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Old 05-23-2010, 08:13 AM   #1
Vinnyzwrx
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Default new short block, bad timing belt tensioner?????

ok, i just put in a new short block from outfront motorsports and im getting a really weird noise that comes on around 2500 rpm and ends at around 3 - 3500 rpm. its a weird rattling noise,


it normally happens when i shift or am driving on light throttle in the above specified rpm range. The only thing i can think of is the timing belt tensioner besides some sort of mechanical problem with the new short block. The engine has about 300 miles on it and is about 5 days old so i really doubt that its a mechanical problem but the noise really sounds bad. help would be greatly appreciated!
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Old 05-23-2010, 10:57 AM   #2
2milehi
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One way to check the tensioner is to take the timing belt covers off and use a screwdriver to apply some extra pressure to tensioner. If the noise goes away then you found it. Hopefully you have Outfront Motorsports aware of this noise.

Have you had this noise since first install or has it got progressively worse?
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Old 05-23-2010, 11:26 AM   #3
Vinnyzwrx
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Quote:
One way to check the tensioner is to take the timing belt covers off and use a screwdriver to apply some extra pressure to tensioner. If the noise goes away then you found it. Hopefully you have Outfront Motorsports aware of this noise.

Have you had this noise since first install or has it got progressively worse?
i finished the install on wednesday and have had the noise since first startup. i thought that it may be some normal new block noise or something so i waited. i intend on calling them first thing monday morning to see what they think/find a solution

thanks for the advise, i will try it tomorrow.
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Old 05-23-2010, 04:59 PM   #4
jaironsti
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Sounds like a rattle to me in the audio when you rev it up. I have never heard a tensioner sound like that, but I could be dead wrong as well. Just my 2 cents.......
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Old 05-23-2010, 05:49 PM   #5
prometheum
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happened to my friend's wrx after his 2.5 swap; timing belt tensioner exploded 250 miles later
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Old 05-23-2010, 06:02 PM   #6
Vinnyzwrx
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Quote:
Sounds like a rattle to me in the audio when you rev it up. I have never heard a tensioner sound like that, but I could be dead wrong as well. Just my 2 cents.......
i dont think that the sound is being produced by the tensioner but rather something else, caused by the bad tensioner.

Quote:
happened to my friend's wrx after his 2.5 swap; timing belt tensioner exploded 250 miles later
thanks, i really hope that its just the tensioner.
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Old 05-23-2010, 09:12 PM   #7
robbieshonda
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sounds like one of the timing belt pullies squeeking to me vinny. take the belt off and spin the idlers ect and see if they are gritty. the smallest one is the one I normally see that goes bad.
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Old 05-24-2010, 10:31 AM   #8
Vinnyzwrx
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Quote:
sounds like one of the timing belt pullies squeeking to me vinny. take the belt off and spin the idlers ect and see if they are gritty. the smallest one is the one I normally see that goes bad.
there all fine, i actually had to replace that small one because it was starting to go bad. i made sure to check them because i have had to replace them before for that reason. im about to head out to see if its the tensioner, i will post my results
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Old 05-24-2010, 05:06 PM   #9
Fongers
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also could be the idler pulley on the AC belt. I had one go bad and it sounded similar to this so check it before going through the trouble of popping off the covers...
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Old 05-24-2010, 08:40 PM   #10
Vinnyzwrx
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Quote:
also could be the idler pulley on the AC belt. I had one go bad and it sounded similar to this so check it before going through the trouble of popping off the covers...
the ac tensioner is new.

i popped off the timing belt covers and the belt is very tight, the tensioner is fine as i suspected it to be since its only 5k mile old. any other ideas?

Quote:
sounds like one of the timing belt pullies squeeking to me vinny. take the belt off and spin the idlers ect and see if they are gritty. the smallest one is the one I normally see that goes bad.
i didnt realize that was you robbie, it sounded weird that someone would reply using my name but i didnt think much of it until i just saw that it was you when i read throught the forum trying to think of ideas.

Last edited by Vinnyzwrx; 05-24-2010 at 08:46 PM.
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Old 05-25-2010, 11:39 AM   #11
Vinnyzwrx
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could all this be a result of a bad front o2 sensor? i know the sensor is really hurting because 2 of the wires are almost disconnected. i accidentially hit the sensor when i was removing the engine from the car. im not getting any check engine light or anything so it seems fine. also today i logged the car with ecu explorer and noticed that the ecu, at a minimum is pulling -14 degrees of timing and -2 knock correction. under acceleration the numbers are all positive, im not sure when these number came about because i just noticed them as being the minimum of the range from max to min. i guess i can attach the log, im not sure if it matters though.

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Old 05-25-2010, 07:26 PM   #12
SteelDragonSTi
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Apparently the timing belt tensioner has to be replaced along with the new timing belt. I found out today when my mechanic was starting the car for the first time after a fresh full engine build. The car was idling fine and then it shuts off. After further inspection he finds the timing is off and the belt jumped 3 knotches. He tells me the tensioner failed and needed a new one. I might have possible valve damage as well.

I wish I had known this prior to the build.
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Old 05-26-2010, 08:38 AM   #13
Vinnyzwrx
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Could this be a bad throw out bearing?
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