Ruh roh Raggy! I hear you knocking…

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JBswth

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Disco said:
@JBswth, it was the inspection cover, apparently. They pulled the cover to check inside the bell housing area, found nothing of concern, put the cover back, started the engine to use a stethoscope to track the sound, and the sound was gone.
The only thing we can think is the cover was put on in just the wrong way that something inside the bell housing, something spinning at crank speed, was tapping it. I have had the engine running several times now, and the noise has not returned.
Click to expand...
That's good, maybe something was in there and fell out unnoticed.
 
Matt Lutz

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So funny this thread is goin on. I have a 81 GMC with a 250 6cylinder. The motor is not the original. I was having an issue with the carb flooding and thru some advice from a mechanic I added a fuel regulator. After a few runs the engine started knocking really bad but it goes away at high speeds. And I am not trying to take over the thread just similar issue.
 
Disco

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Matt Lutz said:
So funny this thread is goin on. I have a 81 GMC with a 250 6cylinder. The motor is not the original. I was having an issue with the carb flooding and thru some advice from a mechanic I added a fuel regulator. After a few runs the engine started knocking really bad but it goes away at high speeds. And I am not trying to take over the thread just similar issue.
Click to expand...
He had you add a fuel regulator on a carb? I would suspect a needle and seat or a float if a carb is flooding, unless you added an electronic fuel pump with a higher output that the mechanical pumps. If you are using a mechanical pump, the needle and seat should be enough to stop fuel flow, as long as everything is working properly.
 
75BEASTK20

75BEASTK20

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USUALLY............if its a ticking sound - it's valve train. Like a bad lifter, broken push rod, that happened to me once. But a loud knocking noise sounds like a rod.
Hard to tell without really hearing it, but sorry you got problems
 
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I've seen lots of cracked flexplates diagnosed incorrectly as rod knock. Is this thing an automatic?
 
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Ricko1966

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Disco said:
Nope. Muncie 4-speed. And it was the inspection cover.
Click to expand...
Sorry,I got sucked back in to a dead thread by post 36. And I think he was referring to post 34 who hijacked your thread LOL.
 
Grit dog

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Disco said:
Gotcha
Click to expand...
Know it’s an old thread, but fwiw, I doubt it was the “inspection cover”.
More like took the cover off, saw what they messed up, fixed it, knew their audience and saved themselves the guilt or embarrassment or potential bad reputation of admitting what they messed up.
Either way, great news! (From 6 months ago).
You got it on the road now?
 
Disco

Disco

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Grit dog said:
Know it’s an old thread, but fwiw, I doubt it was the “inspection cover”.
More like took the cover off, saw what they messed up, fixed it, knew their audience and saved themselves the guilt or embarrassment or potential bad reputation of admitting what they messed up.
Either way, great news! (From 6 months ago).
You got it on the road now?
Click to expand...
I put on a new Holley Q-jet and had her running pretty well. Just needed some fine tuning.

Then the ignition switch disintegrated. All of the plastic in this truck is JUNK. Now that I have some money and it’s not hotter than the fires of damnation, I’ll probably get out there and swap out the turn signal and ignition switches.
 
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