually no mag drop on the surefly.  I'm confident that you can get it to work for you!

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An acquaintance mistakenly timed his SureFly on his G model to the “#1” line stamp (red arrow) on the ring gear, rather than the line stamp that is the actual Top Center timing mark (green arrow).  It made a difference.  (Apologies if this was not helpful.)

image.png

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The timing on the SureFly would have to be out by quite a bit to cause rough running. If it’s running rough on both, the SureFly mag is starting the combustion event well before the legacy mag. If it wasn’t, the SureFly would only cause problems when running as a single.

Good idea to verify the plug wires are going to the correct place (as others have said) but I think the SureFly is running way to much timing advance for some reason.

 

Edited by Shadrach
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15 hours ago, msh9 said:

Once started it runs happily on the old, existing, right mag.

  • Double checked that the p-lead is the correct, advance wire, used with the origin SoS system and original left mag
  •  
  • Checked for split timing between the two mags. My engine has the older base timing of 25 degrees BTDC.
  •  

Agree with previous posts, not sure what do you mean by checking split timing...

Also - You are saying the engine would run on the original Right magneto but then you checked the SoS system... do you still have that installed? 

I have installed the (same) Surefly twice, last year and then this summer on the brand new engine with no issues so I'd be interested to hear what the solution is. Good luck.

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Thanks for all the replies! The mechanic I'm working with said they re-checked the leads on the new harness today and they go to the right cylinders.

We tried installing the unit with the ignition advance off (it was previously on) and that was better at idle, but still quite rough. Starting the engine in that configuration also was challenging, as if the SureFly was unit was doing nothing.

Regarding the comment about timing, the SureFly is indeed timed to TDC of cylinder #1. My comment had to do with making sure that the dip switch settings were set to 25 degrees to match the existing right hand mag's timing.

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1 hour ago, msh9 said:

 

We tried installing the unit with the ignition advance off (it was previously on) and that was better at idle, but still quite rough.

Hmmmmm…

The ignition advance on and off is making a difference at idle….

When is the advance supposed to become active?   Usually in cruise, at lower MP….

Having it on during low RPM doesn’t sound very productive….

During the run-up… both mags are supposed to show near identical results.  If one is running a different timing… it should be pretty obvious in the data…

 

I have a question for ya…

got an engine monitor?

Can you get the data out of it?

Can you share it here?

Has your mechanic installed one of these before?

Got any pics of your installation?

 

Its quite possible, you have a faulty unit…

But if you have no engine data, it is hard to see what is going on…  this can lead to swaptronics and can be an expensive method of finding the problem…

If this is the mechanic’s first installation… his learning curve has become your expense…

 

If you don’t have these things available… it’s no big deal…. Some people have them and engine problem solving becomes much easier…

Some people don’t have them… and the problem solving gets more challenging…

Then there is the people that have the tools, don’t know how to get them to work…. And have to rely on the older system of asking a lot of questions… :)

 

Some install issues can be found with a pic…. From wire runs that can be done better… to other surprises where Eagle Eye Doc usually shows How things are supposed to be done…

Ignition wires are designed to carry very high voltages.  They have been seen to misbehave causing spark plugs to spark when they are not supposed to…

See if you can cover some of these issues….

PP thoughts only, not a mechanic… trying to help with the conversation of problem solving…  

Best regards,

-a-

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When I installed my SureFly about 2 years ago on 67C. I wanted

to  eliminate any  potential  of gotchas,  so I keep the fine wire spark plug gap as came from the tempest factory. Plus early on I had tried to re-gap a fine plugs but  I was 50 50 broke wire of the wire on the plugs. I quit after that. Soon after Tempest came out with the plug pre-gapped fine wires plugs. If recall correctly the Maggie ignition harness that I had was missed labeled ignition leads  and the lengths were a little off but usable. I had  to double checked the Harness  and Sure mag to ensure that firing order was correct.  I  just a little trouble during the Sure Fly installation initially it was installing the mag gear orientation on to the SureFly SIM module.  after we figured it out  It has  worked flawless.

