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Can long nose, (skinny) crank be installed without pulling the engine?



 
 
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  #1  
Old May 22nd 06, 03:25 AM posted to rec.autos.makers.mazda.miata
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Posts: n/a
Default Can long nose, (skinny) crank be installed without pulling the engine?

I recently purchased a super low mileage 1990 miata with short crank.
It's really beautiful and looks like new. I'd like to have the skinny
crank installed for a personal feeling of security when I'm driving
through the desert at night. At his point I don't have a handle on the
possible cost of the replacement.

Can it be installed without pulling the engine? Does anyone know
whether it's the kind of job a local import shop could do or should I
go to the mazda dealer?

Thanks for your help.

Ralph

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  #2  
Old May 22nd 06, 04:09 AM posted to rec.autos.makers.mazda.miata
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Posts: n/a
Default Can long nose, (skinny) crank be installed without pulling the engine?


> wrote in message
ups.com...
>I recently purchased a super low mileage 1990 miata with short crank.
> It's really beautiful and looks like new. I'd like to have the skinny
> crank installed for a personal feeling of security when I'm driving
> through the desert at night. At his point I don't have a handle on the
> possible cost of the replacement.
>
> Can it be installed without pulling the engine? Does anyone know
> whether it's the kind of job a local import shop could do or should I
> go to the mazda dealer?
>
> Thanks for your help.
>
> Ralph


In theory it could be done. In practice it would be much easier to remove
the engine. It is a task that should be done by a very experienced shop,
which may exclude your local dealer.
But, I b'lieve all that really need be done is to replace the bolt holding
the pulley to the crankshaft with the upgraded bolt and properly tighten it,
using thread locker.


  #3  
Old May 22nd 06, 04:41 AM posted to rec.autos.makers.mazda.miata
external usenet poster
 
Posts: n/a
Default Can long nose, (skinny) crank be installed without pulling the engine?

I believe Chas is correct and yes, this can be done with the engine still in
the car. If and when you do this, make sure that the shaped end of the 'key'
goes in first and that the shape of the 'key' matches pretty well with the
shape of the slot. I also think part of the problem is that the key is
simply too short which may allow it to migrate all the way to one end of the
slot where it's more likely to get itself into trouble. A simple bit of
liquid steel in the outer portion of the slot will work as a shim / spacer,
to keep that key from wandering later.

Is the mileage near timing belt time, cause the work greatly overlaps and
could be done together.

Good luck,
Chris
99BBB

"Chas Hurst" > wrote in message
...
>
> > wrote in message
> ups.com...
>>I recently purchased a super low mileage 1990 miata with short crank.
>> It's really beautiful and looks like new. I'd like to have the skinny
>> crank installed for a personal feeling of security when I'm driving
>> through the desert at night. At his point I don't have a handle on the
>> possible cost of the replacement.
>>
>> Can it be installed without pulling the engine? Does anyone know
>> whether it's the kind of job a local import shop could do or should I
>> go to the mazda dealer?
>>
>> Thanks for your help.
>>
>> Ralph

>
> In theory it could be done. In practice it would be much easier to remove
> the engine. It is a task that should be done by a very experienced shop,
> which may exclude your local dealer.
> But, I b'lieve all that really need be done is to replace the bolt holding
> the pulley to the crankshaft with the upgraded bolt and properly tighten
> it, using thread locker.
>



  #4  
Old May 31st 06, 04:33 PM posted to rec.autos.makers.mazda.miata
external usenet poster
 
Posts: n/a
Default Can long nose, (skinny) crank be installed without pulling the engine?

There has been a lot written about the failure of the early crankshaft
noses. My '90 suffered from this and I "fixed" it a couple of times. It
seems stable for now, but I am resigned to the possibility of it failing
again.

Early write ups included the admonishment that one must religiously insert
the key correctly, torque it accurately, etc. My experience suggests that
this is good advice, but there is a part to the story that I believe is
being missed.

