Mazda Engine knocking noise

A Hyster forklift truck came in with a knocking noise under higher rpm.

[@judygeorge5739]

Keep up the good work and keep making such amazing cintent

[@blackriderph4340]

Great job! Very thorough investigation

[@beatricesandiford2212]

This was absolutely fantastic

[@coinkiller5495]

Great video 👍🏼

[@johnconner823]

Kudos to you very well done

[@chriss7031]

As soon as I heard that i thought that was a piston pin noise. a quick check an old timer showed my years ago (now im the old timer lol) was to pull the plug wire at idle and the noise will become more pronounced. if its a rod knock it wont change. Main bearing noise is under load and more like a hammer knocking on the block kinda noise. I liked the use of the extension though. And ive never seen someone scope an engine noise either so that was interesting. That being said ive seen engines come apart for a wrist pin noise only to find the rod bearings wiped out.

[@rosieharvey5437]

Had a great time while watching this video

[@danman9017]

it make sense ,thanks

[@luismelero6198]

Really interesting ! The noyse on botton rods, when seized or cleaered , usually is harder and louder, on my experience. So I think piston pin is the culprit. Is it a pitty can not tear down the engine and check it. Nice can see when, exactly , the noise show up. I gonna make one for myself ! Thanks for share your knolowledge friend.

[@everythingbutkoi6898]

Cheers!

[@alexhopkins1476]

this was pretty interestin

[@SMITT359]

Good video! But customer every check for engine oil, or replace engine oil with filter for truck?

[@forkliftgeek10]

dont know. We are not the company doing maintenance for this customer.

[@terrywells1655]

If that was a piston pin ...on your waveform at the end wouldnt it be showing up during the compressin stroke and not on a valve event ....good job on your videos i enjoy watching

[@forkliftgeek10]

From what I've researched a knocking noise on the compression stroke would point more towards the bottom end (rod cap, rod bearings). The explanation was that piston pin is loaded(pressure pushing down on piston) when going up, but when going down during intake stroke the piston would be held in place until the rod pulls it down(no pressure on top of piston). Customer did not want to go ahead so unfortunately cannot prove it.

[@terrywells1655]

@@forkliftgeek10 yeah i see what your saying i guess you have to hear it in person hard to tell on vid just have to thi k is the noise sound like its at engine speed or half engine speed ....i.e valve related ....where did you get that sensor you were using and what was it....keep up the good work as always i enjoy it was a dealer tech most of my life but been out of it for a while ...enjoy seeing how the technology has progressed....thanks....terry w.

[@forkliftgeek10]

The sensor I was using was a piezo sensor. I took it from a beeper on a dash display. I get what you are saying completely. Valves and rockers where the first thing I checked. Thanks for the kind words.

[@ammarahmed2477]

@@forkliftgeek10 I have Mazda e2000 van same noise from my van engine I don't know how to fix it

[@chriss7031]

@@terrywells1655 thats why you pull a plug wire at idle. see my earlier comment. a misfiring cylinder will have no impact on valve train noise and usually not on a rod knock either. Usually being the key word there. but it will most definitely have an impact on a piston pin noise.