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From: Bulent Aliev <atlasyts@bellsouth.net>
Subject: Re: [FlyRotary] Re: My Turn in the barrel
Date: Sat, 4 Aug 2007 17:03:34 -0400
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>

Looks like Tracy made all the mistakes in one shot that I made in 2  
years. :)
Except I tried to start the engine without the grounding strap, and  
smoked the EC2. He got lucky :)
I feel better now
Buly

On Aug 4, 2007, at 12:11 PM, Tracy Crook wrote:

> The day to install the RV-8 instrument panel finally arrived.  I  
> refuse to do the "upside down, on your back, head on the floor"  
> routine when doing work behind the panel so mine is completely  
> modular with connectors on everything so it can be easily removed  
> and replaced for repairs or modifications. I had very carefully  
> wired and checked everything twice and done 99% of it in the  
> comfort of my shop where it is easier to avoid errors.
>
> With great anticipation I switched on the flight critical and  
> avionics breakers eager to see everything come alive with all the  
> expected readings.    Dang!  The dreaded NOP is flashing in the  
> Tach window of the EM2 indicating no data link communications with  
> the EC2.  Checked the wiring of the two wires involved and sure  
> enough, one of them was on the wrong pin (switched with another  
> wire on same connector).
>
> Fixed that and the NOP was gone but getting a lot of screwy  
> readings on many (actually most)  engine parameters.  Attacked them  
> one by one and started to notice a pattern.  They were all on the  
> same row of pins of the same connector as the NOP problem.  Yep, I  
> had wired them all starting from the wrong end of the connector.    
> Since the cable was already wired into the plane I had to fix it in  
> place.  Bad job even with the instrument panel removed  but I can't  
> imagine having to do it with the panel still in.
>
> That made things a lot better but still had a lot of screwy  
> readings.  EGTs were drifting around, pressures were all high  
> (above redline)  and coolant & oil temperatures were no where near  
> room temperature where they should be.  Only thing looking normal  
> were the 5 air temp channels.
>
> These were all grounding problems.  Teflon tape and anodized  
> fittings prevented ground connection on many sensors, and the  
> ceramic coating on the exhaust manifold managed to isolate the EGT  
> probes which must be grounded at the probe.   There was also a  
> missing ground strap from engine block to firewall.  This didn't  
> cause damage since I did have a cable going from starter mounting  
> bolt directly to neg terminal of battery which is way back behind  
> the rear seat baggage area (for CG reasons).   The small voltage  
> drop through this cable was still enough to cause the engine to  
> rise above ground potential and this offset affects the instrument  
> readings a bit.   Not sure what would have happened if I had tried  
> to start the engine though.  The voltage drop would be a lot more  
> with 100+ amps of starter current.
>
> The urge to hear the object of so much labor and love come to life  
> is almost irresistible but It is a good idea to solve all of these  
> problems before hitting that starter switch.
>
> Tracy
>
>
>
>