Cylinder Damage with Factory Wrench ?

Been there done that... Here's a link to a discussion about the same topic. I haven't attempted to fix mine yet but in this thread you'll find great tips:

https://www.coxengineforum.com/t7586-did-i-ruin-my-brand-new-teedee-cylinder

I've had good results using heavy tape on the wrench to prevent burrs, also use a piece of leather wrapped around top cylinder and pliers all with heat of course.
The real [bleep] is when I'm trying to remove the head and the cylinder comes loose, now you got a head stuck in a cylinder.

While it can happen, it's not caused so much by the wrench. If you think about it the only way to turn a burr into the cylinder is if the wrench slips while loosening the cylinder.

As designed, while loosening you are applying force on the outside of the flat faces.

My advice is to be sure that case is clamped/supported while loosening.

As others have already mentioned, DO NOT try to clear the burr by forcing the piston through the cylinder. It's guaranteed that it will be destroyed.

Ron

Once I had the same issue with my most-belowed 40+ years old product engine having the stepped cylinder without the flats machined in the top fin.

I pushed an old, worn piston down the cylinder from the top and managed to de-burr the exhaust opening without killing the original piston. The compression is still as-new. The good thing is the cylinder is made of mild steel while the piston is hardened steel, so such deburring by pushing an old piston from cylinder top to the bottom will remove the burr without scratching the cylinder wall where the compression is to be retained.Important is to use an old piston out of service.. But I would not try to do this with the genuine piston.

I typically wrap the wrench in plastic foil before removing the cylinder.

I trap the whole wrench sideways on its edges in the vice so the cylinder forks cannot spread. Then I hold the crankcase and insert the cylinder into the forks and turn the crankcase.
Rusty

Sig Skyray wrote:The wrench fits in the exhaust ports and twice now, the cylinder apparently sustains damage to the walls from the use of the wrench evidenced by the piston not wanting to go back in the cylinder past the middle of the ports.

Yes, that is easy to do and I have done it. Back in the old days, one could simply buy a new piston and cylinder set. I've taken a round file and carefully removed the burr inside the cylinder created by cylinder removal wrench. If you are careful, you can reuse that cylinder.

Other solution is to buy the Tee Dee set from Cox Internation, EX Engines or other sources. If the lower powered Babe Bee or Golden Bee and you are not concerned over historic looks, the cheaper Sure Start double exhaust slit set will work. Plus, the later set is cut to use a wrench at the top of the cylinder so you don't damage the exhaust port.

Thanks for the solutions and ideas guys. I did use an old piston in the cylinder first but my piston was still tough going in. I wasn't going to take a file to the cylinder because even with good light and a magnifying glass I could not spot a burr. It's loosened up now, perhaps with some extra wear on the motor but next time I'll have some techniques to deal with it better.

You can use a dremel cut-off disc and simply cut of the topmost cooling fin in two opposing places and then use a regular wrench (or the cox wrench if the head is still on).

Sig Skyray wrote:I wasn't going to take a file to the cylinder because even with good light and a magnifying glass I could not spot a burr.

What you have is not a burr but a slight distortion set up by the wrench action. Basically it is a high spot caused by the bending metal by wrench action. Lightly rubbing the location with a round file will reveal that spot. I realize that it is easy to damage the cylinder. If one is a person who doesn't have much finesse with tools then it may not be a good idea. I've straighten bent crankshafts from crashes by tapping with a hammer, restoring an otherwise unusable engine. Again I don't recommend folk to try this.

I agree, mending these little gems at home requires more skills then I in general have...the only part I have been ever able to bring back to life after a substantially serious damage was a piston rod bent when I used an electric starter on a flooded engine.

I rotated and pressed the rod between the beaks of a plier until the bend disappeared.It was for sure not perfectly straightened but was flush enough not to buckle when the piston was put back in use again...it still is.

In my early years I farkled up some of the dinky engines using brute force... later learned that old castor is a great adhesive--- but instantly gets soft with a little heat.

Like said above if the wrench is placed across both exhaust ports the only damage should be from thin wall cylinder distortion and not a burr. I have watched folks put the wrench through the ports and that is the wrong way to use the tool and guarantees a burr

Other than the plastic parts on some engines, I find that even the heat from BIC lighter flame ( I use a butane torch in the shop) will let most Glow plugs to cylinder or cylinder to case loosen enough to unscrew without any damage except for the black soot

Once I had my full complement of e-bay and swap meet old engines disassembled and working as they were designed--- I started a strict regimen of always running out the last of the castor fuel, cleaning with alcohol, and a few drops of After run oil (ARO) flipped through the innards... I have a few seldom run engines in my shop that 15 years later turn freely until compression and I can dissemble with out damage

The best ARO in my opinion is ANY brand Air Tool Oil...my preference is Marvel brand but I have Campbell Hausfeld, Lowes, and Hitachi stuff

Air tool oils generally have water dispersing agents and mostly do NOT gum up over time

RknRusty wrote:I trap the whole wrench sideways on its edges in the vice so the cylinder forks cannot spread. Then I hold the crankcase and insert the cylinder into the forks and turn the crankcase.
Rusty

