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Good New/Bad News: 235 w/Fenton Headers

Discussion in 'The Hokey Ass Message Board' started by 54LedSled, Sep 15, 2013.

  1. 54LedSled
    Joined: Mar 11, 2011
    Posts: 362

    54LedSled
    Member

    Good News first: Over the last week, I installed my fenton headers along with a new water pump (old one crapped out) and drove the car (open headers) about two miles down to the exhaust shop to get my smithys put on and all the piping done.

    Bad news: When I went to picked it up on Friday it was running like crap in the shop. the engine seemed to idle rough and there a bad intermittent creaking sound coming from the car that sounded to be rpm related. (meaning when I gave it throttle I didn't hear it until it started to idle again.)

    Nothing looked like it was banging from the exhaust work, it wasn't that type of sound. The shop said they weren't sure where the sound came from. I drove the car down the block to the gas station and it performed well, wasn't sluggish at all. However when I came to the gas station to slow down it seemed to idle rough and I heard that sound again under the hood. So I check the oil and put some gas in. Oil was low about a quart so I put some in and fill up the gas. got home just fine and I pulled the plugs.

    Every single plug was BLACK with carbon build up. So I replaced the plugs with new one and fired it up, it idled a little better but still heard the same creaking sound and noticed a cloud of exhaust smoke and smell. I shut off the car and check my #1 plug it was starting to look black again. Oil dip stick is fine. I reset my carb mixture screw back to 2 1/2 turns out per manual and adjusted my idle screw, the car still had the same issues.

    Anyone had similar issues after putting headers on? Any potential fixes? Is it an exhaust leak?
     
  2. 52HardTop
    Joined: Jun 21, 2007
    Posts: 969

    52HardTop
    Member

    Shouldn't that be 1 1/2 out for the air fuel mixture? Sure might be runnin a little rich?
     
  3. belair
    Joined: Jul 10, 2006
    Posts: 8,803

    belair
    Member

    I put Fentons on my 55. After the muffler shop got done, it sounded like crap-big exhaust leak. I found the gasket had slipped when I put the manifolds on, and couldn't hear it without mufflers. Took stuff loose, got it all lined up, and no more problems. Mine leaked at the exhaust, yours may be leaking at an intake port. Basically what 52 hardtop said.
     
  4. 54LedSled
    Joined: Mar 11, 2011
    Posts: 362

    54LedSled
    Member

    Thanks 52hardtop, I will try adjusting the carb again. However, the car ran pretty good before I started to tear the intake/exhaust manifold off to put the fentons on. Not sure why it keep building up carbon on my plugs so quickly.

    belair, when I attached my intake and fentons on I had already attached the gasket to the head the night before, so I was already sealed to the block when I attached them on. Do you think I don't have them aligned right? They look good to me. What the easiest way for me to check if its a leak?

    Not sure if this helps but my exhaust when its idling sounds kind of crappy too, definitely doesn't sound like I have headers on it.
     

  5. chigger
    Joined: Jan 30, 2009
    Posts: 169

    chigger
    Member

    If looking for an intake leak, cold engine, spray around intake, with running, with choke cleaner or starting fluid, if hit leak, rpm will increase. Just be careful with exhaust below.

    Posted using the Full Custom H.A.M.B. App!
     
  6. Ice man
    Joined: Mar 12, 2008
    Posts: 984

    Ice man
    Member

    While its running spray some oil around the intake. if its leaking it will soon be smoking out the tailpipes. Also try a vacuum gauge, should be around 19-20 in
     
  7. 54LedSled
    Joined: Mar 11, 2011
    Posts: 362

    54LedSled
    Member

    Thanks guys...How do I check if its leaking from the exhaust side?
     
  8. JohnEvans
    Joined: Apr 13, 2008
    Posts: 4,883

    JohnEvans
    Member
    from Phoenix AZ

    Exhaust side will be noisy and with your fingers near you will feel HOT gases. Exhaust side has no bearing on sooty plugs rough running,that is a carb issue.
     
  9. belair
    Joined: Jul 10, 2006
    Posts: 8,803

    belair
    Member

    I used some rtv to stick mine back on. Sounds like your gaskets couldn't slip slip like mine did. I don't know if you can put them on backward or upside down. If the gaskets fit the head properly when you put them on, they can't (I would think) be mis-aligned with the manifolds. Ice man and John have you covered on finding the leak.
     
