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V8COOPMAN 07-24-2020 03:57 AM

PCV VALVE SYSTEM for 8BA with Early Intake Manifold

More and more these days, hobbyists are choosing to use a 1949 through 1953 8BA-type block for their flathead engine build. Many of the folks doing so are also opting to use an early style (prior to 1949) intake manifold on their new combination. Either of the two different iterations of manifolds will bolt-on to the newer blocks, and there are two or three good reasons that some people have decided to use an early intake on a later engine. Problem is that the two different engines were internally designed to accomplish crankcase ventilation via two DIFFERENT methods, and the design of the intake manifolds is very much involved in that process. So, the subject comes-up frequently addressing the necessity to relieve crankcase pressure with this hybrid block/intake combination, as well as the desire to evacuate at least some of the miniscule yuckleberries that are produced as a result of the internal combustion process. If many of these impurities are allowed to remain inside the crankcase and polute the oil, they usually lead to the eventual formation of sludge on the internal engine surfaces. Piston blowby produces pressures in the crankcase which if not relieved, will at the very least cause severe oil leaks at several gasket locations, and there is also the possibility of oil being blown out of the oil fill tube, not to mention the possibility that the oil pan can actually deform from internal pressure. The 'factory-stock' 8BA-type intake manifolds have provision toward the front of the manifold to mount a relatively tall tube which employs a removable BREATHER cap on top that allows an entry path for fresh air into the engine crankcase. By removing this breather cap, lubricating oil can also be poured into the crankcase. Additionally, the 8BA-type manifold has a second boss just forward of the oil fill tube to mount a 'road draft' tube. This tube serves as an exit path for crankcase vapors and pressures which build-up inside the otherwise closed crankcase as a result of the piston blowby. Below is a diagram of how a STOCK 8BA normally ventilates. So, where do we go now? 1

Eons ago, The Automakers came-up with a somewhat more-sophisticated technology for not only evacuating crankcase pressure along with sinister contaminents, but also as a method that would at least partially re-burn these crankcase gasses as a form of pollution control to save the World's atmosphere. Of course, we all know of the PCV valve by now as a precursor to more-sophisticated "smog-eradicating" systems that were yet to come. Almost every new American engine employed a PCV valve in some form by the latter part of the '60s. So, who would'a ever thunk (back then) that we might someday be seeing PCV valves on a flathead Ford engine? Well, for one thing, many 'factory' PCV valve applications have the valve mounted in a rubber-ish grommet inserted into a valve cover. Heck, any die-hard old-timer will promptly remind ya that flatheads ain't got no danged valve covers. So, what the heck here, over? What's up is that some folks a while back figured-out that a satisfactory answer to the above situation of using an early manifold on an 8BA could be accomplished by utilizing a PCV valve 'properly' plumbed and 'reasonably' engineered to restore the attributes lost when replacing the original manifold. 2

So here we are again, Heard Saxon and myself-Dick Davidson (DD), with yet another dinky idea for a contraption that will hopefully help to advance the flathead world in some small way. As I alluded-to a month or so ago, we were in the process of developing a PCV valve application for Heard's brand new, shiny 8BA with an early style Thickstun PM 7 intake manifold. Obviously, quite a few people have 'rigged', adapted...or whatever you want to call it....a PCV valve to one of these engines in the past. I never gave it much thought until Heard asked if I had any ideas on how to go about rigging-up a PCV valve to operate PROPERLY and produce the desired results. So, to have even a reasonable chance of pulling this off successfully, I decided to do a little self-education about PCV system specifics using Al Gore's World-Wide-Webb. My eyes were opened right pronto! 3

I found-out rather quickly that PCV valves work in the exact opposite fashion than I had previously believed....check the drawing/chart below! Of course, PCV valves function based on MANIFOLD vacuum produced by the engine. And you should remember that 4-cycle engines normally produce the LEAST amount of vacuum during wide-open throttle (WOT), such as during hard acceleration or 'gettin' on it'! Conversely, the HIGHEST vacuum reading will be experienced at idle, or when the vehicle is traveling on a level surface at a steady speed, and at a constant throttle setting. PCV valves usually consist of a small container with a tiny movable shuttle inside, as well as a tiny spring with varying tension values dependent upon the specific vehicle application. In general, the valve is designed such that the internal shuttle is aerodynamically shaped such that it is able to move in consideration of, and in conjunction with the airflow AND the spring's tension. My biggest mis-understanding in operation was that the valve allows the MOST flow through it as the vacuum reading is at it's lowest, as in WOT (wide-open throttle). The opposite occurs as the vacuum signal increases, like during idle.....when the internal shuttle allows the LEAST amount of flow. This really makes sense when you realize that during WOT (when vacuum is lowest, and the GREATEST flow through the valve is allowed to occur), the largest volume of blowby is being sent past the rings into the crankcase when the highest cylinder pressures are being generated. Inversely, the least cylinder pressure is being produced at idle (when the highest vacuum readings occur), meaning less blowby, and the LEAST flow through the PCV valve. 4

