Knocking / tapping sound over 3k RPM

Posts specific to the 2.0 litre Turbo engine

Knocking / tapping sound over 3k RPM

Postby binary » Fri Sep 28, 2018 2:12 pm

I've now got an ultrex dump pipe installed, and have had the car tuned to suit. Very different car now to standard and is great fun to drive.

I have just noticed a knocking / tapping sound over 3k RPM, most noticeable from 4k onwards. Quite noticeable when raising revs slowly with window down while moving, can't hear it with windows up. Sound is there when revving in neutral but much less. Seems to only be present under throttle, during deceleration the sound disappears.

The sound reminds me of when I spun the big end bearing in an old N/A car I had years ago... but much less noticeable / severe. I'd say it's mild sounding right now. 'll try to get a video of it. The sound follows the RPMs from 3k onwards but can't hear it once revs get say past 5.5k RPM (probably because so much noise). No difference in power at all (from seat of pants feel anyway).

I am thinking it could be rod or big end bearings. Any way to identify this via RomRaider logs? They're all clear so it's not pinging (no FKC / FBKC showing up, IAM still at 1). I'll drop the oil out this weekend and see if there's metal shavings present.

Hoping it's not time for a new motor :(

Update: further research leads me to think it could potentially be the timing belt tensioner. I’ll have a look into that and report back!
MY05 Liberty GT auto wagon | Ultrex dump pipe, tuned by Torqued Performance http://www.torquedperformance.com/
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Re: Knocking / tapping sound over 3k RPM

Postby bigBADbenny » Mon Oct 22, 2018 3:51 am

Keep the oil up and send it :)
Any update?
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Re: Knocking / tapping sound over 3k RPM

Postby binary » Thu Nov 08, 2018 10:00 pm

bigBADbenny wrote:Keep the oil up and send it :)
Any update?


LOL yep decided to do just that! I haven’t been driving it but just started running it again this week, and I’m thinking the sound could be some of my dodgy hack work on the turbo heat shield. I still need to drop the oil and check that, but she’s still running sweet, pulls hard, and doesn’t make any unusual noises from idle to about 4K which is where the tap / knock starts.

Worst case scenario, EJ207 from GRB STI wouldn’t be so bad?! :twisted:
MY05 Liberty GT auto wagon | Ultrex dump pipe, tuned by Torqued Performance http://www.torquedperformance.com/
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Re: Knocking / tapping sound over 3k RPM

Postby bigBADbenny » Thu Nov 08, 2018 10:47 pm

There’s mic kits for this purpose on eBay, or you can tap all the shields manually to see which rattle or ring :)
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