  10. Did you put the steel O-ring thingies back in when you put the intake/exhaust back on?? The fentons - are they original or repros? On 'some' the little retainers on the bolts don't line up evenly on the tabs between the intake and exhaust manifold, and you'll have to grind them down a bit.
     
  11. 54LedSled
    Joined: Mar 11, 2011
    Posts: 362

    54LedSled
    Member

    Mr57, yes I put the intake rings back in. The fentons were used by another h.a.m.ber before me so they lined up pretty nicely, no fab work needed.

    Posted using the Full Custom H.A.M.B. App!
     
  12. 54LedSled
    Joined: Mar 11, 2011
    Posts: 362

    54LedSled
    Member

    To make things hopefully easier, I will try and post a video after work of exactly what the car sounds like.

    When I fired it up yesterday, I could definitly smell fuel in the air. Plus, my brand new plugs going sooty black in a matter of minutes. Sometimes up with my fuel delivery or ignition. Wired thing is carb is brand new and no issues before I did the swap.

    Posted using the Full Custom H.A.M.B. App!
     
  13. racer32
    Joined: Sep 22, 2007
    Posts: 745

    racer32
    Member

    Did you run the choke's stove pipe down to the new header?
     
  14. belair
    Joined: Jul 10, 2006
    Posts: 8,803

    belair
    Member

    And I had to get creative with the throttle linkage. I am still using the stock carb and intake. Are you?
     
  15. ^^^Like^^^

    Are you running an automatic choke? Make sure you still have a good heat source connected to the choke thermostat or the choke may never fully open. That would soot up the plugs. Might also need some heat to the intake at the base of the carburetor.
     
  16. 54LedSled
    Joined: Mar 11, 2011
    Posts: 362

    54LedSled
    Member

    http://www.youtube.com/watch?v=vB2SRqJ80IE

    Here's a video of the engine running for a couple minutes. I got under the car and found exhaust leaks on both sides of the down pipes fittings. Hot pressure gas coming from both so back to the shop it goes for them to fix! I'm starting to feel a bit better.
     
  17. 52HardTop
    Joined: Jun 21, 2007
    Posts: 969

    52HardTop
    Member

    hey ledsled, you've got to re adjust that carb! When I did the two carbs on my 54 235 I could literally see the difference in the exhaust. I had a lot of skipping and missing that was easily seen at my exhaust pipes. As I did the air fuel mixture while watching the vacuum gauge the exhaust evened out and all the missing stopped. I say you should turn the air fuel screw all the way in without tightening when it stops. Then turn it out 1 1/2 turns. try that and see how it is when it's running. Get yourself a vacuum gauge and fine tune to get as close to 20 inches as you can. I think you may be hearing the exhaust leak by the headers. Still you must be running way too rich to be fouling plugs the way you are.
    Dom
     
    Last edited: Sep 16, 2013
  18. Cosmo49
    Joined: Jan 15, 2007
    Posts: 1,302

    Cosmo49
    Member

    Rubber hose to the ear or stethoscope and you will be able to tell us where that squeak is coming from. To me it sounds like your fan is hitting the bottom of the radiator. In addition do the soapy water to identify vacuum leaks around the manifold. I believe you need to pipe heat from BOTH Fentons to have an exit for the exhaust heat...right now you are pumping air into a closed plenum, having two you will have an IN/OUT for exhaust flow.
     
  19. 54LedSled
    Joined: Mar 11, 2011
    Posts: 362

    54LedSled
    Member

    Thanks Dom, the good news is I found the squeaking sound. It was the bottom of the down pipes off the headers that have a connector to the straight pipe going into the glasspacks. I could literally feel hot air all around the fitting on both pipes coming down under the car. So I take it back to the shop tomorrow to have them fix that squeaky leak.

    As for the carb, your right. I need to get that adjustment right on point. I did what you said earlier and left the fuel mixture screw 1 1/2 turns out and have been playing with the idle. However, when I think I'm where I need to be on the idle in Neutral, I put it in Drive the rpms really drop and the motor is struggling to stay alive without gas. ??? I will try to pick up a vacuum gauge at the auto parts store tomorrow. Where's the best place to hook it up?

