Hello all, I am aware the 3FE is a noisy engine, however, there is a clack/knock sound that has been getting more noticeable lately. I suspect the sound is valve related.
Perhaps someone can help me identify what is causing it to see what I need to work on.
Some information:
-1992 FJ80 3FE 182K
-Just checked valve lash, all in spec
-Compression relatively ok
-Pulled plugs one by one and no change in knocking sound
-Using a stethoscope i found out:
a) Noise is coming from the back of the engine (cylinders 4,5 or 6).
b) The exhaust manifold of the cylinders mentioned above produced the loudest knock through the
stethoscope. I could hear the knock in the block and head too, but definitely not as loud.
c) I removed the valve cover and the area between valves #10 and #11 in the valve rocker shaft
produced the loudest knocking sound (as loud as the exhaust manifold mentioned above).
-Knock is loudest between idle and 1500rpm.
-Visual inspection of valve train revealed no abnormalities (at least to my untrained eye).
-Knock is most noticeable when listening behind driver’s side wheel, under the truck (watch attached video), and it's much less perceptible when standing in front of vehicle with hood open.
VIDEO BELOW:
Thank you!
ml111
Perhaps someone can help me identify what is causing it to see what I need to work on.
Some information:
-1992 FJ80 3FE 182K
-Just checked valve lash, all in spec
-Compression relatively ok
-Pulled plugs one by one and no change in knocking sound
-Using a stethoscope i found out:
a) Noise is coming from the back of the engine (cylinders 4,5 or 6).
b) The exhaust manifold of the cylinders mentioned above produced the loudest knock through the
stethoscope. I could hear the knock in the block and head too, but definitely not as loud.
c) I removed the valve cover and the area between valves #10 and #11 in the valve rocker shaft
produced the loudest knocking sound (as loud as the exhaust manifold mentioned above).
-Knock is loudest between idle and 1500rpm.
-Visual inspection of valve train revealed no abnormalities (at least to my untrained eye).
-Knock is most noticeable when listening behind driver’s side wheel, under the truck (watch attached video), and it's much less perceptible when standing in front of vehicle with hood open.
VIDEO BELOW:
Thank you!
ml111