And concerning these PCV valves, one valve does not 'fit all'. Honestly, there's not enough 'engineer' in me to be able to determine EXACTLY what constitutes the "right choice" when it comes to making an educated decision as to which valve is correct for any particular engine. I happened to come across two different and lengthy equations that supposedly figured-into determining a correct set of parameters for the "right" valve. To me, these equations looked like the figuring that was required to set-up a space vehicle for lower Moon orbit, and return to Earth.....complicated shtuff! So, keeping in mind that these things obviously would have to operate based on the MAXIMUM vacuum value generated by the engine, as well as the POSSIBILITY that cubic inches MAY also have some bearing on all of this, I made a determination based on the facts that Heard's fine engine (built by one of our better-known FordBarn regulars in the Northeast) is 284 cubic inches and has a non-stock performance camshaft. Performance cams generally yield a lower maximum-vacuum value at idle than a stock cam does. I had already decided that we wanted to use one of those small, all-metal, early GM PCV valves with the straight through design (as seen in the pics below), both for structural rigidity reasons (we didn't want to use plastic parts), and the fact that they are sized small-enough to fit in our limited available space, plus the diameters of the two connecting points were easily adaptable to readily-available components. So, working with that 284 cu. in. figure as well as the hi-po cam, I decided to look-up the PCV valve part number used on a 1969 302 cu. in. Z-28 Chevy engine which of course, has a performance camshaft. So that's the one that we procured for this affair, and the actual part number will be shown below with all the other part numbers...........(we've already prepared your COMPLETE shopping list for you below) ! 5

It was stated on more than one occasion that MOST PCV valves will function properly ONLY when oriented or mounted vertically, or straight up and down. Most require gravity to figure into the normal operation. That really got me to thinking about how many of these valves that we've seen pictures of, or heard described as mounted horizontally underneath the intake manifold. Sounds to me like most of those are possibly not functioning correctly, if at all. Plus, when you mount one like that, you damned sure can't keep an eye on the valve, much less change it, without removing the entire intake manifold. MY opinion.....that sucks! So, I (WE) were determined (if at all possible) to rig-up a PCV valve system on this engine that made the valve accessible WITHOUT removal of the manifold, plus, any exposed parts had to be aesthetically pleasing. With that, our parameters were set. 6

And with those requirements, there aren't many options available. The idea for the most-efficient purging of the 8BA crankcase with an early intake manifold is for the fresh air to enter the breather cap on top of a custom oil-fill tube mounted in place of the stock fuel pump stand. We're going to run a remote, electric fuel pump. That air is normally drawn through the upper, rear of the valve chamber, and is drawn down into the lower crankcase. From the lower crankcase, the air is sucked-out via the removable, vertical tube that runs vertically up the front of the valve chamber. The air NORMALLY goes up into a chamber in the STOCK intake manifold and exits through the attached road draft tube that is routed outside and down below the oil pan. The air passing the open end of that road draft tube induces a suction, pulling fresh air through the entire engine crankcase chamber, relieving any built-up pressures and flushing-away the un-wanted vapors. About the only place left in our modified state to mount the PCV valve so that it will function properly, AND so that the PCV valve can be serviced without removing the manifold is to mount it inside the detachable custom oil-fill tube/spacer assembly. 7

