Part two:

Some engines will not accept wrenches. I have some with narrow slit exhausts like the Sure Start...but no  slot to attach wrench at the top. Also have a couple with screening over the exhaust ports...also no slot.

For these, you can drill a cylinder size hole in a block of wood (pine or bass preferred), then cut the hole so you can clamp it around the cylinder.

Another way is to use a strap-wrench.

In any case, protect the cylinder and never, ever use a vise-grip or pliers!  

George

Edit: Type oh...

       For those that learned the hard way, I've found an easy way to fix the dreaded Cox burr. Over the years I've ruined many cylinders as Robert described. Even after years of valuable experience screwing up cylinders with the wrench in the exhaust port, I still managed to get one under the ole belt. To fix this I've found a certain size piece of brass K&S tubing which works well to resolve this. I believe its the 3/8 size. I cut it about six inches long and wrap masking tape around the top. The con rod can go inside the tubing at this point and the inside of the piston is slightly beveled. This may require more tape if the fit isn't snug enough. I then lap the cylinder using the brass tubing as a handle to hold the piston and I then apply some metal polish like Mothers or Simichrome in the cylinder as a lapping agent. I've had real good success at doing this. You can install the piston upside down to remove the burr if its a bad one as to not disturb the crown of the piston. I then wash the cylinder itself in hot soapy water I've trimmed a toothbrush to fit the cylinder and I use solvent for the piston rod assembly. I was concerned about how to get the water out of the ball socket joint. I've given some of the Surestarts this treatment prior to running. I've had some real scratchy feeling cylinders. This seems to help the break-in and initial vibration I've had with some of them. I follow up with the Davis Diesel stainless steel brush which claims to provide better performance due to fine crosshatching which provides a better oil film. The wrenches the Robert depicted are somewhat of a find today. I threw more of those wrenches out then I can remember. The full circle one as I call it fits the glowplugs perfectly and in addition fits the real backplate of the Tee Dee's as well. They fit the Norvel engine plugs as well. The black style which they made a semi-circle never worked well for me. The black style seemed to do the most damage for me. The older style that fit the port was thicker and rocked less as to not cause the burrs. Another problem to watch for is the older style Baby Bee,Golden Bee and also Tee Dee cylinder that had the thin walled base where it screws into the case. These over the years congeal with castor and when trying to remove distort. Um, I haven't found a remedy for this. This makes you sick when this happens. I now heat with a heat gun first. Ken