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  #16  
Old 02-14-2010, 11:46 PM
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Re: Noise Under Load and Vibration From Engine

Could the timing belt be off by a tooth cause the vibration? Idles smooth and runs smooth. Only vibrates at 1500 and 5500 RPM. Does not seem to have the power it should either.
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  #17  
Old 02-15-2010, 02:37 PM
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Re: Noise Under Load and Vibration From Engine

Ok so I pulled the front end off the engine, changed the crank pulley and checked the timing belt to see if it had jumped a tooth. Cams were spot on. Cranked the engine vibration still there at around 1500 and 5500. Ugh!!!! I am going to push this thing off a cliff...

But wait I started reading and although I see no one describing the problem as a vibration I did note that the engine has always seemed to have less power that my other SVX which is an automatic. So let's put two and two together, a vibration at two points only through the RPM range and lack of power. The Iris valve apparently transitions or changes open/closed state at 2000ish and 4000ish RPM and if it is not functioning can cause lack of power. So I pulled the power steering resevoir again and got to the iris control vacuum check valve and did the (blow/suck) test (ok no jokes please this has been painful enough) and it is not functioning properly (does not check). So I went to Advanced auto and got an off the shelf $5 vacuum check valve and replaced it.

Problem solved, No vibration and it runs like a bat out of the really hot place.

So take it from me, check the check valve first....
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  #18  
Old 02-15-2010, 02:48 PM
1986nate 1986nate is offline
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Re: Noise Under Load and Vibration From Engine

Quote:
Originally Posted by storm66 View Post
Ok so I pulled the front end off the engine, changed the crank pulley and checked the timing belt to see if it had jumped a tooth. Cams were spot on. Cranked the engine vibration still there at around 1500 and 5500. Ugh!!!! I am going to push this thing off a cliff...

But wait I started reading and although I see no one describing the problem as a vibration I did note that the engine has always seemed to have less power that my other SVX which is an automatic. So let's put two and two together, a vibration at two points only through the RPM range and lack of power. The Iris valve apparently transitions or changes open/closed state at 2000ish and 4000ish RPM and if it is not functioning can cause lack of power. So I pulled the power steering resevoir again and got to the iris control vacuum check valve and did the (blow/suck) test (ok no jokes please this has been painful enough) and it is not functioning properly (does not check). So I went to Advanced auto and got an off the shelf $5 vacuum check valve and replaced it.

Problem solved, No vibration and it runs like a bat out of the really hot place.

So take it from me, check the check valve first....
Glad to see using your head helped you tackle your problem Sure seemed like one hell of a bugger
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  #19  
Old 02-15-2010, 03:09 PM
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Re: Noise Under Load and Vibration From Engine

Thank you, yes that one made me pull my hair out a bit...
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  #20  
Old 02-15-2010, 03:15 PM
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Re: Noise Under Load and Vibration From Engine

Nice find! I know it would make me pull my hair out trying to find it. I tested mine when I pulled everything apart but good to know what a failure will cause.
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  #21  
Old 02-15-2010, 04:19 PM
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Re: Noise Under Load and Vibration From Engine

Did this happen after replacing the clutch? If so you have the Flywheel/Pressure plate balancing marks out of alignment.

Last edited by Bonestock; 02-15-2010 at 04:20 PM. Reason: nevermind... see you found the problem
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  #22  
Old 02-15-2010, 10:24 PM
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Re: Noise Under Load and Vibration From Engine

The pressure plate would only go on one way with the pins on the flywheel that align to the pressure plate holes. Did I miss something?
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  #23  
Old 02-16-2010, 09:43 PM
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Re: Noise Under Load and Vibration From Engine

On Subaru flywheels and pressure plates, you must absolutely align them properly. If not you will know (a bit late.. at start up) when the clutch pedal starts to vibrate.

http://www.competitionclutch.com/ima...structions.pdf




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  #24  
Old 02-17-2010, 12:27 AM
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Re: Noise Under Load and Vibration From Engine

So if understand the directions correctly the pressure plate has a "0" mark on it as does the flywheel. The pressure plate must be at least 120 degrees off of the "0" mark in order to be in balance or the engine would vibrate. Is this correct?

I think I was a bit over excited by the sudden increase in power now that the Iris valve is working correctly and did not notice the vibration was still there. I will pull the transmission replace the flywheel "just as a precaution as it had been resurfaced" and ensure the pressure plate is properly timed for proper engine balance as you suggested.

