Popping under acceleration then started to knock

Engine, Transmission & Driveline

  1. Droppedatbirth

    Droppedatbirth New Member

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    Evening Gents. ( 66 Chrysler 300: 383) so I took the car for about an hour and a half drive tonight and she ran great. Came home and the wife asked me to go to the store I pulled out of the driveway got about a 1/8 mile down the road and I started to get an audible what sounded like a pop pop pop coming from the exhaust ( It sounded like an exhaust leak near the manifold) when I would push down on the throttle. I quickly turned into a parking lot which was right in front of me the car started running really rough and I thought it was going to die I stopped put it in park and it sounded like it cleared up a little bit. Pulled back out went about an 8th mile pulled into my driveway and she’s knocking on the passenger side, sounds like the top end. It’s dark and cold here in Pennsylvania so I’m going to let it set an address it first thing in the morning and I know it’s hard to diagnose over the Internet but I was just wondering if anyone had any thoughts. The car will start back up, it runs rough (sounds like a car with a large cam lope) and has an audible tap from the passenger side that goes along with the RPM. Also I noticed when I shut the car off when I pulled in the driveway and after I started it again there is a audible Whoosh sound coming from the radiator about 10 seconds after the car is shut off. There are no fluids under the car, no antifreeze in the oil and it’s not smoking from the exhaust.

    Thank in advance for any suggestions
     
  2. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

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    It sounds like you may have a bad timing chain that has jumped a tooth. Mopar timing chains will start failing at about 80k under norrnal operating conditions. If you have a timing light, check to see if the timing is jumping at idle, a sign of a loose chain, also check to see if the timing has moved from the desired setting for no apparent reason. You most definitely do not want to drive this car if a timing chain is suspect. You might also want to run a compression check as a broken valve spring could also be causing the symptoms you describe. If a valve spring has failed, that cylinder will usually have no compression. Running a compression check will also give you the chance to check the plugs for antifreeze residue in case a head gasket has failed, another possibility. Do these things and report back.

    Dave
     
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  3. The Goose

    The Goose Senior Member

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    That’s a good start, one last question do you run points and are they new or NOS? I had a new distributor w new points do that to me. Car took a total dive & sounded like a nascar. I swapped in the old distributor as it was dark fired right up and ran fine. The crappy new/junk point set came undone. I’ve run NOS ever since.

    Good luck w the fix hope it’s simple.
     
  4. furious70

    furious70 Active Member

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    To add to Dave, it's easy to pull the valve covers to have a look for a broken spring or rocker
     
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  5. Gerald Morris

    Gerald Morris Well-Known Member

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    Those pathetic asiatic slaves can't/WON'T make something good to save their miserable lives. The new made points distributors are "OK" but as you've found, so have I. Condenser totally failed 8 days from installation. I'd replaced the points immediately, seeing the beer-can quality of what they installed from the slave-line.
     
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  6. Gerald Morris

    Gerald Morris Well-Known Member

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    That sound from the radiator most likely was the coolant running free as your thermostat opened AFTER shutting the engine off. W the water pump not turning, local temperatures will rise, opening the thermostat. Relax, its normal.
     
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  7. halifaxhops

    halifaxhops Well-Known Member

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    New stuff absolutely sucks points have way to low spring pressure and the condensers have a high fail rate when heated. That's why I only use NOS/NORS parts in mine.
     
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  8. Beep Beep Dave

    Beep Beep Dave Senior Member

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    That really is tough, hopefully it is something simple like a coil on its way out. But really you have to start troubleshooting from the beginning. Air, spark, gas and then the mechanical. Or in your case if you can hear metal on metal, might want to start at the mechanical.

    Good luck and let's le know what you find.

    Dave
     
  9. 70bigblockdodge

    70bigblockdodge Old Man with a Hat FCBO Gold Member

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    K.I.S.S. Keep it simple.
    Start it cold see if any exhaust ports don't get hot immediately, check that plug, wires, cap terminal. Then check for vacuum leak around that cylinder. Then look deeper.
    I would guess ignition problem, barring any black smoke and waaaaay rich condition. That's all I have without standing there.
     
  10. C-Sick

    C-Sick New Member

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    Sounds like a cam lobe gone round, and the new tapping would be the loose rocker on that cylinder now.
     
  11. Gerald Morris

    Gerald Morris Well-Known Member

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    You and I are on the same page and paragraph bro. Saving my pennies for YOUR artwork with distributors!
     
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  12. halifaxhops

    halifaxhops Well-Known Member

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    Thanks! That made my morning!
     
  13. Droppedatbirth

    Droppedatbirth New Member

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    Well I finally tore into it and I found the culprit. The spring is not compressed. The rocker doesn’t look bent in any way.

    I hope the valve didn’t touch the piston.

    Question on my plan of attack. Should I

    1. Replace the single pushrod and do a compression check?

    2. Replace pushrod and rocker, compression check?

    3. Replace all pushrods, rockers, springs. The car has 65k on it so I would imagine these are the original components.

    Also can you guys recommend specific parts/ manufacturers etc. that you have had good experiences with. I’m learning as I go so any advice would be appreciated.

    Thank you,

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  14. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

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    Check to be sure the lifter is still in place. Bent push rods are usually caused by a valve that has a rusted up stem and that causes excessive strain on the push rod and it bends. It looks like you are getting plenty of oil to the top end, so I doubt oiling is an issue. Did this car sit for a long time? Remove the rocker shafts and check the rest of the push rods to be sure that none of the rest of them are bent. You can probably just replace the damaged unit if the rest of them are ok. The push rod was probably bent for some time before it gave way and jumped out of the rocker or the lifter. Once they are bent they tend to keep bending until they fail. Replace the damaged unit and turn the engine over by hand to be sure the valve is opening and closing freely. If the valve appears to be operating normally, run a compression check. If the valve got clobbered by a piston it usually will also be bent and you will have little or no compression on that cylinder. In that case, you are headed for a valve job.

    Dave
     
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  15. Droppedatbirth

    Droppedatbirth New Member

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    Thanks Dave, the owner before me had the car for a year he said he put less than 1K miles on it. I’ve only had the car a few months. Not sure of the history of how much it was run past the previous owner. Thanks for the reply, I appreciate it