SNC question - 1990/91 NA6

[rpost77]

History of my 1990/91 NA6:-

Build date from plate in engine bay:- September 1990

Australian Compliance plate from engine bay:- January 1991

Delivery Date (according to entry on Mazda Service sheet):- 31/10/1991

I purchased the car in October 1993 from John Newell Mazda - car had 15000 KMs at the time.

Car currently has 181000 KMs on it.

Had the timing belt replaced at 100000 KMs in May 2001.

The car appears to have a Long Nose Crank - 8 slot pulley. I have seen an SNC pulley - my brother-in-law recently bought a 1989 Eunos import and his car definitely has an SNC (4 slot pulley).

My question - everything I have read on this forum and miata.net seems to indicate that the SNC engines were being built up to early/mid 1991 and the LNC engines weren't introduced until 1991.

Based on that info and the dates for my car, I would expect that mine would have an SNC (happy it does not appear that way!).

Is there a definitive VIN or Engine Number range for the SNC engines somewhere that would confirm whether my car has/had a SNC engine? Or a definite date when the LNC engine was introduced?

Is it possible that mine was originally an SNC - it failed and was returned (would have been still in warranty at the time) and replaced and then I bought it?

Not really a big issue - mainly curious as by all accounts it "should" be an SNC and I've only learnt enough in the past few years to actually be curious.

Any illumination on the subject would be appreciated.

[zephyrus17]

SpeedTheory @ miata.net
If you have a 1991 with VIN 209447 or more, you're safe.

[Matty]

SpeedTheory @ miata.net
If you have a 1991 with VIN 209447 or more, you're safe.

I think that only applies to the US VINs, not ours. Also bear in mind that "1991" is a Model Year in the US, not a calendar year.

Best source would be a Mazda dealership, look up the parts 'fiche and see where there is a breakpoint in the crank part number. The dealer should also be able to tell you what the original engine number of your car was.

[93_Clubman]

SpeedTheory @ miata.net
If you have a 1991 with VIN 209447 or more, you're safe.

I think that only applies to the US VINs, not ours. Also bear in mind that "1991" is a Model Year in the US, not a calendar year.

Best source would be a Mazda dealership, look up the parts 'fiche and see where there is a breakpoint in the crank part number. The dealer should also be able to tell you what the original engine number of your car was.

JDM & USDM yes, but unfortunately I don't believe we've been able to tie it down to a month/ year for Australian delivered MX5s. Mazda Australia could also help - phone: 1800 034 411,
or email: <CustomerServiceEnq@mazda.com.au>, with the question, the VIN, & engine number.