|
A while ago I pulled apart a previously re-build B20A. Everything inside looking good.
The engine runs on LPG (liquid pertol gas) wich has a substantial higher burning temp. Often (as in this case) only the exhaust valves get hardened seats. Apparently the valve guides were not replaced, and due to play, two of the inlet valves are ‘knocked in’about 5 mm !! There was hardly any tension on those two valve springs…

Obviously I’ll put in new valve guides (the valve stems are still excactly 5/16”). And since I’m working on the haed anyhow, I might just do some very minor porting. The exhaust port did not look very effiecient to me. Wouldn’t it be a good idea to cut of a bit in those red areas?

I know it’s very easy to screw up a head but this is very ‘innocent’ porting I would say.
What do the experts think though??
Cheers Ben
--
Daily driver: P130, '65, B18+M47. In the proces of restoring: P131, '69, B20+AW71L. (www.knutselsmurf.web1000.com)
|