Following is a description of our new system as applied, starting in the front of the valve chamber at the removable, vertical tube which fits tightly down into a recessed hole in the block. Heard removed that tube and cut it roughly in half, as can be judged by the picture below. The upper part will no longer be used. The lower piece will have a tapered freeze plug inserted in it's top opening. The tapered freeze plug must be drilled in it's center to accept a BULKHEAD fitting, by 3/8" COMPRESSION fitting on the opposite end. The tapered freeze plug should have the BULKHEAD fitting tightened into the freeze plug, 3/8 COMPRESSION nut pointing UP! The freeze plug should then be hammered snugly into what is now the TOP of the lower piece of the cut-off draft tube. Tap the tube/freeze plug assembly back into the designated hole in front end of valve chamber. Bend a piece of 3/8" soft copper tubing resembling the piece in the accompanying picture. Secure the inverted "U"-shaped end of copper tubing into the 3/8" compression fitting (don't forget your ferrule) mounted in the freeze plug. The remaining straight tail on the copper tubing will lie against the metal tube traversing the length of the valve chamber, secured snugly to that tube with at least two small, screw-type hose clamps. If you shape your copper tube carefully, the configuration will prevent any unlikely chance that the freeze plug would try to raise itself up and out of the big draft tube. The freeze plug is a "Dorman 555-023". The fitting through the freeze plug is described as: "Bulkhead Union 3/8 BULKHEAD COMPRESSION UNION - 18090, IMSBOLT.COM or equivqlent....about $12.00. 8

Continued Below in Post #2!


V8COOPMAN 07-24-2020 03:57 AM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold


At the rear of the engine, we need to prepare for the PCV valve itself. There are several 'key' pieces involved back there. Let's start with the custom oil-fill tube and breather cap. It's available from Speedway Motors under part # "OTB 6825", $108. This is also where you'll ad engine oil. 9

Below the breather tube is a 1" thick spacer. The spacer is necessary mostly for a surface to drill through to accommodate the special, small 90 degree bulkhead fitting that transitions from outside to downward toward the PCV valve. The spacer comes from an eBay ad, which is actually The Dashman Hot Rod & Speed Parts Co., which can be reached at: 608-637-7167. It's described as...."Fits Stromberg 97 48 Ford Holley 94 Intake Fuel Pump Riser Flathead Spacer 1".....$34.95! It's a beautiful CNC-machined piece of aluminum stock. As can be seen in the pictures, Heard carefully machined a flat surface on the inside of the piece with his milling machine, but the piece could easily be shaped with hand tools if you don't have access to a mill. 10

The next piece is a specialty 90 degree bulkhead fitting. It has a barbed nipple fitting protruding through the 3/4" hole drilled through the flat, milled surface on that spacer. The bottom side of the 90 degree fitting has a female 1/4" NPT threaded hole facing downward, which will accommodate a 1/4" NPT male X 3/8" hose barb fitting inside the spacer, pointing downward. This hose barb will accept a short piece of 3/8" fuel hose which will connect the hose barb to the 3/8" nipple on the top end of the PCV valve. This 90 degree fitting is available at Jeg's and others, described as "ICT Billet 3/8 in. Hose Barb to 1/4" female NPT Bulkhead Adapter Fitting", Jegs part number 551660. $20.49. 11

The GM PCV valve is part number "AC DELCO 19303069". Seems like it was about $7-ish. The nipple faces UP and is connected to the brass hose barb via a short piece of 3/8" fuel hose. 12

The PCV valve sits in a rubberized fitting sized to hold these GM PCV valves. It is a Dorman piece, available at parts stores under "Dorman 46038". The slender appendage on the bottom is sized to accommodate a short piece of 3/8" copper tubing, which will connect the Dorman rubber fitting to the extended-length of 3/8" fuel hose that is long enough that you will be able to unbolt and lift the spacer/breather-tube/PCV valve assembly out of the engine and service the PCV valve, WITHOUT removing the intake manifold. As the assembly is replaced back onto the intake manifold, the assembly must be twisted ONE turn, forming a one-turn loop of the hose down inside the valve chamber. Care must be taken to ensure that the hose does not come in contact with any valve springs as it is inserted. The LOWER end of the 3/8" hose is slipped over the rear end of the long piece of clamped-down copper tubing which leads forward to the freeze plug fitting. 13

The final two pieces of this contraption consist of a 1/4" NPT male X 3/8" compression fitting which threads into the pipe thread hole in the top of the common manifold chamber.....'manifold' vacuum source. The single piece of bent copper tubing is connected to the nipple extending out from the 1" spacer via a short piece of 3/8" hose. The other end at the bottom of the inverted "U"-bend is secured in the compression fitting located between the two carb risers. Clean, functional, and simple! And it might even work. It's certainly looks pretty darned decent. 14


