Absolutely necessary. The pressure has to go somewhere. You either have to
have a crankcase vent open to the atmosphere or have one connected to the
intake to be reburned. Early TRs had a vent tube in the bottom of the block
for that purpose. The air pump is used to inject additional air into the
exhaust gasses to lower the percentage of emmissions, not to vent the block.
There is normally the same setup on the valve cover to release pressure that
builds on the top of the engine. Early engines had a cap that allowed
pressure to escape to the atmosphere. Later, it went through several types
of check valves to let the pressure out, but not to allow air to be sucked
BTW, contact me off line if you are looking for used covers. I have
From: firstname.lastname@example.org [mailto:email@example.com]On
Behalf Of Ray Wygonik
Sent: Friday, August 11, 2006 4:27 PM
Subject: Engine breather tube
My 72 MGB does not have a crankcase breather, nor does it have an air pump.
I also noted that side covers with breather tubes are not readily available
new from parts suppliers. What are the thoughs on a crankcase breathers?