Ventilation in Original 427

[dandascott]

I have an original 427 side oiler with the original cast iron heads and original2x4 intake. I am using the "Shelby" LeMans valve covers. I have not run the engine yet and I am looking for some help with the crankacase ventilation. I have read many post on this and seen many variations but I did not see a matching situation to mine (though it surely must exist here).

I plan on only street driving. My plans were to get a K&N valve cover breather for each side and a "S" shaped oil breather attached to the rear of the intake.

With this arrangement do I need some plumbing down the frame rail taking gases away from the engine compartment ? I do not want to drill and tap into the original intake and like everyone I want to minimize oil spray in the engine compartment.

Any advice or pictures will be helpful.

[mr0077]

I'd recommend a PCV fitting at one of the valve covers, with the PCV hose going to the base of the rear carb, and a breather cap on the other valve cover. I'd imagine the S-tube and valve cover breather would provide plenty of ventilation for the crankcase.

[dandascott]

Ken, thanks for the reply. Is there any conceren about only venting gas into one of the carb's, any imbalance issues ? Also, I think the carb's were installed in reverse so are you recomending plumbing to the carb that is closest to the firewall ?
Thanks,

[mr0077]

Well, good question...I assumed you didn't have an existing port on your manifold, but on my (original Ford) 2x4 intake there was a 3/8" port on the back of the rear carb pad just below the rear carb. I used that for the PCV hose. If your manifold has one of these, use it (the front and rear chambers are interconnected inside the manifold, so it shouldn't cause any imbalanced fuel/air conditions). If yours doesn't have one of these, don't use a port on an intake runner; I think you'd be better off to hook it to the PVC port on the "rear" of the front carb, which would be at the front of the motor since they're mounted backwards. Reason I say use the front carb is, although the motor should idle on both carbs, at idle very little flow is pulled out of the crankcase through the PCV valve...since you cruise on the front carb (with factory setup, anyway), most PCV function would be through the front carb...when you're at wide open throttle, very little vacuum is working on the PCV valve, so once again it won't flow much, and the relative volume of the PCV flow compared to the total flow through the carb or carbs is small and would have a pretty much insignificant effect on the F/A ratios.
Does any of that make a darned bit of sense? Hope it helps some...

[Nantucket427]

I started with an oil burning problem a few years back and got into this ventilation stuff thinking that, and to much oil in the heads was the source of my oil burning. I am convinced by all of the replies from guys smarter than I am, that you should run some form of pcv valve. I have run mine from one of the valve covers to a nipple on the rear carb. That way your engine is reburning the vapor rather than have it drip out along the bottom of the car. The original 427s with there pentroof valve covers did not do it this way. They let there oil filler cap and there "S" shaped rear vent, off the intake, do the job but in those days they didn't use PCV any way. Search FE Talk for PCV you should get more information then you can read.