Thread: Can anyone identify this tapping noise?

Do you have the Gap IID tool, or other means of checking the injector balancing offset?

When you are comfortable running the engine again, may need to record the noise from different positions around the engine (and below) to find where it is loudest, plus consider trying a slo-mo video at 240fps of the auxiliary belt. At worst the slo-mo video will just confirm the frequency of the noise - and the belt tensioner gives the overall reference tempo (it bounces on each cylinder firing).

Out of interest - what oil do you use? 5W-40 tends to quieten noisy tappets. Although yours sounds like it needs more than just a thicker oil.[/QUOTE]

Thanks DiscoDB,

I have a launch scanner that i can check the injector balancing offset with and I'll see if I can get a slow-mo recording.
I cant really pin point where the noise is coming from with a stethoscope. I use Castrol Edge 5w-30

IMG_1944_SparkVideo.mp4IMG_1943_SparkVideo.mp4IMG_1941_2.mp4IMG_1942_1.mp4

Interesting videos.

The injector balance is all within normal range even though 3 are high and 3 are low (this is 3 injectors offsetting the other 3).

The slo-mo video clearly shows the loud clunk is in time with one of the cylinders firing. In slo-mo my TDV6 has the same beat to it, but the leading beat is not a metallic clunk like what you are picking up.

I wonder if you have a sticky valve that is slamming shut, or a roller valve rocker with some play, or hydraulic tappet that has collapsed and not fully opening. Maybe time to remove the inlet manifolds and look for something loose, and then rotate by hand and make sure all the tappets/valves are moving freely.

Pity we don’t have the option to remove rocker cover and run the engine to diagnose.

Originally Posted by DiscoDB

Interesting videos.

The injector balance is all within normal range even though 3 are high and 3 are low (this is 3 injectors offsetting the other 3).

The slo-mo video clearly shows the loud clunk is in time with one of the cylinders firing. In slo-mo my TDV6 has the same beat to it, but the leading beat is not a metallic clunk like what you are picking up.

I wonder if you have a sticky valve that is slamming shut, or a roller valve rocker with some play, or hydraulic tappet that has collapsed and not fully opening. Maybe time to remove the inlet manifolds and look for something loose, and then rotate by hand and make sure all the tappets/valves are moving freely.

Pity we don’t have the option to remove rocker cover and run the engine to diagnose.

Thanks DiscoDB,

I actually pulled the RH rocker cover off last night, spun by hand and couldn't see anything out of the norm. I'll have a go
at the LH in the coming days. Not the best job hey! Knuckles look like I've been though fight club

Cheers mate.

Originally Posted by ted2910

Thanks DiscoDB,

I actually pulled the RH rocker cover off last night, spun by hand and couldn't see anything out of the norm. I'll have a go
at the LH in the coming days. Not the best job hey! Knuckles look like I've been though fight club

Cheers mate.

Hey! Don't talk about Fight Club....

Originally Posted by ted2910

Thanks DiscoDB,

I actually pulled the RH rocker cover off last night, spun by hand and couldn't see anything out of the norm. I'll have a go
at the LH in the coming days. Not the best job hey! Knuckles look like I've been though fight club

Cheers mate.

Haven’t had the pleasure yet. Let’s hope you find something. Not something you want to leave to chance when you know it has definitely changed in noise levels.

May pay to also check what oil pressure you are getting.

In the latest LR Time video assembling the 2.7 TDV6 he demonstrated which hydraulic lifters had failed or were failing. Was about 40% in a 186k km engine.

Bit late to the thread and wouldn't like to diagnose 100% without having the car , but it sounds like piston speed ( bottom end ) .
Which means I doubt you would find anything by pulling the other intake, and unless you enjoy doing it ( which would be strange :-) then yep, is worth putting on trailer and taking to good Indy.

Originally Posted by discorevy

Bit late to the thread and wouldn't like to diagnose 100% without having the car , but it sounds like piston speed ( bottom end ) .
Which means I doubt you would find anything by pulling the other intake, and unless you enjoy doing it ( which would be strange :-) then yep, is worth putting on trailer and taking to good Indy.

Is it a spun big end bearing do you think?