Crankcase Ventilation

[roadtrp204]

Looking for ideas, opinions, and/or feedback on how the performance 914s out there are venting the crankcase.

I am thinking of using a negative pressure method I have seen on domestic performance cars. The method involves running a line to the exhaust with a check valve and connecting it to the crankcase vents. The vacuum pulses present in the exhaust draw out blow-by gasses and result in a slight vacuum within the crankcase itself. The check valve is to keep the pressure pulses and a backfire from coming up the vent tube.
Baffels would be a must to keep as much oil out as possible and I plan to exit the tube in the tail pipe extension past the muffler. I also think this could help with some of the oil leaks that tend to form later in an engine's life.

2.0L engine mods include: new complete rebuild; 3-angle valve grind; mid to high range cam; CB performance FI; 050 distributor; and Crane HI 6 ignition.

If your running the HI 6, which tach adapter is required (two are listed)?

Car is still being prep'd, so I would like to take care of most of the small details/upgrades before the engine goes back in.

Thanks,
Chris

[Rich Hilgersom]

I have seen this done on the domestic v8s for years. I also saw one 914 with this setup but it tapped in well before the muffler as did the v8s. As long as the line makes an upright arch the oil will be minimal. I dont think this will have any effect on future oil leaks though :-). The only split case aircooled I have seen that are leak free after a number of miles have had the cases o-ringed, or tightened on a regular basis.

[John Rogers]

As it seems smog checks are not a problem, I would recommend a vent on the crank case, one on each valve cover and tie all three together at a vent can with a filter and drain. Most of the race 914s I have seen use a setup like this. If any oil liquid gets into the exhaust it could burn, especially if it is synthetic. Good luck.