Engine Rattling Sound

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Re: Engine Rattling Sound

Postby peadya100 » Mon May 06, 2013 2:03 pm

Have you had your car looked at by a mechanic just to make sure there isnt something wrong with your engine? Better safe than sorry, theyll be able to diagnose it pretty quickly and on the off chance its something major at least you will have got to it pretty quickly.
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Re: Help!! Engine Knocking!!

Postby libz05 » Mon May 06, 2013 2:21 pm

Robbks wrote:
libz05 wrote:i have the same problem!! engine rattle and it gets quite annoying!
did u find out the issue ?


It's AVCS related
as you go from 1600rpm to 2000rpm, the AVCS system advances the intake cam by about 30 extra degrees. and as such the mechanism on teh front of teh camshaft rattles as it whips around quickly
see maps of AVCS angle here
viewtopic.php?p=304468#p304468


thanks rob!
what would you reccomend!
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Re: Engine Rattling Sound

Postby libz05 » Mon May 06, 2013 2:22 pm

i spoek with jay.ritchie
he said it may be this:
viewtopic.php?f=16&t=19918
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Re: Help!! Engine Knocking!!

Postby Robbks » Mon May 06, 2013 2:25 pm

libz05 wrote:thanks rob!
what would you reccomend!


Turn up the stereo so you can't hear it
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Re: Engine Rattling Sound

Postby Robbks » Mon May 06, 2013 2:27 pm

libz05 wrote:i spoek with jay.ritchie
he said it may be this:
viewtopic.php?f=16&t=19918


well does it do it all the time like the video in the link above?
or is it just a quick chirp as you're driving?

peadya100 wrote:Have you had your car looked at by a mechanic just to make sure there isnt something wrong with your engine? Better safe than sorry, theyll be able to diagnose it pretty quickly and on the off chance its something major at least you will have got to it pretty quickly.


Nope
I can tell when it's a concerning noise and know more about Subaru engine noises than half the mechanics around here.
it only does it at specific load and rpm conditions indicated by the ACVS advance maps posted before.
i.e doesn't do it when free revving

I'm always interested in these mysterious diagnostic powers that people believe some mechanics possess.
Last edited by Robbks on Mon May 06, 2013 2:57 pm, edited 2 times in total.
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Re: Engine Rattling Sound

Postby libz05 » Mon May 06, 2013 2:53 pm

only when im driving! on idle no rattle noise
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Re: Engine Rattling Sound

Postby peadya100 » Mon May 06, 2013 3:23 pm

Robbks wrote:
libz05 wrote:i spoek with jay.ritchie
he said it may be this:
viewtopic.php?f=16&t=19918


well does it do it all the time like the video in the link above?
or is it just a quick chirp as you're driving?

peadya100 wrote:Have you had your car looked at by a mechanic just to make sure there isnt something wrong with your engine? Better safe than sorry, theyll be able to diagnose it pretty quickly and on the off chance its something major at least you will have got to it pretty quickly.


Nope
I can tell when it's a concerning noise and know more about Subaru engine noises than half the mechanics around here.
it only does it at specific load and rpm conditions indicated by the ACVS advance maps posted before.
i.e doesn't do it when free revving

I'm always interested in these mysterious diagnostic powers that people believe some mechanics possess.


Just curious Rob, how can you be so certain of the diagnosis when you havent heard the noise?

Mine turned out to be something completely different to everyones guesses.
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Re: Engine Rattling Sound

Postby bass_straitener » Mon May 06, 2013 3:28 pm

The 05-06 H6 Libs have a very different AVCS map to the 07 onwards cars in stock form.

I couldn't see a huge AVCS change in the 07 maps I've looked at, but agree the earlier H6 cars may make a sound from the cam gear.

You can tune the car to have this removed.

Some of Matt's tunes do attempt to whilst others seem to show the large AVCS jump on transition between cruise and non cruise.

Check with your tuner to get them to smooth the transition points.
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Re: Engine Rattling Sound

Postby Robbks » Mon May 06, 2013 3:29 pm

peadya100 wrote:Just curious Rob, how can you be so certain of the diagnosis when you havent heard the noise?

I'm certain of the noise that I'm hearing in my car.

peadya100 wrote:Mine turned out to be something completely different to everyones guesses.

as for your noise..you'll see my first post had the solution
my options 1 and 2 had specific conditions that were never commented on..