Rusty's method is great. Following other posts, I pre-cooled the engine in the freezer, and once in the wrench's forks, applied flame from a large propane torch to the cylinder/crankcase join.
[ I had removed the plastic carb body beforehand. It's a bit tricky to get the drive washer off when the cylinder/piston/connecting rod are still in place since there is a risk of driving the shaft into the conrod while tapping on the prop screw. ]
Turned hot crankcase with a potholder. Took more torque than I expected to break the threads loose. In one motor the exhaust ports were a little dented by this, but it was at the outside diameter, not the inside, which other posters have said is all that can happen if the wrench does not slip. The other engine showed no marking. The pistons remained free. The released threads showed a residue reminiscent of thread locker.

I had lightly filed the inside of the forks flat and square to give the best possible bearing surface.  
[Edit:  Ooops! Filing the wrench was a bad idea. Although jaws smoother, the looser fit concentrates force at the exhaust ports'  outside diameter points instead of distributing it somewhat over most of the outer thickness of the cylinder wall. As well, the filed wrench no longer fits the venturi.

    PS  MAY 12/17  Repaired one wrench by lining jaws with .016 K&S brass sweat silver soldered. Tests strong enough ordinary use, not sure how it would do on stuck cylinders. Edit of May 27/17: With snug brass liner, the wrench may grab on one side and pull it off line so that one pushes one prong right inside the cylinder. I raised an internal burr this way that impeded the piston and required removal, which I somewhat botched. Sorry little engine. Need to wiggle the wrench carefully to gently persuade it to straight slide into position over the exhaust ports. Perhaps grabs because not skilled enough to file the brass lined jaws perfectly flat and parallel. ]

   PPS May 18/17  The engines vary
                                  Cylinder wrenchable width      Venturi Nut
           T.Hopper                         .273"
           T.D. thin wall #4              .273                           .283
           T.D. bearer #2                 .295                           .274  fin wrenchable flat
           T.D. Cyl #4                      .297                           .277    
It appears that all my wrenches were probably >or= .295 before filing. The screwdriver portion could be filed to fit the prop screw snugly but as is, it can do mtg. bolts and smaller engine prop screws. Can get bent and need hammering back to shape. Needs care in use to avoid slipping.
O.K. Cub instructions say to not tighten cylinder too much, can distort case, increase shaft friction. Not sure about coming loose. Once the carb collet of a Cox Tee Dee .15 came loose and screwed itself forward, braking the drive plate/prop to a stop, a few seconds after steep launch F1C (over grass). Maybe it was loose at startup but I did not notice. In some ways, parts stuck together with dried castor oil may be a benefit.

Used quite a bit of heat, several seconds all around of the blue flame, but not nearly red heat, not nearly what one would use to solder half inch copper tubing in plumbing jobs.
What a relief! Thanks gentlemen, for the tips and encouragement to attempt this. Also thanks for the repair posts on what to do if the work does go wrong and the piston sticks; this helps give confidence to try the removal.
Now that they can be disassembled maybe I can clean the engines properly if they get a snoot full of dirt in the field, so perhaps I can be forgiven the dents. With more practise perhaps one would learn what is too much torque and how much more heating is safe if the acceptable no-dent torque is not enough.

May 20/17  I was having difficulty removing a back plate from a Conquest that had been stored for many years. The edge of the wrench kept slipping out of the grooves, damaging them in the process. I mounted the engine in a Davies-Charlton test stand with wing nut clamps, and put a TD .09 wrench (it is a bit thicker than the Conquest wrench) edgewise in a vise. It was then possible to press the back plate grooves down on to the edge of the wrench, solidly, using body weight. No problem with slipping, unscrewed surprisingly easily compared to how permanently stuck it seemed when trying to do it freehand. This might work without the engine mount to hold and apply torque to the engine, but it helps a lot. It might work on Tee Dee engines as well, using in the vise the edge of a wrench of thickness to fit the grooves well.

If you buy a Sloan strap wrench you will never look back. I never had a cylinder I couldn't remove using it. They're used to tighten plumbing fixtures which are plated. They're made of a durable plastic and inexpensive. I picked them up from work due to them laying in every unit I was working in. In the event I would've known how well they worked I would've picked them all up. Searching on Google and Ebay both turned up the wrench which is under $10. Many have put the wrench in the cylinder with not so promising results. The strap wrench can remove stubborn glow plugs and the thin walled cylinders without damage.

Ken has the proper tools!  

I cut some straps of aluminum from beer cans.  Wrap two turns around the cylinder.   Then slip a small hose clamp over the aluminum and snug it down.  You can then use whatever tool you what to turn the hose clamp with no cylinder damage.

Thanks to MECA member Bill Schmidt for this hint.

And if you need heat, a little butane torch from Harbor  Freight works fine.  A gourmet chef's Creme Brule torch is better made, but your wife may not like it in your workshop.