3/8" compression bulkhead (through freeze plug): #18090....Also at Good parts stores.
1" Aluminum Spacer...Described as "Fits Stromberg 97 48 Ford Holley 94 Intake Fuel Pump Riser Flathead Spacer 1".....$34.95! Dashman Hot Rod and Speed Parts. 608-637-7167.
PCV boot: Dorman #46038.....May have to order at O'Reilly's or good parts store.
Freeze plug: Dorman #555-023.....Good parts store.
PCV Valve: AC Delco #19303069.....Good parts store, eBay.
90 Degree thingie: Jegs #551660.....Others
3/8" NPT x 1/4" NPT male hose barb - don't have the # but easy to source - Speedway or good parts store.
3/8" compression x 1/4" NPT male - manifold fitting: don't have the # but easy to source - Speedway or good parts store.

Before we finish-up here, I should make it clear that once aagain, Heard and I co-ordinated this project long distance. He's just southwest of Daytona, and I'm located 25 miles or so northeast of downtown Houston. As usual, Heard did all the labor and got the dirty hands, did all of the running-around chasing parts, wrote all of the checks, and even took all of the pictures.. All that I do is make sure my hands stay clean, I point frequently, and I shoot-off my big mouth a lot just like most days here on the forum. In spite of my shortcomings, we still enjoyed putting all of this together, and even though neither of us is offering any kind of guarantees, we do hope that some of these ideas and part numbers might come-in handy for a couple of you's guys in the near future. ANY comments or questions are certainly welcome by either Heard or myself. I'll work on getting a link to this PCV project thread just under the "T5 W/TORQUE TUBE" link already located at the bottom, left of all of my posts for easy future reference. Dick D (DD) 16


Ol' Ron 07-24-2020 07:10 AM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold

Gota figger out how to copy this. Fantastic information. I think this is what Grandchildren is for.

Jockeyshift41 07-24-2020 07:26 AM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold

Outstanding tutorial!! Thanks for sharing!:)

flatford8 07-24-2020 08:29 AM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold

Nice job!!!.... thanks for the effort and for sharing it!!... I don’t want no danged yuckleberries in my motor!!!...... Mark

Mr 42 07-24-2020 09:52 AM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold

7 Attachment(s)
Made a similar solution back in 2004 on my 8RT engine.
Did not use a PCV valve, my reason for this was that Volvo B18/B20 Engines, had a line from the crankcase to the intake and the hole entering the intake was around 2mm, not causing any problem for the engine and keeping the crankcase clean.
Since this was a V8 i used a 2.5mm hole.

I let the pictures do the talking.

By the way i don't own the car now , but the new owner is still driving it without problems.

vilanar 07-24-2020 10:37 AM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold

Nice tutorial, thanks for your effort.

KiWinUS 07-24-2020 03:07 PM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold

Bloody awesome mate. That’s incredibly well done Coop. Great work & thanks for the great job of sharing all the details.

cadillac512 07-24-2020 05:29 PM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold

Well done, Coop and Heard! That's nice work,and good thinking. Should function perfectly.


Heard 07-24-2020 07:10 PM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold

Thanks fellas! Always fun doing these things and getting feedback from you guys. There is a LOT of experience on this site. WAY more than I have and I always appreciate the input.

I have to say that the most amazing thing to me about this project was the fact the Dorman freeze plug fit perfectly in that draft tube. It has the exact diameter needed.


macdonge 07-25-2020 10:36 AM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold

Excellent write-up Coop. Now all we need is a similar one for the 59A blocks! ;-)

V8COOPMAN 07-25-2020 01:58 PM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold


Originally Posted by macdonge (Post 1912874)
Excellent write-up Coop. Now all we need is a similar one for the 59A blocks! ;-)

The earlier blocks seem to breathe and relieve (pressure) fairly well in stock configuration. Is it that you just like the idea of using a PCV valve to help the environment.....and to help with the purging of some of the sludge-producing crankcase yuckleberries? I could always think about it if your reasoning is strong enough. DD

macdonge 07-26-2020 05:27 AM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold

Yes, the environment... and the yuckleberries!

Sent from my iPhone using Tapatalk

hotcoupe 07-26-2020 04:26 PM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold

Excellent presentation, thanx.

Fortunateson 07-27-2020 12:24 PM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold

I'm just getting into a C8BA using the newer Fenton intake. However, I don't like the looks of the road draft tube so is there a way to hook up a PCV valve and not use the road draft tube?

