1. Registration trouble? Please use the "Contact Us" link at the bottom right corner of the page and your issue will be resolved.
    Dismiss Notice

Compression on a F-134 engine?

Discussion in 'Early CJ5 and CJ6 Tech' started by 1957Willys, May 7, 2012.

  1. 1957Willys

    1957Willys Member

    Is 120psi on all four cylinders good? I'm having running issues with a F-134 engine it cuts up and pops real bad? I rebuild the carter YF carberator and replaced the fuel pump and the fuel tank and lines but it cleared up a little. But it is still running rough I found the distributor to have never been tuned up before. It still has the factory cap, rotor, point set, and condenser. The distributor cap has spider web like cracks all in the inside of the it and the spark plug wires are corroded into it. I think after I do a tune up it will fix my problem. I'm sure I have answered my own question but I have its always better to ask than to break something?
     
  2. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    On any "new" old car, I always replace all of the consumable ignition parts, along with all the hoses and all the belts. I would replace the ignition wires, spark plugs, distributor cap and rotor, points and condensor regardless of their apparent condition. If any of the old parts look to be in passable condition, put them in a bag and hide them away in the tool box as trail spares.

    Not an expert on the F134, but 120 psi is good. Evenness is important - how even are the numbers? What you do not want is one low cylinder, or lots of variation between the cylinders.
     
  3. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Timgr is dead on. 120# on all four would make me happy, and I would definitely do a full ignition renewal and tune. Cheap insurance.
     
  4. 1957Willys

    1957Willys Member

    I checked the compression today I was scared I had a burnt valve but the way it is running feels like its on random cylinders. Not just the same one constantly on the first stroke of each cylinder compression went strait to 90psi. Is there anyway to remove excessive carbon from the valves like intake cleaner that you would run through you gas tank. Or would I risk burning a hole in one of my pistons of a valves?
     
  5. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Don't over-think this until you do the basic tune up...
     
  6. 1957Willys

    1957Willys Member

    Ok parts will be here tomorrow.
     
  7. cj5lover

    cj5lover Member

    120 psi on all cylinders is very good. consistancy in the numbers is the key. i have the same engine. i have an average of 107 on mine, and it runs great.
     
  8. 1957Willys

    1957Willys Member

    Well I finished the tune up and reset the timing and it runs great! I just purrs so smooth! My new wheels arrived today they go to a M151 and have never been mounted or had a tire on them!
     
  9. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    There you go... Always listen to Timgr!
     
  10. 1957Willys

    1957Willys Member

    I'm still wonder about how to get the excessive amount of carbon in the cylinders and on top of the valves out? I just noticed that its easy to see the intake and exhaust valves with the plugs out when I was doing the compression check ? Do I just run a higher grade of gas or a fuel additive?
     
  11. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    What do you call excessive, and why is it a problem? Unless you are having knocking/detonation I would first try just running it normally for a while.
     
    Last edited: May 9, 2012
  12. garage gnome

    garage gnome ECJ5 welder

    Don't forget, these are older vehicles and don't combust 100% of the fuel like newer vehicles. I wouldn't be worried about it, what color are the plugs? you want them to be a tannish color.
     
  13. nickmil

    nickmil In mothballs.

    Newer vehicles do not combust the fuel 100% of the fuel either. That's why we have catalytic converters and other emissions devices.


    Sent from my iPhone using Tapatalk
     
  14. Jw60

    Jw60 That guy 2024 Sponsor 2023 Sponsor 2022 Sponsor

    I think seafoam or similar poured down the carb, will help clean out the carbon but if it is 1/16 inch bad i would pull the head. being an engine that can take abuse and 72 octane I would learn to read the plugs and go from there. reading plugs is old school and only costs time.
     
  15. 1957Willys

    1957Willys Member

    I'm just going to drive it I have finally got it so runs right. Its time to just enjoy it
     
  16. duffer

    duffer Rodent Power

    Apparently running near perfect? I would also just be using it and most definately NOT taking anything apart just because you see some carbon build up. That may have occured from the timing/ignition problems you fixed and will slowly burn its self out. Unless you do get pre-ignition, just use it.