Reading further into the threads, I see those recommending to file the burr away. I personally wouldn't do that. Find a piece of K&S brass tubing that fits into the underside of the piston skirt. The piston skirt is tapered on the inside. I originally though it was 3/8" tubing but I believe it's 5/16". Cut yourself a piece 4" long and drop the rod into the hole of the tubing. Push the tubing into the underside of the skirt until it's tight. If it's not tight, wrap some masking tape around the tubing until you get a good snug fit. Insert the piston into the cylinder upside down. The tubing will now be sticking out of the top of the cylinder like a handle. The piston will slide easily upside down in the cylinder until the skirt contacts the burr. Use some metal polish ( Mothers) anything that's fine even toothpaste will work. Twirl the handle spinning the piston and lightly pull back on the tubing. The cylinder is dead soft and the burr will quickly go away. When you've loosened up the burr turn the piston around and insert it correctly into the cylinder and do a final lap but don't go to the top of the glow plug landing with the crown of the piston, stay down about 1/8". Don't spend a lot of time doing this as your wearing away material, a few twirls and all is good. This is also a good time if you have a Davis bore brush to run it into the cylinder to provide some cross hatch scratches into the cylinder wall.  Clean everything in hot soapy water followed by a clean water rinse and set aside to dry. I use a heat gun to expedite the ball socket drying. Reassemble and your good to go with no burr and it will run fine assuming you didn't distort the cylinder. Ken

Heat has been mentioned.  

I mention it again.  HEAT IT UP  Use a hair dryer on high, a heat gun, an oven, or even a small torch.  The key is to heat gently and evenly to around 250F.  The castor should start bubbling out of the crevices when you are at the correct temperature.  Due to aluminum and steel having different thermal expansion rates the parts will be very loose and frequently a decent pair of leather gloves or just some rag to protect the hand will be all the tools needed.  Go ahead and use the correct tool if you need.

Phil

I too had problems with pistons jamming in exhaust ports after disassembly.  I found that the current wrenches supplied with the engines were the culprits.  The wrench slots distort when pressure is applied.
 A bunch of early Babe Bee parts I got from the 'bay had an assortment of early Cox wrenches with it. The one with the 360 degree glow plug wrench works the best. The body is slightly wider and the slot longer preventing the wrench from distorting. It is my favorite wrench for Cox reedies.  Big question, is it a Cox wrench? It has no markings

The above wrench is the only Cox wrench that's credible. The others are not worth owning due to them doing more destruction than what their worth. The wrench I show fits Norvel, Galbreath, Glow Bee and also AP heads. I also use it on edge to remove TD backplates due to it being wide enough to fit properly. The newer spanner style wrench that Cox provides for glow plug removal slips, ruins the plug, etc. Even the screwdriver end is horrible. It works great if you want to stab your hand because it's real good for that when you slip off of the prop screw.

Ken Cook wrote:Reading further into the threads, I see those recommending to file the burr away. I personally wouldn't do that.

I read your excellent methodology on carefully lapping the high spot away, and agree it's the better way. Mine is cruder, yes it'll work but then more times than not I was so dissatisfied with marring the cylinder, especially around the exhaust port exterior that I simply went out and bought a replacement. That was back in the days when any hobby shop had parts in stock, were easily obtained and costs were reasonable. (Actually, considering inflation they are still reasonable and I am grateful that companies like Cox International and Ex Model Engines have these in stock.)

George, I do this with brand new Sure Start cylinders. I truly believe in the Davis Diesel bore brush as well. Doing this with new un run engines results in quicker break in, higher performance. I do this exclusively with Fox .35's and I'm usually flying them out of the box the same day. If you ever experienced the new cylinders, they feel very scratchy with the piston inserted and this alleviates that. Keep in mind the new Sure Starts have a boat load of ball socket slop and must be addressed prior to start up. Ken

The methods using no Cox wrench, but instead a padded vise or pliers around the cylinder and heat the crankcase some work without distorting and burring the cylinder. We don't want to be fixing damage but learn how to work without causing it.

My experiencing damages to the Cox early non-wrenchable (without flats on top cylinder cooling fins) goes back to when I was a kid and then a young man. Then, I didn't have the patience nor expertise, figuring Cox wrench was the correct tool, because the wrench just fit the cylinder exhaust ports.

After overtightening tank bolts distorting the soft cast backs, and damages to plastic radio cases and other things, one learns over time just how much tight is tight but not over tight.

Just part of the learning process.

GWILLIEFOX wrote:Ken has the proper  tools!  

I cut some straps of aluminum from beer cans.  Wrap two turns around the cylinder.   Then slip a small hose clamp over the aluminum and snug it down.  You can then use whatever tool you what to turn the hose clamp with no cylinder damage.

Thanks to MECA member Bill Schmidt for this hint.

And if you need heat, a little butane torch from Harbor  Freight works fine.  A gourmet chef's Creme Brule torch is better made, but your wife may not like it in your workshop.

Dear GWILLIEFOX,
Would an ordinary garden hose stainless steel clamp do? They have a bump. Perhaps you mean some kind of specialty automotive or aviation hose clamp?