M42 knocking sound. Tensioner?

[mhuynh]

https://youtu.be/MVJBYj1d1PE

Does this knocking sound resemble a malfunctioning chain tensioner or is it something more serious?

[vpilarrt]

I don't think its the tensioner. Sounds like rod knock but its a little fast, maybe a collapsed lifter. Does it get more pronounced or change when you accelerate from low rpms?

[mhuynh]

I don't think its the tensioner. Sounds like rod knock but its a little fast, maybe a collapsed lifter. Does it get more pronounced or change when you accelerate from low rpms?

Yes, it's rpm dependent

[vpilarrt]

Yes, it's rpm dependent

Yes but does it get louder? More pronounced?

[varg]

Still having this problem? Sounds like valvetrain noise to me because of how slow the knock is, a given valve is only actuated once every 2 revolutions on a 4 cylinder engine so the knock sounds slower than rod knock, which is also typically not very loud at idle unless it's a severe case. Post a video with some revving to and sustaining of 2,500-4,000rpm or so.

[TobyB]

pull coil drivers one at a time, and see if one makes it go away/change a lot.

over the internet, it sounds rodlike.

Maybe you'll get lucky and it's an exhaust leak at the head-manifold interface.
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