Crankase ventilation for a turbo six

[Anonymous]

Update on the engine build. I have clearanced my single rail bellhousing for the twin plate clutch. After 20 or so fittings and grindings it works. Had to take about 3mm out of it around the top of the housing.

The sump is on (with the ears on it) it now has a capacity of 6 litres!

As the car runs LPG there is a block off plate where the fuel pump used to be. I'm considering altering the PCV system. What do you guys think of a vertical 2 inch cylinder filled with stainless steel pot scrubbers (like a VW air cleaner) bolted to the fuel pump hole with the PCV in the top of the cylinder. I'm thinking the crankcase air would then be filtered before being burnt in the engine.

Any oil from the crankcase vapour would then drain back into the sump.

Anybody see any problems with that?

Dom

 

[xctasy]

Sounds like a cool idea. I've jotted down another one which may be better.

Note the following facts.

1. A stock 250 engine may have 3 cfm of blowby with normal pre XF rings at 4800 rpm.

2.On a turbo, your blow-by is proportional to the boost ratio. You would have twich as much, perhaps 6 cfm.

3. 6 cfm is too much to effectively use with a stock PCV system.

4. I'd use a non-return valve, and set it up a negative pressure scavanging system. There would be about 3 psi of backpressure past the turbo, but over 15 psi in the sump. I'd be running a line from the crankcase to below the turbo in the exhast, if it is legal. All blowby would be sucked and disposed of in the exhast.

Option two is to do as you've planned. The first method is used on race cars, and works. The one you've decribed will not help as much. The ring pressures and blow-by won't be reduced with the Vee Dub set-up. At drags, there is a Holden V8-style mod which is similar to what you propose. These are used to stop nasty oil downs happening. It needs to be vented to the atmosphere to have a reduction in crankcase pressures.