Can you run a breather pipe below the Carb blades?

[Pete]

What do people think?

Can you run a breather pipe from the Rocker boxes (or a breather port in the valley) directly to the Full manifold Vacuum port beneath the Carb throttle plates?

I would have thought that this would have an impact on carburation mixture as you are introducing more air into the incoming charge AFTER the carb boosters, Jets, etc.

I want to reduce crank case pressure and I can think the only other (safe) alternative is to route a breather pipe into the Air filter so it does not disrupt the carburation mixture.

Any views?

Thanks

Pete

[Mick70RR]

Why not use a PCV valve?

[Pete]

Why not use a PCV valve?

I would have to engineer one in but as this is merely a one-way valve, the question still remains - would you connect this output to the large port on the carb that is under the throttle blades? I am concerned about affecting the fuel mixture. I do not have an AFR so I cannot easily see the impact.

Cheers

Pete

[Blue]

You would certainly be drawing in oil vapour if not oil itself, you would need good baffles. Better off plumbing into the headers, you might see a little blue smoke but it won't contaminate the intake charge. Why is crankcase pressure an issue?

[Pete]

I am trying to reduce the crankcase pressure as the engine is susceptible to leaking on the manifold to block seal. It is a Stage VI inlet so no bolts across the valley.

[Blue]

Gotcha, in which case assuming you have sufficient valve cover breathing, sounds more like a straightforward leak rather than a pressure problem. Assume you are using silicone on the block rails? If the intake is a very tight fit, or metal to metal you will need a different sealer, silicone doesn't work very well unless there is a bit of gap to fill.

[Pete]

I have found that the high temperature Silicon used on Glass Oven doors works bet, the "normal" Silicon lasted about 30 minutes, but as there was a port welded into the inlet at the valley I put a simple air breather filter on it.

That started puking oil within 10 minutes.

I can block it off, but I was looking at other alternatives.

[Blue]

There will be a lot of oil getting chucked around the valley, if you have a breather on there it's probably best to run a hose up to a small breather tank to allow it to puke and drain back.