2f Engine knock help (Video attached) (1 Viewer)

[Seth S]

Just fired it up, warmed enough to level the idle, and went through pulling one plug at a time. Noticeable impact to rpm and no noticeable quieting of the engine. Noise sounds really prominent down low and near the fire wall. Double checked the clutch and no change either. Definitely sounds worse now after sitting and oil psi might have been lower. So no more running it from here on out. Will plan to pull the motor and tear down. It’s my reward for repairing all the intake and exhaust manifolds

I pulled the valve cover earlier and verified the top end was all good and quiet. Recently did the valve adjust and all the lifters were in good shape and moving properly.

 

[Spike Strip]

If there's no change to knock when plugs wires are pulled, could be something in the valve train. You might try running the engine with the valve cover off and a stethoscope on each rocker and see if you can pinpoint anything.

 

[Natev22]

I have been driving mine this whole time and it has not gotten worse. It goes away at around 1000-1200 RPM. I think @OSS first suggested that it is probably transmission gears banging due to uneven combustion. when I scoped mine, it was the loudest on the bottom of the engine near the inspection cover. I guess it could possibly be a bearing at the bottom on that last cylinder, but when I tested by pulling individual spark plugs, nothing changed. Mine also only does it after the engine warms up. So maybe as the oil warms and loses some viscosity, It allows the chatter to come back. So I'm not sure why that would be transmission related. I don't know. For me, life is too busy to spent too much time trying to figure it so I just drive it.

 

[Seth S]

I have been driving mine this whole time and it has not gotten worse. It goes away at around 1000-1200 RPM. I think @OSS first suggested that it is probably transmission gears banging due to uneven combustion. when I scoped mine, it was the loudest on the bottom of the engine near the inspection cover. I guess it could possibly be a bearing at the bottom on that last cylinder, but when I tested by pulling individual spark plugs, nothing changed. Mine also only does it after the engine warms up. So maybe as the oil warms and loses some viscosity, It allows the chatter to come back. So I'm not sure why that would be transmission related. I don't know. For me, life is too busy to spent too much time trying to figure it so I just drive it.

in my case this noise is new and getting worse.

 

[OSS]

’ve been chasing a similar knock and will pull the pan soon.

Your knock is different than Seth's mayhem. Yours sounds like misfiring or uneven compression which can make the crank bang. My engine did that at idle when I bought it with only 42K on the odo and it turned out that my #4 exhaust valve was leaking & didn't have compression on that cylinder. After the head/valve job, the idle was much smoother and that banging noise just like yours went away forever.

 

[Natev22]

Your knock is different than Seth's mayhem. Yours sounds like misfiring or uneven compression which can make the crank bang. My engine did that at idle when I bought it with only 42K on the odo and it turned out that my #4 exhaust valve was leaking & didn't have compression on that cylinder. After the head/valve job, the idle was much smoother and that banging noise just like yours went away forever.

Any idea why it only does it when the engine comes up to temp?

 

[Natev22]

Any idea why it only does it when the engine comes up to temp?

 

[OSS]

My banging noise was definitely worse sounding when engine all warmed up. Probably because oil gets thinner so there's more space for things to move around. Not sure.

 

[aviafx]

Any idea why it only does it when the engine comes up to temp?

Mine also does this. BARELY audible on startup/cold but loud and noticeable when warm. Almost in the same spot, 5th or 6th cylinder/back of oil pan/inspection cover area. I did swing the truck by Georg's last April and his guys stethoscoped it in that area, they were thinking a wrist pin but couldn't confirm without a teardown.

Your knock is different than Seth's mayhem. Yours sounds like misfiring or uneven compression which can make the crank bang. My engine did that at idle when I bought it with only 42K on the odo and it turned out that my #4 exhaust valve was leaking & didn't have compression on that cylinder. After the head/valve job, the idle was much smoother and that banging noise just like yours went away forever.

Time to make some adjustments and check compression. Kudos for the responses.

 

[Natev22]

I would think a bad wrist pin would definitely sound different if you pull the spark plug off that cylinder

 

[Ackcruisers]

@Natev22 has the knock abated or is it still there?

 

[Natev22]

I have no idea.

I bought a new house on the water, sold my land cruisers and bought a boat.

I now drive a Hyundai hybrid and am not looking back. Lol

 

[Seth S]

I have no idea.

I bought a new house on the water, sold my land cruisers and bought a boat.

I now drive a Hyundai hybrid and am not looking back. Lol

This is the way