[barabus]

My Testa has thrown a belt months ago, i replaced it and that one started fraying. It was time for my cam belt service so i told him about the alt belt. He said the pulley seems slightly out of allignment so he re-alligned it. Half way home from the service garage as i applied some heavy right foot it shot off again. Had the car traillered back to garage the tech will look into the problem but can't think what can be wrong? Any ideas why it should be throwing belts?

Another problem while i'm at it was the tuning was way out on the left bank he could'nt set it correctly while the right bank was spot on, as i'd just replaced all 12 injectors he said it must be the metering head, does this sound right?

Now he's got the car back he'll take off the metering heads and send them away for cleaning and i hope that solves that problem?

So that's me Carlos again.

[Granucci]

MY mind: has to be alignment or tensioner. Need a serious look, you seem to be getting lucky. Fraying means only to me there is something messin with it, so if you can open that baby up and rev while in the shop, might see it.

r

[Boxer]

Originally Posted by barabus

My Testa has thrown a belt months ago, i replaced it and that one started fraying. It was time for my cam belt service so i told him about the alt belt. He said the pulley seems slightly out of allignment so he re-alligned it. Half way home from the service garage as i applied some heavy right foot it shot off again. Had the car traillered back to garage the tech will look into the problem but can't think what can be wrong? Any ideas why it should be throwing belts?

Another problem while i'm at it was the tuning was way out on the left bank he could'nt set it correctly while the right bank was spot on, as i'd just replaced all 12 injectors he said it must be the metering head, does this sound right?

Now he's got the car back he'll take off the metering heads and send them away for cleaning and i hope that solves that problem?

So that's me Carlos again.

Could the alternator be flexing on its mounts?

Also is the right spec belt fitted. Had a similar problem a few years ago when Ferrari sourced the wrong spec belt and it kept jumping whenever I accelerated hard.

[barabus]

Originally Posted by Granucci

MY mind: has to be alignment or tensioner. Need a serious look, you seem to be getting lucky. Fraying means only to me there is something messin with it, so if you can open that baby up and rev while in the shop, might see it.

r

While the engine was out techy put a straight edge on the pulleys' there was a slight way out and he rectified it, or so he thought?

Originally Posted by Boxer

Could the alternator be flexing on its mounts?

Also is the right spec belt fitted. Had a similar problem a few years ago when Ferrari sourced the wrong spec belt and it kept jumping whenever I accelerated hard.

Dayco belt supplied by Maranello UK. Bolted down good and proper so not flexing. However it is not the original alternator, a new one was fitted when the regulator went bust and could'nt find a replacement. This belt was OK until i accelerated hard.

[Boxer]

Originally Posted by barabus

While the engine was out techy put a straight edge on the pulleys' there was a slight way out and he rectified it, or so he thought?

Dayco belt supplied by Maranello UK. Bolted down good and proper so not flexing. However it is not the original alternator, a new one was fitted when the regulator went bust and could'nt find a replacement. This belt was OK until i accelerated hard.

Something is flexing under load and causing the belt to pop. DO you still have the older frayed belt? If so can you compare the inner grooves to the new one.

[carguy]

It's possible that the crankshaft and alternator pulleys could be mis-matched, meaning different groove dimensions and shapes? I do recall that some years ago that other TR owners had this issue, and they changed the alternator pulley to fix it.

The stock TR alternator mounts snugly into the left side cambelt cover, and there is practically no room for misalignment. Since you have a different alternator, it's very possible there are still alignment issues with the crankshaft pulley. Does your TR have a Bosch or a GM alternator?

Also be sure the correct tension is applied to the belt, a "rule of thumb" is that you should be able to "wobble" the belt back and forth about 1/2 inch to maybe 3/4 inch when it's tight, does this make sense?

[Gcalo]

Originally Posted by carguy

It's possible that the crankshaft and alternator pulleys could be mis-matched, meaning different groove dimensions and shapes? ---

That's a great point.

You may have an incorrect alternator pulley.

[barabus]

Originally Posted by carguy

It's possible that the crankshaft and alternator pulleys could be mis-matched, meaning different groove dimensions and shapes? I do recall that some years ago that other TR owners had this issue, and they changed the alternator pulley to fix it.

The stock TR alternator mounts snugly into the left side cambelt cover, and there is practically no room for misalignment. Since you have a different alternator, it's very possible there are still alignment issues with the crankshaft pulley. Does your TR have a Bosch or a GM alternator?

Also be sure the correct tension is applied to the belt, a "rule of thumb" is that you should be able to "wobble" the belt back and forth about 1/2 inch to maybe 3/4 inch when it's tight, does this make sense?

It's an AC Delco replacement alternator and the original pulley was put back on. The belt tension was applied by my mechanic so he should know the correct tension. He was thinking that maybe there's a lip on one side of the pulley and that it could have possibly been put on the wrong way, is this possible?

[Stkes]

Had The Problem frequently, just as described....when I changed the Service garage, they told me, One should use The "aged" spare part that's in the toolbox of The Car....since then it Never came up again.....don't ASK me why?....

[Gcalo]

An overtightened belt can do a lot of damage.

Maybe that was issue?

[Petervg1]

His Ferrari Service Bulletin might help: http://ferrari.cdyn.com/service_bulletins/sb10-19.pdf

[tazandjan]

Peter- That is a pretty nice website, thanks. Especially handy for owners of older cars.

[Petervg1]

You're welcome Terry :-)

[wetpet]

great post!

Originally Posted by Petervg1

His Ferrari Service Bulletin might help: http://ferrari.cdyn.com/service_bulletins/sb10-19.pdf

[Granucci]

Originally Posted by Stkes

Had The Problem frequently, just as described....when I changed the Service garage, they told me, One should use The "aged" spare part that's in the toolbox of The Car....since then it Never came up again.....don't ASK me why?....

welcome to the site.

However, I will take a bit of exception to the belt in the toolbox as it's for display only IMO unless you knew it's age and condition.

Age and condition is a key factor in some failures, too. I suspect they used that belt as the replacement one was incorrect and/or after replacing the belt, again, got it right in the adjustment/alignment: May never know.

Correct belt, fresh one off the shelf is key. RICAMBI IIRC threw out a bit of dated parts just for the expire reason...more likely the age would have some not only suspect, but could make one a bit liable.

I know this can start the endless belt discussion, but having fresh correct belts is better than an old one or one where the history is unknown.

2cents.

[Brian]

Originally Posted by Granucci

welcome to the site.

However, I will take a bit of exception to the belt in the toolbox as it's for display only IMO unless you knew it's age and condition.

Age and condition is a key factor in some failures, too. I suspect they used that belt as the replacement one was incorrect and/or after replacing the belt, again, got it right in the adjustment/alignment: May never know.

Correct belt, fresh one off the shelf is key. RICAMBI IIRC threw out a bit of dated parts just for the expire reason...more likely the age would have some not only suspect, but could make one a bit liable.

I know this can start the endless belt discussion, but having fresh correct belts is better than an old one or one where the history is unknown.

2cents.

Exactly correct.

The single V belt was a stupid idea for a 125 amp alternator and was a source of constant trouble. Ferrari abandoned it early on and offered a retrofit kit mentioned above.

The standard V belt needed to be so tight to be reliable it really overstresses the bearings in the alternator.

Ferrari only offers retrofit kits when they know and cannot deny they really stepped in it.


That was only one of 5 TSB's on the issue of Testarossa alternator belts by the way if that tells you anything.