Can't shake the knock...

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Re: Can't shake the knock...

Postby jslayz » Fri Jun 19, 2015 9:26 pm

Wow, you must be relieved!
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Re: Can't shake the knock...

Postby cynner » Tue Jul 07, 2015 8:46 pm

An unfortunate turn of events...

The knock came back... must have been a coincidence that changing the pitch stopper helped.

I spent an hour with my mechanic today, probing the engine with a stethoscope and knock ears. I'm able to replicate the knock by revving the engine under idle to around 2500-3000...

With the knock ears it sounds like a rattle. With the probe it sounds like a low grumble. The loudest spots are off the block itself, so it looks like there is something going on internally.

My mechanic suspects the big end bearing :(
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Re: Can't shake the knock...

Postby bigBADbenny » Wed Jul 08, 2015 8:28 am

Did you soft mount the ebcs yet?
Also put the knock ears on the starter motor, the drive gear may not be entirely disengaging. If so hit it with some aerosol dry lube.
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Re: Can't shake the knock...

Postby cynner » Wed Jul 08, 2015 8:45 am

I put the knock ears on the boost control bracket - was very quiet. All i could head was the vacuum pshhts :)

If the starter drive gear wasn't disengaging, wouldn't that make the noise all the time? I'll check it out though.

KiDo thinks it wouldn't be the big end bearing as it would have let go by now. This noise has been happening for 6 months.
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Re: Can't shake the knock...

Postby bigBADbenny » Wed Jul 08, 2015 10:39 am

I'll have to put the mic on my ebcs, then on block adjacent.
Did you listen whilst driving or just in neutral?
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Re: Can't shake the knock...

Postby cynner » Wed Jul 08, 2015 10:49 am

Did both. While driving it seemed louder... but in neutral it sounded more like a low grumble...

I'll try to record it...
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Re: Can't shake the knock...

Postby cynner » Wed Jul 08, 2015 10:57 am

Just bought this... should come in handy! http://www.ebay.com.au/itm/Professional ... 3a928bf3f0
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Re: Can't shake the knock...

Postby THE SpecB » Wed Jul 08, 2015 10:06 pm

cynner wrote:Just bought this... should come in handy! http://www.ebay.com.au/itm/Professional ... 3a928bf3f0



Nice kit looking forward to see results Kim

It does not seem like a big end would be evident all the time now. Have you considered tensioner pulleys etc ? Water pump it pulleys in general. Kido also posted that solenoids can knock if not working correctly ?
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Re: Can't shake the knock...

Postby cynner » Thu Jul 09, 2015 10:39 pm

I'm going to get my oil pickup inspected (and replaced with a killer B unit)... there's a chance this has been causing the noise.

However, if it's started to cause big end noise (even if very very slight) - I guess there's no going back after that?
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Re: Can't shake the knock...

Postby cynner » Mon Jul 13, 2015 3:17 pm

Had the opportunity to get a couple of other mechanics listen to the car with knock ears, stethoscope, etc.

They weren't able to hear anything sinister - the engine sounds fairly healthy to them. I'll replace the oil pickup anyway, and will see how things go.

From what I can find, it is not uncommon for cars to spit out -1.4 or -2.8 FBKC from time to time for no apparent reason... maybe it's normal and I'm just being paranoid because I see it on my ODB bluetooth tablet display. Most people would be completely unaware of what is happening in their engine...

Ignorance was bliss! :roll:
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Re: Can't shake the knock...

Postby dr20t » Mon Jul 13, 2015 6:42 pm

Have you listened for the knock with the knock ears yourself?

Knock is very distinctive and sounds like a zap / pop
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Re: Can't shake the knock...

Postby bigBADbenny » Mon Jul 13, 2015 11:44 pm

I have my btssm knock alarm configged with FKC(deg) with the alarm set to -1.5.
How is yours configured?
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Re: Can't shake the knock...

Postby cynner » Mon Nov 09, 2015 7:22 pm

Problem solved (sorta).

With the engine and turbo both replaced, and sensors and exhaust all replaced or ruled out - it only really left the gearbox or clutch. I started to wonder whether having Kart Boy shifter bushings could be causing excess vibrations through the gearbox area (the knock sensor is very close to where the gearbox and engine meet).

So, I asked my mechanic to put the old rubber bushings back in.

Since then, pretty much zero knock! A couple of minor blips here and there - but 95% improvement.

This has caused close to 2 years and many $$$$ troubleshooting :( And something so simple. Argh!
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Re: Can't shake the knock...

Postby <GB> » Tue Nov 10, 2015 2:13 pm

cynner wrote:Problem solved (sorta).

With the engine and turbo both replaced, and sensors and exhaust all replaced or ruled out - it only really left the gearbox or clutch. I started to wonder whether having Kart Boy shifter bushings could be causing excess vibrations through the gearbox area (the knock sensor is very close to where the gearbox and engine meet).

So, I asked my mechanic to put the old rubber bushings back in.

Since then, pretty much zero knock! A couple of minor blips here and there - but 95% improvement.

This has caused close to 2 years and many $$$$ troubleshooting :( And something so simple. Argh!

I had lots more engine noise when I put a pitch stop mount on, was this one of the mounts you replaced? its the one under the intercooler to the fire wall
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Re: Can't shake the knock...

Postby cynner » Tue Nov 10, 2015 2:35 pm

Nup, just the kart boy shifter bushing. Also Nolathane front control arm bushes, but they had been in there a long time.

The instant we took out the kart boy shifter bushing, it stopped 95% of the feedback knock alerts I was getting on my bluetooth adaptor.
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