Short nose crank, worth worrying about?

[patmahe]

Hi all,

Just wondering what versions this appeared on and when and is it worth worrying about? Would an Mx-5 having one put you off buying?

[GravelBen]

Was only on '89 and some '90 cars from memory, and not worth worrying about IMO - I've even heard one MX5 mechanic say he's personally seen more long nose failures than short ones.

[Salgar]

I think the short nose cars has a lot less power than the others.

[GravelBen]

Salgar said:

I think the short nose cars has a lot less power than the others.

No difference in power - just the short nose crank is slightly more susceptible to damage from clumsy mechanics.

[MX-5 Lazza]

GravelBen said:

Salgar said:

I think the short nose cars has a lot less power than the others.

No difference in power - just the short nose crank is slightly more susceptible to damage from clumsy mechanics.

In fact, as the crank is lighter it's more likely to have a touch more power

[Garath3231]

MX-5 Lazza said:

In fact, as the crank is lighter it's more likely to have a touch more power

Thats exactly right, infact some people believe it to be the sweetest engine.

in my opinion, don't worry about it, I've seen both types fail

[Liokault]

Fundamentally, it will fail. I got my car with an SNC and it failed after 16 years. It’s only a matter of time.

If it came down to a really nice rust free car with a SNC or a rusty car without, I would go with the SNC as a new engine is easy to fit where you will be chasing rust forever.

[anonymous-user]

I agree - the condition of the body is far more important. The engine is easy to replace, there are loads around and it's a pretty simple DIY job. Mine was a full recon engine and cost £250 IIRC, fitting took perhaps 1/2 a day and all you need are a basic toolset and a small engine hoist (which you can rent for a weekend for a few quid).

If (or when) the body rusts that's when it starts to get expensive and tricky to fix.

[Liokault]

JimSuperSix said:

I agree - the condition of the body is far more important. The engine is easy to replace, there are loads around and it's a pretty simple DIY job. Mine was a full recon engine and cost £250 IIRC, fitting took perhaps 1/2 a day and all you need are a basic toolset and a small engine hoist (which you can rent for a weekend for a few quid).

If (or when) the body rusts that's when it starts to get expensive and tricky to fix.

Also, if you find a car with no rust and good paint, it will probably be a later car anyway, hence no SNC

[Digby]

All about the big nose, short nose and long nose (long nose being a service part)

http://www.miata.net/garage/crankshaft.html

I have a 92 car with a big nose crank (8 slots in pulley) and it was wobbling all over the place when I got it.Incorrect/bad maintenance is often to blame with those.The difference, it would seem, is that they can often be fixed as damage to the crank is far less likely.With a short nose, any wobble is mostly put down to bad design and if left, the crank wears and the car will begin to lose power.

I was told my car was as good as dead and needed a new engine back then.I did some digging, however and ended up getting it fixed at a friends garage for the fraction of the cost of a new engine.Touch wood, it still seems fine and it's just as quick as the day I got it.