I just recently bought a nitro buggy rc It brought a vx-18 engine. were could i find parts for these engines.?

I just recently bought a nitro buggy rc. It brought a vx-18 engine. were could i find parts for these engines. also what can you do to loosen the piston sleeve.

On Protech's website there is a list a dealers that can supply you with parts.
http://www.protech.be/html/Dealers.asp

There is also this site (not in english)
http://www.difference.com.br/difference_loja/index.php?cPath=34&osCsid=f3efbdfd8562c2ca765d656e2240dbb8

For the sleeve, sometimes you can just turn the crankshaft a few items and it will move out slightly. Then you can just pull it out. If the lip of the sleeve is not sunk into the block. You can often get a small flathead screwdriver under it, and move the sleeve out. If the lip is sunk into the block, and it wont move out by turning the crankshaft, you will need to put a ziptie in the exhaust port, and turn the crankshaft. It will be pushed out slightly after this. Remove the ziptie and see if you can pull it out by hand.

Good luck and happy bashing