Timing Belt Idler Pulley question

The saga of replacing my water pump continues. Finally swapped out the
water pump, and now am putting everything back together. For those of
you who have not ever considered replacing your water pump - it is a
rather time consuming endeavor on the Miata - remove the cam shaft
cover, accessory belts, timing belt, etc...

Anyhow, putting it all back together now. After torquing the timing
belt idler pulley to the specified torque - should the idler pulley
spin or be locked down tight? In other words, do I need to buy a new
timing belt idler pulley?

kc

On 21 Jan 2007 16:49:18 -0800, wrote:

>The saga of replacing my water pump continues. Finally swapped out the
>water pump, and now am putting everything back together. For those of
>you who have not ever considered replacing your water pump - it is a
>rather time consuming endeavor on the Miata - remove the cam shaft
>cover, accessory belts, timing belt, etc...
>
>Anyhow, putting it all back together now. After torquing the timing
>belt idler pulley to the specified torque - should the idler pulley
>spin or be locked down tight? In other words, do I need to buy a new
>timing belt idler pulley?
>
>kc
It should definitely spin after torquing. I don't know if you need to
buy a new one or not, but if it doesn't spin freely, loosen it and fix
what ever is hanging it up.

"Natman" > wrote in message
...
> On 21 Jan 2007 16:49:18 -0800, wrote:
>
> It should definitely spin after torquing. I don't know if you need to
> buy a new one or not, but if it doesn't spin freely, loosen it and fix
> what ever is hanging it up.

I may be missing something here, but I remember torquing the idler pulley
after having the replacement timing belt in place. That being the case,
how is the idler pulley gonna spin freely if it applying tension to the
timing belt?
As I say, maybe my brain is suffering from frostbite, but...

Pete

Pete (at) wrote:
> "Natman" > wrote in message
> ...
> > On 21 Jan 2007 16:49:18 -0800, wrote:
> >
> > It should definitely spin after torquing. I don't know if you need to
> > buy a new one or not, but if it doesn't spin freely, loosen it and fix
> > what ever is hanging it up.
>
> I may be missing something here, but I remember torquing the idler pulley
> after having the replacement timing belt in place. That being the case,
> how is the idler pulley gonna spin freely if it applying tension to the
> timing belt?
> As I say, maybe my brain is suffering from frostbite, but...
>
> Pete

The tension pulley is definitely torqued after replacing the timing
belt. I could not find anything that said when to torque down the
idler pulley. My other thought was that while I could not spin the
pulley, that the timing belt could. For sure - the pulley was not
turning (by hand) when I took the timing belt off - so - what does that
mean? That is the million dollar question.

I am going to try and clean up the surface of the pulley (by the head
of the bolt) in case anything is causing friction, and potentially just
tighten to the min torque and see how that does. This project has
already taken longer than I had hoped - true I had to leave town for a
week - but two weekends later - still no car.

Any other ideas?

kc

In article .com>,
wrote:

> the pulley was not
> turning (by hand) when I took the timing belt off - so - what does that
> mean?

A seized pulley gets replaced. They typically last long enough that they
only need replacement at every other timing belt change. But at 114k,
when my water pump started leaking, the bearings in both pulleys were
dry and on their last legs.

On 22 Jan 2007 16:06:24 -0800, wrote:

>
>Pete (at) wrote:
>> "Natman" > wrote in message
>> ...
>> > On 21 Jan 2007 16:49:18 -0800, wrote:
>> >
>> > It should definitely spin after torquing. I don't know if you need to
>> > buy a new one or not, but if it doesn't spin freely, loosen it and fix
>> > what ever is hanging it up.
>>
>> I may be missing something here, but I remember torquing the idler pulley
>> after having the replacement timing belt in place. That being the case,
>> how is the idler pulley gonna spin freely if it applying tension to the
>> timing belt?
>> As I say, maybe my brain is suffering from frostbite, but...
>>
>> Pete
>
>The tension pulley is definitely torqued after replacing the timing
>belt. I could not find anything that said when to torque down the
>idler pulley. My other thought was that while I could not spin the
>pulley, that the timing belt could. For sure - the pulley was not
>turning (by hand) when I took the timing belt off - so - what does that
>mean? That is the million dollar question.
>
From your first post: " After torquing the timing
belt idler pulley to the specified torque - should the idler pulley
spin or be locked down tight? "

From this I assumed that the pullet turned freely *before* you
tightened it down. If you can't turn the pulley by hand, then it has
siezed and will need to be replaced.

