Annoying ticking sound while driving.

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salami340

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Hey all, I wasn't sure if I should put this in the Engine forum because I'm not quite sure if it is the engine making this sound (Or trans). It is a 1971 Demon with a 340 and 4 speed (Non Numbers engine and trans). I don't know a whole lot about the engine and trans build other than they were rebuilt about 10 years ago to stock specs.

I have this ticking sound that has been bothering me that I've been trying to track down. While accelerating at around 2k to 3k RPM I can hear this rapid ticking. It stops when I let off the gas and starts again as soon as I hit it. It also stops if I give it half throttle and bring it up above 3k RPM. I don't hear it sitting still regardless of the RPM. I even went as far as bring it up to 3000 rpm on a lift in gear and didn't hear it.

Initially I thought it was something behind the dash or floor rattling but I think I've pretty much eliminated everything it could be including disconnecting the speedometer cable. So now I am leaning towards engine or trans. Below is a link to a sound clip that I recorded while driving (It should play in your browser). At about 30 seconds and 50 seconds you can hear it pretty good. I'm hoping someone will have an idea what this could be because it is really bothering me.

 
Do you have a shroud?

Is it possible that your engine mounts are bad and the engine is shifting under certain conditions and the fan is grazing the shroud?

If it is an automatic the flex plate could be cracked?
 
AJ/FormS said:
I've heard that a time or two; but I can't remember it. Lemmee think on it.
Can you feel it on the shifter?
Click to expand...
Cool thanks, let me know if you think of anything. I don't recall feeling anything in the shifter but I'll go for a drive tomorrow and see.
 
Check your driveshaft for possible interference. Maybe a weight is hitting the exhaust under acceleration ? Which tou might not hear in lower gears due to engine roar?
Stab in the dark
 
Dana67Dart said:
Do you have a shroud?

Is it possible that your engine mounts are bad and the engine is shifting under certain conditions and the fan is grazing the shroud?

If it is an automatic the flex plate could be cracked?
Click to expand...
Funny, my dad was actually telling me it could be the fan. That could make sense. I'll have to get under there and see what I can find. The engine mounts looked brand new but I will take another look. It's a manual so don't need to worry about the flex plate.
 
A bit tricky to do with a manual but if you can safely load up the engine with the hood up you might be able to see the engine rock.

Also look at the blade tips and the inside of the shroud for signs of contact.

Another thought is if the thrust bearing is going maybe the crank is moving and hitting something.

But as my dad always said...

KISS (keep it simple stupid)

look for the low hanging fruit first
 
mbaird said:
Check your driveshaft for possible interference. Maybe a weight is hitting the exhaust under acceleration ? Which tou might not hear in lower gears due to engine roar?
Stab in the dark
Click to expand...
Hmm, that could be possible I'll check it out when I'm under there tomorrow
 
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