Tach setting for a Lycoming IO-540

dsaucier

I love flying!
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Mar 6, 2012
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5
Does anyone know what the correct Tach PUL/REV setting is for a Lycoming IO-540 is?
 

kellym

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Sep 29, 2013
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272
What ignition system do you have?

I have Bendix 1200 series magnetos. A friend with same system discovered 1.5 is the correct setting. I find it strange that six cylinder setups are almost ignored in the install manual, and the EMS settings files for six cylinder Lycoming or Continental leave this setting at 1.0, which is what is used for four cylinder engines. This thread is first I have seen discussing the issue.
 

dynonsupport

Dynon Technical Support
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Mar 23, 2005
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The default for all installs is 1.0 on the pulse/rev setting. The screen config files don't change this. Different ignition systems have different pulse/rev outputs, so we don't even try and guess at what you have. 1.0 is in there because it's the first integer, not because it's right for any specific install.
 

kellym

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Sep 29, 2013
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The default for all installs is 1.0 on the pulse/rev setting. The screen config files don't change this. Different ignition systems have different pulse/rev outputs, so we don't even try and guess at what you have.  1.0 is in there because it's the first integer, not because it's right for any specific install.

Every six cylinder magneto ignition will have 50% more pulses than a 4 cyl magneto ignition system. So if 1.0 is correct for a four cylinder engine, 1.5 must be correct for a six cylinder magneto system.
I understand not second guessing electronic ignitions, but pulse counting for magnetos is not going to vary, whether it is Bendix or Slick, the magnetos will fire exactly the same number of times.
You don't have any beta testers with six cylinder magneto driven engines???
 

jakej

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Oct 10, 2007
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Location
Adelaide, Australia
It's really no big deal here IMO, just try different values & it'll be obvious which one is correct - you're allowed to work this out for yourself, it won't break the box  :)

Jake J
 
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