I am not able to visualize  the "used with the origin SoS system and original left mag " comment. If I am not mistaken  the SOS would supply 14v to the SOS (equivalent of the door bell buzzer to supply spark at TDC through the retard set of points on the  left mag)  as you twisted and press in ("PUSH to START" and would hear a buzzing sound)   to start the  engine on the Bendix start switch. The Sure Fly at least the revision installation manual that I had said you are suppose have connect directly to the  battery. I might misunderstanding you but SOS components serves no purpose in the Sure Fly installation.  But for what it is worth especially on flight critical systems keep the changes to minimum initially then once proven then add the wider gap plugs or ??? . If you have too many changes at once you are more likely unable to establish  a good baseline on what worked and what didn't. There are  too many unknowns. it and you will usually spend more time in the long run fixing it. I don't mean sound preachy  but what I have experience in make a lot changes at once.   I am not sure if I helped.

 

James '67C

Edited by jamesm
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36 minutes ago, jamesm said:

But for what it is worth especially on flight critical systems keep the changes to minimum initially then once proven then add the wider gap plugs or ??

With regard to the plug gapping, that is one of the suggestions made to me by SureFly as I attempted to troubleshoot my installation.  "Gap the plugs wider...no wider... as wide as possible..."  I forget the actual number suggested, but I went somewhat less than their suggestion, but still much wider than the standard plug gap, I believe 0.025".  I do have to wonder, where did you get the desire to gap plugs that wide?  It certainly isn't in the installation manual.

I do agree with you @jamesm, I can't understand the "used with the origin SoS system and original left mag" comment.  The SoS system does not have a use with the Surefly system.  I can't imagine that the OP and his A&P connected the SureFly to the SoS "p-lead"...

My Maggie harness was perfect, so I can't suggest any problems with it, but others have suggested that mislabeled wires happen.  I would carefully check the firing order in the surefly installation manual against the wires.  It's a long shot, but worth it.

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Well I stand corrected on spark plug gaping. When I spoke to Sure fly ~2 years ago If I recall correctly, I recall them saying you get most benefit by advance timing. Perhaps it's my own inclination not to widen the spark  plug gap. 

As far Maggie ignition miss label lead lengths off a little. This is relatively minor issue. My setup as run flawless and been running great.

Perhaps Maggie may have different  ignition lead lengths for the M20E model engine installation.

My point was to place emphasis on the ignition connections. Again just my opinion and observations.

 

James '67C

Edited by jamesm
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1 hour ago, Browncbr1 said:

Surefly mags are known to not operate properly with massive plugs.  They need a new Kelly harness and finewire plugs.   They recommend gapping about twice as wide as traditional mags.  Up around .320” or more

In my experience with Surefly, it does not need a new harness, fine wire plugs or twice the gap as a magneto.  I guess I'm one of the lucky ones that installed the gear, timed it without issue, did not mess around with cap/wires and spark plugs and has experienced no operational issues since install.

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2 hours ago, Browncbr1 said:

Surefly mags are known to not operate properly with massive plugs.  They need a new Kelly harness and finewire plugs.   They recommend gapping about twice as wide as traditional mags.  Up around .320” or more

I don't know.  Mine works fine with the standard gap massive plugs.  Only 50 flawless hours thus far.  Maybe problems will crop up later.

Original single key gear worked with no problem.  I was going to order a Kelly harness until I called and got the run around.  Took about 1 minute to order from Maggie.

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52 minutes ago, Culver LFA said:

In my experience with Surefly, it does not need a new harness, fine wire plugs or twice the gap as a magneto.  I guess I'm one of the lucky ones that installed the gear, timed it without issue, did not mess around with cap/wires and spark plugs and has experienced no operational issues since install.

My Surefly was installed 3ish years ago, used the existing slick harness,  massive plugs and retained the SOS, everything works great.  crossfingers, knock on wood

Don't remember my mechanic changing the plug gaps. 

can give you my mechanics contact info if nec

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4 hours ago, Browncbr1 said:

Surefly mags are known to not operate properly with massive plugs.  They need a new Kelly harness and finewire plugs.   They recommend gapping about twice as wide as traditional mags.  Up around .320” or more

I'm running at approximately 30 hours on new massives gapped to .025"  (I think you meant .032"... .320" is close to 3/8")  Been running great.  I had to get a new harness because of the change from Bendix to Slick style connections.  I learned that the ACS harness was not up to the surefly...and had to buy a better one.  I would recommend a replacement harness if yours is not in fairly pristine condition.  Things in the harness that can be ok with magnetos are not with the surefly.