    I also need to get some more plugs as the ones that I had in when I shot the video today were already pretty black with soot. I may also re-check timing, although I'm not getting any popping or backfire at all. ??
     
  20. 54LedSled
    Joined: Mar 11, 2011
    Posts: 362

    54LedSled
    Member

    My stock intake had a metal heat tube to the choke, but when I went to try and re-bend it, it broke. So I am currently using a piece of rubber hose with a brass nipple at the choke....could that be causing me to run rich? Not enough heat?
     
  21. dimebag
    Joined: May 16, 2009
    Posts: 622

    dimebag
    Member
    from Joliet, il

    Rubber hose coming off hot exhaust is a bad idea, re-bend some copper pipe for the heat riser. Also did you check that the float is not stuck, sounds kinda like that motor is drowning in fuel....
     
  22. 54LedSled
    Joined: Mar 11, 2011
    Posts: 362

    54LedSled
    Member

    Thanks dimebag will do. I will also give the carb a good couple taps to free up that float if it is indeed stuck.
     
  23. Old Iron Nut
    Joined: Jun 15, 2012
    Posts: 90

    Old Iron Nut
    Member

    Had this happen to mine earlier this year. Parked over night, went out the next day and it ran pretty poorly, fuel smell, smoke, and when I checked the plugs they where sooted up. Messed with it for awhile and decided to try my old timer tricks, tapped the carb a couple times with a screw driver, tried starting it again and like magic it was fixed. Found the float was hanging up on a burr near the float pivot pin, quick fix with a file.
     
  24. High5
    Joined: Jul 2, 2012
    Posts: 185

    High5
    Member

    I would definitely look inside the carb throat and make sure the butterfly for the choke is completely open. It doesn't take much closure of the choke to cause what your video shows.

    Depending on the age of the carb, the coil inside the automatic choke housing may be worn or the adjusting screws have backed out slightly causing the spring to reset itself. It's worth a check at least.
     
  25. oldolds
    Joined: Oct 18, 2010
    Posts: 3,220

    oldolds
    Member

    Too much restriction from the mufflers will cause your problem with the plugs. A plugged converter on a modern car will foul plugs. Take the mufflers off and see what happens. That is when the problem started.
     
  26. 54LedSled
    Joined: Mar 11, 2011
    Posts: 362

    54LedSled
    Member

    UPDATE: I put on a copper tube this morning and that made a huge difference in heat transfer to the choke. I also cleaned and replaced the plugs. After dialing down the mixture and idle screw and double checking timing, the car started to really smooth out, aside from the existing exhaust leak.

    So I decided to take it for a test drive for a little more fine tuning. The throttle response was really good, the car got up and moved! So I decided that well enough to drive it back to the exhaust shop to fix the leak. Once I get it back tomorrow, I'll fine tune that carb some more.

    I'll post more after that...
     
  27. 52HardTop
    Joined: Jun 21, 2007
    Posts: 969

    52HardTop
    Member

    Good for you man. That's too pretty a ride to have it sitting in the garage!
    Dom
     
  28. You're heading in the right direction. Somewhere in the choke housing there should be a small vacuum port which helps pull the heated air thru the metal tube into the housing where it in turn heats the choke thermostat spring. With time and use that port can get plugged with dirt and schmutz. Make sure the port is open and clear to manifold vacuum.

    In your part of the country having a working automatic choke probably isn't that big of a deal. Mainly you'll just need to make sure that after the engine has warmed up slightly the choke blade at the top of the carb is fully open. For the time being at least you could just wire it up to hold it open at all times. It may stumble for a minute or two when first started cold but I'm guessing in San Antonio it should warm up pretty quickly.
     
  29. 54LedSled
    Joined: Mar 11, 2011
    Posts: 362

    54LedSled
    Member

    UPDATE: Everything done, the car is running a lot better now! Thank you everyone for all your help. Now its time to cruise... :)
     
  30. Good job! And thanks for the update. Everyone pitches in with suggestions but most of the time we never find out if we helped the situation or not. :D
     

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