Flathead PCV ????
 

In my continued quest to make my '52merc engine run cleaner I am fabricating

a positive crankcase venting system for it. Because I'm going to run duel carbs

I know I will have less vacuum to work with, therefore I have drilled and tapped

my duel-carb manifold for 3/8" NPT fittings in both main channels to supply the

PCV valve with as much vacuum as this set-up can muster! I will be installing

an air intake at the other end of the intake manifold.

Take a look at the pictures and let me know what you think.

Derek.

Re: Flathead PCV ????
 

You could just drill a 1/4" hole into the other plane from one of the new ports on your dual carb intake to accomplish the same thing, and have simpler cleaner plumbing. (That's what I did to the Edelbrock dual intake on my '51 with great results) Use 3/8" vacuum hose, not that clear plastic stuff. And the air intake/oil fill really should be left in the stock location at the front of the intake on an 8BA intake. :)

Re: Flathead PCV ????
 

Nice looking work.

Re: Flathead PCV ????
 

Can you post a picture of your method of PVC ? How does it work?

Derek

Re: Flathead PCV ????
 

As your main objective would be to capture blowby, I think you should rethink the "air intake" you plan to install, to provide filtration, and even some restriction, rather than a free flow intake.

Re: Flathead PCV ????
 

The pictures are not the best as the car is in cold storage, but hopefully they will show what you want. I removed the oil fill/breather pipe on the close up shot to better show the pcv, grommet, hose and intake fitting. I drilled and tapped for 1/4" pipe externally, then 1/4" hole into the other plane, so all 8 cylinders act on the pcv. The system has worked very well for many years and miles.
Clicking on the pictures will enlarge them.

Re: Flathead PCV ????
 

V8 Bob, I wanted to distribute the vapour from the crankcase to all 8 cylinders and have it burned off evenly. Some systems send the vapours to the front cylinders only, either way will work. My rear fuel pump opening will have a filter mounted on it to make sure only clean air gets sucked into the engine.
The front/existing oil fill tube will have a tight fitting plug, removable for oil filling. This system duplicates all new modern PCV on new cars.

Re: Flathead PCV ????
 

I'm going to install one in the fuel pump plate. I need to make some type of baffle first. I'm going to drill into the plenum and install a fitting with a tube that will use both banks. This is a 276" motor we are putting in a 30 Model A. It is 3X2 so it will mostly run off of the center carb.


I didn't read V8 Bob's post, but that is what I'm going to do as well.

Re: Flathead PCV ????
 

The plumbing on my engine is pulled by all 8 cylinders. Drilling through and into the other plane allows this with just one external port.
If you learn more about how the 8BA ventilation system works, you'll realize air enters the front oil fill, flows to the rear and down into the crankcase, then up through the front stand pipe that leads to the original road draft tube, or a modern pcv. Bringing fresh air in only at the rear does not flow over most of the valve chest in an 8BA flathead. Place the filter over the oil fill tube for best ventilation.

Re: Flathead PCV ????
 

You have to engineer a PCV system, to make it effective. Install the PCV valve where the Ford road draft tube is, supply a vacuum to it with a connection that takes the fumes and burns them-off in All the cylinders. Supply clean filtered air to the crankcase by installing
a filter as far as possible away from the PCV valve. Don't forget to seal the dipstick with a
grommet, to stop unfiltered air ingress, now you are doing it like new car manufactures!
Check my other PCV posts, I will keep updating.

Re: Flathead PCV ????
 

You just don't understand the 8BA engine. The 8BA intake manifold design and gasket completely isolates the road draft port from the intake oil fill and fresh air intake. Do you really think Ford would have allowed intake air right next to the road draft? :confused:

Instead of all your planned visible plumbing, you could plumb (tee) both intake planes on the bottom of the intake to a pcv installed in a capped off vertical stand pipe. That's the way my modified 286" flatty is in my '32. Completely hidden and trouble free.

Re: Flathead PCV ????
 

The ford front road draft tube connects to the metal tube in the front of the block (on 8BA) this leads down into the crankcase and isolates the draft tube from the
valve chamber, even though the fill tube and the draft tube are mounted close together. By using the rear fuel pump area as the filtered intake that fresh air is drawn through the valve chamber and down through the drain-back holes into the lower crankcase and eventually up the front tube to the road draft tube or a PCV
valve !
All information on these sites is help and guide not to promote differences and
arguments.

Re: Flathead PCV ????
 

Knowing the 8BA engine ventilation is a must before adding a pcv, and simply replacing the road draft tube (internally or externally) with a pcv connected to manifold vacuum, along with a tight fitting dip stick and distributor, will ensure very good crankcase ventilation.

Re: Flathead PCV ????
 

Yes, indeed.


https://www.fordbarn.com/forum/attac...0&d=1577980037

Re: Flathead PCV ????
 

My DIY catch can -- filter --for cleaning and catching residue oil from the vacuum line running between PCV valve and vacuum source fitting below carburetor. Consists of a few 2 inch pvc fittings coupled together to make a container about 3 inches round by 5 inches high. Insert filter material in container, tap an inlet, outlet and drain opening in container. Top screws off for future filter changing and unit can be drained from bottom drain fitting at any time. The other hose fitting is on the other side--1/4 thread with hose barb.

Re: Flathead PCV ????
 

Quick question (been following threads like this forever). Since I moved to Nevada/much dust in the air I've been considering installing one. ANYWAYS;
Did anybody think about the a/f consequences (leaning out)
thankx

Re: Flathead PCV ????
 

There shouldn't be any consequences. I have no noticeable plug color change, performance issues or loss of manifold vacuum. No good reason not to install a pcv. :)

Re: Flathead PCV ????
 

Should the inlet to the system have any restrictions other than a filter? I am planning to plumb into the inside of the air cleaner. It seems like I remember my 70 302 would run different when I took the oil cap off where it was open to atmosphere. But maybe I'm not remembering right.

Also, does the PCV valve itself need to be vertical to work right?

Thanks everyone for all the feedback on this thread.

Sent from my SM-G973U using Tapatalk

Re: Flathead PCV ????
 

That's because the PCV valve was in the oil filler cap and when the cap was removed the system was altered.
This is how I am plumbed into my air cleaner.
https://www.fordbarn.com/forum/pictu...ictureid=41477
https://www.fordbarn.com/forum/pictu...ictureid=41476

Re: Flathead PCV ????
 

OK: I now have my 8BA duel carb PCV system completed. Here's how I did it.........

The PCV valve and grommet is one to fit a 1998 ford f150 4.6 lt..........The oil cap is for a

1992 ford Festiva car. and the fresh air intake breather is a K&N #62-1600RD-L mini filter mounted on a pipe nipple (1/4") at the former fuel pump location. see pictures.