Hi folks,
Quick question, does anyone know were to find spare parts for a G21/35? I bought one on the 'Bay, and the compression is minimal at best. I need a piston and sleeve. Thanks for looking.
Tom Taylor
Super Tigre parts
Stuka Stunt Main Forum · 5 of 5 known posts recovered
Your best bet is to use piston expansion method of baking in the oven. Take the engine apart. Place the piston only in the oven at 500 degrees for 1-2 hours. Remove piston and allow to COOL NATURALLY. The heat expands the piston and when it cools, it does not go all the way back to its former size. Put the engine back together and lubricate the engine. You will notice considerably increased compression. I have done a McCoy Redhead that had almost no compression and it now has good compression and starts/runs fine. Other fliers on this board have used this method on Johnsons, Vecos, K&B Greenheads.......any engine with a cast iron piston. Since parts for the old G-21 are hard to find, I would recommend this method of restoration..........it works.
SRiese5283 · Jun 17, 2004 07:37 PM
#2 source
YEP It works.....
I use to hear of some sort of "heat / heavy oil treatment", I think it was. As I recall it might have been a process that G. Aldrich once used to restore compression on the iron pistion / steel sleeve type model motors .... does anyone know the process (perhaps heat followed by oil dip)? I'm not sure if George was expanding the piston, shrinking the sleeve, or both? Would it not be wise to jig up the piston in the oven so as to avoid any "uneven loads" on it? THANKS!