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347 Stroker Making Chirping Noise - Fuel Pump Eccentric

case12

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Joined
Oct 8, 2004
Messages
1,450
Location
Crystal Lake, IL
My 347 has developed a chirping noise. It is not any of the belts or accessories as we went through the process of elimination with these. The mechanic is saying that it is fuel pump eccentric. He determined this by taking out the mechanical fuel pump, and adding an electric pump and the noise went away. He put the mechanical pump back on and it came back (they tried to lube the arm, but it didnt help). I searched the web but found nothing like this.

The noise is a "chirp" and comes and goes, but is very loud and obnoxious. Has anyone heard of this, and what is the repair? Ideas?

Casey
 

franklinair

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Mar 1, 2007
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4,738
The eccentric gets splashed with oil/lubricant. Try a new fuel pump.

Neil
 
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case12

case12

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Oct 8, 2004
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Crystal Lake, IL
Trying another fuel pump seems like a good idea. I will do that. But I also wonder why the mechanic feels the eccentric needs to be replaced - not getting splashed with oil? I think I will call the people that hand built the engine on Monday too....Casey

- (this started after I got about 100 miles on the engine)
 

davidathans

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Jul 25, 2004
Messages
703
Location
San Fernando Valley, California
Im running a mechanical fuel pump made by holley that i believe is 130gph. if you eliminate the mechanical fuel pump and go with only an electric one...it will increase your performance, but if the pump goes bad, you are stuck. i run a combination of the two on my car. i only need the inline electric fuel pump (holley red 7psi 110gph) located right where the gas tank is, when i am drag racing. Good luck casey
 

franklinair

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Mar 1, 2007
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I think what you're actually hearing is the diaphragm IN the fuel pump (chirp-chirp-chirp).

Neil
 

rvrtrash

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Apr 25, 2003
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I'd try a new fuel pump also. It's a lot cheaper and easier than replacing the eccentric, which requires taking everything off the front of the engine.

Steve
 
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case12

case12

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Crystal Lake, IL
I ordered one. The original replacement ones were only $45. I will let everyone know when it arrives and if it fixes the problem. I havent replaced a fuel pump before, but I assume it is just draining some gas from two hoses and then just two bolts to change it out - it seems straight forward. Casey
 

franklinair

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Piece of cake. Two fuel lines (guzinta & guzouta). When inserting the new fuel pump, be sure the arm goes UNDER the eccentric on the timing gear.

Neil
 
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case12

case12

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Oct 8, 2004
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Crystal Lake, IL
OK - I finally got the new pump installed. It turned out not to be a piece of cake 'cause I had to learn the hard way to install your hard line fitting BEFORE putting the pump on - I spent an hour trying to align the fitting before a friend told me what to do.

SO - it unfortunately did not make the noise go away, so we can now also rule out the pump. I guess my mechanic may have it right with the eccentric. Its covered under the engine warranty, so I guess we head that direction now.

It is a real loud (embarising) chirp, so it makes the car not so much fun to drive until we get it fixed. I am up for any other ideas before we start tearing the front of the engine off.

Casey
 

HappyHour

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Jul 24, 2007
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496
Location
Bay Area\ SoCal
Hope you pinpoint the cause Casey. Maybe you can tell them you were dragging a Mopar RoadRunner and your 347 CS "ate that thing for lunch"?
 

robert campbell

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Apr 10, 2007
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Casey,
Have the guy who built the engine also check to see if the "oil slinger" is in front of the lower timing gear. It is a thin stamp steel round slinger that throws oil up on the chain and ecentric. May want to take a close look at the chain and gears while it is apart if they did not install the slinger.

Rob
 

rvrtrash

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Apr 25, 2003
Messages
3,649
Casey,
Have the guy who built the engine also check to see if the "oil slinger" is in front of the lower timing gear. It is a thin stamp steel round slinger that throws oil up on the chain and ecentric. May want to take a close look at the chain and gears while it is apart if they did not install the slinger.

Rob

I posted about the slinger and then deleted after re-reading the symptoms. If the engine was built with a double roller chain and gears, sometimes the slinger won't fit and rubs on the inside of the timing cover. I had to leave mine off.

Steve
 
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case12

case12

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Location
Crystal Lake, IL
Probably take it apart 2nd week of August. I am trying to drive it as much as possilbe to flesh out any other issues. None so far - the engine is very strong and we gave it really good workout a couple days ago - everything from burn-outs to running it up to about 90mph. I sure wish the engine loud chirping sound wasnt there, because everything else is strong (I may have to adjust the timing or fuel mix a bit - it idles a bit rough). It is just a real annoying loud chirp. I put my stethescope on it and it seems to be coming from the timing cover right aroudn the fuel pump/cam area. It starts up after the car runs for about a minute, and then gets louder and softer while driving. I really cant get a good pattern of when/why other than that. I am so happy with the engine, I really hate to stir up any other problems by taking the front off, but it looks like that is what we have to do. Thanks, Casey
 

robert campbell

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I posted about the slinger and then deleted after re-reading the symptoms. If the engine was built with a double roller chain and gears, sometimes the slinger won't fit and rubs on the inside of the timing cover. I had to leave mine off.

Steve


Casey,
Would love to see this ecentric! Never heard of a chirp from it. Usually the fuel pump does the chirping like Neil said. But you have eliminated that!! Stranger things have happened!! let us know how it turns out.

Rob
 

@Holmes

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Joined
Dec 22, 2006
Messages
238
Location
McAllen, Texas
waterpump? The back cover as you know is in the chain cover and its cherp could sound like its comming from the eccentric
 
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