I've got an engine from an MX5 which was an NA car which I think means 1989 - 1992. I have the exact number but I was too naive to get the registration / VIN etc. from the scrappy. I do not have a donor. Will I need a catalyst?

Shouldn't do, but you will need to prove the age of the engine - possibly a letter from the manufacturer stating the age of the engine no.

You do not need a cat if you can prove your engine is from a July '95 car or earlier. If you cannot prove it though...

Don't know if this is true for the MX5 but the Haynes manual on the ST1100 gives engine dates for the engine code... Worked for me (though I also got a letter of confirmation from Honda UK at great cost- £35!!!)... but then my SVA tester was pretty trusting and also took my photograph of the engine number (which is only accessible from under the car) as proof of engine identity.... As it happens that photograph was actually of my engine and not a different one but......

I contacted Mazda UK with my MX5 engine number, VIN number etc... and they spoke to Mazda in Japan and they then sent me a letter confirming the date my engine was manufactured.

It was a total ball ache and Mazda UK initially said they couldn't do it - however I managed to beat them up enough and they contacted Mazda Japan.

Give Mazda UK a ring on 0845 603 0229

Good Luck

As Smart51 says; you shouldn't need a CAT if you can prove the age of your engine. My car has no CAT and my engine was built June 1993 or 1994 - I forget.

[Edited on 26/3/07 by JAG]

Many thanks everyone. I'll get in touch with Mazda as you suggest JAG and take the pain!

UK spec 5's are cat spec from '92 I think, only the grey imports (eunos roadster) can be cat free up to 95. I know this because I SVA'd an 1992 import in 1999.
There are many ironies & idiosyncracities in these rules.... It was only because it was an import that I got away with a carbed v8 in mine, had it been a UK model I would have needed cats/injection
Good luck!
Bob