Robbks wrote:
peadya100 wrote:Nah its not happening on boost, its happening at 1500-2000rpm.

at the point right before boost come one.. like 0-1psi on medium throttle..?

If so i had two causes of this noise on my GT Fozz.
1) Wastegate chatter. ...........
......................
2) Compressor Surge.....................
...................
otherwise it could just be a rattling heat shield.
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Re: Engine Rattling Sound

Postby peadya100 » Mon May 06, 2013 3:56 pm

Robbks wrote:
peadya100 wrote:Just curious Rob, how can you be so certain of the diagnosis when you havent heard the noise?

I'm certain of the noise that I'm hearing in my car.

peadya100 wrote:Mine turned out to be something completely different to everyones guesses.

as for your noise..you'll see my first post had the solution
my options 1 and 2 had specific conditions that were never commented on..

Robbks wrote:
peadya100 wrote:Nah its not happening on boost, its happening at 1500-2000rpm.

at the point right before boost come one.. like 0-1psi on medium throttle..?

If so i had two causes of this noise on my GT Fozz.
1) Wastegate chatter. ...........
......................
2) Compressor Surge.....................
...................
otherwise it could just be a rattling heat shield.


Yeah im not saying you may not be right, i just meant how can you be so certain for the other H6 lib?
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Re: Engine Rattling Sound

Postby peadya100 » Mon May 06, 2013 3:58 pm

For example, my car made its noise at the exact same engine revs, and didnt do it free revving, only under load.
Isnt it a little early to definitely say its the AVCS thing you were talking about?
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Re: Engine Rattling Sound

Postby bass_straitener » Mon May 06, 2013 4:23 pm

peadya100 wrote:For example, my car made its noise at the exact same engine revs, and didnt do it free revving, only under load.
Isnt it a little early to definitely say its the AVCS thing you were talking about?


I think I predicted as well the heatshield noise. That area is subject to extreme heat and they tend to fail.

You only hear it due whilst under load due to the resonant frequency being different than when free revving.

My wife's Foz has a similar noise at the moment.
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Re: Engine Rattling Sound

Postby peadya100 » Mon May 06, 2013 4:25 pm

bass_straitener wrote:
peadya100 wrote:For example, my car made its noise at the exact same engine revs, and didnt do it free revving, only under load.
Isnt it a little early to definitely say its the AVCS thing you were talking about?


I think I predicted as well the heatshield noise. That area is subject to extreme heat and they tend to fail.

You only hear it due whilst under load due to the resonant frequency being different than when free revving.

My wife's Foz has a similar noise at the moment.


Hahaha.. sorry i wasnt trying to point out that no-one guessed my noise, more that the actual cause of the noise was one of many possible things suggested and hard to diagnose without seeing/hearing it in person.
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Re: Engine Rattling Sound

Postby Robbks » Mon May 06, 2013 4:27 pm

without driving it or opening the bonnet I can't

But that's why we ask the posters to provide very specific info which very few are capable of doing.
i.e how long does it rattle for. (in my case it's a very short "tiktik")
does the rattle stay constant if you can maintain the load and rpm for a few seconds
does it rattle on acceleration, deceleration or constant throttle?
if you hold rpm but quickly blip the throttle, does it change (This was the key to diagnosing my own compressor surge issue)
And provide a video/ sound clip/ logging info if you have it/ can get it

Some of these questions got lost in the earlier diagnosis.
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Re: Engine Rattling Sound

Postby peadya100 » Mon May 06, 2013 4:31 pm

Robbks wrote:without driving it or opening the bonnet I can't

But that's why we ask the posters to provide very specific info which very few are capable of doing.
i.e how long does it rattle for. (in my case it's a very short "tiktik")
does the rattle stay constant if you can maintain the load and rpm for a few seconds
does it rattle on acceleration, deceleration or constant throttle?
if you hold rpm but quickly blip the throttle, does it change (This was the key to diagnosing my own compressor surge issue)
And provide a video/ sound clip/ logging info if you have it/ can get it

Some of these questions got lost in the earlier diagnosis.


Completely agree Rob.. i was more asking because i didnt want libz05 to go away from the thread convinced it was the same problem you have without getting it checked.

MSR went over everything in my engine, including taking the car out for about 30 mins with the laptop before handing it back to me. And although he thinks it was the heat shield, it could have been one of the other 50 things he checked before taking it out for the test drive too.

I think getting everyones opinions on here really helps.. especially in my case as it helped me discount the easy to check stuff.
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