As to plug gap,  I'm seriously thinking about switching to UREM37BYs, because of the possibility of gapping larger (and the shorter plug that fits under my pressure cowl), however, they do not make that plug in fine wire... I know the tech I was speaking to was going to switch to automotive plugs in his experimental to get better gaps.

08-00248b.jpg

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1 hour ago, cctsurf said:

I'm running at approximately 30 hours on new massives gapped to .025"  (I think you meant .032"... .320" is close to 3/8")  Been running great.  I had to get a new harness because of the change from Bendix to Slick style connections.  I learned that the ACS harness was not up to the surefly...and had to buy a better one.  I would recommend a replacement harness if yours is not in fairly pristine condition.  Things in the harness that can be ok with magnetos are not with the surefly.

As to plug gap,  I'm seriously thinking about switching to UREM37BYs, because of the possibility of gapping larger (and the shorter plug that fits under my pressure cowl), however, they do not make that plug in fine wire... I know the tech I was speaking to was going to switch to automotive plugs in his experimental to get better gaps.

08-00248b.jpg

Yes, thank you.  .032” gap.    I check gaps with my .032 safety wire.  Experimental guys say they go bigger like .045..    That’s good to hear about massive performance.  I just looked on spruce and was disappointed to see the price of finewires went from $75each to $120each.   Massives are still $30 though.  I remember surefly advising that finewires are needed, but maybe they made some changes to the mag programming or hardware?  Not sure, but glad it works ok.  I was an early adopter of the surefly, so I’m not sure if we have identical mags or not?

Edited by Browncbr1
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Any engine will operate more efficiently with increased timing lead, but too much timing results in detonation and excess heat even before detonation.

‘Any engine will tolerate a lot more timing at partial load, (manifold pressure), that is why way back maybe 60 years or so automobiles got vacuum advance, so when running around at low load, there was a LOT of advance, now of course for more than 20 years automobiles actually have”knock sensors” and electronic ignition that runs timing as high as possible at all times, right up against the detonation limit, get a load of low octane fuel and it will automatically retard timing to keep from detonating, if your engine can make use of it, higher Octane in modern cars will result in increased HP as it allows more timing, but average car can’t make use of higher octane.

‘Spark plug gap wise. more is always better if and only IF the ignition system has enough voltage and current to support it, again modern automobiles have such powerful ignitions that they run huge gaps and have incredible arcs that have enough energy to ignite very lean mixtures smoothly. Not enough energy and excess gap will cause misfires. just not enough energy to fire the plug under high pressure reliably.

The limit of modern ignition systems is a spark plugs electrodes wear rate, too much energy and you burn up plugs, so you now have exotic materials in electrodes to allow high current and plugs that will last 100,000 miles or more.

‘Finally and this is a real issue, is that changing timing can often alter the vibration profile of an engine and that can cause damage to a propellor, I know some Hartzell props may have issues with that, so I’d call the prop manufacturer and make sure the prop I had is OK with whatever ignition timing or ignition system was going to use.

‘Fine wire plugs really will last longer than your engine, they are expensive but I believe they pay for themselves, my experience with them is that the engine starts easier, can run leaner more smoothly saving starter wear and fuel. Fine wire plugs made more difference on my IO-540 and an IO-520 than Gami injectors did on both engines, your mileage may vary.

 

Edited by A64Pilot
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ALRIGHT,

sorry for the delays. First, thank you all for the many suggestions. The suggestions to watch the engine monitor were good; incidentally the plane was also having a JPI EDM 900 installed while this was being done.

 

With that said, today, the mechanic tried swapping out the ignition harness with another one. SureFly works beautifully now.

Looks like the issue was the new harness we previously ordered to go with the SureFly was setup for right rotation instead of left. Two cylinders were swapped and the leads mislabeled. Very frustrating that it took us this long to figure out and partly because we assumed the new harness we ordered was good. That's what we get for making assumptions. In any case, that's getting returned and hopefully we'll have everything back together soon.

 

Thanks again everyone!

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