REFLECTOR: Franklin Cylinder Removal

[Laurence Coen]

John,

I agree with your mechanic that 73 is okay.  Before you pull a jug there a 
number of things you should do to make sure that it is necessary.  The best 
tool for examining a suspect cylinder is a borescope.  An educated eye can 
determine a lot about the health of a jug with this device.  Another thing 
that is a very useful indicator of ring wear are your spark plugs.  Oil on 
the lower plug is fairly common but oil on the top plug is a pretty good 
indication of worn rings.  Increasing oil consumption is another good 
indicator.  Kurt makes a good point about the possibility of a sticky valve. 
I think most Franklin valve problems can be traced to failure to lean during 
ground operations.  Listening for a hiss at the exhaust, intake and 
crankcase can tell you where the air is going.  In other words, find the 
problem before you try to fix it.

Larry Coen
N136LC
SE/RG Franklin/IVO


--------------------------------------------------
From: <aminetech at bluefrog.com>
Sent: Saturday, January 10, 2009 7:14 AM
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Subject: Re: REFLECTOR: Franklin Cylinder Removal

> Thanks Brian.  I'm aware of the manifold issue, but it's important
> and good that you mentioned it.  I'm rethinking to just redo the
> bad cylinder(s).  A compression test, with the engine warm, showed
> 75-80 in all but one.  The #2 initially showed 60.  The mechanic
> moved the prop and it went up to 73.  He said that was ok and to
> keep flying and checking it.  I'd appreciate any comments on this.
>
> John
>
> --- michalk at awpi.com wrote:
>
> From: Brian Michalk <michalk at awpi.com>
> To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
> Subject: Re: REFLECTOR: Franklin Cylinder Removal
> Date: Thu, 08 Jan 2009 09:24:29 -0600
>
> When reinstalling, you must torque down the intake manifold before
> tightening the attach nuts.  If not, you will crack your cylinders.
>
> If you have a PZL engine, the sleeves are of a different steel alloy.
> They are more difficult to replace and remove, but if your shop uses the
> proper procedure and tools, there isn't a problem.
>
> If you have any questions, the Franklin people in Colorado are pretty
> sharp.  It seems they are doing some volume these days.  Of course A-1
> in Jewett, Texas probably has the most experience.
>
> aminetech at bluefrog.com wrote:
>> Looks like I have at least one cylinder with bad rings, so I've
>> decided to have all the cylinder sleeves and rings replaced.
>> I've never removed the front two cylinders (# 1 and 2) and it looks
>> like there is not enough lateral clearance with the
>> engine in place.  Anyone know the easiest way to remove them?
>>
>> Thanks,
>>
>> John
>> ------------------------------------------------------------------------
>>
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