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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. Dr.Theo
    Joined: Jun 25, 2004
    Posts: 148

    Dr.Theo
    Member

    have you tried hand feeding the motor gas?
     
  2. Buzznut
    Joined: May 9, 2008
    Posts: 2,349

    Buzznut
    Member

    Do you have an exhaust leak on the side that is weak? No backpressure could cause these syptoms. Did you pull the head? May have head gasket leak...not necessarily a situation where water is being introduced into the block, but maybe just an air leak causing the drop in vacuum and poor performance. This whole thing sounds to me like either bad fuel delivery, lack of combustion or poor combustion (even though you have compression - does it smell rich?) or poor airflow/exhaust either to or from the heads. You have either a blockage or a leak would be my guess...
     
  3. The Atf Will lube the valve guides and clean the combustion chamber some. It will also temporarily boost the compression. Mainly it will smoke a lot.:eek: Take off both exhaust manifolds at the heads. Then start it up You can then tell for shure which cyls are firing from the flame or lack of flame. OldWolf
     
  4. 50dodge4x4
    Joined: Aug 7, 2004
    Posts: 3,534

    50dodge4x4
    Member

    Man, I've been following this from the begining. I know what I would do if it was mine. Drive the stupid thing. You have been through all the easy stuff and spent a bunch of money on it already. The next real step would be pull the engine and completely rebuild it. If in reality it is only running on 1/2 the engine, it needs rebuilding any direction you go, anything less would be putting off what will need to happen at some time.

    Your choices are:
    1) To continue to dump money into it with little or no improvement.
    2) Quit messing around and rebuild the engine, replace the exhaust, replace the entire fuel system (including tank, fuel lines, fuel hoses, fuel pump, just everything), and replace the ignition system.
    3) Drive it until whatever is wrong shows up without a doubt, then fix it or park it. If it has not been run consistantly, what ever the issue is may just go away or improve with running time.

    Some engines just do not run smooth or deliver even power, as long as it does not effect how it drives dramatically, or drives you crazy with the way it runs, just drive the thing. If it is undrivable, look at your choices above. I had an old Plymouth that idled poorly. Replace everything on the ignition before I checked the compression. Had 7 around 145-150 and 1 @ 125. My wife and I drove that car over 100,000 miles ourselves, it was one of the best, most relaible cars we have ever had.

    Drive your car, save up the money to rebuild it or replace it and be done. Gene
     
  5. lolife
    Joined: May 23, 2006
    Posts: 1,125

    lolife
    Member

    I don't believe only 4 cylinders are running. That and the statement that the timing is stable is completely unbelievable. Maybe do a reverse flush on it, and a head job, or better yet, just replace the tired motor. Mechanical things wear out.
     
  6. blown green t
    Joined: Nov 18, 2008
    Posts: 144

    blown green t
    Member

    I think it's time to take it to a mechanic. A few hundred for diagnostics is better than a few thousand on rebuilding a good engine. Something is being overlooked or misdiagnosed.
    Good luck.
     
  7. Radio Joe
    Joined: Jan 9, 2007
    Posts: 306

    Radio Joe
    Member

    Well I'll post the results of my last testing and leave it at that.

    I shoved small wires between the wire and spark plug boot at the spark plug on the bad side then started the engine. I shorted each spark plug starting at #1. first I checked that a spark jumped from the ground wire to the wire I stuck into the wire. then I shorted the wire. with cyls 1,3,5 and 7 shorted there is no change in idle (rough). Then I put the car in gear- Idles the same as before (Rougher then not in gear).

    Then I took the car down the driveway. There is a bog but if I flutter the gas pedal it will go. It defintiely runs worse. So that shows that the drivers side cyls are doing SOMETHING above idle.

    Next I shut the egine off and inserted the short wires into the pass side splug wires at the spark plug. Stated the car and began shorting wires one by one just as I did on the drivers side (first checking a spark jumped, then shorting it). shorting cyl #2 made the idle get rougher, shorting #4 made it even rougher, shorting 6 was even rougher and whenI shorted #8 the engine died. It would not start like this.

    So engine is running at above idle (I would say around 2k rpm I dont feel a miss anymore) but the drivers side is still the problem.

    Can someone post a short video of a spark plug firing from their engine. The spark I am getting to jump is orange in color and I would expect witht he coil and ignition system I have that the sprk would be bigger. Maybe not.
     
