Morris Minor Owners Club

Hi all.

I am using the original (Champion N5) spark plugs in my Morris. I have noticed that the more recent A engines use the N5Y plugs where the nose is protruding. Is this also a better option for my 1098 engine, or should I stick with the N5 plugs? Why do the more recent A engines use the protruding plugs?
Cheers,

Rein

I have mostly used Champion N9Y plugs in previous 948/1098 cars. I am currently using NKG BP6ES with sucess. These are similar to the N9Y with the extended nose. I dont know how true this is but I was told a while ago that the extended nose made for better firing as the plug tip was not so shrouded.

Thanks.
Makes sense to me. When I got the car N9Y spark plugs where used. I changed them to N5 because this is what the workshop manual lists. They perform well, but I also remember I didn't have any issues with the N9Y plugs. Maybe the A engine isn't particular when it comes to spurk plugs?

It normal 'tune' it's not particular - and I'm not sure if N5Y plugs are available. Normal use would be N9Y or even N12Y. I use N6Y plugs in my Mini - but that's a 'hard' plug for a modified engine.

N5 and N5Y are available. N5 is a little bit more dificult to get. I will try N9Y again for my next set of plugs and see if I notice any difference.

I am currently using NKG BP6ES with sucess. These are similar to the N9Y with the extended nose. I dont know how true this is but I was told a while ago that the extended nose made for better firing as the plug tip was not so shrouded.

I have been told that as well and that NGK plugs work better if you have an unleaded head.

I cannot find an N5Y listed for Champion, but there are both N4Y and N6Y, so if there is an N5Y, it would be in between these two and would be a very 'cold' plug, suitable only for very highly modified engines.

The 'fire better' debate was proven in the mid/late 1960's when the 'projected core nose' design of plug appeared. There were a number of research papers produced by the Automobile Division of the IMechE at the time, which demonstrated very clearly they were much more tolerant of 'less than ideal' combustion conditions than the previous 'flat core' N series.

The equivalent of an N5 is either the Champion N9Y or NGK BP6ES, both are the same basic design. When Champion introduced the 'Y' suffix range, they also changed the numbers relating to the heat range for the plug, so there is no equivalence in application between lower number end of 'N' series, e.g. N4 and N4Y.

The Champion number decreases as the plug gets 'colder' or 'harder', whereas NGK increase! For the projected core nose ranges, both have very similar heat ranges at number 7.

Just to add my penyworth, Rein, I've been using NGK BP7ES on my completely standard 1098 Traveller without any problems. I started using such a cold plug because I had occasional pre-ignition when pulling hard with a loaded car and trailer. Now gone to BP6ES 'cos I tend to do more short and trailerless journeys. Generally, I prefer to use the coldest plug that doesn't foul and have been happy with NGK range in all my cars, etc.
All in all, I don't think the choice in NGK plugs is critical - they seem to be quite tolerant. Regards, MikeN.

Thanks.
Good to know that the N5 is similar to the N9 and that the Y is an actual improvement. Now I only need to stock N9Y or BP6ES because my motorbike uses them too.

Cheers

Ah - Burt Munro would be proud of you!

Ah - Burt Munro would be proud of you!

?? Lost on me!! Please explain.