The original crankshaft pulley on my car is different from the replacement
part in what I consider a critical way. The original part has a 1mm relief
where it sits on the seat of the crankshaft nose; the replacement part does
not. This means that the original pulley flange was 1mm closer to the engine
block than the replacement. The difference this makes is that the original
part rubbed against the engine block; the replacement does not. More
specifically: the original part rubbed at a "high side" arc, other areas of
the pulley did not.

Why is this important? Consider the effect of an asymmetrical contact
between the pulley and the engine block over time. It creates a constant
"flexing" that leads to deterioration of the mechanical joint. Not
understanding this at the time, I removed the pulley to replace the oil seal
believing that by strictly following the instructions in the shop manual,
all would be OK. I was wrong. My first clue should have been the relatively
small amount of force required to loosen the nut; on other cars I have done
(including a couple of Mazda Protégés) this involved considerable effort.

If you must do this (because you want to replace the oil seal), I suggest
the following:

1. purchase a new pulley if the original has the 1mm relief on the seat
side
2. ensure the new pulley does not have the 1mm relief on the seat side
3. clean the nose shaft and pulley bore carefully, use alcohol to remove
any oils and use JB weld to bond the surfaces.
4. use a new keyway and torque to the specified number (80 - 87 lb/ft).
Allow sufficient cure time for the adhesive.

I believe that the pulley design which allowed the interference between the
pulley and the crankcase is the root cause of the problem. Contributing to
this is likely the weak design that has been the subject of much discussion
in the enthusiast community. Considering the merit of the latter: adding
the JB weld is good insurance.

Good luck with this. It's a great car for certain!

Ken


"Chris D'Agnolo" > wrote in message
...
> I believe Chas is correct and yes, this can be done with the engine still

in
> the car. If and when you do this, make sure that the shaped end of the

'key'
> goes in first and that the shape of the 'key' matches pretty well with the
> shape of the slot. I also think part of the problem is that the key is
> simply too short which may allow it to migrate all the way to one end of

the
> slot where it's more likely to get itself into trouble. A simple bit of
> liquid steel in the outer portion of the slot will work as a shim /

spacer,
> to keep that key from wandering later.
>
> Is the mileage near timing belt time, cause the work greatly overlaps and
> could be done together.
>
> Good luck,
> Chris
> 99BBB
>
> "Chas Hurst" > wrote in message
> ...
> >
> > > wrote in message
> > ups.com...
> >>I recently purchased a super low mileage 1990 miata with short crank.
> >> It's really beautiful and looks like new. I'd like to have the skinny
> >> crank installed for a personal feeling of security when I'm driving
> >> through the desert at night. At his point I don't have a handle on the
> >> possible cost of the replacement.
> >>
> >> Can it be installed without pulling the engine? Does anyone know
> >> whether it's the kind of job a local import shop could do or should I
> >> go to the mazda dealer?
> >>
> >> Thanks for your help.
> >>
> >> Ralph

> >
> > In theory it could be done. In practice it would be much easier to

remove
> > the engine. It is a task that should be done by a very experienced shop,
> > which may exclude your local dealer.
> > But, I b'lieve all that really need be done is to replace the bolt

holding
> > the pulley to the crankshaft with the upgraded bolt and properly tighten
> > it, using thread locker.
> >

>
>



  #5  
Old June 1st 06, 05:42 AM posted to rec.autos.makers.mazda.miata
external usenet poster
 
Posts: n/a
Default Can long nose, (skinny) crank be installed without pulling the engine?

One more thing:

Add an additional shim to the keyway if the channel is worn and there is any
radial slop. Even with the JB weld, it is a good idea to not depend on the
adhesive to keep things aligned. Put the additional shim on the correct side
so that the original relationship of the pulley to keyway (and crankshaft)
is maintained.

