Knocking noise after new exhaust gaskets

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LAVA

LAVA

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I had felpro exhaust gaskets on my headers and they leaked bad. I put Remflex gaskets on and now it sounds like a random engine knock. It's not constant, only every few seconds and comes and goes. Can a exhaust leak cause this? Or is this a random failure in the engine?
 
Carbon knocking around as it loosens up? Does it burn oil ? I agree with Workingdog1- it was possibly there before - ya just could not hear it.
 
You may have changed the location of the exhaust/header causing a close tolerance somewhere.
 
Ironically enough, I had this happen one time. Customer brings in 68 Charger with a freshly rebuilt 426 Hemi. The left exhaust manifold gasket was wasted. Was extremely loud. Fixed that and then heard a lot of valve lash from the right side of engine. Number 6 intake lifter was wasted too. New engine time. Hopefully this is Not your problem.....
 
408 swinger said:
Ironically enough, I had this happen one time. Customer brings in 68 Charger with a freshly rebuilt 426 Hemi. The left exhaust manifold gasket was wasted. Was extremely loud. Fixed that and then heard a lot of valve lash from the right side of engine. Number 6 intake lifter was wasted too. New engine time. Hopefully this is Not your problem.....
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Jeez now you just made the guy go into panic mode. Lol! Prayers it’s not that and just a lifter tapping or something simple.
 
LAVA said:
I had felpro exhaust gaskets on my headers and they leaked bad. I put Remflex gaskets on and now it sounds like a random engine knock. It's not constant, only every few seconds and comes and goes. Can a exhaust leak cause this? Or is this a random failure in the engine?
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If it’s an automatic trans, chk converter bolts.
Especially if it changes when in gear or neutral/park
 
LAVA said:
I had felpro exhaust gaskets on my headers and they leaked bad. I put Remflex gaskets on and now it sounds like a random engine knock. It's not constant, only every few seconds and comes and goes. Can a exhaust leak cause this? Or is this a random failure in the engine?
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Did you replace the collector gaskets? If you did, you probably turned the collector flanges and moved one of the piped close enough to something that the pipe is hitting it. I would check that first. You should be able to just loosen all three bolts and turn the flanges to reposition the pipe.
 
RustyRatRod said:
Did you replace the collector gaskets? If you did, you probably turned the collector flanges and moved one of the piped close enough to something that the pipe is hitting it. I would check that first. You should be able to just loosen all three bolts and turn the flanges to reposition the pipe.
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That was my first thought. I can't imagine not hearing an engine knock before changing a gasket, and then hearing it afterwards.
 
RustyRatRod said:
Did you replace the collector gaskets? If you did, you probably turned the collector flanges and moved one of the piped close enough to something that the pipe is hitting it. I would check that first. You should be able to just loosen all three bolts and turn the flanges to reposition the pipe.
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I did have to pry the right side out to get the new gasket in. I was thinking somewhere in the exhaust has to be my noise. So I tightened all of the exhaust gaskets at the collector too and started it. The sound was still there but its not there at 2000 rpm. When I let it warm up for a minute or two at 2000 rpm the noise was gone when I went back down to idle. Could it be a bad lifter that had to pump up? or did the exhaust just seal itself at temp? I guess time will tell when I take it out next time
 
RustyRatRod said:
Did you replace the collector gaskets? If you did, you probably turned the collector flanges and moved one of the piped close enough to something that the pipe is hitting it. I would check that first. You should be able to just loosen all three bolts and turn the flanges to reposition the pipe.
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Yea, I did also check to see it the pipe was hitting anything. All if clear there
 
So what engine is this? Just curious, will 340/360 headers seal against a 318 head? Vertically, they are different.
 
IMHO - retorque the exhaust gaskets - when the engine warms up, the exhaust expands and takes up the tolerance. When it's cold, the exhaust flange hitting the head when the correct cylinder fires because it isn't torqued properly)
 
harrisonm said:
That was my first thought. I can't imagine not hearing an engine knock before changing a gasket, and then hearing it afterwards.
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90wt and exhaust cutouts fix rod knocks
 
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