PCV ideas?

69427 · #1 03-31-2021, 04:47 PM

I need to plumb up a PCV system for my street rod '51 truck. My present selection of parts on the engine doesn't accomodate that, so I expect I'll have to get fancy here. I'm using 60s vintage finned Corvette valve covers (with no oil cap or PCV hole) and a late vintage Edelbrock manifold (which doesn't have an oil fill tube like the older intakes). This is just a toy vehicle, so I don't mind popping off a valve cover each oil change to fill the pan. But that still leaves the PCV issue. I don't want to molest the valve covers, so I'm kicking around three other options.

Drill/tap a hole in the intake behind the carb to vent the valley area, feeding into the PCV valve and into the carb. Short clean setup. But, I don't know if there's a lot of oil spray in there, and I would need to weld in a baffle setup under the manifold.

I kicked around doing the fresh air source plumbed into the fuel pump plate area, but at first glance it doesn't look like there's space to run a tube/hose into that area. Hopefully I'm wrong.

A second fresh air source I'm considering is the dipstick tube. Making a Y connection into the tube, or a short extension at the top of the tube might work. I don't know how much the crank throws oil splash into that area while it's running, though.

I pondered valve cover spacers to put the PCV plumbing into, but they're expensive, and I don't care for the look of them.

Final option that has occured to me is placing a fresh air inlet into the front half of the intake. Haven't considered all the up or down sides, but this option/placement is a more direct connection to the crankcase/sump than at the top of the valve covers.

Just looking for additional thoughts and opinions here.

Thanks,
Mike

BBShark · #2 03-31-2021, 09:58 PM

To be honest with you, I don't really understand completely how a PCV system works. I understand what it does but I really struggled with this when I was doing my engine.

For instance, why is the vent on the passenger side and the PCV on the drivers side? Why do most diagrams show the PCV system (in a V8) as a clockwise circuit?

My uninformed response to your question:

I think the lifter valley is a good place to plumb the PCV valve. I seen a fair amount of really old, dirty engines and the underside of the intake is the cleanest part of them. As far as fresh air vent, I think your idea of teeing into the dipstick tube would would work it the demand for air was pretty small.

69427 · #3 04-03-2021, 05:39 PM

Quote:

Originally Posted by BBShark

To be honest with you, I don't really understand completely how a PCV system works. I understand what it does but I really struggled with this when I was doing my engine.

For instance, why is the vent on the passenger side and the PCV on the drivers side? Why do most diagrams show the PCV system (in a V8) as a clockwise circuit?

My uninformed response to your question:

I think the lifter valley is a good place to plumb the PCV valve. I seen a fair amount of really old, dirty engines and the underside of the intake is the cleanest part of them. As far as fresh air vent, I think your idea of teeing into the dipstick tube would would work it the demand for air was pretty small.

Yeah, I'm going with the PCV valve drawing from the intake manifold, and the fresh air (or overpressure relief) line connected to the dipstick tube. I ran all over town trying to find someone who stocks a 3/8" pipe tap to use on the manifold, and finally found one.

On a side note, the latest intake I have on the '69 I modified it to allow a vacuum/pressure gauge to plug into the valley area. I've always been interested in what the crankcase pressure is at WOT on that engine, and I'll see what the results are at the next track day.

bobs77vet · #4 04-07-2021, 03:57 PM

i dont know how this would work on a SBC but i absoulely love this set up. i have toyed around with PCV setups on my 37 ford flat head, i just hate the smell of draft tubes and leaks casued by poor ventilation. this MGB set up is the sweetest set up I have seen and has eliminated almost all leaks in the MGA

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heres now it works, and it has a vintage flair to it

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69427 · #5 04-09-2021, 07:58 PM

Quote:

Originally Posted by bobs77vet

i dont know how this would work on a SBC but i absoulely love this set up. i have toyed around with PCV setups on my 37 ford flat head, i just hate the smell of draft tubes and leaks casued by poor ventilation. this MGB set up is the sweetest set up I have seen and has eliminated almost all leaks in the MGA

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heres now it works, and it has a vintage flair to it

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Interesting setup. I'll need to sit down with a cup of coofee and read through it all.

Certainly has me curious.