Thread: crank case side breadther as oil drain

I am trialing a new centrifigal filter. I need to drain the oil to somewhere. The oil is fed from 3/8" supply.

I need two things to make this filter work:

1. oil supply 3/8" ID
2. oil drain 25mm ID for at least 100 mm from the filter, then it can reduce to 20mm.

oil supply
I am looking at feeding the oil from the filter housing. I can use the Land Rover choice of housing, remove the shut down switch and fit a oil feed OR convert the plug to a oil supply. Alternatively I can use a twin filter housing and convert the plug to oil supply, although the diameter is smaller than 3/8". another option is tap a supply into the cooler oil supply pipe.

oil drain
The filter needs free flowing drainage to work so I need a drain at the filter with a 25mm ID. I am wanting to drain back to the purpose designed oil drain point (diamond plate near starter).I need at least 20mm ID which makes it very close to the starter. However the breather pipe is much easier placed. I have two choices for using the breather:
a. use the existing breather pipe as a drain and fit a provent to do the breather job; OR
b. fit a 4BE tappet cover with bigger breather pipe and use the existing side cover for a drain; OR
c. fit a another side breather cover and use that as oil drain and keep the other side cover as a breather.

advice about these options would be appreciated.

Originally Posted by isuzurover

As above - however above or below the oil level won't matter.

I was told it needs to be above the oil level. It needs large diameter drain to allow air back up the pipe. I'm not sure I buy this explanation as oil volume is continually supplied to replace the oil that drains.

Anyway as an update, I have supply from a fitting silver soldered to filter plug and will drain back to breather. I had the local exhaust shop weld a 1" tube to the front plate that will connect to the provent.

Will the provent t into tha alternator drain ok? I think it should given the small volume from the provent.