The Ford Barn

Ab4875 · 06-17-2015, 04:36 AM

I've got a 1939 Canadian Mercury motor that has a PCV valve fitted. The motor hesitates if I give it rapid throttle. If I remove the PCV valve the problem goes away.

Does anyone have any experience with these old PCV valves? Is it worth leaving it on motor? The valve doesn't have spring and seems to rely on gravity to close.

The motor is off a locomotive that used to operate in a munitions store west of Sydney during WW2.

Snouts out · 06-17-2015, 05:12 AM

Get rid of it,39 flathead with a pcv? I've never seen one!

51 MERC-CT · 06-17-2015, 05:32 AM

Having trouble trying to visualize what you perceive to be an "old" PCV valve. Just about all PCV valves that I know about on these engines are installed where they can't be seen and were not part of the original engine.
Some pictures of the installation would be worth a thousand words.

JSeery · 06-17-2015, 07:26 AM

PCVs were used on military/commercial engines that could not use "open air" ventilation. Engines in closed spaces, like enclosed inside a vehicle required the PCV setups. Other military additions were oil coolers and/or remote filters.

51 MERC-CT · 06-17-2015, 07:29 AM

Quote:

Originally Posted by JSeery

PCVs were used on military/commercial engines that could not use "open air" ventilation. Engines in closed spaces, like enclosed inside a vehicle required the PCV setups. Other military additions were oil coolers and/or remote filters.

Thanks for the input. Would still like to see the setup.

scooder · 06-17-2015, 07:34 AM

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Yes they do exist, I have one. It's called a Donaldson crankcase ventilator. It is PCV valve, it has no spring as you say just gravity and vacuum control the opening and shutting. They were used mostly on military allocations, it goes with an oil bath oil fill/ breather. You might try placing a light spring inside (they come apart by UN screwing the two halfs) to help address the hesitation, stop the shuttle dropping so quickly.
These don't shut fully, even with text high vacuum shuttle up position, there is a lot of vacuum loss.
What we gota remember in hard military type use they don't have the same sort of off idle use, more like all or nothing. So you may not get satisfactory results.
possibly a power valve that opens at a lower vacuum reading might work.
If you just remove it, you'll need to have some other breathing system, go back to stock, if it's got the correct pan for the PCV, you'll need to swap the sump to a stock one with the little triangle road draught breather. This was omitted on the PCV application.
Be carefull with this as your in Aus it may be a Lucas starter/sump/flywheel combination. This lot if you don't know has to be swapped as a whole system.
I think you should have a play with it, see if you can get what you want from it. A genuine Vintage PCV is a very rare thing, and cool if it works.
Good luck, let us know your results.
Martin.

JSeery · 06-17-2015, 07:34 AM

There have been diagrams posted in the past.

scooder · 06-17-2015, 07:36 AM

Forgot, I can't do pics at this time, but my PCV is picture on a thread on the HAMB from a couple of years back, I think Bruce Lancaster started the thread about them, can't look for it now, I'm at work on dinner break.
Martin.

1952henry · 06-17-2015, 06:27 PM

Willys jeeps used a Donaldson pcv setup. Probably similar. One could post on the cj2a page for help.

Ab4875 · 06-17-2015, 08:14 PM

Thanks for the info guys. It is a Donaldson Crankcase Ventilator.

Scooder, I found the HAMB thread you mentioned. It's from 2004 and it looks like the photos are long gone.

Here is my valve. It doesn't look like it will come apart. I can't see a seam where the halves join. I think the spool is installed and then an orifice plug is pressed into the female side of the unit.

0F4A3519.jpg 0F4A3520.jpg

I've got some photos of the unit installed on the engine I'll post later.

Ab4875 · 06-17-2015, 09:38 PM

I stand corrected.

0F4A3528.jpg 0F4A3526.jpg
0F4A3530.jpg 0F4A3529.jpg

Ab4875 · 06-18-2015, 06:50 PM

Here are some photos of the motor showing the PCV setup.

0F4A2862.jpg 0F4A2785.jpg
0F4A2749.jpg 0F4A2723.jpg

51 MERC-CT · 06-18-2015, 07:13 PM

If you really want to use a PCV valve, you may be able to adapt a modern valve such as this.

