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Discussion Topic:
Engine "Knock" Video. Your Opinions Please
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39Fordfan |
08-12-2024 @ 1:12 PM
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Member
Posts: 205
Joined: Oct 2009
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Thank-you very much for your reply TOMO!
I pulled each spark plug wire at a time with it running and was unable to affect the knock one way or the other. The knock didn't go away nor did it get louder.
I will be looking into your method with the Seafoam to see about dissolving the carbon and will keep you posted.
Thanks again!
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TomO |
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08-05-2024 @ 3:34 PM
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Senior
Posts: 7384
Joined: Oct 2009
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Start by using a stethoscope or a long screwdriver held to the engine and your ear to determine if the noise is coming from the left or right bank and from 6te front or rear of the engine.
Next short out one plug at a time in the area of the noise to see if it goes away and only affects one cylinder.
MMO making the noise disappear for a few seconds, may indicate a carbon knock. it would be only one cylinder making the knock if it is a carbon knock. Sea Foam spray would help dissolve the carbon causing the noise. Spray the Sea Foam into the carburetor for about 15 seconds and then spray enough to stall the engine. Leave the car sit overnight and then start it and drive it with varying speeds on a highway. This should clear any carbon causing a problem.
Tom
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39Fordfan |
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07-27-2024 @ 12:09 AM
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Hi MG. You are correct, the knock is louder on the second video. But I think it's because I was holding my phone with my left hand while I poured the MMO with my right hand in the 2nd video; I held the phone with my left hand which left the microphone in a better position to record the sound than the way I recorded it with my right hand in the the 1st video.
The knock though louder in the 2nd video definitely disappeared with the Marvel Mystery Oil at about the 22 second mark and comes back at about the 27th second mark. Thanks! I appreciate hearing your opinion and we'll see. I suppose it's possible that there's more than one place in the engine that needs attention, though I hope not...
This message was edited by 39Fordfan on 7-27-24 @ 12:17 AM
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39Fordfan |
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07-26-2024 @ 11:59 PM
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Hi 40cpe. You are right, the MMO does slow the engine speed down. I sped the idle up a bit to start with because I was worried the MMO might stall out the engine. The knock normally occurs at slow idle speed but this time it disappeared with the Marvel Mystery Oil at about the 22 second mark and comes back at about the 27th second mark. Thanks!
This message was edited by 39Fordfan on 7-27-24 @ 12:10 AM
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MG |
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07-26-2024 @ 9:10 PM
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Senior
Posts: 1300
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39Fordfan - I did watch the video where you poured MMO down the carb, and to me, the "knock" sounded even more pronounced than in your first video and not at all "disappearing"...
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40cpe |
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07-26-2024 @ 7:15 PM
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It sounds like the MMO slows the engine speed when the noise goes away. I'm not there to hear it, but I would slow the engine idle speed at the carburetor to see if it affects the noise.
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39Fordfan |
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07-26-2024 @ 5:01 PM
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Hi MG. Thanks for your reply.
I was wondering if you happened to see the last post of the thread with the 2nd link to the video of me doing a test by pouring Marvel Mystery Oil down the carb with the engine running and the knock disappearing? If it was a rod knock or bearings would it still behave like this during this test? I'm not contradicting you, I'm just trying to get to the bottom of this in order to figure out what to do next.
Thanks!
Video Link
https://www.youtube.com/shorts/caXWZR2PJVM
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MG |
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07-26-2024 @ 4:09 PM
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Senior
Posts: 1300
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That sure does sound like rod knock to me...
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39Fordfan |
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07-26-2024 @ 10:40 AM
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Posts: 205
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Hi 37RAGTOPMAN.
Thank-you so much for your reply! I was definitely going to ask for some tests I could do to try and isolate where this knock is coming from.
After doing some tests you recommended here are my best attempts at answering your questions...
* The engine runs smooth, no shakes.
* Pulling plug wires with it running made no difference to the knock.
* Taking the belt off made no difference to the knock.
* The knock doesn't get louder when you rev the motor, it just knocks faster.
* I didn't test the fuel pump as I wasn't sure exactly what to do? Do you pull the whole fuel pump body off of the manifold? Or are you saying to pull the fuel pump body apart at it's center?
* I Dripped Marvel Mystery Oil down the carb with the engine running. It definitely quieted the knock to what I would say no knock for a about 5 seconds! Then after the MMO dripped through the knock came back.
For anyone still interested, I made a video of me pouring the Marvel Mystery Oil down the carb with the engine running so you can listen and see if you agree it made a noticeable difference quieting the knock? If so, how would you recommend I go about my next steps with correcting the striking valve or valves? Thanks!
Video Link
https://www.youtube.com/shorts/caXWZR2PJVM
This message was edited by 39Fordfan on 7-26-24 @ 2:31 PM
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37RAGTOPMAN |
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07-23-2024 @ 3:58 PM
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Senior
Posts: 1992
Joined: Oct 2009
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does the engine run smooth or shakes.
did you try dripping marvel oil down the carb with engine running, you might have stricking valves.
what you need to do is some testing,
with a insulated plyers remove one spark wire ar a time,
if the noise goes away or is less, that cylinder is the problem. wrist pin, piston. or connection rod,,
I would also take the generator belt off, see if that make a diference,
does the noise get worse when you rev the motor up ?
also tempory lift the fuel pump and check the push rod,. for a few seconds,
do some testing and get back to up
hope this helps 37Ragopman, ,Maine
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