ragedracer1977 Posted January 11, 2020 Report Posted January 11, 2020 Set timing exactly to TDC. Set dip switches correctly. Ran a manifold pressure line. Engine seems to start pretty good, at least as good as it used to. Runs good at idle, mag drop check is good at 1800 RPM. At full power, its missing a little when on only the surefly mag. I called them, they said check the timing. I triple checked. It's right. I pulled the plugs, checked gap, cleaned, etc. No change. Still just not quite right. They're closed now, so I thought I'd reach out here. Any ideas what the heck I'm doing wrong? Quote
philiplane Posted January 11, 2020 Report Posted January 11, 2020 what brand/type spark plugs do you have? How old are they? Quote
takair Posted January 11, 2020 Report Posted January 11, 2020 34 minutes ago, ragedracer1977 said: Set timing exactly to TDC. Set dip switches correctly. Ran a manifold pressure line. Engine seems to start pretty good, at least as good as it used to. Runs good at idle, mag drop check is good at 1800 RPM. At full power, its missing a little when on only the surefly mag. I called them, they said check the timing. I triple checked. It's right. I pulled the plugs, checked gap, cleaned, etc. No change. Still just not quite right. They're closed now, so I thought I'd reach out here. Any ideas what the heck I'm doing wrong? Might be worth swapping plugs top to bottom to see if problem moves to the mag....rule out the plugs that way. Could be the harness too. To check the timing, are you looking at the light flash sequence? I had a bad dip switch. Switch was set correct, but the sequence was not correct. Had to check it three times before I believed my eyes. Quote
ragedracer1977 Posted January 11, 2020 Author Report Posted January 11, 2020 17 minutes ago, philiplane said: what brand/type spark plugs do you have? How old are they? Tempest massive urem37by. Less than 50 hours. Engine ran perfectly on the left mag before, mag was overhauled 12 hours ago Quote
ragedracer1977 Posted January 11, 2020 Author Report Posted January 11, 2020 4 minutes ago, takair said: Might be worth swapping plugs top to bottom to see if problem moves to the mag....rule out the plugs that way. Could be the harness too. To check the timing, are you looking at the light flash sequence? I had a bad dip switch. Switch was set correct, but the sequence was not correct. Had to check it three times before I believed my eyes. Brand new harness. Light flash sequence is correct Quote
takair Posted January 11, 2020 Report Posted January 11, 2020 10 minutes ago, ragedracer1977 said: Brand new harness. Light flash sequence is correct Hmm...Perhaps try the top to bottom swap on the plugs and the. It seems like a talk with a SureFly.... Quote
carusoam Posted January 11, 2020 Report Posted January 11, 2020 See if Bob has anything to add from his experience... @Bob_Belville (sure-fly Mag question) Best regards, -a- Quote
ragedracer1977 Posted January 11, 2020 Author Report Posted January 11, 2020 14 minutes ago, takair said: Hmm...Perhaps try the top to bottom swap on the plugs and the. It seems like a talk with a SureFly.... Yeah. I just have to wait to Monday. Booooo. I'll try swapping plugs see what happens Quote
ragedracer1977 Posted January 11, 2020 Author Report Posted January 11, 2020 I came back to the hangar. Just couldn't take it. I spent 30 minutes checking for TDC. I used a digital dial indicator to verify. It sure looks like it was off by 2 degrees. 2. I'm wondering if in the final torquing of the nuts, it slightly shifted? This time, I left battery timing power hooked up all through the process. The light never came on while torquing and no matter how many times I spin the prop, it goes out exactly at what I'm indicating is TDC. So... Here's hoping. Gotta put it back together and see. Oh, and I had to take the battery box out by myself. Not an easy proposition on an old C model. Bolts in the box, nuts in the cockpit. But, American ingenuity got it done. 3 Quote
