3/16 in vacuum port ok for PCV valve

[Sledge]

My engine manufacturer has recommended that I use the large (3/8 in.) vacuum port on the carb baseplate for my power brake vacuum cannister, and find an alternative port for the PCV valve. I have been using that port for both functions. The car runs great but uses more oil than I'd like. So, this is his suggestion to reduce oil consumption.

The only other full manifold vacuum port I have is a 3/16 in. port on the baseplate. Would that be adequate for a properly functioning ME Wagner PCV valve? Or do I bite the bullet and have a port machined into the intake manifold?

Or, was the advice to find another vacuum port a questionable suggestion in the first place?

I get 13" of vacuum at idle and drive the car on the street only. The engine is a new installation. Brakes work fine although I understand conventional wisdom says I need 18" vacuum for proper brake boost.

All help appreciated!!!

[cycleguy55]

Originally Posted by Sledge

My engine manufacturer has recommended that I use the large (3/8 in.) vacuum port on the carb baseplate for my power brake vacuum cannister, and find an alternative port for the PCV valve. I have been using that port for both functions. The car runs great but uses more oil than I'd like. So, this is his suggestion to reduce oil consumption.

The only other full manifold vacuum port I have is a 3/16 in. port on the baseplate. Would that be adequate for a properly functioning ME Wagner PCV valve? Or do I bite the bullet and have a port machined into the intake manifold?

Or, was the advice to find another vacuum port a questionable suggestion in the first place?

I get 13" of vacuum at idle and drive the car on the street only. The engine is a new installation. Brakes work fine although I understand conventional wisdom says I need 18" vacuum for proper brake boost.

All help appreciated!!!

IMO, it sounds like your engine manufacturer is recommending a half-baked workaround as an alternative to fixing the real problem.

[RockBit]

You need to make sure your valve cover is baffled under the PVC valve. If it is not, that explains the higher oil consumption. You may also want to install an oil catch can between the PVC valve and the port.

I would just tee off the line going into the 3/8 port for the PVC and the power brake booster.

[Sledge]

Yep, the cover is properly baffled, and yep, the PCV 3/8 in. hose tees into the 3/8 in. hose to the brake vacuum cannister.

I was thinking that the suggestion may have been a bs response but I wanted to check....

Thanks