383 tapping noise

[c1500sbc]

I will also add, I did remove each spark plug wire on the driver side one at a time. The tapping noise never went away, which makes me hesitant to believe it’s a wrist pin issue.

Maybe it’s just a collapsed lifter but I don’t see how it would make a separate noise than the clatter of a loose rocker arm??

[Baprace]

c1500sbc , is there a button to control camshaft end play ? Second item pull the lifters and check the sides to make sure the lifter is not touching the lobe next to it , last , check the fuel pump pushrod for wear on the cam side.

I just listened to the utube and it is broken for sure , possibly the piston skirt is cracked , my guess would be a broken crankshaft or spun mains.

[c1500sbc]

c1500sbc , is there a button to control camshaft end play ? Second item pull the lifters and check the sides to make sure the lifter is not touching the lobe next to it , last , check the fuel pump pushrod for wear on the cam side.

I just listened to the utube and it is broken for sure , possibly the piston skirt is cracked , my guess would be a broken crankshaft or spun mains.

I would assume it does have a cam button. I’ve actually never had the timing cover off this motor. It is a two piece rear main with a roller cam. It’s running an electric pump, so no push rod for it.

You think it’s a BROKEN crankshaft? It’s a pretty fresh motor, forged internals. Anything is possible though!

[Baprace]

c1500sbc When I listened to that video a few times I hear bearing screaching at the 12 - 14 second of the video that tells me at least it has a spun bearing , it has the sound of a main bearing issue ( deep & heavy ) with screach noise , a rod bearing would have a noise like a tappet and would get louder with some light throttle , that engine sounds like it has a bucket of bolts just thrashing around at idle speed. Now you have to watch the oil filter brand as the are not the same microns for flo , many FACTORY filters are too fine to pass anything more than 10w oil in warm weather , always use a race filter and it does not need heavy oil if the engine is built correct. I have had a couple of Blu#P#i## catalog engines in my shop and I would give that brand a D- for machining ability and componets used, but their warranty was always honored

[HQM383]

Rod bolts near where a drivers side dipstick is can make contact with the sump at the radius near the gasket flange.

[allencr267]

Can't tell, sounds like crank not cam speed.

[c1500sbc]

I’ve always run a wix filter and 5w30 in this motor. Oil pressure has always been high. Higher than I like honestly. 75psi cold and 55 at hot idle. Which is why I’ve always run 5w30.

I got the lifters out. All looks normal there. Rockers look fine also. Got the head off. Pistons from the top side look normal. I did find that I can rock the pistons in the cylinders and make a knocking noise. What was weird is they all had about the same movement side to side, but when I was spinning it over checking them, I realized that cylinder five (where the noise sounded most prominent) at one point would not rock at all. It was solid with no movement side to side. Then, spinning it over more, it started to rock again.

No idea if that means anything. I’ll have the other head off and the bottom end apart tonight I hope.

[77cruiser]

Windage tray rod bolts touching?

[rfoll]

Windage tray rod bolts touching?

I have been there before. Everything was fine until I bolted the oil pan on. The pan squeezed the curved tray into the rod bolt area and when started sent steel shrapnel everywhere.

[BOOT]

I did find that I can rock the pistons in the cylinders and make a knocking noise. What was weird is they all had about the same movement side to side, but when I was spinning it over checking them, I realized that cylinder five (where the noise sounded most prominent) at one point would not rock at all. It was solid with no movement side to side. Then, spinning it over more, it started to rock again.

No idea if that means anything. I’ll have the other head off and the bottom end apart tonight I hope.

The turbo guy could rock the piston with a broken ring.

[c1500sbc]

Well, it’s a broken piston skirt on cylinder number 5 and 6. Weird that they are opposite cylinders and fire right after one another? What other than detonation would cause just the piston skirt to break? I haven’t gotten the bottom end fully apart yet. Could a damaged wrist pin cause the skirt to break? All the piston faces look fine. All cylinder walls look good also.

[dannobee]

Tear it down and check piston to wall clearance.

[F-BIRD'88]

Could be just the vibration shock of detonation.
High speed detonation is brutal and you don't hear it.
You can check all the other pistons for stress too.
Pins. rod bearings. etc.

[F-BIRD'88]

Could be diz cross fire under boost, too.
Carbon track diz cap / rotor ...Plug gap too big. ....
Old diz cap or wires.. Boost always finds the weak parts.

[BOOT]

Check the rod bearings tops for detonation. I'm no builder but kinda weird how the broken skirts line up with the cam lobes.