Um, I have this discontinued Thunder tiger 2 stroke 40 engine. I want to replace the top part were the glow plug goes but one of the hex scrrews got the thread grinded of. Can u guys pls help me find a way to get it of.

And Does any one know Trent Combs

If the inner hex is deformed so the wrench can't turn the screw...
1) if the screw head is accessable, grind a slot in it with a Dremel Cut-off wheel, then use a straight blade screwdriver.
2) A left-hand tap will often work well as a screw remover.
3) the "Torx" bts will somnetimes grip in a hex key screw when the correct hex key won't turn the screw.

If the screw is stripped in a manner that turning it doesn't remove it...
Gently insert a straight blade screwdriver between the head and the engine cylinder case. Twist or pry with gentle pressure as you turn the screw.
Whent he screw is out... hopefully (rarely happens [img]i/expressions/face-icon-small-sad.gif[/img] ) the screw is stripped not the case threads. A stripped screw is easy to replace.
If you have to re-tap the case, you have to go to the next larger (sometimes 2 sizes larger...) screw dia. You'll also have to drill the head's hole for that screw to accept the larger screw, and you may have to grind the fins and redo the flat for the screw head to seat properly on the engine head.

Also keep the rest of the screws tight while trying to remove the bad one.
later daveo

FFHuber's suggestions are all good. I would add, there are also screw removers commonly called "easy outs" in various sizes. They usually require that you drill into the screw enough for it to grab the screw then back it out. Sometimes a little heat carefully applied will loosen the screw enough to make it easier to remove.

If the threads in the case are in fact stripped, and you tap it out for a larger screw, the load on the head is not balanced and there is the possibility of warping the head. Here is a method that I have used with some success. Drill and tap the hole for a larger screw (two sizes larger if there is enough metal). Using "lock-tite", or similar thread locker, screw in place an ALUMINUM screw. Then cut off the protruding part and carefully dress it flush with the case. Then drill and tap into the resulting plug the original thread size and use the original size screw.

I know Trent Combs. Haven't seen him around the forums in quite a while though.

If you could would you give me his email address. My email address is [email protected]