What's this noise??
04-20-2024, 11:01 AM
#4
Hate to say it, but sure sounds like a rod knock. but I'm not there and just listening to your vid, could be deceiving.
Does it follow engine rpm..?
Don't drive it would be my advice....
Does it follow engine rpm..?
Don't drive it would be my advice....
Last edited by allcool; 04-20-2024 at 11:07 AM.
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zbomb (04-20-2024)
04-21-2024, 04:02 AM
#6
Racer
Put your stethascope on the cats. They can make an alarming amount of noise when they start to come apart. I heard this while running my new 4l rebuild and thought I was old knock. Turns out it was the cat. Heart attack for not.
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allcool (04-21-2024)
04-21-2024, 04:53 AM
#7
Frequency of knocking noise is too high imho for it to be rod knock.
Considering each cilinder fires once every 2 crankshaft rotations, idling at 850rpm would yield knocking noises of 425 knocks per minute if 1 rod bearing had failed.
This noise sounds more like 1300 knocks per minute, which would require 3 rods knocking and all on one bank, to make it sound as rhythmic as it does in the video.
Not impossible but unlikely, I think.
Considering each cilinder fires once every 2 crankshaft rotations, idling at 850rpm would yield knocking noises of 425 knocks per minute if 1 rod bearing had failed.
This noise sounds more like 1300 knocks per minute, which would require 3 rods knocking and all on one bank, to make it sound as rhythmic as it does in the video.
Not impossible but unlikely, I think.
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04-21-2024, 11:40 AM
#8
04-21-2024, 11:46 AM
#9
Rennlist Member
Frequency of knocking noise is too high imho for it to be rod knock.
Considering each cilinder fires once every 2 crankshaft rotations, idling at 850rpm would yield knocking noises of 425 knocks per minute if 1 rod bearing had failed.
This noise sounds more like 1300 knocks per minute, which would require 3 rods knocking and all on one bank, to make it sound as rhythmic as it does in the video.
Not impossible but unlikely, I think.
Considering each cilinder fires once every 2 crankshaft rotations, idling at 850rpm would yield knocking noises of 425 knocks per minute if 1 rod bearing had failed.
This noise sounds more like 1300 knocks per minute, which would require 3 rods knocking and all on one bank, to make it sound as rhythmic as it does in the video.
Not impossible but unlikely, I think.
04-21-2024, 01:01 PM
#11
Frequency of knocking noise is too high imho for it to be rod knock.
Considering each cilinder fires once every 2 crankshaft rotations, idling at 850rpm would yield knocking noises of 425 knocks per minute if 1 rod bearing had failed.
This noise sounds more like 1300 knocks per minute, which would require 3 rods knocking and all on one bank, to make it sound as rhythmic as it does in the video.
Not impossible but unlikely, I think.
Considering each cilinder fires once every 2 crankshaft rotations, idling at 850rpm would yield knocking noises of 425 knocks per minute if 1 rod bearing had failed.
This noise sounds more like 1300 knocks per minute, which would require 3 rods knocking and all on one bank, to make it sound as rhythmic as it does in the video.
Not impossible but unlikely, I think.
But sure sounds like rod knock I've heard too many times before.
We don't even know what rpm is in the vid, cold start could be over 1000rpm. Or if engine otherwise is running fine with great hot idle oil pressure. Or if noise goes away at higher rpm. Sure sounds like its coming from bottom of engine.
Not even sure what his only reply to my post meant, when he said:
"Originally Posted by NewbieFromNY
When you shut the car off it's faster."
unless he was trying to be a ball breaker...
Not sure if its the big end or pin end rattling around, or even the piston slapping around as the poster did not reply to my question does the noise exactly follow rpms.
Yes,,, could be a belt driven accessory, doesn't sound like it but possible,, and an easy check by removing the belt. But would not rule out internal engine reciprocating parts quite yet at 121,000 miles and been making a "strange tick" for a long time,, especially after listening to his video... hope I'm wrong, been there before.
If its a rattling exhaust, when car is off, banging on mufflers or cats with bottom of closed fist/palm should let you hear at least a similar rattle....
jmo
Last edited by allcool; 04-21-2024 at 01:10 PM.
04-21-2024, 01:13 PM
#12
Frequency of knocking noise is too high imho for it to be rod knock.
Considering each cilinder fires once every 2 crankshaft rotations, idling at 850rpm would yield knocking noises of 425 knocks per minute if 1 rod bearing had failed.
This noise sounds more like 1300 knocks per minute, which would require 3 rods knocking and all on one bank, to make it sound as rhythmic as it does in the video.
Not impossible but unlikely, I think.
Considering each cilinder fires once every 2 crankshaft rotations, idling at 850rpm would yield knocking noises of 425 knocks per minute if 1 rod bearing had failed.
This noise sounds more like 1300 knocks per minute, which would require 3 rods knocking and all on one bank, to make it sound as rhythmic as it does in the video.
Not impossible but unlikely, I think.
04-21-2024, 05:30 PM
#13
I once had a collapsed lifter that sounded similar to what you have .
