Flathead PCV retrofit

[Paul Phillips]

At the risk of starting a debate, I thought I would share the approach I am using to eliminate the draft tube function and fit a basic PCV system.  The draft tube will remain for 'looks', and the modification is fairly subtle.  There is an unseen blocking plate under the valley vent manifold where it normally would feed the draft tube.  The oil filler cap/dipstick was dismantled and the copper wool renewed as well, so it should breathe easily.

After all the accessory drives, linkage & lines are back on the engine and it is in the car, I think one will almost need to be looking for it to see the changes. 

As to why, I am doing a lot cosmetically to the underside in the restoration, but also want to drive the car when finished, not just show it, and would like to minimize the oily tracks the draft tube vent leaves under the car.  I am grateful to the way that oil preserved the lower body & frame over the years prior, but will count on epoxy primer for corrosion protection in the future.

Let the comments begin!

[R Schroeder]

As a retired machinist, I would have to say, very nice job on the spacer block, and tube.
Is that cover you mounted it into exposed to direct oil splashing ? That would be my only concern. You wouldn't want it sucking oil out as you drive.
I am not familiar with this type of engine. That is why I ask.
But other than that, it looks great.
Are you going to paint it green also ?
Roy

[Steve Passmore]

This is nothing new as my 37 and 38 Cadillac has this type of venting into the manifold and air cleaner but Cadillac thought better of it and changed it to full external venting between 38 and 41 maybe because a worn out motor would pump to much oil fumes into the carb or they found the engine ran better without it.
This change was around the time they increased the horse power to 150 and they kept external venting till the end of the Flathead engines, lets hope you don't see a reduction in your BHP.
The mess under the car you speak of would have only been from a well used motor, I'm sure they didn't leave the factory spewing out oily fumes. If you have rebuilt your engine which looks very good, I'm sure you didn't really need to revert back to the older system.

By the way Roy, there's a baffle arrangement under each valve cover to prevent oil moving up into this venting system.

[R Schroeder]

Sort of figured there was some sort of baffle in there , but didn't know for sure.