Timing Curve

[Mattax]

I tested disabling the pcv system by clamping off the hose in the back of the carb.
I don’t understand how a pcv system is really supposed to work, and I don’t think I am alone. Many people think they dont belong on a hot rod, other say they are a “must have”.
I rigged up a “catch cup” around my breather on the valve cover. Idle mixture was way rich without the pcv, so I adjusted mix screws in to about 5/8 turns total.
Afr at idle was about 13 at 11” hg at. 650 rpm in gear... about the same as with pcv.
The car drove fine on a 15 mile trip.
I saw no blow by at idle and ther was no oil in my catch cup.

Next I took the clamp off the pcv hose and spliced in an off the shelf oil/water separator for a air compressor.
While adjusting the mixture screws after about a minute of total run time oil started showing up in the separator, which surprised me. The cyclone action inside the separator was really effective looking. Maybe I can figure out how to post a video...
After a 15 mile drive I had “some” oil in the little separator.

Not sure what I will do about this from here. Might do a road draft tube... ran out of daylight.

Engine is new with about 700 miles total and has used a quart of oil. I don’t think the pcv is where all the oil is going though.

The PCV valve needs relatively high vacuum to close down at idle. The objective is to reduce airflow through the valve while engine is drawing the least amount of air past the throttle. There are some old posts here about PVC valves that have a soft enough spring in them to do that with engines that had somewhat lower idle vacuum than most factory cars.

AMC actually put the flow rates in their shop manuals. I posted those here
https://www.tapatalk.com/groups/racingf ... -t680.html