Loud knocking noise from the 454

[Frylock]

Was installing the second gas tank and wanted to test it so I started it up and was blessed with a loud a$$ knocking sound that kills the engine after a few seconds. Sounds like the fan is hitting something so Im thinking its top end. Pulled the cover off the driver side head and pulled all the rods checking for anything bent or broken. Found nothing, did find that they are roller rockers from Comp Cams part #1411 that are adjustible.

Trying to retorque them now, but I have to turn the engine by hand to get me a zero lash so I can set the pre-load of the rocker arm....

Whats the best way of turning the crank by hand? sorry for the nub question but I havent played with engines much untell now.

Also, anyone have any other ideas to what could be causing this knocking? This sound has presented itself before this but very seldom and it goes away each time after just a moment. Engine had plenty of oil in it, with plenty of oil in the heads when I pulled the cover. Engine was working great the night before and earlier that day. Any other ideas I can try before having to pull the entire head off would be a blessing.

[TheBigDogg]

Was it a knock or a tapping sound? If the sound is what caused the engine to stop running you might have a more serious problem,

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[Frylock]

[quote="TheBigDogg"]Was it a knock or a tapping sound? If the sound is what caused the engine to stop running you might have a more serious problem,

Sent from my SAMSUNG-SM-N900A using Tapatalk[/quote]




I wanna know how I can kill a engine just from starting it. Did no reving or anything that would of been hard on the engine and all of a sudden it takes a shit.

A few of the plugs did have some oil in them, the engine does burn a little oil, but no more then my JK does

Been considering dropping the 383 I bought for the Jeepster in the truck, this problem may of made my decision easy. Atleast then I can rebuild the 454 for a high compression engine if its not totally shot.

Will try and get a sound clip made up

[TheBigDogg]

Was the 454 stock? That 383 will be plenty for it

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[Repsolaaron]

You can turn the engine with the crank shaft pulley and breaker bar.

[garbageman]

pull the oil plug and see if there is any metal in the pan, screen the oil thru a t shirt and see what kind of metal if any.

[Frylock]

[quote="garbageman"]pull the oil plug and see if there is any metal in the pan, screen the oil thru a t shirt and see what kind of metal if any.[/quote]


Thanks! will get that done today after work.

[Uncle Cracker]

if you get it running, use a long, wood handled screw driver like
you would a stethoscope. put it on the heads and the block, and the pan, both sides,
to determine where the noise is coming from.
there are just too many places a 454 can knock ,including near the torque converter,
if you broke a flex plate

[Desert Dog]

I had almost the exact thing happen in an old 350 and it turned out to be the harmonic balancer was separating, and this took out the main bearing. It was a loud clunking noise that was really bad at start-up and would stall the engine. I would inspect the easy stuff first.

Hopefully you don't need a crank kit, or something more complicated (and expensive).

[Frylock]

drained the oil just now, everything went through a tshirt type of wrag, clean as a wissle



DD Im thinking you are onto something, the engine was moving around quite a bit while it was making that clunking noise. Were you able to see the balancer was messed up with the belts still on? or did you have to pull it all apart to tell? Mine looks fine just from a quick inspection...but it does look as old as the block...

[Frylock]

Pulled the passenger head cover, everything was clean and nothing looked or felt broken. Did try and start the engine without the coil fuse in, no knocking while it tried to start. To me it should make the noise regardless if the engine was firing or not if metal was hitting metal.



Took a prybar to the harmonic dampener, feels solid to me with no movement in any direction. Not to say this isnt the problem, but I would find it hard to believe it was slipping.

[Desert Dog]

[quote="Frylock"] the engine was moving around quite a bit while it was making that clunking noise.[/quote]
Hmmmm.

Motor mounts?

Flywheel?

A bad Crankshaft would do it too?

PS: A friend of mine helped me take the harmonic balancer off to check it and found the rubber to be bad. It was literally shaking the engine apart. There are several videos online explaining how to diagnose a bad HB;
https://www.youtube.com/watch?v=CDr7Kwgo-Jw

Here is a way to check if it spun on the rubber without removing it from the engine;

The only way to tell if one has slipped is to check for TDC or top dead center and its relationship to the timing mark on the balancer.
a. Pull of the cap and the number one plug
b. With a socket on the harmonic balancer bolt, place your finger over the sparkplug hole and turn the engine over.
c. As you turn the engine over feel for the compression stroke (watch the rotor to confirm you’re on the compression stroke)
d. Once you have confirmed you’re on the compression stroke place a large screw drive into the spark plug hole.
e. Continue to turn the engine over with one hand while holding the screwdriver with the other. As the piston moves up it will force the screwdriver down. When the screwdriver is no longer moving you’re at TDC.
f. Look at the harmonic balance and timing tab on the front engine cover. The timing tab should have a 0 mark on it and this should line up with the mark on your balancer. If you’re only off a couple of degrees you’re okay (The piston has a dwell angle, the point between where it stops going up and starts going down.). If it is off by more then 10* then you have a slipped balancer

[Frylock]

update

picked up a digital timing light and swapped out the spark plug cables with the ones from the 383 with HEI. Reading 14 at 550rpm with the distributors vacuum advance hose plugged. Some specs are telling me this is normal, others are saying it should be around 4 stock (however I donno if this engine is stock). Either way I dont think the harmonic balancer has moved if its THAT close.

The timing light was used on all cables and they all checked out good.

Still havent done the test with the screwdriver in #1 piston, just because I will have to drop the radiator to turn the crank by hand and that means I cant run it anymore.

Anyone have any other ideas that I should try while the engine can still run? I tried poking a wood handle screwdriver around but the engine stalls on me, making it hard to really get anywhere.

who wants to help pull a 454 out of a lifted truck this weekend?

[Frylock]

finally made a short video to share

http://youtu.be/L9hYhIJ7J_8


lets play, guess whats making this sound.

[Frylock]

found a youtube video of a 454 with rod knock that sounds nearly identical to my knock, so I did a little test by removing the spark plug cables from the distributor one by one with the truck running (dont do this if you have a heart condition ). Distributor was putting out plenty of juce . The knock never even missed a beat, so I am at a complete loss now. Guess I will have to pull the engine to see whats wrong.

[Frylock]

If you guessed a cracked head you are correct!

Last night I found crude oil looking crap coming out of a rust hole in my muffler

atleast I wont have to pull the engine

toying with the idea of getting some new lifters, cam and maybe some performance iron heads. Would like to get my compression up around 8.5-9/1 at the very least for a supercharger down the road