Register now to get rid of these ads!

Technical Road Draft Tube Extension?

Discussion in 'The Hokey Ass Message Board' started by blowby, Jun 26, 2020.

  1. blowby
    Joined: Dec 27, 2012
    Posts: 6,744

    blowby
    Member
    from Nicasio Ca

    A friend has a sweet 57 Bel Air we rebuilt about 30 years ago. Bone stock 283 with a Muncie. He hasn't put a ton of miles on it but is starting to smell fumes in the cab, even after sealing all the floors, shift boot etc..

    He's thinking of going PCV but doesn't want to drill valve covers. He asked about extending the road draft tube. I did this years ago on a tired motor, must have been about 16 at the time, don't remember if it worked. Don't want to dig into the engine runs great, no smoke, just this minor annoyance.

    Thoughts?
     
    chryslerfan55 likes this.
  2. tubman
    Joined: May 16, 2007
    Posts: 5,114

    tubman
    ALLIANCE MEMBER

    "Red Green" it. Find a suitable piece of tubing and duct tape it on temporarily and see what happens. You can even try different lengths this way too.
     
    blowby and warhorseracing like this.
  3. I've read that the reason the tube ends where it does is because the air flowing by it creates a vacuum of sorts to help pull the fumes out. But I would find a fitting from a 66/67 that had a pcv inline. Also make sure that the filler tube cap/breather isn't plugged (you can wash it out).

    [​IMG]
    [​IMG]
     
  4. You can convert to a pcv system, there are numerous threads on this site that talk about that. I've used a BBC valve cover grommet in the road draft hole to hold a pcv valve then run a hose to an appropriate port on carb. On a bone stock 283 you will probably need to install a carb spacer with a pcv port.
     
    vtx1800, blowby and olscrounger like this.
    Register now to get rid of these ads!

  5. BamaMav
    Joined: Jun 19, 2011
    Posts: 4,261

    BamaMav
    Member
    from Berry, AL

    You can extend the draft tube with a radiator hose. Used to do it all the time on some of the old trucks I've driven. It would get the end closer to the ground, so hopefully the fumes would go under rather than through the firewall or vent windows.
     
  6. tubman
    Joined: May 16, 2007
    Posts: 5,114

    tubman
    ALLIANCE MEMBER

    I guess "Red Green" isn't big in California (or Alabama either).:rolleyes:
     
  7. Big in my living room.
    [​IMG]
     
  8. I extended the road tube on my Stude pickup farther back under the truck bed frame because I got tired of smelling the fumes.
    Ace Hardware tubing and zip ties solved the exhaust fume smell by moving the fumes to the rear.
    about 25 yrs ago. still doing its job

    WHY BE ORDINARY ?
     
    blowby, chryslerfan55 and Driver50x like this.
  9. clunker
    Joined: Feb 23, 2011
    Posts: 1,613

    clunker
    ALLIANCE MEMBER
    from Boston MA
    1. MASSACHUSETTS HAMB

    Heater hose worked for me. Also running 1/2 quart low (oil not blood). Thought of converting to pvc, but don’t really like doing things the right way on my own time.


    Sent from my iPhone using The H.A.M.B. mobile app
     
    blowby and TWKundrat like this.
  10. blowby
    Joined: Dec 27, 2012
    Posts: 6,744

    blowby
    Member
    from Nicasio Ca

    Hey I'm a Red Green fan, just never saw him extend a road draft tube. :)

    Thanks for the replies, let you know how it works.
     
    scotty t and chryslerfan55 like this.
  11. This might just be the most profoundly, personal insight I've ever seen on the HAMB. :cool:

