Technical 59AB crankcase vent system. Opinions

Garpo · May 8, 2023

The 39 guy said: ↑

Hi Joel, your system looks like it will work great. But since you asked the question I thought I would post up this section from my old build thread just for the sake of conversation. This system has been working fine in my coupe for a few thousand miles. The thread covers some of the stuff mentioned in comments on this thread so I hope it may helpful to others that are considering this modification.

Sam

Crankcase ventilation is today's subject. I wanted to change the ventilation system from the stock passive or draft tube style to a more modern PCV system.

This is a kind of oversimplified drawing of the stock system used on the 59 series engines. Air was*****ed into the engine at the air breather at the back of the engine on the same pedestal the fuel pump was attached to. The crankcase blow by gases would then find there way out of the the cam gallery through a steel tube near the the front right corner of the block and pass through a cavity in the block and finally out to atmosphere through a hole in the oil pan.

I wanted to use the more modern system as shown in this Overhead V8 drawing.

So I modified my flathead's system by putting a plug in the cam gallery draft tube and installing a PCV in the front of the intake manifold. I also plugged the hole in the oil pan.

I am using speedways four barrel intake manifold. I have had this intake for 4 years and have not seen one on a driven flathead yet..... I hope the darn thing works OK.I know it is not traditional but Uncle Mike wanted a four barrel carberator and this one looked like a better choice than the Edelbrock or Offenhauser intakes. The intake is a beautiful 2 piece casting.

My main complaint about this manifold and possibly one of the reasons you don't see any of them is that they do not include the flanges needed for the openings at the front and rear of the intake for the breather and or PCV valve.I asked Speedway if they had any thing to fit the openings and they said no and after further questioning they said they did not have any plans to make any either. I mentioned that they had produced an incomplete product and that I didn't think most people would be willing to fabricate the flanges required to use the manifold. Well I guess it wasn't the tech guys problem.... I still don't see any flanges offered in their catalog.

I had to make both flanges.

I designed this part for the breather on the back.I cut it out 1/2" aluminum scrap and then attached it to the face plate on my old lathe for some machining.
A trial fit of the breather.

The finished part. This breather provides the intake air for crankcase. I can't resist polishing aluminum.....

This is the lifter valley intake for the draft tube that vents the crankcase. You can see the plug press fit into the top of the tube. I left the whole pipe in there so oil would not run out of the crankcase into the cavity that leads to the outlet on the oil pan flange.

I machined the plug out of 1/2 aluminum to a pressed fit

A little ultra black silicone was applied to ensure a seal.

This is the draft tube outlet in the oil pan. I made a steel plug for it too so moisture wont sneak up into the block. Probably was an unnecessary step.

Tacked.

Finished .

Up front I had to make another plate to hold the PCV valve I used an aluminum type valve cover grommet to receive the PCV Valve.

The PCV valve is plumbed to a vacuum source in the carburetor adapter plate on the intake manifold.

So that's the crank case evacuation system. Once again let me say the engine has not been run yet so I don't know how well this system will work. I think it should work OK on this little engine if it works on the larger overhead engines of the 60's and 70's. I will be sure to post the results once I get the engine running.
Click to expand...

Very similar to the set up I have used on a couple of engines.
On mine I used a sealed cap on the oil filler, and a vent hose from the filler tube to the air cleaner. Been working great for years.

46international · May 9, 2023

Mart, from Mart's Garage on here and has a Youtube channel, installed a PCV system all under the intake by just drilling into the bottom of the intake, the valve just screws into the intake and hangs down into the lifter valley. He did a complete video on it on Youtube.

46international · May 9, 2023

here is the one PCV video I could find.

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Technical 59AB crankcase vent system. Opinions

Garpo

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Technical 59AB crankcase vent system. Opinions

Garpo

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