Ab4875 · 06-18-2015, 07:20 PM

Here's a video of the engine running:

https://youtu.be/lsYWZfMIvWg

Bluebell · 06-20-2015, 05:58 AM

Hi, Not trying to be rude, but are you sure it's a 1939 motor? If so, I'd say the manifold has been changed.
There was another thread recently and Bruce Lancaster talked about the introduction of the "Hydrovent"(pcv system) being introduced with the rope seal rear main in 1942. The engines prior to this had the slinger at the rear main, and the crankcase ventilation system if fitted would draw in dirt into the engine around the rear main. Up until the 42 engine, they were(in my opinion) all draft tube type with no pcv system.

I am the owner of the inlet manifold that was asked about on this forum (on 13th june) It is military and takes the big generator (12 volt)with the extra support mounts on the manifold. It has the hole at the back where the pcv valve is fitted the same as yours.
The Hydrovent was plumbed up with the pcv valve pipe going in at the front under the generator. Yours has a plug there just in front of the front oil filler tube mount (blanked off on yours)
The hydrovent had a thin alloy plate between the carb and the manifold.Yours is plumbed directly into the manifold.
I believe your inlet manifold with the pcv system is off a later motor.

Bruce Lancaster · 06-22-2015, 11:31 AM

I now have most of the pieces of one of these setups. The one shown is different from mine, but I think the same valve...the one in post 12 uses a boss (undrilled on mine) at rear, mine has the valve vertically beloe right of carb and draws from a drilled hole below generator/right over the stack tube in valley.
I think mine is the more common...I've seen a number of manifolds with the hole in the front, and there are diagrams of the one I have in the 1943 updates of wartime manuals.
The big iron valve might be big enough for some moder valve to live inside!
A possibly useful aside: At least some wartime US MD and GPW Jeeps seem to have used this setup, and the valves are available in repro from the Jeep resto places. I don't know any more about the jeep setup. The valves look to be similar to Ford.
On the vac loss issue...the apertures in the valve are quite large, but the actual flow restriction seems to be via tiny holes in the final hookup to manifold.

Bluebell · 06-23-2015, 05:14 AM

Bruce, when did Ford start making the inlet manifold with the hole at the front for the oil filler as per the one seen on this 39 motor?

Ab4875 · 06-23-2015, 06:47 AM

I've got a few other manifolds with the PCV setup. Some are aluminium and some are steel. I also have a different engine that has a 12 volt POD generator. I'll try and take some photos in the next couple of days.

scooder · 06-23-2015, 07:36 AM

Quote:

Originally Posted by Bluebell

Bruce, when did Ford start making the inlet manifold with the hole at the front for the oil filler as per the one seen on this 39 motor?

I ain't Bruce but, the manifold with the oil fill on the right side of the generator, earliest I seen is 43, but wasn't on all of them. Post war US didn't have it, post war Canadian had them and the Canadian manifold was aluminium, exactly the same as the iron war time one. Not sure if all post war Canadian had this oil fill though.
Martin.

Bruce Lancaster · 06-23-2015, 08:56 AM

The front-filler manifolds I have are aluminum C11A's, 1941 intro. They seem to have been cast for possible use as universal replacements, as there is provision between the ports on left for drilling for the earlier style vacuum taps. At least some have the square carb flange that allows drilling for a 4-bolt carb, and I think they have a boss at rear for the PCV location in back! Will have to look in the basement tonight.
My setup has the plate below carb to tap very small holes into both sides on manifold with valve mounted vertically below right front of carb. Pipe for collecting the fumes is simply 1/4 fuel line with a fitting that goes into a 1/8 pipe hole on right side of gen mount.
My first one came from Joblot NOS in a military crate...at the time, they also had a huge stash of postwar C7RA aluminum heads.

I can't see the details where pipe goes through manifold behind carb on the engine shown above...is it into the boss some manifolds have for vac brake booster? I think those arealarge pipe thread hole with very small drillings within into both sides of manifold. If so they would function just like the carb plate, tapping both sides and presumably serving as the flow restrictor in the system.

06-17-2015, 04:36 AM	#1
Ab4875 Senior Member Join Date: Dec 2013 Location: Sydney, Australia Posts: 112	PCV Valve on a 1939 Canadian Mercury motor I've got a 1939 Canadian Mercury motor that has a PCV valve fitted. The motor hesitates if I give it rapid throttle. If I remove the PCV valve the problem goes away. Does anyone have any experience with these old PCV valves? Is it worth leaving it on motor? The valve doesn't have spring and seems to rely on gravity to close. The motor is off a locomotive that used to operate in a munitions store west of Sydney during WW2.

06-17-2015, 05:12 AM	#2
Snouts out Senior Member Join Date: Dec 2013 Location: Covedale,oh Posts: 226	Re: PCV Valve on a 1939 Canadian Mercury motor Get rid of it,39 flathead with a pcv? I've never seen one!

