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[maracus]

Here's a naive question...

What does 'knock' sound like?

I have a noise. Happens when loaded in high gear under as much acceleration as the auto box will allow before kicking down, but the closest way I can think to describe it is it sounds like them little clip-on bicycle spoke things that u used to get from kellogs, kind of tinny sort of clickclickclickclickclickclick sound, at first I thought it was a rattle of some sort but then I was trying to get it to do it with experienced ears in the car he seems to think it's knock, although it didn't actually do it at the time its one of those things that don't happen when you try and make it.

I'm about to paperclip (light not on at present) and start looking for an air leak somewhere Bu any tips or anything anyone can add??

[Kevin Wood]

Knock sounds like something that would make you stop the engine immediately before it kills itself, although a few layers of sound deadening might mask it a bit in an Omega.

I would guess this is probably a small exhaust / manifold gasket leak as the engine has a knock control setup which would avoid knock. Worth checking the engine codes, though.

[maracus]

Codes are clear... It seems to remind me of a similar noise an old astra made after we (I say we it wasn't me it was him ) fitted a uprated camshaft minus one of the little bearing balls in one end of the shaft and it used to rattle under load going uphill in 5th I'd put that down to the missing bearing... Hence why I thought this rounded like more of a rattle..

If it's something worn like the tensioner rattling or something I'm not worried if it breaks I'll call the AA get home and fix it; but if it's knock I'm dealing with, I'd best admit my tradition and bring my cav out of 'winter storage' lol and sort it ASAP!!

So is knock REALLY OBVIOUS then? I've never had it pointed out to me like "that's what knock sounds like"

[maracus]

And to add, the manifold on one side don't sound great it's abit not tight somewhere, but I don't think it's that, the noise has started since I last had the plenum off hence I think I might be drawing air in somewhere and getting a lean mix?? Though surely the engine management would pick up on that???

[Kevin Wood]

The (C20XE?) ball bearing in the end of the camshaft was to block an oilway that would otherwise bleed the oil pressure away so the knock was probably the bottom end complaining in that case.

It's very difficult to diagnose noises remotely, to be honest.

[maracus]

The (C20XE?) ball bearing in the end of the camshaft was to block an oilway that would otherwise bleed the oil pressure away so the knock was probably the bottom end complaining in that case.

It's very difficult to diagnose noises remotely, to be honest.

It was some old 1400 8v sh!ts n giggles n all that, agreed noises are spelt differently online hence hard to disgnose lmao I was just curious as to what knock ACTUALLY sounds like...