PCV installation on a flathead?

[John-T-53]

Has anybody ever installed a PCV system on their flathead? I'm looking to put one on mine when I get the motor back.

I put a system in my small block Chevy motor recently...just removed the road draft tube, installed a grommet and pcv valve with a hose to the vacuum port below the throttle plate on the carb. It works fine and there's no more crankcase fumes inside the car.

I checked out some of the PCV installation sheets on this website under "downloads" and they look quite complicated. Anybody get into this territory lately?

[MBF]

That's what I did-made a big difference in the color of the oil between oil changes. Also cleaned up some of the sludging. I found a road draft tube that was on a parts truck. The tube was cut off and had a welded on nipple. I put a piece of hose over it, plugged in a PCV valve, and ran a hose up to the vac port under the carb. Using a sintered filter on my oil fill cap as the air inlet. Mike

[grey beard]

John,

Mike is right - they make a measurable difference in keeping the crankcase cleaner and free from condensation. You can either retrofit a hose connection onto the top of your old road draft tube - after you close the tube off - or buy a PCV system from Vintage Power Wagon - link on this forum - and just hook it up. They were used on military vehicles in WWII.

The rest is just as Mike described. Plum the vacuum line to the pipe plug opening underneath your carburetor on the intake manifold. It's best to find an oil fill cap with no vent, so you can direct a hose from your oil fill tube into your air cleaner to serve as a source for clean air entering the crankcase, to replace the air being pulled from the engine by the PCV system. Otherwise you will be pulling unfiltered air into the engine through your oil filler cap.

Good luck. Let us know how it works out. Your engine will stay a lot cleaner with the PCV system, especially if you use a 180 degree or higher thermostat to keep the block temperature up where condensation really can evaporate.

[Guest P15-D24]

are on the DOwnloads page on the main site. It was a factory option for P15s and D24s as the instructions are specific to those series.

[John-T-53]

Do you guys think the original oil fill cap with the oil-soaked wire gauze is sufficient for a source of clean air? What about changing the element inside of the cap to something more dense?

If a hose were run to the air cleaner, it would have to tap into the inner core of the assembly where the clean air is flowing.

Looking at other PCV systems on modern cars (well, up into the 80s at least), there usually is a breather hose running to the air cleaner with a separate, dedicated cleaning element - usually a white throw-away guaze type you can get at any parts store (Fram, STP, Purolator, etc).

With my small block system, I kept the original fill cap (same wire guaze element) and clean it regularly, then resaturate with 50wt.

[MBF]

The PCV air filters on 80's GM products were a fiberglass mesh inside the air cleaner house, but outside of the filter element. I'm confident the one that I'm using from an 80's Dodge slant 6 is adequate. I want to make up some type of a cold air kit for my 52 1 ton to give it a shot at some ambient air, and get rid of the oil bath air cleaner and replace that with a paper type filter. When I get that done, I'll tap into the filter for an air source. Mike