On Jan 22, 7:37 pm, Natman > wrote:
> On 22 Jan 2007 16:06:24 -0800, wrote:
>
>
>
>
>
> >Pete (at) wrote:
> >> "Natman" > wrote in message
> . ..
> >> > On 21 Jan 2007 16:49:18 -0800, wrote:
>
> >> > It should definitely spin after torquing. I don't know if you need to
> >> > buy a new one or not, but if it doesn't spin freely, loosen it and fix
> >> > what ever is hanging it up.
>
> >> I may be missing something here, but I remember torquing the idler pulley
> >> after having the replacement timing belt in place. That being the case,
> >> how is the idler pulley gonna spin freely if it applying tension to the
> >> timing belt?
> >> As I say, maybe my brain is suffering from frostbite, but...
>
> >> Pete
>
> >The tension pulley is definitely torqued after replacing the timing
> >belt. I could not find anything that said when to torque down the
> >idler pulley. My other thought was that while I could not spin the
> >pulley, that the timing belt could. For sure - the pulley was not
> >turning (by hand) when I took the timing belt off - so - what does that
> >mean? That is the million dollar question.From your first post: " After torquing the timing
> belt idler pulley to the specified torque - should the idler pulley
> spin or be locked down tight? "
>
> From this I assumed that the pullet turned freely *before* you
> tightened it down. If you can't turn the pulley by hand, then it has
> siezed and will need to be replaced.

But, if the pulley is spinning - then it is spinning metal on metal,
vs. the tension pulley which spins freely and does not touch the metal
behind it. As for the idler pulley, I don't know how it could have
ever spun freely - the bolt head presses against the pulley - what
would sieze? Are we sure it should spin freely?

Are we sure it should spin freely?

If it doesn't, you will be replacing the new timing belt very shortly, as
well as getting a new idler pulley.
If tightening the mounting bolt causes it to not turn freely, something is
wrong.

When we replacet the timing belt on my 99, both pulleys felt a bit rough, so
they were replaced. They did turn freely.

> wrote in message
ups.com...
>
>
> On Jan 22, 7:37 pm, Natman > wrote:
> > On 22 Jan 2007 16:06:24 -0800, wrote:
> >
> >
> >
> >
> >
> > >Pete (at) wrote:
> > >> "Natman" > wrote in message
> > . ..
> > >> > On 21 Jan 2007 16:49:18 -0800, wrote:
> >
> > >> > It should definitely spin after torquing. I don't know if you need
to
> > >> > buy a new one or not, but if it doesn't spin freely, loosen it and
fix
> > >> > what ever is hanging it up.
> >
> > >> I may be missing something here, but I remember torquing the idler
pulley
> > >> after having the replacement timing belt in place. That being the
case,
> > >> how is the idler pulley gonna spin freely if it applying tension to
the
> > >> timing belt?
> > >> As I say, maybe my brain is suffering from frostbite, but...
> >
> > >> Pete
> >
> > >The tension pulley is definitely torqued after replacing the timing
> > >belt. I could not find anything that said when to torque down the
> > >idler pulley. My other thought was that while I could not spin the
> > >pulley, that the timing belt could. For sure - the pulley was not
> > >turning (by hand) when I took the timing belt off - so - what does that
> > >mean? That is the million dollar question.From your first post: "
After torquing the timing
> > belt idler pulley to the specified torque - should the idler pulley
> > spin or be locked down tight? "
> >
> > From this I assumed that the pullet turned freely *before* you
> > tightened it down. If you can't turn the pulley by hand, then it has
> > siezed and will need to be replaced.
>
> But, if the pulley is spinning - then it is spinning metal on metal,
> vs. the tension pulley which spins freely and does not touch the metal
> behind it. As for the idler pulley, I don't know how it could have
> ever spun freely - the bolt head presses against the pulley - what
> would sieze? Are we sure it should spin freely?
>

In article . com>,
wrote:

> But, if the pulley is spinning - then it is spinning metal on metal,
> vs. the tension pulley which spins freely and does not touch the metal
> behind it. As for the idler pulley, I don't know how it could have
> ever spun freely - the bolt head presses against the pulley - what
> would sieze? Are we sure it should spin freely?

Both pulleys contain sealed ball bearings. Eventually, the grease
migrates out past the seal, and shortly thereafter the dry bearing will
seize. A seized pulley will destroy the belt in short order.

The goal is to change them just before this occurs. :-)

On 22 Jan 2007 21:46:31 -0800, wrote:


>
>But, if the pulley is spinning - then it is spinning metal on metal,
>vs. the tension pulley which spins freely and does not touch the metal
>behind it. As for the idler pulley, I don't know how it could have
>ever spun freely - the bolt head presses against the pulley - what
>would sieze? Are we sure it should spin freely?

The idler pulley has a center mounting piece about 1.25 inches in
diameter. Outside of the center is the inner race of the bearing that
remains stationary. The brown seal and the outer race of the bearing
turn with the pulley.

Yes the pulley HAS TO TURN. No question about it.

The bolt should touch the center mount AND NOTHING ELSE. Judging by
the mark on my old pulley the washer under the bolt was about 5/8" in
diameter. If yours is so large that it touches anything else, you are
using the wrong bolt / washer. Or possible you are trying to install
the pulley upside down. The pulley shoud be installed with the
projection in the center TOWARD the engine block.