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Old October 2nd 06, 08:11 PM posted to rec.aviation.owning
Peter R.
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Posts: 1,045
Default Why is LOP (lean of peak) controversial?

Matt Barrow wrote:

That's not the point except you're jumping ahead in the troubleshooting
sequence.


Ok, but I was simply attempting to explain the reason for my "blissful"
ignorance. I didn't read John Deakin's articles the first time and think,
"Gee, my temperatures are so much lower than what he is cautioning against
that *my engine* must have some other explainable problem."

Instead, I simply read it and thought, "Hmm, looks like overheating
cylinders are not my problem."

The primary point is that your CHT reading were not just low, buy WAY low.


Again, TA Turbo didn't say to me on the phone today that my reported CHTs
were WAY low. "Lower than average, but not unbelievable" was the phrase
used.

It takes some "getting to" to find if it's the JPI, the probes, the baffling
(do you have TA's "Liquid Air" baffles?), or any of a myriad potential
problems.


The aircraft has the optional TA cheek plate louvers installed for summer
flying (as opposed to the shark-gill louvers, which is what I use in
winter), which provides a 10-20 degree lower CHT, and it has a TA optional
cooling baffling installed on the pilot's left of the cowl opening, which I
believe is to allow better airflow to the back cylinders.

In addition to the JPI tests pointed out elsewhere, I was also given
another pointer by TA Turbo. I need to check the probe wiring and compare
that with the setting in the JPI. If yellow/red wiring from the probes is
present, the JPI should be set to "K thermocouple." White/red is "J
thermocouple."

The TATurbo maintenance director said that an incorrect setting in the
EDM-800 would result in a minus 40 degree difference from actual CHT
reading. He then commented that if I see 320 degrees on hot day and this
error were present, he would still be impressed with an actual 360 degree
CHT.


--
Peter