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Cylinder Removal Procdeure

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Geoff May
Active Member

G'Day All,

Greetings from down-under.

I need to remove a cylinder from my Franklin. I've looked for a procedure to do this everywhere I can think of. The Stinson and Franklin manuals say how to build, but not how to dismantle.

So, does anyone have a procedure and/or guidance for pulling a cylinder without doing any damage and/or disconnecting unnecessary components.

I'm particularly looking for the sequence.

So, thanks in advance.

Cheers.....Geoff, 108-3, VH-BPS

Geoff May, 108-3, VH-BPS

Quote
Topic starter Posted : 27/11/2020 7:25 am
Sean
 Sean
(@seancrottyaol-com)
Active Member

Geoff,

I just replaced a middle cylinder in my 160hp Franklin and had my AP chat a bit with Chris Collum at Aerworx. Also Susan Prall at Franklin Parts has some special tools that make it easier to remove and replace. They both can be found via their websites.

Also, Jack Stewart could be a big help.

217-371-3542.

ReplyQuote
Posted : 27/11/2020 8:39 pm
Sean
 Sean
(@seancrottyaol-com)
Active Member

Mistype - I have a 150hp.

ReplyQuote
Posted : 27/11/2020 8:54 pm
Robert Picard
(@bob-picard)
Trusted Member

Geoff,

Before removing your cylinders, I highly recommend you watch Mike Busch's Savvy Aviation webinar on YouTube entitled "cylinder work: risky business". Although he discusses Lycomings and Continentals in general terms, the subject matter should apply to Franklins as well.

Bob Picard

Bob PicardN6346M Stinson 108-3 Floats/Skis/Wheels
N48923 Taylorcraft L-2B skis/WheelsAnchor Point, Alaska

ReplyQuote
Posted : 27/11/2020 10:57 pm
Eddie
(@906co470)
Eminent Member

  This should help get you started. Hopefully I did not miss too many steps. Order the tools from Franklin Engine Company. You will not regret that decision. The Franklin engine is a great engine and is reasonably easy to work on. I stress following the book as written to do the work on it. It will keep you out of trouble. This is different in several ways from your "other" aircraft engines. I forgot to ad in my instructions to be very careful reinstalling spark plugs. There is a torque value for that operation and it will be painful if not followed. Those helicoil threads in the cylinder are easily damaged. 

Eddie Stewart
Elmore City, Oklahoma
N906C 108-3 Continental O-470

ReplyQuote
Posted : 28/11/2020 6:13 am
Geoff May
Active Member
Posted by: @906co470

  This should help get you started. Hopefully I did not miss too many steps. Order the tools from Franklin Engine Company. You will not regret that decision. The Franklin engine is a great engine and is reasonably easy to work on. I stress following the book as written to do the work on it. It will keep you out of trouble. This is different in several ways from your "other" aircraft engines. I forgot to ad in my instructions to be very careful reinstalling spark plugs. There is a torque value for that operation and it will be painful if not followed. Those helicoil threads in the cylinder are easily damaged. 

Eddie,

Thanks for the doc. I was looking at writing something myself. That will save a lot of time. I will add anything else that I find and upload.

I have the tools from Susan.

I'm aware of the spark plug torque figures - my mechanic has put a sign on the baffles listing it.

Thanks to the others who have replied - I will check Mike Busch's video.

I'm taking this slowly and I'll report how it goes, but don't hold your breath.

Cheers...............Geoff

 

Geoff May, 108-3, VH-BPS

ReplyQuote
Topic starter Posted : 28/11/2020 12:03 pm
Will Ware (Webmaster ISC)
(@stinsono)
Member Admin

@geoffmay

 

Thanks to both of you, this document will be a great addition to our Tech library. Please continue to collaborate on it and when it’s finished I will make it available to other members. 

Thanks for using the site guys!

ReplyQuote
Posted : 28/11/2020 1:51 pm
Sean
 Sean
(@seancrottyaol-com)
Active Member

Geoff,

I reached out to Mike from Savvy on this issue and this was his reply:

 

Sean, the risk of replacing a single cylinder is a lot less than that or replacing multiple cylinders at once. I would suggest rechecking the torque if any of the cylinder hold-down nuts that you can easily get a base wrench on after about 10 hours. —Mike

ReplyQuote
Posted : 28/11/2020 6:33 pm
lawheelock
Prominent Member

Geoff,

Glad to see you posting here.  It has been a few years since we met at Oshkosh.  I think it was a same year that Ian was there.

