What Were They Thinking to Remove Cylinder

happydad wrote:

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   I usually use at least a 1/4 inch thick belt, or double wrap a thinner leather belt. I have even used a pair of leather gloves in an emergency. Just heat carefully, take your time with the vise grips and reheat if necessary.

Grabbing around the main part of the cylinder, not the fins, avoids damaging the fins........

Many times, Peddler's Malls or flea markets will have vendors selling leather scraps. I bought a piece of 1/4" thick scrap and cut it into 1/2" wide strips that I use for unscrewing all sorts of items where I don't want to mar the surface.
For COX cylinders, I leave the glowhead lightly screwed in place and grasp the upper part of the cylinder and a fin or two on the head. With the head in the cylinder, I am more comfortable applying force without the chance of distorting the cylinder itself.

andrew wrote:...With the head in the cylinder, I am more comfortable applying force without the chance of distorting the cylinder itself.  

Yes I feel this way too..in addition to the glow head, I would also crank the piston up to the TDC to increase the cylinder rigidity.

I have a reedy in as-new condition except the ball-joint connection that is a bit slack. No flats machined in the top fin for the wrench, unfortunately.

The cylinder thread seems to have cured into the crankcase neck. I heated the crankcase for some time, then tried a leather strip wound around the cylinder and a vice grip, but there is no physical force imaginable that would be able to beg the rascal to unscrew..there is no way either I  use the fork end of the COX wrench tucked over the exhaust ports to remove the cylinder as originally intended by COX. That would only result in external (in the best case) burrs on the cylinder. The sides of the exhaust port are not parallel with the forks so the latter sits on the ridges of the port that will burr at a small torque applied already.

Now I have dropped the engine less the red postage stamp back-plate into pure methanol and hope the caked castor between the threads will soften after a few days of such a bath, enabling me to dismantle the engine and set the ball-joint connection.

Admin wrote:They actually suggested the use of pliers...

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That, without a leather belt, is simply brutal that I would never do...

The best way I have found to remove stuck cylinders/glow heads is a four hour crock pot A/F boil, provides heat and lubrication (sort of).  If possible I loosen the head or position the piston so the exhaust port is open, but I never force anything and will never use compressive force on any cylinder.   A hundred or so engines and the crock pot method has never let me down.  Messy and time consuming but effective.

Learned this the hard way after destroying a couple of locked up Wen/Mac - Testors engines.  Then I joined this forum and someone here mentioned crock pots.  Thanks someone.

So,

While not the best way, the cylinder was designed to be removed with the factory wrench through the exhaust slots.

If done carefully no damage occurs.

Laughs in hacksaw, pliers are for lightweights

I have milled the top of the cylinder on a couple Reedies to use the wrench. I find the cylinder has to be tighter than the plug, or you end up removing the whole unit. The TD wrench is a bit weak to hold on to the top cylinder slots for that purpose IMHO. Just have to show my favourite pic here. No I didn't do it. I made the thrust washer though. I will use this stub to machine some ports some day maybe.

Cribbs74 wrote:So,

While not the best way, the cylinder was designed to be removed with the factory wrench through the exhaust slots.

If done carefully no damage occurs.

That's what I use on engines that are not top slotted after an A/F boil, but I buffer the wrench first with electrical tape.  Not sure if it does any good but it's a confidence builder.  Slit exhaust engines that I have done have always been top slotted that I can remember.

I have probably done (disassembled cleaned) less than a dozen TD/Medallions.  Quickly learned never to A/F boil one of those.  

balogh wrote:

Admin wrote:They actually suggested the use of pliers...

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That, without a leather belt, is simply brutal that I would never do...

Wow no joke the pliers just HURTS to see that!

I guess they thought the kid would smash it to bits after a few flights and buy a new one??
Ice

Cribbs74 wrote:So,

While not the best way, the cylinder was designed to be removed with the factory wrench through the exhaust slots.

If done carefully no damage occurs.

In most cases very true. I once got a 1971 or so .010 that had never been run but wanted to clean and remove cylinder. It was so stuck that the wrench produced a small burr inside the corner. Thankfully after several hours with magnifying glass and surgical instruments got the burr off the cylinder wall and the motor runs perfect. However that was not a good feeling to be sure! But after thousands of goes on all cylinders wrench in the port worked great.
Ice

Ugliest picture ever!!!

One of the older British motors said to use a piece of leather and pliers carefully. DC or Merlin? I don't remember who. Pretty careless for Cox to put the pliers on the instructions to save the money for cutting the slots in the cylinders. Notice the case on my pic has a patch. The rod went through the case on my flying buddy's motor and he soldered it up. It worked OK, he said, but then he gave it to me. I was a kid then. I have/had a turned cylinder so it would fit in a speed plane better, but seems to have vanished. Some of the plastic parts look pretty nasty on most of my TDs, faded and repaired where the venturi goes in. I was going to order a bunch of stuff from Cox International, but never seem to get aroun tuit. I rarely fly them now. Windy area here.

One time, I too had used leather gloves to aid in removing a Cox cylinder. They were a new pair, a gift from my father...... Well, allow me to say that they then had a few added slits in the finger I wrapped around teh cylinder. Oh well, I can at least say I used them.

The picture is actually genius. Buy the plane, break it, buy parts....

Classic pliers, what’s a few teeth Mark’s?

As far as I am concerned to me a COX engine is not just a toy but an aesthetic pleasure too..I hate seeing that signature COX cylinder shape mauled...

balogh wrote:As far as I am concerned to me a COX engine is not just a toy but an aesthetic pleasure too..I hate seeing that signature COX cylinder shape mauled...

I'm with you Andras! Butchers are for meat not these little cylinders. And YES hey need to look good too!!
Thanks
Ice

Yeah, they are beautiful little gems aren't they...……..

As mentioned earlier, a leather strap is all that's needed. Just heat up the crankcase and adjust the length of the strap so that you get a nice pinch. The principle is the same as for oil-filter removal tools on car engines. With a few different holes in the strap you'll have a tool for all cox engines sizes, and also for PAW and Webra diesel engines etc.

Kris, that's genius. Thanks! A trip to the shoe repair guy around the corner tomorrow.

I see a sleeve around the port on the carb body on your TD. I'm guessing that's a fix for a cracked venturi? Very slick! That's going in my tool box. Thanks for that one too!

Surfer_kris wrote:As mentioned earlier, a leather strap is all that's needed. Just heat up the crankcase and adjust the length of the strap so that you get a nice pinch. The principle is the same as for oil-filter removal tools on car engines. With a few different holes in the strap you'll have a tool for all cox engines sizes, and also for PAW and Webra diesel engines etc.

That is what the English motor manufacturer recommended, that I was thinking. Good tool for the flight box for sure.

Tee Bee wrote:Ugliest picture ever!!!

Kind of reminds me of someone who fixes a nicely chromed urinal flushometer or sink faucet using a regular pipe wrench. I don't know what possesses people to put out such bad advice and that in official literature. Obviously the person who wrote such instructions does not have a mechanical background.

rsv1cox wrote:Yeah, they are beautiful little gems aren't they...……..

They clean up nicely. I've used a fine file to clean up the burrs, although in the rough there is hope of restoration.