I’m curious about the engine mount style you guys are
using with this voltage drop situation.
I can’t imagine this problem occurring with the
bed-mount/aluminum plate between the oil pan and engine block configuration.
Surely a 3/8” or ½” plate of aluminum and 20 bolts
will conduct from housing to housing? - unless maybe it was anodized?
Jeff
From: Rotary motors in
aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mark Steitle
Sent: Monday, November 23, 2009 4:41 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: No start
Glad you got things figured out (we were running out
of suggestions). Sure gives one a good feeling after battling a
problem for so long. BTW, I have two grounds on my engine. One is
to the front cover, one to the front side housing. I'll check into
moving one up to the starter.
On Mon, Nov 23, 2009 at 3:33 PM, Steve Brooks <cozy4pilot@gmail.com> wrote:
Al & Mark,
I would say that many people may have their ground to the engine block. Mine
has been that way since I built the plane, and worked fine for three or four
years before I started having an issue.
I had to order a couple of new crimp connectors, so that I can make a longer
ground cable. Hopefully they will arrive before Thanksgiving, so that I can get
it all hooked up over the long weekend.
Steve Brooks
Al Gietzen wrote:
Steve,
I read your other post on what you discovered regarding your bad ground. I
wonder how many of us have our engine grounds tied to a bolt near the front
cover or end housing? (Mine does...)
Mark S.
Mine does as well – bolts to the front cover. I have never had a starting
issue, but I have followed this discussion with interest because a couple of
years ago I did a starting spark check and found the sparks considerably weaker
than the mode 8 (or whatever) check. I just assumed it was due to the voltage
drawdown when the starter was running. Now it’s worth another look.
I recall giving it some thought when doing the wiring (My EC/EM manuals
apparently predated Tracy recommended wiring diagram). I concluded that the
various things bolted to the engine, like the manifolds, would provide good
conduction paths regardless of the sealing between layers – and the 20B
has a couple more layers. Both my intake and exhaust flanges are continuous and
connect all the layers, and there are other things making the connection to the
front cover, so this would be less of an issue compared to an installation
having separate flanges to each housing.
Anyway, Steve; I’m glad you found the problem. And thanks; it’s a
help to the rotary community, and again proves the value of a list such as
this.
Al G
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