    I just wish I knew exactly what the hell it meant. o_O
     
  12. Mr48chev
    Joined: Dec 28, 2007
    Posts: 27,214

    Mr48chev
    ALLIANCE MEMBER

    All the extended road draft tubes in the world aren't going to help at low speed or at an idle when no air passes the end of the tube to draw air though the crankcase and out the end of the tube.
    The piece that 1oldtimer showed in post 3 is the correct way to install a PCV on that engine and the only noticeable thing without hunting is the hose that runs from it to the intake or carb base.
    That is also standard equipment on mid 60's Small Block Chev V8 engines.
    Seems that we bought them from Chevrolet for under 5 bucks back in the 70's when we didn't jack one off an engine at the wrecking yard. They may be spendy now. https://www.classicparts.com/1956-67-PCV-Draft-Tube-Assembly-S_B/productinfo/86-141/
    The grommet with pcv valve in the hole the draft tube came out of. works fine as long as you leave the baffle in the lifter valley.
     
    partssaloon, blowby and chryslerfan55 like this.
  13. BamaMav
    Joined: Jun 19, 2011
    Posts: 4,261

    BamaMav
    Member
    from Berry, AL

    I have no idea of what or who you're talking about. If it's a TV program, I haven't seen much TV in 35 years since I started driving a truck.....
     
    Elcohaulic likes this.
  14. Almostdone
    Joined: Dec 19, 2019
    Posts: 280

    Almostdone
    Member

    Here’s a PCV installed using the fitting posted earlier. So far I’m using the filter in the cap of the oil filler tube as the fresh air source.
    9150E9F9-AB12-4948-9784-33161CBD3B80.jpeg
     
    brEad and blowby like this.
  15. tubman
    Joined: May 16, 2007
    Posts: 5,114

    tubman
    ALLIANCE MEMBER

    I know what you're saying, as I winter in Florida and nobody down south knows about him. It's PBS TV show about a bunch of Canadians who live out in the woods and have, umm, I would say, the simple life. One of his "shticks" is that he can fix anything with duct tape. (They also have belt sander races.)

    It is hilarious (since I am from Minnesota and see folks like this once in a while), but it just doesn't work south of the Mason-Dixon line.
     
    vtx1800 and 67L36Driver like this.
  16. e1956v
    Joined: Sep 29, 2009
    Posts: 1,528

    e1956v
    Alliance Vendor

    “Duct tape the handyman’s secret weapon “
    “Don’t forget I’m pullin for ya”
    Rothchilds sewer and septic sucking service



    Sent from my iPhone using The H.A.M.B. mobile app
    www.speedoservice.com
    Should I rush your rush job or the rush job I was rushing when you rushed in?
     
  17. 61Cruiser
    Joined: Dec 5, 2013
    Posts: 116

    61Cruiser
    Member

    I’m with “1oldtimer” on this. Did the same thing on my 61 Belair. No more little drips on the driveway. Except from the c/I p/glide of course.


    Sent from my iPhone using The H.A.M.B. mobile app
     
  18. Mimilan
    Joined: Jun 13, 2019
    Posts: 598

    Mimilan
    Member

    Paul, You can buy a grommet kit that replaces the road draft tube.
    that's what we have in our 57
    https://www.corvettecentral.com/c1-...v-valve-conversion-replaces-road-draft-301229

    You still keep the original tomato can and no mods are needed on the valve covers
     
  19. clunker
    Joined: Feb 23, 2011
    Posts: 1,613

    clunker
    ALLIANCE MEMBER
    from Boston MA
    1. MASSACHUSETTS HAMB

    Ha!

    I’ve spent a good portion of my life building custom things for wealthy people, everything has to be perfect, I have to agonize over every stupid detail. When I’m on my own time, (doing things for myself), it actually brings me great joy to do things half-ass, take short cuts and make an utter mess. OF COURSE taking the time to properly convert a draft tube to a functioning pvc system is the right way to go. Fuck that. It was way more fun and satisfying grabbing some shitty hose and a clamp and half-doing it that way.

    Now if @blowby didn’t share my desire to make a big mess (even just a little bit-way down deep in his psyche) he would never even consider a hose on a downdraft tube. But he did. I think, as an animal in the wild might signal it’s intent to others of it’s species with a call or a growl, I’m picking up an indication here of similar motivation. Call me crazy...