V8COOPMAN 07-27-2020 07:34 PM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold


Originally Posted by Fortunateson (Post 1913611)
I'm just getting into a C8BA using the newer Fenton intake. However, I don't like the looks of the road draft tube so is there a way to hook up a PCV valve and not use the road draft tube?

Hello Fortunate....This might be interesting, at least to YOU and me. Can you give me an exact model number for that Fenton manifold, or maybe a better description? Can we assume that it IS an intake made for the later '49-'54 engine? No mistake there, the rest of you's guys! The "C"8BA is the Canadian version, and Canuck flatheads lasted into 1954 beyond the border. Any other interesting details about your project? DD

Fortunateson 08-04-2020 09:37 PM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold

Hey V8C...

Sorry for the slow reply. As stated the engine is a C8BA but it's an interesting engine. When I bought the engine the seller was throwing in the Fenton intakewith three 97s and two sets of original Eddie Meyer heads (block previous to the 8BA and 8BA styles) along with a set of wire wheels that may go on one of my '47 Buicks. He claimed that th engine came out of a Mercury but it had C8BA cast into the block and we all know that that's no Merc block. Anyway, when I was tearing it down this spring it had frozen up a bit but everything unbolted really easily and the pistons freed themselves. When I pulled the crank there was the tell tale oval dimple and wider counter weight and the desired 4" stroke. This engine was never rebuilt and the heads indicated Merc. But heads are easy to swap of course. There was also the Merc cam. So I believe that at the particular time this engine was assembled in Oakville they did not have any Merc blocks ready so they just threw the Merc crank, pistons, cam, and heads on it to get it down the line.

Really didn't pay that much for it considering what I got in the bargain. A couple of cracks that will be pinned and a couple of tiny "Ford p/n" cracks as well. Machine shop has been in business since well before WWII so they are heavily experienced.

I had the cam reground by a local shop that began in the mid fifties so more experience there also!

Any way I think in the pics to follow you will see that the Fenton intake is indeed for the 8BA series of blocks. (I have another block but was confused do when I saw 0BA, or is that 1BA, cast but then found out that indicates 1950/51.).)

So getting back to my original question, any guidance for a PCV for this intake?

Fortunateson 08-04-2020 09:45 PM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold

Having trouble loading pics from cell phone; something about a missing security token?

V8COOPMAN 08-05-2020 12:11 AM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold


Originally Posted by Fortunateson (Post 1916883)
Having trouble loading pics from cell phone; something about a missing security token?

Hello Fortunate......I was wondering where you had gotten off to. We have several items to cover here. First of all, the "security token" thing many times means the picture is too 'big' for this site. SOMETIMES, e-mailing the pics to yourself mystically takes care of re-sizing them to an appropriate size. IF after trying that the pics still won't post, try e-mailing them to me and I will attempt to post them here for you. I still need to see some of the details of the intake you're wanting to use before I can come-up with any reasonable ideas. My e-mail:

Of course, you realize that the "C"8BA block is a Canadian-produced version of our Yankee 8BA block. Understand that many people are surprised to hear that at least here in the States for 1949 thru 1953 automobiles, the Ford and Mercury engines shared the same identical BLOCK with each other, although each of the two brands used their own proprietary cylinder heads, intake manifold/carburetor, crankshaft, pistons, camshaft, flywheel and pressure plate, and sometimes water pumps. I won't arbitrarily state that that's ALSO the way it was in Canada, but there's no viable reason for the Canucks to have invested the phenomenal expense of tooling-up for TWO identical blocks with different ID markings. And since Mercurys are a product of the parent FoMoCo, the 'Ford' ID-nomenclature (8BA) with the Canadian "C" in front of it wins-out, I'm sure. And you are correct in assuming that "0BA" and "1BA" represent 1950 & 1951 model years respectively. One more thing....if your cylinder heads are marked "8CM", the Mercury-ONLY oil pan should look like the one below with the three studs and "L"-bracket. It'll also have a unique oil pump/pick-up and windage tray only found on the Mercs. Try e-mailing those manifold pics to yourself. If you still aren't able to post them here, e-mail them to me and we'll see what we can do. Dick D


Fortunateson 08-05-2020 02:24 AM

Re: PCV VALVE SYSTEM for 8BA with Early Intake Manifold

Yep, that's the oil pan I have... a little different from my other one where the engine came out of truck. That one was rebuilt at one point but it doesn't have the 8RT casting mark so I presume they fitted a car block into the 1/2ton truck.

I'll be checking on the oil pump...

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