Ken


"KWS" > wrote in message
...
> There has been a lot written about the failure of the early crankshaft
> noses. My '90 suffered from this and I "fixed" it a couple of times. It
> seems stable for now, but I am resigned to the possibility of it failing
> again.
>
> Early write ups included the admonishment that one must religiously insert
> the key correctly, torque it accurately, etc. My experience suggests that
> this is good advice, but there is a part to the story that I believe is
> being missed.
>
> The original crankshaft pulley on my car is different from the replacement
> part in what I consider a critical way. The original part has a 1mm relief
> where it sits on the seat of the crankshaft nose; the replacement part

does
> not. This means that the original pulley flange was 1mm closer to the

engine
> block than the replacement. The difference this makes is that the original
> part rubbed against the engine block; the replacement does not. More
> specifically: the original part rubbed at a "high side" arc, other areas

of
> the pulley did not.
>
> Why is this important? Consider the effect of an asymmetrical contact
> between the pulley and the engine block over time. It creates a constant
> "flexing" that leads to deterioration of the mechanical joint. Not
> understanding this at the time, I removed the pulley to replace the oil

seal
> believing that by strictly following the instructions in the shop manual,
> all would be OK. I was wrong. My first clue should have been the

relatively
> small amount of force required to loosen the nut; on other cars I have

done
> (including a couple of Mazda Protégés) this involved considerable effort.
>
> If you must do this (because you want to replace the oil seal), I suggest
> the following:
>
> 1. purchase a new pulley if the original has the 1mm relief on the seat
> side
> 2. ensure the new pulley does not have the 1mm relief on the seat side
> 3. clean the nose shaft and pulley bore carefully, use alcohol to remove
> any oils and use JB weld to bond the surfaces.
> 4. use a new keyway and torque to the specified number (80 - 87 lb/ft).
> Allow sufficient cure time for the adhesive.
>
> I believe that the pulley design which allowed the interference between

the
> pulley and the crankcase is the root cause of the problem. Contributing to
> this is likely the weak design that has been the subject of much

discussion
> in the enthusiast community. Considering the merit of the latter: adding
> the JB weld is good insurance.
>
> Good luck with this. It's a great car for certain!
>
> Ken
>
>
> "Chris D'Agnolo" > wrote in message
> ...
> > I believe Chas is correct and yes, this can be done with the engine

still
> in
> > the car. If and when you do this, make sure that the shaped end of the

> 'key'
> > goes in first and that the shape of the 'key' matches pretty well with

the
> > shape of the slot. I also think part of the problem is that the key is
> > simply too short which may allow it to migrate all the way to one end of

> the
> > slot where it's more likely to get itself into trouble. A simple bit of
> > liquid steel in the outer portion of the slot will work as a shim /

> spacer,
> > to keep that key from wandering later.
> >
> > Is the mileage near timing belt time, cause the work greatly overlaps

and
> > could be done together.
> >
> > Good luck,
> > Chris
> > 99BBB
> >
> > "Chas Hurst" > wrote in message
> > ...
> > >
> > > > wrote in message
> > > ups.com...
> > >>I recently purchased a super low mileage 1990 miata with short crank.
> > >> It's really beautiful and looks like new. I'd like to have the

skinny
> > >> crank installed for a personal feeling of security when I'm driving
> > >> through the desert at night. At his point I don't have a handle on

the
> > >> possible cost of the replacement.
> > >>
> > >> Can it be installed without pulling the engine? Does anyone know
> > >> whether it's the kind of job a local import shop could do or should I
> > >> go to the mazda dealer?
> > >>
> > >> Thanks for your help.
> > >>
> > >> Ralph
> > >
> > > In theory it could be done. In practice it would be much easier to

> remove
> > > the engine. It is a task that should be done by a very experienced

shop,
> > > which may exclude your local dealer.
> > > But, I b'lieve all that really need be done is to replace the bolt

> holding
> > > the pulley to the crankshaft with the upgraded bolt and properly

tighten
> > > it, using thread locker.
> > >

> >
> >

>
>



 




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