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  #21  
Old 04-19-2022, 03:09 PM
rv8ch's Avatar
rv8ch rv8ch is offline
 
Join Date: Feb 2005
Location: LSGY
Posts: 4,700
Default

Quote:
Originally Posted by Fred.Stucklen View Post
I always lean way past peak EGT on taxing, for exactly that reason. To the point of having to increase the mixture sometimes when I need more power. This week I ohmed out all the ignition leads, checking them for intermitant connections or excessive resitance. No issues found.

I'm seriously thinking about going back to the aviation plugs & harness again to get a better data point on performance.
There are a lot of people flying with the pmags and the auto plugs, and those are what is recommended by the emagair team. I'd keep looking for the root cause of this problem.
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Mickey Coggins
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  #22  
Old 04-21-2022, 04:35 PM
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Fred.Stucklen Fred.Stucklen is offline
 
Join Date: Oct 2006
Location: Brooksville, FL
Posts: 447
Default Spark Plugs

Quote:
Originally Posted by Fred.Stucklen View Post
I have since confirmed that all the new spark plug wires are around 110 ohms each, with no intermitance detected. The BREIX plugs came out all dark black like they were subjected to a VERY rich fuel flow. Even the exhaust pipes were black! And I always run LEAN of peak! It's like the plugs are not burning the fuel....

Today I pulled the BREIX plugs (gaped at 0.035") and replaced them with BRES-3961 plugs gaped at 0.045". I've also cleaned the injectors per the Lycoming SB. I will test fly it tomorrow to see if there has been any improvement to the leaning .....
After a long discussion with EMAG support, we've come to the conclusion that my running rich issue may be some sort of timing issue between the aviation plugs and auto plugs. Since the evidence seems to support a late firing, resulting in higher EGT's and lower CHT's, advancing the timing slightly may make a big difference. Since I have an EI Commander that has the ability to offset the timing curve with a a user inputted offset, advancing the timing (in 1.2* increments) is somewhat easy. I'll start at that value, and test fly to see what the results are.

If anyone has an EI Commander that they use with PMAGS, I'd like to know what your setting values are.
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Fred Stucklen
wstucklen1@cox.net
RV-7A N924RV Flying (2000 Hrs & counting)
RV-6A N926RV 875 Hrs (Sold)
RV-6A N925RV 2008 Hrs (Sold)
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  #23  
Old 04-22-2022, 09:55 AM
dcl dcl is offline
 
Join Date: Mar 2012
Location: UK
Posts: 53
Default

Call me old fashioned, but the first things I would do:
1. hook up a timing light and check the actual timing against the fly wheel marks. All the electronics get their info from electronics, the fly wheel does not lie.
2. Check the leads are all to the correct cylinders. Ridiculous I know, but worth checking.
3. Where did you source the auto spark plugs ? There are some of dubious quality around….
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  #24  
Old 04-22-2022, 10:42 AM
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Fred.Stucklen Fred.Stucklen is offline
 
Join Date: Oct 2006
Location: Brooksville, FL
Posts: 447
Default Sparkplugs

Quote:
Originally Posted by Fred.Stucklen View Post
After a long discussion with EMAG support, we've come to the conclusion that my running rich issue may be some sort of timing issue between the aviation plugs and auto plugs. Since the evidence seems to support a late firing, resulting in higher EGT's and lower CHT's, advancing the timing slightly may make a big difference. Since I have an EI Commander that has the ability to offset the timing curve with a a user inputted offset, advancing the timing (in 1.2* increments) is somewhat easy. I'll start at that value, and test fly to see what the results are.

If anyone has an EI Commander that they use with PMAGS, I'd like to know what your setting values are.
Checked mechanical TDC timing today, and verified with a timing light. Timing light results where the same as indicated on the EI Commander. Via the EI Commander, increased the Adv Offset by 2.4* and flew the plane. MAJOR difference in performance! I can now run well lean of peak again (similar to where I ran the aviation plugs).

I have no idea why I needed to run these plugs/wires with a more advanced timing. I haven't pulled the cowls to looks at the plugs yet, but will guess that they are no longer black with soot.
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Fred Stucklen
wstucklen1@cox.net
RV-7A N924RV Flying (2000 Hrs & counting)
RV-6A N926RV 875 Hrs (Sold)
RV-6A N925RV 2008 Hrs (Sold)
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  #25  
Old 04-22-2022, 11:26 AM
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rv8ch rv8ch is offline
 
Join Date: Feb 2005
Location: LSGY
Posts: 4,700
Default

Quote:
Originally Posted by Fred.Stucklen View Post
...

If anyone has an EI Commander that they use with PMAGS, I'd like to know what your setting values are.
Glad you found a solution, Fred.

To answer your question, here's my timing, which is working great.

Click image for larger version

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In words:
RPM max:2816
ADV max: 32.2
ADV shf: -1.4
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Mickey Coggins
Fresh Ukraine update and photos from RV-6 owner Alex 28 June 2022!
http://www.rv8.ch/help-people-in-ukraine/

Please send him a bit of money so he can keep providing food and essentials to civilians affected by the war.
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