  8. Radio Joe
    Joined: Jan 9, 2007
    Posts: 306

    Radio Joe
    Member

    I cant freakin believe it.......


    Looks like it may be a carb issue after all.

    I pulled the bad sides plugs and squirted some gas in the cyl then put the plug back in. then shorted the entire good side and tried to start the car. Wouldnt start. Thinking maybe I put too much gas in the cyl I held my foot to the floor and tried again- It started and ran. As soon as I took my foot off the pedal it died. Hold pedal half way to floor and start it - It runs. Runs rough because half the engine is still shorted but it does run.

    SO it looks like the carb after all. I still dont understand why it is only effecting the drivers side- The reason I ruled out the carb was because of the intake design- half the engine shouldnt be effected by a bad carb.

    This will be the second time this damn holley carb has caused me soo much problems. Im gonna buy a new carb and throw this one at the wall....
    I'll report after I get a new carb

    For all of you that said carb and I said "But that cant be" YOU ARE THE MASTERS, I AM THE IDIOT!

    By the way, feel free to point out how this could have been checked long ago and how much of an idiot I am...
     
  9. gasserjohn
    Joined: Nov 9, 2008
    Posts: 1,218

    gasserjohn
    Member

    please post a photo showing the intake runners
     
  10. Buzznut
    Joined: May 9, 2008
    Posts: 2,349

    Buzznut
    Member

    Orange/Pink spark still sounds wrong to me...it should be blue. I think you aren't getting enough spark to the plugs and that is at least PART of your poor running issues...it's lacking decent combustion. Honestly, even though not traditional and I will get a lot of flack for this I'm sure, Edelbrock Performers are typically more consistent and reliable in my experience than Holleys. If this is a daily driver and you need reliability, do yourself a favor and go buy a 600 cfm Performer.
     
  11. Radio Joe
    Joined: Jan 9, 2007
    Posts: 306

    Radio Joe
    Member

    Heres a picture of the intake I have from the service manual.

    And the spark is more like a purple- Orangish blue color.
     

    Attached Files:

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

    Radio Joe
    Member

    it wasnt the carb. Although I need to look into better filters- with 2 filters I still had crap in the carb.

    Problem was the intake valves on the bad side. The lash was spec according to my manual but just because I was about to give up I pulled the valve cover and loosened the intake valves a half turn and fired it up. Immediately the engine sounded better. put the cover back on and tested it .

    That was it! Only thing I can guess is the lifters are pumping up higher after it is running. And apparently the are pumping higher than when I first got it on the road.
    DEFINTITY PROBLEM SOLVED!!!!!!!!
     
  13. brewsir
    Joined: Mar 4, 2001
    Posts: 3,278

    brewsir
    Member

    I'm glad that worked...but why did the compression show OK at first?
     
  14. Radio Joe
    Joined: Jan 9, 2007
    Posts: 306

    Radio Joe
    Member

    OOPS! I meant it was the EXHAUST valves that were too tight. Not the intake.

    Like i said, the only thing I can think is that the lifters are pumping up more while it is running then when off or just turning over. It really doesnt make sense that they are too tight at idle, but still show good compression. This weekend Im gonna check compression again- just to see what it reads now..

    I dont really know. :confused:

    BUT IT WORKED!!
     
  15. swifty
    Joined: Dec 25, 2005
    Posts: 2,217

    swifty
    Member

    Lifters on a 318 Poly are solids so they won't be pumping up.

    Good that you've found the problem tho.

    swifty
     
  16. Radio Joe
    Joined: Jan 9, 2007
    Posts: 306

    Radio Joe
    Member

    Yeah thats what some of the guys over at Moparts said- So I dont know how all the rockers on one side tighened up. The car ran good when I first put it on the road and then progressively got worse without me touching anything...

    :confused::confused::confused:
     
  17. JohnEvans
    Joined: Apr 13, 2008
    Posts: 4,883

    JohnEvans
    Member
    from Phoenix AZ

    Gee !! Valves tightening up after running awhile. One of two things wear OR what's known as valve seat regression,meaning the seats are wearing usually caused by unleaded fuel. Being it was only on one side I would think too tight adjustment to start with, everything settles in and Whoops!!
     

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