06-17-2015, 05:32 AM	#3
51 MERC-CT Senior Member Join Date: May 2010 Location: East Hartford, Ct Posts: 5,898	Re: PCV Valve on a 1939 Canadian Mercury motor Having trouble trying to visualize what you perceive to be an "old" PCV valve. Just about all PCV valves that I know about on these engines are installed where they can't be seen and were not part of the original engine. Some pictures of the installation would be worth a thousand words. __________________ DON'T RECALL DOING SOMETHING FOR MYSELF BASED ON SOMEONE ELSE'S LIKES OR DISLIKES

06-17-2015, 07:26 AM	#4
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: PCV Valve on a 1939 Canadian Mercury motor PCVs were used on military/commercial engines that could not use "open air" ventilation. Engines in closed spaces, like enclosed inside a vehicle required the PCV setups. Other military additions were oil coolers and/or remote filters.

06-17-2015, 07:34 AM	#6
scooder Senior Member Join Date: Jul 2010 Posts: 2,595	Re: PCV Valve on a 1939 Canadian Mercury motor Sponsored Links (Register now to hide all advertisements) Yes they do exist, I have one. It's called a Donaldson crankcase ventilator. It is PCV valve, it has no spring as you say just gravity and vacuum control the opening and shutting. They were used mostly on military allocations, it goes with an oil bath oil fill/ breather. You might try placing a light spring inside (they come apart by UN screwing the two halfs) to help address the hesitation, stop the shuttle dropping so quickly. These don't shut fully, even with text high vacuum shuttle up position, there is a lot of vacuum loss. What we gota remember in hard military type use they don't have the same sort of off idle use, more like all or nothing. So you may not get satisfactory results. possibly a power valve that opens at a lower vacuum reading might work. If you just remove it, you'll need to have some other breathing system, go back to stock, if it's got the correct pan for the PCV, you'll need to swap the sump to a stock one with the little triangle road draught breather. This was omitted on the PCV application. Be carefull with this as your in Aus it may be a Lucas starter/sump/flywheel combination. This lot if you don't know has to be swapped as a whole system. I think you should have a play with it, see if you can get what you want from it. A genuine Vintage PCV is a very rare thing, and cool if it works. Good luck, let us know your results. Martin.

06-17-2015, 07:36 AM	#8
scooder Senior Member Join Date: Jul 2010 Posts: 2,595	Re: PCV Valve on a 1939 Canadian Mercury motor Forgot, I can't do pics at this time, but my PCV is picture on a thread on the HAMB from a couple of years back, I think Bruce Lancaster started the thread about them, can't look for it now, I'm at work on dinner break. Martin.

06-17-2015, 06:27 PM	#9
1952henry Senior Member Join Date: May 2010 Location: North Dakota Posts: 1,787	Re: PCV Valve on a 1939 Canadian Mercury motor Willys jeeps used a Donaldson pcv setup. Probably similar. One could post on the cj2a page for help. __________________ I dig coal, which provides motivation for EVs.

06-17-2015, 08:14 PM	#10
Ab4875 Senior Member Join Date: Dec 2013 Location: Sydney, Australia Posts: 112	Re: PCV Valve on a 1939 Canadian Mercury motor Thanks for the info guys. It is a Donaldson Crankcase Ventilator. Scooder, I found the HAMB thread you mentioned. It's from 2004 and it looks like the photos are long gone. Here is my valve. It doesn't look like it will come apart. I can't see a seam where the halves join. I think the spool is installed and then an orifice plug is pressed into the female side of the unit. 0F4A3519.jpg 0F4A3520.jpg I've got some photos of the unit installed on the engine I'll post later.

06-17-2015, 09:38 PM	#11
Ab4875 Senior Member Join Date: Dec 2013 Location: Sydney, Australia Posts: 112	Re: PCV Valve on a 1939 Canadian Mercury motor I stand corrected. 0F4A3528.jpg 0F4A3526.jpg 0F4A3530.jpg 0F4A3529.jpg Last edited by Ab4875; 06-18-2015 at 06:48 PM.

