Knoking in lower engine

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barracudadave67

barracudadave67

FABO Gold Member
FABO Gold Member
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Burlington, Wi.
Hi everybody
I have a knok in my lower engine ( 69 B-Cuda, 1973 340 mild street build about 12-15 yrs ago). it started 2 (two) yrs ago. It sounded like the headers hitting the frame rails, so I never worried that much about it till now, but it is not hitting the frame rails. My son, and I checked it out yesterday, with a stethascope, and the only place we can hear, or get, the sound in the tscope is on the bottom of the oil pan. The headers are not hitting any where. The only time it knoks is at idle (850RPM). A little gas and 1000 RPM no knok. It runs great, and is quick, no driving noise at all. It has hydraulic lifters, not solids. It also has a windage tray. When idileing it does not jump all over, after it warms up it idels smooth.

So I am trying to figure out what it could be. I am leaning toward the windage tray or the oil pick up tube (its stock). One of the two might be making contact with the other. It "Ps" me off to have to pull the pan cause its super clean, no leaks.
I havn't taken a pan off a car for a while, Will I have any trouble taking it off,??. The FSM says to drop the center link. Also, whyle were at it, what are the best gaskets to remount it with.
Thanks for all the help, and suggestions.
Just an ole man asking.
barracudadave67
 
Sometimes the fuel pump can make weird noise. Have you run it long enough and hard enough that you don't think it's a rod, etc?

Anything show up in the oil?
 
Converter bolts?
What is your oil pressure?
 
Oil press good 70 psi at running, and high at idel. Converter bolts all tight, could see nothing wrong in there.

I drove it for 2 summers like it is, with nothing happening. Just makes noise at idel. Like I say it sounds like headers hitting the frame rail, but its not.

I'll check out fuel pump tomorow.
 
Piston slap? Broken piston skirt? Noise travels... 4.0 Jeeps had some piston skirts break... lots of people thought a rod was knocking.
 
Flaexplate to crank bolts, they get a little movement and sounds like a knock i had the problem only at idle.
 
Trying to make up my mind wether the knok is in the bottom of the engine, or the tranny bell housing. Either way I hate to take it all apart, it has no leaks, and runs great except at idel.
barracudadave67
 
An Update on the knock. I went and pulled the starter, and the dust plate off the bottom of the tranny, and checked out the 4 bolts that attach the torque converter to the flex plate,and low, and behold they were wrench loose. I retorqued them all (270inlbs, or 22.5 ft lbs), now no more knock at idel, or higher RPMs I was going to pull the bolts one at a time, and lock-tight them but there was to much tension on them.
Thanks for the ideas from every one here. Great place.
barracudadave67
 
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