Tech: Cheap and easy pcv on your 49-53 ford flathead v8

[moefuzz]

.


No need to spend $50 bucks on someone's wizzy "PCV" kit,
For around $5, you can install a PCV system on your Flathead..







There are many benefits in replacing the road draft tube with a proper Positive Crankcase Ventilation system on your Late model Flathead V8.


A): it helps eliminate the embarrassing smelly/hot fog that wafts out from under your hood at the stop light.

B): It helps to create a consistent vacuum inside the crankcase and oil galleys.
An actual vacuum/draw inside of your crankcase will aide in keeping the oil and oily residues from being pushed out from every available seal, gasket or open "hole" that is and/or resides in what we think of as an automobile engine.

C): A PCV system will help eliminate moisture that can and will accumulate in your engine oil and hence your oil pan, engine and intake galleys. Moisture is a major cause of internal engine sludge that builds up (over time) and generally coats all manor of things like intake valves, stems, springs and lifters.

D): When you think about it, The road draft tube is actually just a huge open leak unto an engine. While a great idea when it was designed, it was obsolete when the idea of a closed or semi closed System with a proper PCV valve was invented.

E): Eliminating the road draft "hole" and replacing with a proper PCV sets you on the path of creating an enclosed (as opposed to wide open hole) oil galley and crankcase. which brings us to;

F): Eliminating the open hole of the road draft tube shuts out the probability that the filler cap/breather will suck in air/dirt/moisture and debris as you drive along..
At throttle and while working the engine, your engine creates Pressure and this pressure will be pushed out the road draft tube (not to mention and/all gaskets/seals and other non sealed surfaces) and along with the pressure comes hot fog/moisture and oily residues..
Which directly relates to;

G): oily/grime. As you drive/work the engine, the inherent pressure of the working engine escapes from every available seal/gasket etc. and carries with it oily residue that coats your clean engine, engine compartment, firewall, chassis eventually swirling around and being carried away at and around your rear bumper...
...At working pressure, Everything accumulates an oily coating, even the guys headlights in your rear view mirror.

If an engine didn't have an open port like the road draft tube and filler cap,
at speed/work, the oil pan would become pressurized to the extent that it could deform
or balloon the oil pan.
This especially true of race engines with high lift cams.
At speed/load, Vacating the pressure is a priority.


H): rerouting the "open" hole of the road draft tube has the effect of "tightening up" your engine vacuum under load/work. Installing a regulated valve in the form of a PCV has the effect of regulating drafts(vacuums) and working pressures that build in the crankcase at various engine rpms and loads.
As a side benefit of enclosing or eliminating the road draft tube, your engine vacuum is aided by way of allowing built up pressures in the crankcase to be directed into the intake where the cylinders draw it into the combustion chamber.






The PCV valve in itself is similiar in principle to a common regulator found on things like air compressors and/or oxy acetylene bottles.
:A PCV valve restricts and regulates air flow in one direction.







.

 

[34PKUP]

.


part two, 'Pictures' for this tech article will be up shortly.....



There are many benefits in replacing the road draft tube with a proper Positive Crankcase Ventilation system on your Late model Flathead V8.


A): it helps eliminate the embarrassing smelly/hot fog that wafts out from under your hood at the stop light.

B): It helps to create a consistent vacuum inside the crankcase and oil galleys. An actual vacuum inside of your crankcase will aide in keeping the oil and oily residues from being pushed out from every available seal, gasket or open "hole" that is and/or resides in what we think of as an automobile engine.

C): A PCV system will help eliminate moisture that can and will accumulate in your engine oil and hence your oil pan, engine and intake galleys. Moisture is a major cause of internal engine sludge that builds up (over time) and generally coats all manor of things like intake valves, stems, springs and lifters.

D): When you think about it, The road draft tube is actually just a huge open vacuum leak unto an engine. While a great idea when it was designed, it was obsolete when the idea of a closed System with a proper PCV valve was invented. Having a huge vacuum leak causes your engine to run just a little less efficiently than when not having a gaping hole/road draft tube installed.

E): Eliminating the road draft "hole" and replacing with a proper PCV sets you on the path of creating an enclosed (as opposed to wide open hole) oil galley and crankcase. which brings us to;

F): Eliminating the open hole of the road draft tube shuts out the probability that the road draft tube will (at times) be actually sucking in air/dirt/moisture and debris as you drive along.. To put this into perspective, At idle and part throttle, your engine makes vacuum and the road draft tube is the open end were the internal vacuum can "draft" air into the engine.
At throttle and while working the engine, your engine creates Pressure and this pressure will be pushed out the road draft tube (not to mention and/all gaskets/seals and other non sealed surfaces) and along with the pressure comes hot fog/moisture and oily residues..
Which directly relates to;

G): As you drive/work the engine, the inherent pressure of the working engine escapes from every available seal/gasket etc. and carries with it oily residue that coats your clean engine, engine compartment, firewall, chassis eventually swirling around and being carried away at and around your rear bumper...
...At working pressure, Everything accumulates an oily coating, even the guys headlights in your rear view mirror.


