The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Rgs-Bill on 31.03. 2013 19:51

Title: Overhead valve oiling
Post by: Rgs-Bill on 31.03. 2013 19:51
Has anyone out there tried the restricter bit with a cotter pin.  Some one told me to put the bulbous end of the cotter pin inside the oil return stand pipe in the oil feed tank, then bend the feet around the outside of the tube to hold it in place.  He said this will provide a small amount of restriction, and force a little more oil up to the rockers about 25% a little more or less.  I have this question, if you put up to 25% more rocker box oil up there, and BSA does not use valve guide seals, would that not cause more frequent spark plug fouling ?? Please anyone respond to this, the more the merrier, all Ideas are good , just some are better than others.

               Thanks Much
Title: Re: Overhead valve oiling
Post by: bsa-bill on 31.03. 2013 20:15
not sure I have heard of a problem with under lubricated rockers being a design feature of A's but I aint heard all the stories.!
given that the return side has more output then the feed side of the pump then the engine will have some spare capacity there but 25% more going to the rockers than was designed for - dunno - will there will come a point when this extra (25%+25% of 25%+25% of 25% of 25%) overwhelms the pump, perhaps not but you see where I'm going.
BSA already worked out the size of little hole needed to allow enough oil to lube the Rockers
Title: Re: Overhead valve oiling
Post by: Greybeard on 31.03. 2013 20:40
I understand that the A engine originally relied on oil mist for rocker lubrication but the pipe feeding the rockers was added later when the rockers were found to be not getting enough oil. I imagine that the rockers don't actually need a huge amount of oil.

Neil Ives UK