tmo Posted January 11, 2020 Report Posted January 11, 2020 5 hours ago, ragedracer1977 said: Set timing exactly to TDC. At a risk of sounding silly - this is for the Surefly to know where TDC is, not to tell it when to fire, right? Quote
ragedracer1977 Posted January 11, 2020 Author Report Posted January 11, 2020 35 minutes ago, tmo said: At a risk of sounding silly - this is for the Surefly to know where TDC is, not to tell it when to fire, right? Correct. And, success! Apparently that 2 degrees really matters. It runs like a champ now! 7 Quote
rbridges Posted January 11, 2020 Report Posted January 11, 2020 So was the 2 degree difference causing it to fire early or late? Quote
ragedracer1977 Posted January 11, 2020 Author Report Posted January 11, 2020 10 minutes ago, rbridges said: So was the 2 degree difference causing it to fire early or late? Early 1 Quote
carusoam Posted January 11, 2020 Report Posted January 11, 2020 Great follow-up, Brice. Thanks for sharing the details... Keep an eye on CHTs if they are hotter than normal... timing may have advanced... If colder... timing may have decreased closer to a TDC... Not sure if only 2° would make the difference that you initially saw... PP thoughts only, not a mechanic... Best regards, -a- Quote
MisfitSELF Posted January 11, 2020 Report Posted January 11, 2020 Are you using "fixed" or the "advanced" timing? Quote
ragedracer1977 Posted January 11, 2020 Author Report Posted January 11, 2020 10 minutes ago, MisfitSELF said: Are you using "fixed" or the "advanced" timing? Advanced. I also saw some advice to leave the manifold pressure connection disconnected while timing. I originally did not. It's possible that made the difference Quote
ragedracer1977 Posted January 11, 2020 Author Report Posted January 11, 2020 14 minutes ago, carusoam said: Great follow-up, Brice. Thanks for sharing the details... Keep an eye on CHTs if they are hotter than normal... timing may have advanced... If colder... timing may have decreased closer to a TDC... Not sure if only 2° would make the difference that you initially saw... PP thoughts only, not a mechanic... Best regards, -a- Honestly, it probably would have been fine. When I said missing, it wasn't like shake the cowl off missing, it just wasn't quite right. You get to know your engine, and what it sounds and feels like. And it was a little off what it was like on a fresh magneto. Now it runs like a sewing machine! 1 Quote
Browncbr1 Posted January 11, 2020 Report Posted January 11, 2020 Someone here was burning up BY plugs with the surefly and had to switch to finewire. Keep eye on your plugs Quote
J0nathan225 Posted January 11, 2020 Report Posted January 11, 2020 11 minutes ago, Browncbr1 said: Someone here was burning up BY plugs with the surefly and had to switch to finewire. Keep eye on your plugs YUP! All is well now with fine wires on the surefly side. I think factory gap is less than ideal for the surefly side, it produces alot stronger spark gapped wider you may have 0 issues with massives. 2 Quote
Bob_Belville Posted January 11, 2020 Report Posted January 11, 2020 16 hours ago, carusoam said: See if Bob has anything to add from his experience... @Bob_Belville (sure-fly Mag question) Best regards, -a- Jon beat me to it. Lynn @AGL Aviation, as of the last I heard, had had only one plane with issues with Surefly - the one with massive plugs. Secondly, I believe he was told by SF that the EI worked better with wider gap than spec'd. 2 Quote
ragedracer1977 Posted January 12, 2020 Author Report Posted January 12, 2020 7 hours ago, Bob_Belville said: Jon beat me to it. Lynn @AGL Aviation, as of the last I heard, had had only one plane with issues with Surefly - the one with massive plugs. Secondly, I believe he was told by SF that the EI worked better with wider gap than spec'd. Supposedly they used to recommend a .036 gap, but could not for certified planes, because that's so far out of "spec". I gapped mine to .025. I'm due for an oil change in about 20 hours (which will be before the end of this month - Yuma formation clinic will put a lot of hours on!). I'll pull them at oil change and see how they look Quote
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