I assume you are removing a cylinder with the engine mounted in the plane?  What you have to disconnect and remove is somewhat dependent on which cylinder you need to remove.

First, I would like to ask,why are you removing a cylinder?  Lots of cylinders have been removed that really did not need to be as several things can be done with them in place.

#1 cylinder I have found is the most difficult to remove as you have to remove more baffleing at the rear and often you will have to raise the engine a little and remove the left rear engine mount ear to access the hold down nut.  And if that is the one you need to remove, I hope the long bolt was installed correctly with the head down as it is impossible to get the bolt out without lifting the engine high off the mount if it was not installed the way Stinson did with the head down. 

Of course you have to remove the intake manifolds and intake tubes on the side that you are removing the cylinder from.  On the original 150 configurations, the intake manifold bolts were recessed socket head (Allen) and safety wired.  Later versions used hex head cap screws with a screwdriver slot to help running them in and out in the confined spaces.  I had to shorten an Allen; wrench to access the recessed head screws after cutting the lock wires.  They are a real pain to re-install but one does not have to worry about them backing out later after the lockwires are installed.  Probably #2 cylinder is the easiest to remove and install.

I ask why you are removing the cylinder because I have been able to correct small exhaust valve leakage by lapping it to the seat without removing the cylinder.  It involves using the rope trick to be able to remove the keepers and springs on the valve so that it can be moved and rotated in the cylinder.  Then with both spark plugs removed, the valve can be pushed into the cylinder far enough to see the face through the sparkplug opening.  Then using an artists brush or a stick, put a very small amount of valve lapping abrasive on the valve face and proceed to lap the valve like you would with the cylinder removed. You can chuck the valve stem in a battery operated drill motor protecting the stem as well as you can with some fabric or shim material from the jaws of the drill chuck. Then after it appears that you have restored the face to where it may seal, clean what you can from the valve and oil the face and the stem in the guide.  Put the valve spring and keepers back on and see if you have improved the compression.

Another tip is that I have found on Franklin engines, a differential compression reading of under 60/80 usually does not justify removal.  Using the guidelines of a Continental service bulletin and a calibrated differential compression (leak) tester, I have found that readings as low as 45/80 psi to be perfectly acceptable.  The final or maybe the initial evaluation is best performed with an automotive type pressiure compression guage, turning the engine with the starter through 3 or 4 compression strokes until reaching peak.  Checking the cylinder in question against the others and if rasonably close, it will perform very welll.

This thinking is based on the differential compression guage is a static test.  Slight leakages around valves or rings often result in mechanics condeming a cylinder needlessly.  The automotive test is a dynamic test and evaluates better how well the engine performs.  Even with slight leakages, there is not enough time in actual operation for performance to be affected. 

It all depends on why you think you need to remove a cylinder.

Cheers,

Larry Wheelock

 

 

 

Larry Wheelock, A&P/IAStinson 108 N584LW 180 LycTexas in Winter; Indiana in Summer

ReplyQuote
Posted : 30/11/2020 12:03 am
lawheelock
Prominent Member

Goeff,

One other point, if you have to remove a cylinder.  Follow the Franklin manual to the letter on re-assembly which means installing and removing the intake manifold twice.once without gaskets before final tightening of the hold down nuts and then with gaskets after the cylinder is securely torqued in place.

I usually agree with Mike Busch on most issues mainly minimal maintenance, but I don't think he has much if any experience on the unique features of Franklin engines like the lack of through bolts affecting cylinder on both sides of the crankcase.  There are some through bolts on Franklins but they are not a part of cylinder hold downs.

Larry

Larry Wheelock, A&P/IAStinson 108 N584LW 180 LycTexas in Winter; Indiana in Summer

ReplyQuote
Posted : 30/11/2020 12:12 am
Geoff May
Active Member

Larry and Co,

Thanks for the notes and your continuing stewardship of our aircraft.

