Dominator crankcase breather

The pre-60s Dominators had a simple breather. It generally consisted of a piece of Copper tubing that ran from the back of the engine down to the gearbox sprocket. When the engine was running the timing of the breather disc, sitting at the end of the camshaft, allowed excess air out of the crankcase along this tube. The same disc then prevented air being sucked back along the same tube. In essence the disc acted as a one-way valve. You only really need a one-way valve in the circuit if the main breather has been re-positioned to a different part of the engine. ie. on the timing cover.

If your pistons, rings and bores are in good shape, there won't be much oil getting into a breather bottle.  No need for a valve at the outer end  My reading of breather systems is that it is preferred to have a valve at the crank case end, rather than at the catch tank

The standard breather doesn't allow much flow, but seems to work OK, at least with a lowly tuned motor.  I'm nut sure exactly what was fitted by the factory, but my 88 has a 2" long pipe extending backwards from the top rear of the crank case.  I fed a plastic pipe from this to a plastic bottle behind the gearbox, and then added another from the oil tank (actually a battery vent pipe)

Paul

George:

The item you are talking about is a PCV valven not a PVC valve.

The initials stand for Positive Crankcase Ventilation whis is what it is supposed to accomplish.

Mike

Many American cars use such a valve, in their rocker covers, so if you contact an American car parts supplier you should be able to buy one. Try American Auto Parts in Watford. There is PCV  valves that have a 90 degree bend at the top, these are used on earlier small block Chevrolet engines, and a straight in and out type.

VW Beetles use such a valve. I bought one once from a local specialist. Can't remember why. I never used it.

The breather was originally designed to lubricate the rear chain, with oil mist.  Providing the engine is in good condition, little oil should be discharged, once the sump has been cleared by the oil pump.  O.K. there may be a few oil drips, after a brisk run, but, it did not bother me in the 50´s, and does not now.  What is wrong with a drip tray?