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| | | | Joined: Jun 2021 Posts: 13 'Bolter | | 'Bolter Joined: Jun 2021 Posts: 13 | I installed a PCV valve on my 1957 235 on top of the draft tube and routed the tubing over to where the wiper connection normally is on the intake manifold. Since this engine will operate in a dusty environment, being installed in a forklift, I wanted to do something better than the breather oil fill cap for air intake to the crankcase. I’m also installing a 14” diameter by 2.5” tall modern air cleaner in place of the old oil bath filter. I’m planning on offsetting the 14” air cleaner such that it resides over the carburetor and cantilevered over the valve cover. A brace would be a 3/8 NTP tube that would connect and provide an air path from the valve cover to the air cleaner. My question is would the amount of vacuum within the air cleaner be small enough compared to the intake manifold vacuum such that they don’t cancel each other out and make the PCV valve ineffective?
Any words of wisdom would be appreciated.
Thanks, Paul | | | | | Joined: Feb 2016 Posts: 1,987 'Bolter | | 'Bolter Joined: Feb 2016 Posts: 1,987 | As long as the filter isn't too restrictive from dust you should be fine.
1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy
| | | | | Joined: Mar 2014 Posts: 4,483 Moderator, Electrical Bay | | Moderator, Electrical Bay Joined: Mar 2014 Posts: 4,483 | Hi Paul,
The best thing would be to run your PCV intake into the clean air portion of your air cleaner. Sounds like you already know this, but you want the air being sucked into your engine to be as clean as possible or all is for naught. I have roughly the same size air cleaner as yours. I used a non-vented filler with a grommet on top (which in my case is where air enters the engine) and ran a hose from there right under the air cleaner to a fitting I installed under it. The amount of vacuum inside the air cleaner (unless you have one of those odd little tuna can-sized filters) won't matter at all. Good luck.
~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
| | | | | Joined: Oct 2021 Posts: 6,772 'Bolter | | 'Bolter Joined: Oct 2021 Posts: 6,772 | Farmer Paul, You should read this. It's a carefully researched PCV upgrade solution specifically for this engine. It's complete with theory of operation, measurements of vacuum pressure, photos, and instructions how to do it yourself, or you can purchase a complete conversion kit with pre-bent steel vacuum line, the correct pcv valve for this engine, grommets, etc. By the way, the recommended port is exactly where you installed - the wiper port on the intake manifold. Instructions to make it yourself and theory of operation: http://devestechnet.com/Home/PCVInstallCustom Made Kit: http://devestechnet.com/Services/PCVUpgrade
Last edited by Otto Skorzeny; 10/16/2021 1:24 AM.
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
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