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Old 11-08-2017, 03:51 PM   #1
Hoovercw
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Default Pcv

I had a good friend tell me about installing a PCV into his model a engine years ago. It helped with oil leakage. I am putting my engine together and am interested if anyone else out there had done such a thing. From what he remembers it was a valve for a pinto and he placed it into a drilled and tapped hole on the valve cover. I know it would have to be a very weak vacuum so it doesnít rob the rear thrust bearing of lubricant. Any ideas?
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Old 11-08-2017, 03:59 PM   #2
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Default Re: Pcv

Why would you want to mess with a good thing. Engines have lasted 90 years and are still going strong.

I would spend time and money on ride/handling/brake improvements. Enjoy.
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Old 11-08-2017, 04:36 PM   #3
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Default Re: Pcv

It could possibly go on a redesigned breather cap and pipe around to go into the vacuum on the intake manifold?
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Old 11-08-2017, 04:40 PM   #4
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Default Re: Pcv

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Originally Posted by Sunnybrook Farm View Post
It could possibly go on a redesigned breather cap and pipe around to go into the vacuum on the intake manifold?
Why do a lap of the motor? Just connect the hose through a fitting in the valve chamber cover. If done discretely, no one is likely to see it. You'd still need to block off the filler cap.
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Old 11-08-2017, 04:55 PM   #5
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Default Re: Pcv

My father experimented with this many years ago and it did not work. The issue with what your friend is trying to accomplish is that if you have a bad enough oil leak that you need vacuum to correct, you have a bad vacuum leak also unless a positive seal is used on the rear main. At either point, all you end up with is a bad vacuum leak that creates poor performance, and a messy oil leak too. Several have either manufactured a rubber rear main seal, -or modified an existing seal to be used on a Model-A rear main, but many of those have also proved to have issues.
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Old 11-08-2017, 04:56 PM   #6
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There are a couple of articles regarding this in the old issues of The Restorer magazine. Itís fairly easy to do. It mostly takes some of the blow by out of the crankcase so it doesnít go out the filler cap. Itís not going to really help with a leaky main bearing issue. If your main bearing seal is bad, the little blow-by that you have in the crankcase is not going to increase the pressure that much. The other way of saying this is that the PCV valve is not going to reduce the pressure in the crankcase that much. It could be a good thing to do for other reasons, not really for stopping a main bearing leak.
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Old 11-08-2017, 07:14 PM   #7
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Several years ago I bought a pcv kit from a fellow in Ohio (I believe), but I never got around to installing it. If you're interested, I will dig it out and sell it for what it cost me. PM me if interested.
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Old 11-08-2017, 10:58 PM   #8
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Default Re: Pcv

Just got an engine with a breather pipe (1/2" copper) tapped into the upper rear valve cover..its cut off at the bottom, like a road draft tube.I think I'm going to take it out and plug it, my reasoning is any atmospheric pressure in the valve chamber is a good thing.
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Old 11-08-2017, 11:36 PM   #9
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Default Re: Pcv

I have a breather setup on my old cast iron Volvo. It has to be pretty intricate to work right, but when it is set up correctly it keeps the crankcase under vacuum for all but full throttle at medium to low revs. One necessity is a vacuum port in the manifold, and another in the venturi. The one in the manifold has to be pretty small to avoid acting as an air leak. The one in the venturi draws nothing at idle and more as the airflow goes up, so it never really misbehaves like a manifold leak. If you want to do it, I suggest buying a vacuum gauge so you can see what's really going on.
The other necessity is a low pressure popoff or reed valve. At full throttle, no little carb port will flow enough. You need somewhere for the ring blowby to go so you don't pressurize the crankcase. Is is even true of a good tight motor. Some blowby just happens.
My honest opinion is it is more trouble than it is worth on a model A.
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Old 11-08-2017, 11:42 PM   #10
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Default Re: Pcv

I went to TX meet with a fellow from Oregon that had made a real air filter that wat up on top of his engine. He had tapped into the side of the air cleaner and ran a hose to the valve cover where he had a PCV valve. He took all that off for fine point judging in the touring class and did very well. Put it back on and drove to the east coast to visit relatives. He said that the PCV valve kept his engine compartment spotless, and it was, He used a large paper filter on the top of his engine and a plastic pipe to the carb. Looked very well done to me.
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Old 11-09-2017, 09:00 AM   #11
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Default Re: Pcv

I ran a line from the crankcase to the carburetor's intake throat which evacuated the crankcase. However, it made no difference in leakage or cleanliness of the motor oil, so I scrapped the idea.

As for leakage from the flywheel housing, I did discover on both of my Model A's that it was predominantly transmission oil, not motor oil. Ford specifies one pint of oil in the transmission. I habitually filled the oil until ran out of the fill plug hole. That is overfilling the transmission and the cause of oil leakage.
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Old 11-09-2017, 10:33 AM   #12
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Default Re: Pcv

Quote:
Originally Posted by Bob Bidonde View Post

As for leakage from the flywheel housing, I did discover on both of my Model A's that it was predominantly transmission oil, not motor oil. Ford specifies one pint of oil in the transmission. I habitually filled the oil until ran out of the fill plug hole. That is overfilling the transmission and the cause of oil leakage.
From "Model A Instruction Book" (page 13)...

"The new lubricant is poured into the transmission through
the filler hole, located at the right hand side of the transmission
case. Pour sufficient lubricant in until it reaches the level of
the filler hole."


http://www.palmbeachas.com/Model-A-I...ion-Manual.pdf
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Old 11-09-2017, 12:47 PM   #13
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Default Re: Pcv

It will help in the leakage problem. Race cars do this and also gain horsepower.
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Old 11-09-2017, 02:02 PM   #14
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Default Re: Pcv

Thanks for all of the replies. I don't know that I will have a leakage problem as I am finishing assembly. He was just saying that all stock model As leak a little and this reduces it somewhat. From a half dollar size spot in the garage to a dime size for example. Also, it is supposed to reduce the fumes coming out of the filler tube as well as gunk buildup in the engine. I have a lot of confidence in this guy as he has done some pretty impressive stuff I have seen with my own eyes. He has been doing flathead v8 stuff for the past decade and is just a little fuzzy on remembering the exact valve he used when doing this to the model A.Looking at the setup in the m151 jeep and liking it.
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Old 11-09-2017, 07:20 PM   #15
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Default Re: Pcv

I have a good friend who now lives in Arizona.
For sometime now he has been working on something that will greatly reduce or stop the common oil drip as well as the blow by in the engine compartment.
He has about 15 of the units installed and being tested presently.
Two of them were on cars driven in this years MAFCA tour on the West Coast with very positive results.
If interested in this unit PM me and I will put you in touch with this man.
Very inexpensive.... and only 5 minutes to install.

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