06-18-2015, 06:50 PM	#12
Ab4875 Senior Member Join Date: Dec 2013 Location: Sydney, Australia Posts: 112	Re: PCV Valve on a 1939 Canadian Mercury motor Here are some photos of the motor showing the PCV setup. 0F4A2862.jpg 0F4A2785.jpg 0F4A2749.jpg 0F4A2723.jpg

06-18-2015, 07:20 PM	#14
Ab4875 Senior Member Join Date: Dec 2013 Location: Sydney, Australia Posts: 112	Re: PCV Valve on a 1939 Canadian Mercury motor Here's a video of the engine running: https://youtu.be/lsYWZfMIvWg

06-20-2015, 05:58 AM	#15
Bluebell Senior Member Join Date: Nov 2012 Location: Tauranga, New Zealand Posts: 726	Re: PCV Valve on a 1939 Canadian Mercury motor Hi, Not trying to be rude, but are you sure it's a 1939 motor? If so, I'd say the manifold has been changed. There was another thread recently and Bruce Lancaster talked about the introduction of the "Hydrovent"(pcv system) being introduced with the rope seal rear main in 1942. The engines prior to this had the slinger at the rear main, and the crankcase ventilation system if fitted would draw in dirt into the engine around the rear main. Up until the 42 engine, they were(in my opinion) all draft tube type with no pcv system. I am the owner of the inlet manifold that was asked about on this forum (on 13th june) It is military and takes the big generator (12 volt)with the extra support mounts on the manifold. It has the hole at the back where the pcv valve is fitted the same as yours. The Hydrovent was plumbed up with the pcv valve pipe going in at the front under the generator. Yours has a plug there just in front of the front oil filler tube mount (blanked off on yours) The hydrovent had a thin alloy plate between the carb and the manifold.Yours is plumbed directly into the manifold. I believe your inlet manifold with the pcv system is off a later motor. Last edited by Bluebell; 06-20-2015 at 06:10 AM.

06-22-2015, 11:31 AM	#16
Bruce Lancaster Member Emeritus Join Date: May 2010 Location: Madison, NJ Posts: 5,230	Re: PCV Valve on a 1939 Canadian Mercury motor I now have most of the pieces of one of these setups. The one shown is different from mine, but I think the same valve...the one in post 12 uses a boss (undrilled on mine) at rear, mine has the valve vertically beloe right of carb and draws from a drilled hole below generator/right over the stack tube in valley. I think mine is the more common...I've seen a number of manifolds with the hole in the front, and there are diagrams of the one I have in the 1943 updates of wartime manuals. The big iron valve might be big enough for some moder valve to live inside! A possibly useful aside: At least some wartime US MD and GPW Jeeps seem to have used this setup, and the valves are available in repro from the Jeep resto places. I don't know any more about the jeep setup. The valves look to be similar to Ford. On the vac loss issue...the apertures in the valve are quite large, but the actual flow restriction seems to be via tiny holes in the final hookup to manifold.

06-23-2015, 05:14 AM	#17
Bluebell Senior Member Join Date: Nov 2012 Location: Tauranga, New Zealand Posts: 726	Re: PCV Valve on a 1939 Canadian Mercury motor Bruce, when did Ford start making the inlet manifold with the hole at the front for the oil filler as per the one seen on this 39 motor?

06-23-2015, 06:47 AM	#18
Ab4875 Senior Member Join Date: Dec 2013 Location: Sydney, Australia Posts: 112	Re: PCV Valve on a 1939 Canadian Mercury motor I've got a few other manifolds with the PCV setup. Some are aluminium and some are steel. I also have a different engine that has a 12 volt POD generator. I'll try and take some photos in the next couple of days.

06-23-2015, 08:56 AM	#20
Bruce Lancaster Member Emeritus Join Date: May 2010 Location: Madison, NJ Posts: 5,230	Re: PCV Valve on a 1939 Canadian Mercury motor The front-filler manifolds I have are aluminum C11A's, 1941 intro. They seem to have been cast for possible use as universal replacements, as there is provision between the ports on left for drilling for the earlier style vacuum taps. At least some have the square carb flange that allows drilling for a 4-bolt carb, and I think they have a boss at rear for the PCV location in back! Will have to look in the basement tonight. My setup has the plate below carb to tap very small holes into both sides on manifold with valve mounted vertically below right front of carb. Pipe for collecting the fumes is simply 1/4 fuel line with a fitting that goes into a 1/8 pipe hole on right side of gen mount. My first one came from Joblot NOS in a military crate...at the time, they also had a huge stash of postwar C7RA aluminum heads. I can't see the details where pipe goes through manifold behind carb on the engine shown above...is it into the boss some manifolds have for vac brake booster? I think those arealarge pipe thread hole with very small drillings within into both sides of manifold. If so they would function just like the carb plate, tapping both sides and presumably serving as the flow restrictor in the system.