Britbike forum Forums Thread Like Summary - Aluminum to Aluminun gripped

Hi; I am trying to start my old pre unit but does not want to cooperate.
I have spark; gasoline and compression (...) but no start
Checking by the plugs holes, I noticed that one of the exhaust valves is not "showing" all the traveling so I was trying to remove the inspection cap but is just almost seized there. Like welded.
Perfect hexagon to fit a wrench and now is just rounded almost useless, due to impossible to remove it! The other 3 can be removed in a breeze so I have now a more difficult scenario to try to move the damn cap.
I have a big wrench and did not moved a bit also I sprayed WD40 without any success.
What about warming the rockers? or could be even worst? though the only thing that I have to heat there is a hair drier.

Thanks

boil the jug and pour hot water over it?

Hi Bob; few hours ago I put that heat gun that I bought to work; then I used the chisel and hammer again; nothing. Repeated the process with more heat and the cap turned off!. Threads perfect and all new due the cap was new actually...
Strong concise hammering. I heated several times the cap.
The thickness of the cap is good so may be with a lathe I can manage to let it nice again; with the hexagon possible I need to go from 1 inch to 15/16 but I do not know how I can do it right. You know, now, the "faces" are all different.
May be any of you machinists can share a simple way to have them right.

Thanks