1st start after 1st time doing timing belt.

[Richey]

I finally got the car started again but I don't have any other 944s to reference the sound of the car against. It sounds pretty much like it did before I started but with no real reference it could have been wrong to begin with.

Using the 3d Printed Carpokes tool I had the tension spot on and paid very careful attention that it didn't change after I locked down the tension pulley. Even with that (and the twist method on the balance belt) I hear a whining sound.

A lot of the videos I watched said I should be able to barely move the water pump pulley which I could not when tensioning with the 3d tool so I just gave it a try and slightly loosened it. The sound does not change.

I'm already struggling with my OCD for everything being perfectly done with out being able to use a reliable tool so I may or may not be obsessing over nothing.

[PSU_Crash]

I trust the printed tool for the timing belt.
That whine is from the balance belt being too tight. (So I'm told) Mine sounds exactly like that and has for over 1k miles. Recent revelations have shown me that I likely have the balance belt too tight. It's time for me to check the timing belt tension anyways. Good time to get the balance belt correct. I hope, or like you my OCD is taking over and everything is fine.

[Richey]

So how do you get the balance belt tension correct? I'm concerned about loosing it too much and getting the balance shafts out of time with each other.

I trust the printed tool for the timing belt.
That whine is from the balance belt being too tight. (So I'm told) Mine sounds exactly like that and has for over 1k miles. Recent revelations have shown me that I likely have the balance belt too tight. It's time for me to check the timing belt tension anyways. Good time to get the balance belt correct. I hope, or like you my OCD is taking over and everything is fine.

[Tom]

So how do you get the balance belt tension correct? I'm concerned about loosing it too much and getting the balance shafts out of time with each other.

I trust the printed tool for the timing belt.
That whine is from the balance belt being too tight. (So I'm told) Mine sounds exactly like that and has for over 1k miles. Recent revelations have shown me that I likely have the balance belt too tight. It's time for me to check the timing belt tension anyways. Good time to get the balance belt correct. I hope, or like you my OCD is taking over and everything is fine.

The amount of tension will not affect their sync. Your belt is likely too tight based on the whine. If you shoot for just the slightest hint of a whine, you'll be in the middle of the factory spec range. Unfortunately, that might take a little trial and error.

p.s., don't forget the clamp on the intercooler coupler...

[jeyjey]

One of my balance shafts was 180º out when I got the car. It won't do any harm (other than premature wear on your engine mounts if left that way for long periods of time). IIRC, it showed up mostly as excess vibration down around 2K RPM -- though I don't know if how much it's out by changes the resonant frequency or not....

[walfreyydo]

I have found that the tension on the balance belts to ensure they dont whine is lower than what you would expect.

This is typically why most cars have the whine. Very common. Just loosen incrementally until the whine goes away, making sure that the belt isnt slapping around (too loose). Do this with your belt cover off, and after adjustment, start the car with the cover off and observe. Or you can leave it as-is and it wont make any difference or harm, just whine a bit.

The adjustment pulley (on the bottom) is an eccentric sort of design so you have to rotate/clock the gear to reduce or increase the tightness. Thankfully its pretty easy to reach and adjust from below with the covers off, even with the car on the ground. Adjusting this pulley should not affect the balance shaft orientation as long as you dont skip any teeth on the belt

[danmartinic]

Cold Engine


Fully Warm Engine


The problem is the new belt is stiff and when wrapping it around, it tends to push out. Just leave as loose as possible while still on the gears. Yes, it will seem way too loose

[Richey]

I made a small adjustment last night then shot the video and kind of called it a night. I left the covers off knowing I would likely have to make some adjustments. I'll put a few hundred miles on the car and then put them back on.

I have the offset wrench that barely clears the belts and such so making adjustments isn't too bad. The pain in the ass part is getting up and down repeatedly until it sounds right.

I have found that the tension on the balance belts to ensure they dont whine is lower than what you would expect.

This is typically why most cars have the whine. Very common. Just loosen incrementally until the whine goes away, making sure that the belt isnt slapping around (too loose). Do this with your belt cover off, and after adjustment, start the car with the cover off and observe. Or you can leave it as-is and it wont make any difference or harm, just whine a bit.

The adjustment pulley (on the bottom) is an eccentric sort of design so you have to rotate/clock the gear to reduce or increase the tightness. Thankfully its pretty easy to reach and adjust from below with the covers off, even with the car on the ground. Adjusting this pulley should not affect the balance shaft orientation as long as you dont skip any teeth on the belt

[Richey]

p.s., don't forget the clamp on the intercooler coupler...

LOL, I'm fighting that awful airbox design that clamps around the pipe. The clamp is there but it's slid down out of sight. Since I'm taking the airbox on and off to make adjustments it's just laying there for the time being so I don't suck anything into the intake that's not just air.

[t36]

another point to note. Smaller microphones are sensitive to higher frequencies and the tone of a whining belt is usually amplified/exaggerated quite a bit. I have a hunch that some belts well in spec would sound whiney with a mic up close. So the audio references can be challenging. But I'm like you, my obsessiveness had me dialling in the balance shaft belt for a while. Don't forget the roller with the controversial spacing that can add to the noise. some say it should pre-tension the belt up to 1mm, others say in static position it should have no contact.