Is this piston slap or rod knock? (Video of sound)

[Scott Niven]

Ok, this is slightly different from other posts, Im working on an engine from a Irish 03 Toyota Yaris (1SZ-FE). Its a project to get an EFI engine running outside of the car as Im new to tinkering with cars/engines and wanted a good project.

Now, I have the engine idling fine, no codes, smooth running. The only thing I have noticed is there is a distinctive quiet knock from the engine when Idle.

Here is a video of the sound in question. You can hear it near the bottom of the engine, there are other noises im aware of, such as injectors, purge valve(which is pretty evident in the video) etc.

Good examples around 30sec, 48 sec:

Any help, advice is greatly appreciated!

Topic

[Mike]

Honestly, it sounds like valve clatter to me.

[Bluesnut]

It sounds like valve clatter to me also. Inspection and adjustment of valve lash is a normal recommended maintenance procedure but like most mechanical lifter engines it never gets done or even thought of.

[Scott Niven]

Thanks guys, ill take the valve cover off and check the clearances. At least I know now it probbally won’t destroy itself!

[Author]

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