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help- 318 running on 4 cylinders.

Discussion in 'The Hokey Ass Message Board' started by Radio Joe, Jun 16, 2009.

  1. twofosho
    Joined: Nov 10, 2005
    Posts: 1,153

    twofosho
    Member

    Lets see, new points, plugs, condensor, rotor, cap, and wires. Stock intake non 180 degree, right? Weak spark and a lean mixture on one bank of an intake manifold split bank to bank could be your culprit all right. After everything you're replaced, without test gear, the first thing I'd do though is slap on a different coil, check the points to make sure you haven't burned them up running without a ballast resistor, replace the points if they need it, and add that ballast resistor. 16-18 thou sets you close on dwell.

    Sounds like it's time for a Mopar electronic distributor, maybe converted to HEI with the module from a mid 90s Chev PU.
     
  2. Darby
    Joined: Sep 12, 2004
    Posts: 426

    Darby
    Member

    I have no idea why it would only affect one bank, but how's the ballast resistor in the car? If you've been able to change parts and improve the spark, that's a cheap thing to try, even if it doesn't make sense.

    Did you clean the exhaust cross-over passage out when you had the intake off? Is the intake gasket correct so that it's blocking/not blocking the way its supposed to for that crossover? Some issue with that cross-over is my best guess, even though I'd expect to see a difference in plug color on the affected side...

    I have a factory '66 manual here if you need any specs for timing, lash etc.
     
  3. Mr48chev
    Joined: Dec 28, 2007
    Posts: 29,826

    Mr48chev
    ALLIANCE MEMBER

    Just a note: Ever since my old high school auto shop teacher said "this is the way you do it," to run a compression test I have proped the throttle blades wide open and cranked each cylinder so that I can hear the compression hit the gage 5 times. It's worked for me for 47 years now.

    That is with all of the plugs removed.

    The main thing is that you have dead even compression on each cylinder which should eliminate valves, valve train and rings from the issues.

    When you turn the rotor/distributor shaft by hand you are turning against the advance and it shouldn't turn in the opposite direction.
    the normal way to get the rubbing block up on the cam is to bump the engine over so that the rubbing block of the points is on a high point of the cam to adjust the points.

    The bushings in the distributor could be worn to the point that the shaft is moving around a bit and the dwell is chainging. this would show up on a scope pattern real quick.

    The engine wanting that much more than the recomended advance might point to a worn timing chain but I don't think that is all of the problem/

    What about the cap? how does it look inside? carbon tracks? cracks? other marks?
     
  4. Radio Joe
    Joined: Jan 9, 2007
    Posts: 306

    Radio Joe
    Member

    Ive tried running both with and without ballast resistor- right now the coil is an accell coil but I swapped it out for the MSD coil off my corvair. No difference. I have the ballast resistor connected right now.

    Voltage at Battery when running is right around 13 volts. Even when revving. Voltage at coil is 10volts but when revved it gets around 12 volts.

    I have the service manual on CD

    Timing chain is NEW.

    Im going to run another compression test and I will report what I see on each cylinder.

    I did clean the carbon out of the intake when I had it removed. It wasnt very blocked but I cleaned what was there.

    Old cap was fine- new one is still new ;-)

    I have been considering the electronic distributer change, but dont want to drop that cash and then find it didnt help. I may do the GM upgrade because is cheaper- I have the instructions from when I was going to do it to the corvair.

    manifold supplies gas to cylinders 1,7,4,6 from one side and 3,5,2,8 from the other.
     
  5. gasserjohn
    Joined: Nov 9, 2008
    Posts: 1,219

    gasserjohn
    Member

    YES it would be that only one head effected or only one bad enough to show up he said always low on power.....hope he lets us know outcome
     
  6. Radio Joe
    Joined: Jan 9, 2007
    Posts: 306

    Radio Joe
    Member

    gasserjohn- Im sorry somehow i completely missed your post. That could defintiely be a cause of it... In that condition the compression would be good but not getign enough gas.

    Do you think this is something i can determine by pulling the intake and looking down the runner in the head or would i have to pull the head completely off?
     
  7. Radio Joe
    Joined: Jan 9, 2007
    Posts: 306

    Radio Joe
    Member

    Cant find any close pictures of the heads with the intake off, but I think I am lucky in having the poly heads- Looks like the intake valve is not too far from teh intake runner so I am goign to order new intae gaskets and risk it by pulling the intake.. Wish me luck. I'll report my findings.
     