    Sent from my iPhone using The H.A.M.B. mobile app
     
    brEad and ClayMart like this.
  20. denis4x4
    Joined: Apr 23, 2005
    Posts: 3,518

    denis4x4
    ALLIANCE MEMBER
    from Colorado

    C697CDEB-747A-404F-842A-C7B99583639F.jpeg

    Here’s a Model A aftermarket accessory with a flex tube extension.
     
    brEad and CME1 like this.
  21. 67L36Driver
    Joined: Jun 1, 2020
    Posts: 68

    67L36Driver

    Ever since we pulled the valve covers off my buddy’s vet to do the valve lash (30-30 cam) Nov. ‘65, I’ve been a great believer in positive crankcase ventilation. Chocolate shake under the valve covers.

    Added a PCV and no more moisture. Less oil leakage to boot.

    Ford’s beloved flat motors would benefit greatly from a PCV. Or, any engine pre 1963.
     
  22. blowby
    Joined: Dec 27, 2012
    Posts: 6,744

    blowby
    Member
    from Nicasio Ca

    This is for a friend Clunk, not me. I'm 3/4 ass or better, I'd probably just drive around with my paint respirator on. He's barely 1/8 ass on a good day so I felt it best to get more suited opinions. He did ask about a tube extension messing with the breathing characteristics, with I thought was a valid concern. An extension should end pointed downward to retain the suction effect me thinks. The pcv conversion are tidy too, his call. I guess the only hard part if finding manifold vacuum. He does have power brakes as I recall.

    Here's an old photo of me working on his engine, coincidentally showing the road draft tube in place.
    Me.jpg
     
    clunker likes this.
  23. Truck64
    Joined: Oct 18, 2015
    Posts: 4,084

    Truck64
    Member
    from Ioway

    It kind of begs the question, if the reason the engine is so stanky is because of excessive cylinder blowby, a PCV system isn't going to work very well at all will it?
     
    Johnny Gee likes this.
  24. I'd thought of a few different interpretations of your philosophy quoted above, and some of them weren't encouraging. :confused: Thanks for clarifying the logic to your approach.

    The expression "Don't let perfection get in the way of progress" seems to sum up your mindset here. ;)
     
    clunker likes this.
  25. HEY! We get PBS. We have to go up the hill and turn the antenna but we do get PBS.
     
    ClayMart and blowby like this.
  26. jimmy six
    Joined: Mar 21, 2006
    Posts: 6,738

    jimmy six
    Member

    Blowby, I don’t have PCV system on my engine either. To take away the smell I bought a Stant oil fill “breather” cap with a 1/2” hose fitting and ran a hose in to the air cleaner to an 90* fitting I found in front of the carb. Takes the smell away. I’m sure if you had a lot of blow by it would be detrimental to your carb and you would at least be looking at new rings. Mine just helps with smell and when I pull into the garage.
    Not sure but I’m guessing while your driving the 45* angle of the road draft tube is pulling the blowby out of your engine and at idle your sucking out with the carb(maybe). Anyway it sure helped with my smell. Every thing was under $10.
     
  27. Yes, it will cut down on the smell at idle......but a worn engine is still a worn engine.

    BTW, if the correct fitting can't be found used (new ones are pricey) you can modify the road draft tube to fit.
     
  28. blowby
    Joined: Dec 27, 2012
    Posts: 6,744

    blowby
    Member
    from Nicasio Ca

    OK to Tee off the power brake port for the PCV kit?
     
  29. Mimilan
    Joined: Jun 13, 2019
    Posts: 598

    Mimilan
    Member

    Where is this port? In the carb or the manifold?

    With the power brakes it only draws a vacuum NOT flow [so maximum volume is when the diaphragm is fully displaced]
    The PCV it pulls volume of air [it breathes]

    Having the PCV draw air into the manifold can lean out those particular cylinders.

    The PCV port on a carb is best
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2020 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.