H): eliminating the "open" hole of the road draft tube has the effect of "tightening up" your engine vacuum -in general-.
As a side benefit of enclosing or eliminating the road draft tube, your engine vacuum is increased which in turn helps thing like vacuum wipers work a little bit better as your engine is better able to regulate an enclosed or regulated crankcase as opposed to just having a gaping hole.


----------------------------------------


The PCV valve in itself is similiar in principle to a common regulator found on things like air compressors and/or oxy acetylene bottles.
:A PCV valve restricts and regulates air flow.


In summing up, A regulated air flow thru your engine is far superior to just having the "gaping hole" of a Road Draft Tube as pointed out thru the many benefits as listed above..




.




part two, 'Pictures' for this tech article will be up shortly.....

Wow! and I thought I was confused

 

[petehoovie]

Flathead V-8 Parts : Mercury : Carburetors & Accessories : 1949-53 FORD FLATHEAD PCV VALVE KIT - From JAMCO - http://jamcosuspension.com/products/sfID1/121/sfID2/80/sfID3/146/productID/1504

click images to enlarge


PCV4953
1949-53 FORD FLATHEAD PCV VALVE KIT



$39.95





1949-53 FORD FLATHEAD V-8 PCV VALVE KIT REPLACES THE ORIGINAL VENT TUBE WITH A MODERN "PCV" VALVE. IT WILL ELIMINATE BLOW BY SMOKE AND KEEP CONDENSATION OUT OF THE CRANKCASE.

 

[moefuzz]

.



First, lets look at a typical 49-53 8BA Flathead V8,
It's road draft tube and the back of the intake at/or under the carb
->where the vacuum line/wipers usually resides.




We're all familiar with the The typical 8BA and it's road draft tube,

Did you know that it's actually just a potential gaping 1 1/4" leak into your engines internals?

At the cap/breather, it's sucking in dust, dirt and moisture, at the road draft tube, it's spewing oily residue into and under your hood.






A quick look at the intake, under the carb at the back....



Most 49-53 intakes will have both the small barb (either straight or 90 degree elbow) for your vacuum wipers as well as this plug pictured at lower right.

This plug is where we are gonna plumb our PCV in at..

----------------------------------------------------


Now, the obvious question here is:
Why not just put a tee into where the wiper tee/port is????


well, you don't want your vacuum wipers and PCV sharing the same vacuum line or port.
The chances of oily residue being transferred directly into your Valuable Vacuum Wipers is high.

-Protect and keep any and all of your vacuum accessories physically separated from your PCV
or risk sludging them up.






So pull the plug from the back of the intake and head over to NAPA and ask the guy
if he can match up and supply you with a 3/8" barb that matches your threaded pipe plug....

While your there, get 2 feet of actual Emission/fuel line,
don't substitute or come home with vacuum line...

Total cost up here was $4 for the above items, prices will vary...



------------


The next stop is the local pic-n-pull where you'll need to find a 70's or 80's Ford with PCV system..



We're looking for the oil breather/cap on the valve cover that holds the factory PCV and it's grommet.

They come as both straight up or 90 degree angled PCV valves and the grommet is the same regardless of straight or angled.

The grommet has a lip on it that will help in snugging up the newly
installed PCV valve into the hole were the former road draft tube used to go.

The actual PCV valve can be found from under the hood of a 4.2 liter V8 as found in many Downsized sedans like the 80's LTD ii, Fairmont, or even a late 70's mustang ll.
Or, One from a 6 cylinder in any 80's small car or truck is also acceptable.

Pic N Pull chargd me $1.

Clean and install the grommet and make sure the inner lip isn't kinked
(as evident here on the left (irregular installed shape/opening))
or the Grommet and PCV valve will have a tendency to walk out as you
motor along.

Install the barb and cut the emission hose to size while keeping the line
tucked down and resting on the top of the block (along side your intake).
On the barb, Teflon tape is optional for brass/pipe fittings but since this is a vacuum line I opted for it. -your choice-

Keep things tidy...

The effects of vacuum/pressure are more pronounced at speed/load.
That is where the engine vacuum drops into a pressure.


At idle with the the new PCV line completely plugged at all ends.
and while simulating an open hole at the road draft tube:

16 1/2 inches of vacuum at 3400 feet above sea level.

With the gaping hole into the galley plugged and the PCV installed,
I gained a little better than 1/2 inch vacuum over the
road draft tube/system open valley.

At speed and under load, while the vacuum drops to zero and the crankcase starts to build pressure is where the real difference will be.




Total cost under $6



.

 

[Chris]

This will be a good read

 

[JSeery]

Not sure if there is a lack of understanding or it is just how it is written up, but this is not how a PCV works. They do provide many benefits, but not as explained. If anything a PCV system will reduce manifold/intake vacuum.

 

[moefuzz]

a PCV system will reduce manifold/intake vacuum.