  8. gasserjohn
    Joined: Nov 9, 2008
    Posts: 1,219

    gasserjohn
    Member

    can someone post photo of a valve that has the stem&back side valve face gunked up you see it in the gas commercals on tv.....if the heads are not matched one may have a different angle or height so manifold is not sealing if leakng into valley there would be high vacuum present inside the engine;also you'd think engine would use oil& smoke?
     
  9. Radio Joe
    Joined: Jan 9, 2007
    Posts: 306

    Radio Joe
    Member

    I was thinking of that- Even if I cant see any build up I could atleast check to see if the valves seal and then open and see how much they actually flow through the valve.

    I think I know what im looking for- Ive seen those cleaner ads with the gunked up valves.

    I have to order in the intake gaskets so I think it will be Wednesday before I ca get it done.
     
  10. recardo
    Joined: Aug 31, 2006
    Posts: 833

    recardo
    Member
    from Winslow

    My money's on a valve job. Pop the heads and take them to your favorite machinist.

    [​IMG]
     
  11. Ford406go
    Joined: Jun 21, 2009
    Posts: 22

    Ford406go
    Member

    Hey Radio Joe, I am Sarah... I'm new to this but my old man has a 65 Sport Fury.. with the Big Block Engine (318 ?) bolts through the valve cover top... anyway if that is the same engine... He had the same problem... The fix ? a new vaccum advance on the dist. Was sticking at low RPM.. and as he put it... Pulling too much vaccum from the intake or carb.. Hope this helps.
     
  12. Radio Joe
    Joined: Jan 9, 2007
    Posts: 306

    Radio Joe
    Member

    Okay for those of you keeping score at home, here is the compression numbers.

    1= 150
    3= 155
    5= 142
    7= 145
    2= 140
    4= 150
    6= 150
    8= 155

    Biggest difference is 15 lbs- According to the 1966 Plymouth Fury service manual cylinders should not differ more than 20lbs.

    So compression looks good to me- Im gonna proceed with pulling the intake and checking the intake valves.
     
  13. Radio Joe
    Joined: Jan 9, 2007
    Posts: 306

    Radio Joe
    Member

    Wouldnt bad valves show bad compression?
     
  14. gasserjohn
    Joined: Nov 9, 2008
    Posts: 1,219

    gasserjohn
    Member

    that would take all the fun out of this >for him&us too
     
  15. cmyhtrod
    Joined: Nov 29, 2008
    Posts: 360

    cmyhtrod
    Member
    from ct

    are you positive that the plug wires are going to the correct cylinders? I know that sounds dumb, but........shit does happen, also Im thinking the distributer bushings are shot
     
  16. Radio Joe
    Joined: Jan 9, 2007
    Posts: 306

    Radio Joe
    Member


    Yes Im sure- And I have double, triple quadripple checked multiple times. When i first got the car running I had a backfiring problem that turned out to be crossed wires. I felt really stupid for that one.

    Gotta agree with Gasserjohn- I like to know I was able to find and fix the problem- Even if I need help, I need to have my hands in there. The only thing I let a "shop" do is exhaust work or machine work after I removed the parts. :D
     
  17. blackrat40
    Joined: Apr 19, 2006
    Posts: 1,167

    blackrat40
    Member

    Hey Joe,
    Do you think there's any possibility there could be a solid piece of something that
    slipped between the head/manifold/gasket at last assembly that is holding the manifold
    up just enough to leak on one side?
     
  18. Radio Joe
    Joined: Jan 9, 2007
    Posts: 306

    Radio Joe
    Member

    The car is still running- Actually runs half decent... just a little rough. I drive it to work every day.

    Anything is possible but if thats the problem, the leak is in the valley cuz I sprayed cleaner around the intake where it mounts to the head and the idle sped didnt change.
     
  19. lolife
    Joined: May 23, 2006
    Posts: 1,125

    lolife
    Member

    You mention that the vacuum needle wiggles, and the only two reasons that normally occurs is a bad ignition (checked good), or sticky valves. See row 2 in the chart that Recardo posted above.

    The compression is a static measurement, while the vacuum is a dynamic measurement. Compression is a good thing though.

    Does this thing use oil? Smoke at startup, and then goes away after it warms up?
     
  20. Radio Joe
    Joined: Jan 9, 2007
    Posts: 306

    Radio Joe
    Member

    No smoke on startup at all and no smoke when running. not using any oil.

    New intake gaskets are in tomorrow afternoon so by tomorrow night I should know if there is anything on the valves.
     
