Help with engine noise???

-
SleeperScamp

SleeperScamp

Well-Known Member
Joined
May 8, 2006
Messages
2,081
Reaction score
58
Location
Texas
Last October while driving my Duster I noticed a noise coming from the engine (340). Not a deep knock but more of a higher pitched "rattle" coming from deep in the engine.. I immediately pulled over and killed it and summoned a trailer to get it home and it's been sitting ignored in my shop ever since. I finally got the nerve to take a look at it this week. I pulled the valve covers and all the push rods seemed to be fine so I then drained the oil through a screen and looked closely at the filter and didn't notice any metal. I then pulled the oil pan and I don't see anything wrong just by looking with my eyes. Where do I go from here??? Engine was rebuilt about eight years ago but has only a few thousand miles on rebuild..
 
Well,since the pan is off,Theres two things that come to mind.
Timing chain,Wristpin(s),or front rod bearing(s). Oh wait, thats three.
Start with the chain and wrist pin exam. If its not there, pull the rod cap off #1, and/or #2.
With the pan off its easy to check all of these. The chain is as simple as; A) stick something up in the chain house and move the chain back and forth, or B) rock the crank back and forth, and watching the chain action at the lower sprocket. Wrist pins can be checked the same way; rocking the crank, and also listening.I mention the front rod bearings, because in my experiences, those are the first to go.
 
SleeperScamp said:
Last October while driving my Duster I noticed a noise coming from the engine (340). Not a deep knock but more of a higher pitched "rattle" coming from deep in the engine.. I immediately pulled over and killed it and summoned a trailer to get it home and it's been sitting ignored in my shop ever since. I finally got the nerve to take a look at it this week. I pulled the valve covers and all the push rods seemed to be fine so I then drained the oil through a screen and looked closely at the filter and didn't notice any metal. I then pulled the oil pan and I don't see anything wrong just by looking with my eyes. Where do I go from here??? Engine was rebuilt about eight years ago but has only a few thousand miles on rebuild..
Click to expand...

1:automatic/stick(any converter change, bolts backing out? Possible cracked flexplate ,bolts backing out?)
2 : timing chain swap?( sometimes things loosen up, a fuel pump eccentric/ timing chainoulubrication tang)
3: something loose , on the exhaust( loose clamp somewhere, my choice).
Sounds like , light metal on light metal ringing. I would roll undercar, look for loose fasteners..
 
SleeperScamp said:
Last October while driving my Duster I noticed a noise coming from the engine (340). Not a deep knock but more of a higher pitched "rattle" coming from deep in the engine.. I immediately pulled over and killed it and summoned a trailer to get it home and it's been sitting ignored in my shop ever since. I finally got the nerve to take a look at it this week. I pulled the valve covers and all the push rods seemed to be fine so I then drained the oil through a screen and looked closely at the filter and didn't notice any metal. I then pulled the oil pan and I don't see anything wrong just by looking with my eyes. Where do I go from here??? Engine was rebuilt about eight years ago but has only a few thousand miles on rebuild..
Click to expand...

How was it running when the noise started? Missing or running rough?
 
Keep in mind it was four months ago but I do remember the car running fine and it seems the noise was throughout the rpm range if I remember correctly..
 
Throw out bearing? Thing is, it doesn't sound like you ran it to try to diagnose exactly where it was coming from, you just snatched it apart. I know you don't want it hurt, but you gotta pinpoint it.
 
It was not something that was just real obvious. You could hear it pretty good at higher rpm but not at idle. In other words higher rpm made the same noise louder if that makes sense..
 
RustyRatRod said:
Throw out bearing? Thing is, it doesn't sound like you ran it to try to diagnose exactly where it was coming from, you just snatched it apart. I know you don't want it hurt, but you gotta pinpoint it.
Click to expand...

You are right. I was scared!!!!!!
 
SleeperScamp said:
You are right. I was scared!!!!!!
Click to expand...

I can't really blame you but now it may be difficult to find. I would maybe stick the pan back on put oil in it and bust it off and try to find it. It won't hurt it anymore than it already is idling or free revving enough to track it down. Maybe pull one wire at a time until you find one that makes the noise slack off. There's your faulty cylinder....IF that's what it is.
 
RustyRatRod said:
I can't really blame you but now it may be difficult to find. I would maybe stick the pan back on put oil in it and bust it off and try to find it. It won't hurt it anymore than it already is idling or free revving enough to track it down. Maybe pull one wire at a time until you find one that makes the noise slack off. There's your faulty cylinder....IF that's what it is.
Click to expand...

Sounds like a plan. I don't know of anything else to do at this point. Maybe I was overly paranoid and was hearing things...
 
Did you lift the hood while the engine was running to tell if the noise was inside the engine?

Or could it possibly be an exhaust gasket leak at the head?
 
Yeah I had a rattle in the engine, 408 stroker. I could not figure it out, good oil pressure, pulled sump, all bearings good, until I noticed the balancer wobbling abit too much. Yes the dreaded broken cast eagle crank!Rebuilt it with forged steel crank and forged pistons. Lucky I caught it before any other damage.
 
I guess while laying on my back looking at the rotating assembly while someone turns engine over by hand I could tell if crank was broke???
 
SleeperScamp said:
I guess while laying on my back looking at the rotating assembly while someone turns engine over by hand I could tell if crank was broke???
Click to expand...

I would certainly like to think so. lol

So there were no metal shavings in the pan? At All? To me, that rules OUT anything coming apart in the engine right there. If the engine had a knock, rest assured, there'd be some evidence.
 
You know what; I started thinking about the post which talks about a higher pitched sound. Then I remembered it was a 340. 340s have oem windage trays. I suppose they could ring a higher pitch, deep in the motor. So two other things come to mind; The dipstick rattling on it, or a reciprocating/rotating part slapping it. Hope its the dipstick. Just a thought.
 
SleeperScamp said:
Last October while driving my Duster I noticed a noise coming from the engine (340). Not a deep knock but more of a higher pitched "rattle" coming from deep in the engine.. I immediately pulled over and killed it and summoned a trailer to get it home and it's been sitting ignored in my shop ever since. I finally got the nerve to take a look at it this week. I pulled the valve covers and all the push rods seemed to be fine so I then drained the oil through a screen and looked closely at the filter and didn't notice any metal. I then pulled the oil pan and I don't see anything wrong just by looking with my eyes. Where do I go from here??? Engine was rebuilt about eight years ago but has only a few thousand miles on rebuild..
Click to expand...

i put together a 340 and the windage tray had a light bend in it,,didnt notice it was hitting the crank until i turned the motor by hand and saw it.check it out,nothings perfect man
 
AJ/FormS said:
You know what; I started thinking about the post which talks about a higher pitched sound. Then I remembered it was a 340. 340s have oem windage trays. I suppose they could ring a higher pitch, deep in the motor. So two other things come to mind; The dipstick rattling on it, or a reciprocating/rotating part slapping it. Hope its the dipstick. Just a thought.
Click to expand...

good suggestion man!!
 
You must log in or register to reply here.
-

Back
Top