V2Rocket

I did a full rebuild on my motor between 5000 and 10,000 miles ago and recently noticed a difference in sound from my timing belt. I was very used to the high-pitched whine it would make but lately it is a lower sound. Being a string musician (orchestra) I associate a lower pitch with a looser string (in this case a belt). I will be needing the car for the next few days for work. What are the odds that a belt, properly tensioned at time of installation, would fail/slip after 10,000 miles of stretching?

Hopefully I can tear into the front end on Monday.

Wipeout

I know that people tend to re-tension the belts periodically.

What do you play? I'm an orchestral percussionist, myself.

nh7cy

I'm assuming you were using new timing belts at the time of rebuild. Did you check your tension after the first 1k? The belts are going to stretch a bit over 10k, the reason why tensions for new belts and used belts are different. I'd double check the tension on those belts just to be sure they aren't too lose just to play it safe.

V2Rocket

They were properly tensioned new belts at the completion of the build. I did not check the tension after 1000 miles.

Wipeout - I play viola and first violin.

Wipeout

Very cool.

I'd check and perhaps retension the belts. After schwank and I did my cam gasket we had to reinstall the timing belt, belt had a high pitched whine at 2000 RPMs for a while untilit broke itself in.

jaje

Always retension your new belt after 1k miles (Porsche requires it). I just did a full change about 800 miles ago and I can hear the difference in the sound and getting ready to retension mine.

V2Rocket

Looks like I need to bust out that funky two-prong tool again...to the attic!

greenshoes3

those are girl instruments......

sillbeer

Percussionist rule! I played orchestral, concert as well as street/drum corps

Jfrahm

New belts get scary loose after a few hundred miles. Since it only takes 10 minutes I retensioned mine at 500 and 1000 miles, easier to do that than keep the revs down and be paranoid. If you commute in your car 1000 miles should be no problem since you'll put on some lazy miles pretty fast. Actually 1000 miles is probably fine any old way but you might be pretty taken aback by how loose it gets.

Some wrenches put them on really tight and let them wear and stretch in, I think this is pretty dumb. Puts too much pressure on the waterpump, crank/cam snout, etc.

-Joel.

yellowline

That's your problem. I initially set my last belt to 4.0 on the 9201 scale, as per the factory instructions. In 1200 miles, it was about a 1.5. Spec on a used belt is about 2.7, I think (off the top of my head).

Wipeout

Orchestra, Concert, Jazz, and Samba for me. I think we need a drummers thread in the OT - I know there are at least 2 other drummers thataway.

Mongo

Just retension. Mine did the same after rebuild. I still have to retension my new belt on the car right now.

apierce918

you had it too tight to begin with if you had the high pitched whine, if its lower, its probably in spec where it should be

Mongo

He's right. These things should really sound like sewing machines. BTW, are you sure it's the timing belt you're hearing and not the balance shaft belt?