Twin Cam restrictor

[IamScotticus]

is it not typical for a dry sump scavenge to pull enough volume from the bottom end, that not much outward venting occurs on the top end?

[jbcollier]

The scavenge pump is always a much higher capacity than the the pressure pump.  They do not pump air and will not create a vacuum in the crankcase.

[SENC]

I'd also suggest joining and asking questions on lotuselan.net.  That is probably the most active forum for Lotus twin cams and there are a good number of folks there with dry sump systems. 

 

Leaks at the timing case/head/block area are not uncommon for a number of reasons, including gasket failure... you'll find a number of threads on such at the aforementioned forum.

 

Agree with JB that this is a lot of pressure, but I'm not familiar with dry sump systems so it may be typical.

[wdb]

Glad to hear you found your leak source. All this crankcase pressure talk was probably just a distraction!

 

That oil tank is pretty cool. If my 'in period' tank had been that cool I wouldn't have bought a new one. 

 

The little filter is a pretty common item in Autozone and similar type stores. 

 

https://www.autozone.com/intake-system/universal-air-filter/p/spectre-black-breather-filter/415841_0_0

 

The breather vent in the head I was asking about is the one in the side of the head, behind the intake runner. On my Se7en it has a 90 degree rubber thingie, which used to go to a plastic catch bottle. It now connects to the oil tank. In the Elan there is a tube running straight into the airbox.  In your case I'd open that second point on the top of the oil tank and connect the two. Perhaps connect it to the cam cover breather and run them both to the same point? If I had added the cam cover breather I would have connected it to the unused spot on the catch can. Depending on how you vent the oil tank you might have other options as well.