[TR] Venting the TR3A Valve Cover

[Rick]

My TR3A came to me a few years ago with a usable TR4 Valve Cover. This
cover, with an oil filler vent capped with a SEALED cap, and a small fume
vent, appears to be the only type available today. The TR3A OEM breather cap
will not fit on the filler vent, so whatever venting is needed must be
accommodated by the fume vent and the open crankcase vent in the engine
block. The fume vent was originally there to carry the fumes and air into
the carb air filter of a TR4. I originally plugged this vent with a short
piece of oil line, but I noticed today that there is a modest pulsing
pressure there (3-4 psi?) that must originate in the crankcase, and I'm now
wondering if plugging it was a wise thing to do. How should I set this valve
cover up?

 

 


Rick in Seattle

1960 Triumph TR3A

1970 BSA 441 Victor Special

1975 Norton 850 Commando Mk3