Thank you for the information and detailed instructions.
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  #25  
Old 03-18-2010, 08:09 PM
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Re: Noise Under Load and Vibration From Engine

I have transmission out and flywheel off. I have a new flywheel but do not see any marks on it. The ACT pressure plate has a mark that looks like an arrow stamped in it. Any ideas on the flywheel? Any way to tell if no marks on it?
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  #26  
Old 03-19-2010, 09:12 AM
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Re: Noise Under Load and Vibration From Engine

Called the Flywheel company and they said the flywheel is zero balanced and therefore does not have any marks on it. You can put the pressure plate in any position and it should be fine.

On another note I was looking through flywheel diagrams and noticed the small plate that is put on with an AT flyweel does not go on with a MT flywheel. I had put that on with mine. Could this cause an imbalance?
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  #27  
Old 03-20-2010, 11:32 PM
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Re: Noise Under Load and Vibration From Engine

Quote:
Originally Posted by storm66 View Post
Ok so I pulled the front end off the engine, changed the crank pulley and checked the timing belt to see if it had jumped a tooth. Cams were spot on. Cranked the engine vibration still there at around 1500 and 5500. Ugh!!!! I am going to push this thing off a cliff...

But wait I started reading and although I see no one describing the problem as a vibration I did note that the engine has always seemed to have less power that my other SVX which is an automatic. So let's put two and two together, a vibration at two points only through the RPM range and lack of power. The Iris valve apparently transitions or changes open/closed state at 2000ish and 4000ish RPM and if it is not functioning can cause lack of power. So I pulled the power steering resevoir again and got to the iris control vacuum check valve and did the (blow/suck) test (ok no jokes please this has been painful enough) and it is not functioning properly (does not check). So I went to Advanced auto and got an off the shelf $5 vacuum check valve and replaced it.

Problem solved, No vibration and it runs like a bat out of the really hot place.

So take it from me, check the check valve first....
I've only drove 2 SVX's. Mine and another one. The other one seemed to have more power than mine. I have a power steering leak. It's the O-ring. I'm going to be replacing it on Monday. I would like to check my Iris valve to see if this is my problem with the power, but have no idea what or where it is. Can some please elaborate on what it is and how to change it? Any pics? Part number from Advanced?
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  #28  
Old 03-24-2010, 12:55 AM
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Re: Noise Under Load and Vibration From Engine

Iris valve vacuum check valve is located just behind the power steering pump under the intake. It is black and cylindrical shaped and connected to two vacuum lines. I would replace it with a new one from an auto parts store (advance auto Part No. 47149) . Universal fit works fine. Replace the vacuum lines while you are at it. Make sure your orient it properly so that the the intake can draw vacuum into the vacuum tank (intake side can suck vacuum through the valve) but will not let the vacuum escape from the tank (valve does not allow vacuum to escape the tank).

You may have to remove the power steering tank (replace the power steering tank o-ring while you are at it) to get to the iris valve.

Once you have it back together reach under the intake (be careful watch your hands) to the iris valve acuator arm and rev the motor over 4000 rpm for a few seconds. You should feel it move activating the iris valve. If you don't you may still have a vacuum leak or have the check vavle on backwards.
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  #29  
Old 03-24-2010, 01:01 AM
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Re: Noise Under Load and Vibration From Engine

Update on the noise under load. Pulled the 5MT and tore it down had three bad bearings in the transmission. No wonder it made noise under load. Changing all seals and gaskets while I have it down. Transmission repair not for the light hearted. lots of gears, and bearings, and syncronizers, Oh my...

Bought a new flywheel and took it with my pressure plate to a machine shop to have them balanced together just to be darn sure no vibration will occur.

I'll report more once it is all back together.
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  #30  
Old 03-24-2010, 08:43 AM
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Re: Noise Under Load and Vibration From Engine

Quote:
Originally Posted by storm66 View Post
Update on the noise under load. Pulled the 5MT and tore it down had three bad bearings in the transmission. No wonder it made noise under load. Changing all seals and gaskets while I have it down. Transmission repair not for the light hearted. lots of gears, and bearings, and syncronizers, Oh my...

Bought a new flywheel and took it with my pressure plate to a machine shop to have them balanced together just to be darn sure no vibration will occur.

I'll report more once it is all back together.
What bearings and how many miles on the 5spd, just wondering
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