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

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.

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

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

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