I've removing the cylinder because of really bad oil fouling. Here's the #2 lower plug...

2020 11 21 11.27.22

...and it is the #2 cylinder that's coming out and the engine is still in the plane.

I do have, and will follow, the Stinson and Franklin manuals.

After Mike Busch's video I was wondering about though bolts. Nice to know I won't have to worry about them.

Larry, Ian and I have actually been to a few of your forums over the last few years. Always something else to learn.

 So, I'm still working up the procedure document - I'm changing to a checklist format as I find I miss fewer things that way. Hope you don't mind, Eddie.

TAFN.

Cheers..........Geoff

Geoff May, 108-3, VH-BPS

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Topic starter Posted : 03/12/2020 6:30 am
Sean
 Sean
(@seancrottyaol-com)
Active Member

@geoffmay

That is the exact cylinder I just replaced on my 150hp Franklin. I’ve got about five hours on the cylinder and knock on wood - the Franklin has been sounding strong with rated power and no vibration. So far I’m down about half a quart of oil. You are in great hands listening to this group. Best of luck and FLY SAFE!

ReplyQuote
Posted : 03/12/2020 11:41 am
Eddie
(@906co470)
Eminent Member

@geoffmay Feel free to modify, change or even delete as needed. I started to put as the first step, disconnect your negative battery cable, but was not sure you would get the tongue in cheek reference to a well known automobile publication we use in the states. Any procedure that they guide you on, even if it has nothing to do with electrical has you disconnect the battery cable before starting the project. Good luck with your cylinder change. 

 

Eddie Stewart
Elmore City, Oklahoma
N906C 108-3 Continental O-470

ReplyQuote
Posted : 03/12/2020 4:09 pm
lawheelock
Prominent Member

Geoff,

Personally I would not remove a cylinder just because the lower plug had a lot of oil on it.  I often find a bottom plug in lots of different engines that have a lot of oil on the but find there is little to nothing wrong justifying pulling the cylinder,  One needs to review other considerations.  Like how long has it sat without running?  What is the oil consumption rate?  Use a borescope to look in and see if there are marks on the cylinder walls that might imply a broken ring.  What was the differential compression?  Often, if a ring is broken, the oil will tend to seal the cylinder and it could actually show a higher (lower leak rate) than the others. 

I often use an aerosol can of starting fluid (known as ether here) with caution to clean oil from a plug as it is a good oil solvent and dries quickly.

A badly worn intake valve or guide can let the cylinder suck a lot of oil around the intake valve and if it sets for a while, accumulate on the plug. 

There are relatively low priced borescopes available that have an articulating tip and work with a smart phone for display and saving the images.  ATS Aircraft Tool Supply has one.  I bought one 3 or 4 years ago and as I recall it was under $300, well worth it with just not removing one cylinder.

  Even lower cost than when I bought mine.  aircraft-tool.com

" ARTICULATING RIGID USB BORESCOPE P/N VA-400The new Vividia VA-400 is USB controlled video borescope with a variable 1-way articulating tip that connects to any Android™ or Windows™ device. The probe, at only .33” (8.5mm) diameter, will fit into a spark plug port for cylinder inspections.

Price:$199.95Sale:$179.95 "

There is an app in Google play that is free.  I think it is called Camera Fi

The one for an iphone is more money, but I am very happy with mine and I use an Android phone and have an Android tablet with bigger screen but have not tried that.

 

 

 

 

Bottom line is I am always hesitant to pull a cylinder without lots of good reasons.

 

Cheers,

Larry

 

Larry Wheelock, A&P/IAStinson 108 N584LW 180 LycTexas in Winter; Indiana in Summer

ReplyQuote
Posted : 04/12/2020 6:14 am
Geoff May
Active Member

Will and all,

I finally pulled the cylinder yesterday (Saturday) without significant trouble.

I've updated the procedure and am attaching it here.

Thanks to everyone who added to the process.

I've included some things that might be peculiar to my plane. Any comments, additions suggestions are welcome.

Once it's stable, I'll export as a PDF.

HTH.

Cheers...........Geoff

Geoff May, 108-3, VH-BPS

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Topic starter Posted : 13/12/2020 11:19 am
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