timing belt noise

[tnporsche]

I just changed the timing belt and bal belt. I don't have a tension tool.

After changing the belts and rollers it has a low pop sound at the front. It stops when warm.

Sounds like one is too loose right?

The bal belt seemed loose before so it is a little tighter than before. So for that reason it must be the timing belt.

The question is, If it has a spring tensioner, how do you make it tighter?

Lastly Does anyone have a belt tool for rent?

Thanks
Merry Christmas All
Lowell

[Techno Duck]

Your description of the sound needs some work. Ive never heard of a low pop sound from the timing belt area. Tapping and whining yes, i cant imagine a pop though.

To add tension to the timing belt, you need to loosen the two nuts on the face of the tensioner, then you can push it to the left (if your facing the engine) to add tension. Push it to the right if you want to take tension off. There is a special tool (the same one that holds the balance shaft sprockets) to do this, you can see the two holes for the pin wrench. You really dont need the wrench and can achieve the same results by hand or with a pry bar.

You should not be getting a pop or any strange sounds if you lay the tensioner on the belt with just the spring tension. The spring tensioner typically does not tension the belt enough, but in my experience never far enough out of spec to cause strange sounds. I find if you lay the tensioner on the belt with spring tension, then lightly nudge it onto the belt more (push it onto the belt to add tension) you get pretty darn close to the exact tension. You can also use the 'twist' method. You should be able to twist the belt roughly 90 degrees at the longest span..you will probably have to take the belt guard off the waterpump to do this.

[tnporsche]

It kinda sounds like putting your finger on the edge of a oscillating fan. (everyones done that right)

Do the belts get tighter or looser when warm?

[Eldorado]

slightly looser

what method did you use to measure the tension?

[tnporsche]

Twist 90 deg for balance belt, but it is tighter than it was.

figured spring would do for timing belt

[Techno Duck]

Belts get tighter as the engine heats up...

I believe the noise you are describing is what it sounds like when the timing belt taps the rear timing belt cover. Based on your description, i think you need to add a little tension to it (the timing belt).

You may consider investing in the Arnnworx belt tensioner also. Its ~$120 of peace of mind knowing it was tensioned right.

[bazar01]

Try releasing the belt tensioner in the morning when the engine has not been run overnight.
Then double check with the 90 degree twist.

[tnporsche]

I loosened the two nuts on the spring tensioner and it moved on its own a little. I retightened the nuts, and started it up; no noise.


I have a new question though, and rather than starting a new thread,,

This a automatic 1988 non turbo 8v. What RPM should it turn at 70 mph????

This one is 4000 rpm @ 70 around 3000 @55

That seems a little high to me but I have never ridden in a 944 before.
Thanks

[Techno Duck]

That is normal because the auto tranny on the 944 series cars is not the greatest. 3-speed auto with no overdrive. I had an automatic 924S which used the same transmission..car was nice for a daily driver around town but on the highway i really hated it.

[Razorback1980]

Yep, I have one of those....that's normal.