It will help regulate and restrict it.

 

[JSeery]

Sorry, totally disagree. A PCV system is a controlled vacuum leak into the intake manifold, that's what makes them work.

 

[51 MERC-CT]

.

D): When you think about it, The road draft tube is actually just a huge open vacuum leak unto an engine. While a great idea when it was designed, it was obsolete when the idea of a closed System with a proper PCV valve was invented. Having a huge vacuum leak causes your engine to run just a little less efficiently than when not having a gaping hole/road draft tube installed.

E): Eliminating the road draft "hole" and replacing with a proper PCV sets you on the path of creating an enclosed (as opposed to wide open hole) oil galley and crankcase. which brings us to;

F): Eliminating the open hole of the road draft tube shuts out the probability that the road draft tube will (at times) be actually sucking in air/dirt/moisture and debris as you drive along.. To put this into perspective, At idle and part throttle, your engine makes vacuum and the road draft tube is the open end were the internal vacuum can "draft" air into the engine.
At throttle and while working the engine, your engine creates Pressure and this pressure will be pushed out the road draft tube (not to mention and/all gaskets/seals and other non sealed surfaces) and along with the pressure comes hot fog/moisture and oily residues.. .


H): eliminating the "open" hole of the road draft tube has the effect of "tightening up" your engine vacuum -in general-.
As a side benefit of enclosing or eliminating the road draft tube, your engine vacuum is increased which in turn helps thing like vacuum wipers work a little bit better as your engine is better able to regulate an enclosed or regulated crankcase as opposed to just having a gaping hole

In summing up, A regulated air flow thru your engine is far superior to just having the "gaping hole" of a Road Draft Tube as pointed out thru the many benefits as listed above..

Would like to see the stock road draft tube setup that created any vacuum.

 

[JSeery]

Would like to see the stock road draft tube setup that created any vacuum.

And with the PCV now you are creating a negative pressure in the crankcase and the inflowing air better be filtered!

 

[51 MERC-CT]

It will help regulate and restrict it.

The primary function of the PCV valve is to close off the back flow to the crankcase in the event of a back fire. Not to regulate flow.

 

[JSeery]

Yep, a lot of confusion going on here.

 

[39 Deluxe]

Agreed, crankcase will not be vacuum, especially considering how leaktight most of our flatties are.

PCV uses vacuum in the intake tract to vent positive pressure from the crankcase and direct it to the combustion chamber. PCV valve only opens at high vacuum conditions (i.e. idling, decel). It does not create a vacuum "leak" per se, as it is regulated by the design of the PCV valve itself. My real world experience is that the PCV system does not have a significant effect on manifold vacuum at idle, nor does it seem to have much affect on idle speed or mixture. I guess if you've got a ton of blow-by, results may vary.

PCV on a flathead, good idea to eliminate draft tube "steam" and oily vapor smells. I wouldn't expect any other improvements.

Also related to this setup....what about sealing the oil filler tube with a non-breathing cap? Or at least a cap that routes vapors to the air filter somehow...otherwise you've still got oil vapor escaping to the car. This would be similar to how Ford did it in the late 60's to 70's.

 

[JSeery]

Agreed, crankcase will not be vacuum, especially considering how leaktight most of our flatties are.

PCV uses vacuum in the intake tract to vent positive pressure from the crankcase and direct it to the combustion chamber. PCV valve only opens at high vacuum conditions (i.e. idling, decel). It does not create a vacuum "leak" per se, as it is regulated by the design of the PCV valve itself. My real world experience is that the PCV system does not have a significant effect on manifold vacuum at idle, nor does it seem to have much affect on idle speed or mixture.

PCV on a flathead, good idea to eliminate draft tube "steam" and oily vapor smells. I wouldn't expect any other improvements.

Yep, but it darn sure doesn't increase manifold vacuum!

 

[petehoovie]

The primary function of the PCV valve is to close off the back flow to the crankcase in the event of a back fire. Not to regulate flow.

Looks as though the JAMCO unit just evacuates any blow-by out of the crankcase and reroutes it to the exhaust via the intake manifold using vacuum to do so....

 

[OLD AS I]

I saw an article some time ago that suggested putting a common PCV on the underside of the intake manifold, drill a hole and tap suitable to screw the valve in, using a common PCV as is used in GM V8's

 

[Capt Kirk]

.
A): it helps eliminate the embarrassing smelly/hot fog that wafts out from under your hood at the stop light.

Personally, I like when "A" happens. The people in their BMW next to me at the stop light might not...but I don't care.

 

[Kahuna]

As mentioned by J & others, a PCV valve is a controlled air leak

 

[52 Ford]

Thank you for this information. What is the consensus PVC good or Bad overall for the engine?

 

[51 MERC-CT]

Thank you for this information. What is the consensus PVC good or Bad overall for the engine?

The intention of the system is to prevent crankcase blow-by gasses from entering the atmosphere.
If it were bad for the engine the manufacturers would not be installing them on cars.