  21. ChryslerRodder
    Joined: Nov 9, 2008
    Posts: 70

    ChryslerRodder
    Member

    You are running a points ignition, what kind of plug wires do you have? If you have a set for electronic ignition those are different than standard wires. I think that the resistance is different between the two.
     
  22. 61 chevy
    Joined: Apr 11, 2007
    Posts: 891

    61 chevy
    Member

    broke valve springs:eek:
     
  23. i have it solved... first remove the gas cap, have a friend or relitive move the car away, then have same friend or relitive place a new old car where your car was, now throw the gas cap over your right sholder.. you won't be needing it..
     
  24. lolife
    Joined: May 23, 2006
    Posts: 1,125

    lolife
    Member

    That's a new one on me.

    Anyway, I'll throw this out: are all the plugs the same model and part number?

    Also: I learned this from Cheech and Chong: Check the tire pressure :p
     
  25. mtpockits
    Joined: May 20, 2009
    Posts: 175

    mtpockits
    Member

    not sure whats going on with yours but mine in my 61, runs 100% better with a electronic distrubuter and electronic regulater in it, it not even the same car anymore.
     
  26. Radio Joe
    Joined: Jan 9, 2007
    Posts: 306

    Radio Joe
    Member

    Sorry so late- There was a hold up on the gaskets. I got the intake gaskets today and yanked the intake. The gaskets looked okay- no noticeable leak I could see. Looking into the heads the intake valves had some crud on them but not anything that would cause the gas not to get to the cylinders. I cleaned the valves of anyway. Attached is 2 pictures looking into the #1 intake runner. First shows that you can see the spark plug with the valve open (little light shoved into the port) and the second is with the plug removed and the light shoved into the spark plug hole. As you can see it opens wide enough.

    Then I rotated each cylinder until the valve was closed and sprayed a bunch of carb cleaner into the port until there was a puddle around the valve. I let that sit for about 5 minutes to see if it leaked out- None of them leaked.

    I also made sure there was no blockage in the intake anywhere.

    So I put it all back together and it runs just the same as it did.

    So I am still chasing the problem. Good compression, valves open fine and no leakage at the valve. means I left wth Fuel and spark again. Why its only effecting one side I dont know but it seems that the heads and cylinders are okay.

    I guess I will look for the electronic distributer for it and go from there. Anyone know which cars had the right one- I'll buy it off ebay.

    I thought it was late 70's SB chryslers but my dad has a 79 transvan I was going to pull the dist. out of when I am visiting this weekend but he said it has points :confused:
     

    Attached Files:

  27. Radio Joe
    Joined: Jan 9, 2007
    Posts: 306

    Radio Joe
    Member

    plug wires are what they gave me when I asked for new wires at orielleys.

    Plugs are all the same number and are the right ones for the car.
     
  28. Dr. Frankensickle
    Joined: Feb 7, 2007
    Posts: 383

    Dr. Frankensickle
    Member
    from Kansas

    I had a similar problem on a 66 poly 318.....at idle it hit just fine,rev it a bit and it dropped the back 4 cylinders in the cap rotation,pulled and plugged the vacuum advance and she'd hit on all 8 but ran like shit,turns out it was a 50 cent brass bushing in the distributor housing that was worn out and the vacuum advance would pull the rotor far enough away from the back four in rotation on the cap far enough cause them to not fire......drove me nuts till I figured it out.
     
  29. Chrysler electronic ignition distributors from '73 til the vacuum advance disappears should work. That '79 van may have had lean burn and recieved a complete back date by someone to alieviate cronic headaches. The earlier units may have an advance curve that works well. There is a wiring diagram on the Allpar website.
     
  30. cornfield rodder is right, but not all cars and truck had lean burn on them in the late 70's early 80's. Just avoid the lean burn like the plague and get the distributor, control module, ballast resistor and wiring harness for the ignition system.

    Here are two possible wiring scenarios, I would wire for the 4 pin and not worry about the other pin, works fine without it.

    [​IMG]

    [​IMG]

    A good tip for you: make sure the control module is well grounded or you may have some other mystery problems.

    While you are at it, if the small block you are peeling the ignition off of has the standard (not the 100 amp huge mother) alternator, grab that too, along with the plug, harness and voltage regulator. This gives you a much better voltage regulator and a dual field alternator (one field is constant output which works very well with the electronic ignition).

    Here's a diagram for that as well:

    [​IMG]
     

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