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305 engine tick

Discussion in 'Chevy Trucks' started by 81c1500, Sep 1, 2004.

  1. 81c1500

    81c1500 Junior Member
    Messages: 29

    I have a ticking noise that in the engine that varies with engine rpm. The engine feels as if it has adequate power but this ticking noise is irritating. Does anyone have any idea of what it is? Thanks
     
  2. Plow Meister

    Plow Meister PlowSite.com Addict
    Messages: 1,174

    Like finding a needle in a haystack

    Could be the valve train, bearings, bad injector, crack in the distributor housing, etc.
     
  3. Robhollar

    Robhollar Senior Member
    Messages: 766

    Its prob a collapsed lifter, if thats what it is I wouldn't too much about it....Rob
     
  4. derekbroerse

    derekbroerse 2000 Club Member
    Messages: 2,377

    Can also be an exhaust leak, often sounds like lifters. Check for loose or broken studs and bolts, or obvious signs of leakage (ie: soot on the head castings or the pipes below)
     
  5. Robhollar

    Robhollar Senior Member
    Messages: 766

    Good call Derick, forgot all about exhaust tick!!!
     
  6. gpin

    gpin Senior Member
    Messages: 390

    Our old Chev 305 probably has the same lifters out of the the old Mopar slant 6s. If the motor was too quiet you might grind up the flywheel with the starter. If it has power leave it alone, or invest in a new radio to cover it up.
     
  7. Mebes

    Mebes Senior Member
    Messages: 408

    Early 1980's 305's had a problem with soft camshafts that wore flat on the backside of the cam lobe.
    Didn't affect power much, but the ticking will become louder over time.

    Try adjusting your valves.
     
  8. derekbroerse

    derekbroerse 2000 Club Member
    Messages: 2,377

    Yeah I remember those camshafts, we replaced a lot of them in the shop years ago... not sure how many were affected or of them how many would have lasted this long :D

    Oil pressure was never mentioned. If the pressure is really low, the top end of the engine will tend to starve first. Usually this condition goes away as the throttle is increased due to increased oil pressure. Heavier oil can also help quiet things a bit, but if the cam/lifters are gone they are gone.

    Alot also depends on mileage on the engine.... condition of the truck, and how much $ you'd like to spend to get rid of the irritation.
     
  9. tony h

    tony h Junior Member
    Messages: 20

    Does it quiet down after driving it a while? Then probably Lifters.

    My '85 305 with 275K on it is starting to get noisey. It's leaky Lifters because it quiets down and runs strong after it runs a bit... they pump back up.

    The engine has never been opened up except for a Timing Chain. So I guess I owe it to the old girl to freshen up the Lifters.
     
  10. 81c1500

    81c1500 Junior Member
    Messages: 29

    The engine maintains the ticking noise through out the throttle range, and also still ticks after prolong driving. I have 173k or so on the odometer. The oil pressure stays about 20-25psi at idle and increases with throttle increase. Thanks
     
  11. derekbroerse

    derekbroerse 2000 Club Member
    Messages: 2,377

    That still sounds suspiciously like an exhaust leak to me.... did you look for signs of it? Could also be a cracked exhaust manifold.....
     
  12. 81c1500

    81c1500 Junior Member
    Messages: 29

    I found the leak on the passenger side where the manifold meets the y pipe. Is there and easy way to put a new retaining bracket on. The threads on the manifold plate (3 bolts) are salt eaten to nothing. I think the exhaust manifold o-ring gasket is the source but if I take this apart the bolts or whats left of them will break. Thanks
     
  13. derekbroerse

    derekbroerse 2000 Club Member
    Messages: 2,377

    Those type of leaks can be a royal PITA.

    What you should have there is three studs threaded into the cast iron manifold. There should be a three-holed flange over a flared end on the pipe, with a donut in between.

    If the donut is gone you will have to remove the pipe from the manifold, and yes, likely the rest will break too so be prepared to pull the manifold. If it is a stud, they do make a little repair 'clamp' as a temporary fix until you can remove it and fix it properly. Looks a lot like a little c-clamp.. To get broken studs out once the manifold is off, sometimes you can heat the ear a bit with a torch and back it out with vise-grips (if you have enough to grab)... other times it needs to be drilled out.

    If the flange or pipe-flare is rotted beyond use, you will need a repair piece made by a muffler shop.