What gives CAT engines their distinctive "whine" noise?

I have a question, sure to make you shake your head, but here goes. If I change only the bearing on my 12.7 bull gear. Retorqe it properly, will the gear lash be affected? It’s obviously set perfect now, as it’s lasted so long. Is it possible to simply check gear lash afterwards, and if ok leave it be? Or does the idler and gear lash have to be disturbed to replace the bearing only? Never set a gear lash, on anything before, a bit intimidated about getting it wrong

 

Hey, thanks guys, wow, great group of replies here.

Thanks for affirming my inclination that the sound is in fact due to the straight cut timing gears. You can hear it in some of the smaller displacement engines they made as well such as the 3126 / C7 platforms and even the old (big) 3408 V8s have the same whine to them too. You don't however hear it in the 3160 / 3208 platforms.

Moderator 'Mack E-6' mentioned the Detroit Series 60's have the same sort of noticable whine to them and couldn't agree more.

As mentioned in my first post, many big diesel engines have a whine to some extent but the CAT engines seem to have it more apparent. The Cummins "Big Cam" engines for example don't really have any whine at all in comparison.

 

Mr. 1XHeavy, wow you are truly a subject matter expert, thanks for taking the time to respond. You certainly went above and beyond anything I was expecting.

 

Yea the isx sounds almost like its gonna fall apart lol. I like how they sound. The DD15s I've been around sound terribly bland. An old PLN E-7 is silky smooth, esp if running 15.3 pistons. The later Etech's sound clackty with the unit pump setup

 

I thought I was the only person who thought that about the isx. Some of them sound sooo bad

 

Yup and even brand new ones too. It's a real wierd wooshing/hammering sound. There just a terrible engine in my opinion. Lol.
Whenever I see a newer kw or pete on side road with hood up it seems it's always a red motor.

 

I think all new engines sound like a vacuum cleaner. Don't know if they suck or not, never driven one. All I've ever had are old school cats. But in my opinion they sound like a vacuum cleaner.

 

My father had an '06 ISX (EGR only) and I never really noticed that chugging sound with his, either from the passenger seat or when driving past while pulling. Mostly just sounded like turbo whistle more than anything else.

My favourite engine sound has got to be the old MBN CAT when you crest a hill, back out of the power, grab a split on the button, then gradually feed back into the power. That turbo spool and engine growl gets me every time.

 

That's the sound of money blowing out the stacks my MBN does it too.