REFLECTOR: vernatherm

Thu Nov 17 11:14:08 CST 2011

My engine is a PZLI understand that it came fitted with the extra oil line
to the rear case (flywheel end) to add lubrication to the gears back there.
It does not supply oil to the fuel pump.

The fuel system on my engine is a continental injection system. The boost
pump is a single speed electric vane type pump. The main pump is a
continental mechanical unit driven by gearing in the front of the engine.
This pump and the fuel metering valve were just rebuilt. I had a local A&P
set the fuel pressures after the rebuild. EGTs are easily controlled now. I
have not tried running near peak yet because CHT & oil temps have been too
high.

Give me a call and I’ll give you my mailing address for the spring.

Grover

919-612-0442

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From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Brian Michalk
Sent: Thursday, November 17, 2011 11:47 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: vernatherm

If you can get your CHT's down, your oil temp will come down.  Try easy
things first.  If your mag is set at 28, then on your next takeoff, while
over a suitable field, turn off the Lightspeed.  See if your CHT's and oil
temp goes down, and if you can maintain a sustained climb.  Make sure your
bottom plugs are oil free before flight.

I have used a timing light on my Franklin with the wings removed, and it's
scary.  Other than that, I don't know how it could be done, except maybe
from the bottom side.

Be careful with going the no bypass route.  It's there to prevent bursting
the oil filter and cooler.  I will check to see if I have any of the stiffer
PZL springs.  I think they cost less than $10.

Are you running the older diaphragm fuel pump, or the newer vane pump?  Is
that hose used for lubricating the new vane fuel pump?  I don't have either
on my engine, and it's been a while since I was in the business.  I'm
running a gear pump at 45PSI.

On 11/17/2011 10:28 AM, Grover McNair wrote: 

Brian,

The CHTs are higher than I would like. On climb out I cannot run full power
very long at all. I barely get to 1000” agl before the CHTs get up to 390F.
If I level off and keep the rpm around 2500, these temps will stabilize.
The oil temp continues to rise though. 

My engine has a mag for the top plugs and a Lightspeed ignition for the
bottom plugs. The mag is timed at 28 degrees. With the light speed system I
am not sure about the amount of advance. After speaking with Lightspeed they
recommended putting a timing light on the engine to determine where it is
firing. I don’t know how to do this safely. Any ideas? 

The Franklin bypass valve looks very restrictive internally. My thought was
to modify it to make all of the oil flow to the oil cooler all of the time
and have a vernatherm control the flow returning to the engine. Regardless I
would like to try a stiffer spring. 

I am changing the flexible lines from the engine to the firewall from ½ to
5/8. The lines though the fuselage and to the cooler are 5/8.

For oil temp, there is an adapter in the line that runs from the bypass
valve to the rear engine casing.

Thanks for giving this some thought. I look forward to hearing more.

Grover  

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From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Brian Michalk
Sent: Wednesday, November 16, 2011 4:31 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: vernatherm

Do you have high CHTs as well?
If you are aggressive on your timing, retard it to 28BTDC, and see if your
temps go down.

I don't think adding a vernatherm is going to help you.  The Franklin has a
pressure bypass, and with hot oil, all of it should be going through the
cooler.  You can try a stiffer spring on the bypass if you are not getting
max oil through the cooler.  I think I still have some, if you want one.

Most everyone I know is running 5/8" lines to the cooler(s).  What size are
yours?  Also, where are you measuring your oil temps?  245F is too high, and
it means that in some portion of your system it's hotter.

On 11/16/2011 2:32 PM, Grover McNair wrote: 

The franklin engine I have in my 173LW  is running high oil temp, 245+.
Having read recent posts, I am planning to install a larger oil cooler with
a vernatherm. I would appreciate comments from those who have done this. Is
there a modification necessary for the factory oil bypass valve? 

Grover McNair

N832AB

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