Dumb spark plug question: Metric or not?

Have a 2000 Mazda Protege ES.... built in Japan.

I'm going to attempt to change the spark plugs myself
but have no idea if the actual plugs themselves in this
vehicle require a metric wrench!

If one buys say Autolite or whatever plugs.... is the
hex head on them metric as well and therefore requires
a metric spark plug wrench?

In article >,
wrote:

> If one buys say Autolite or whatever plugs.... is the
> hex head on them metric as well and therefore requires
> a metric spark plug wrench?

All sparkplug wrenches are metric. Always have been.

"Lanny Chambers" > wrote
> All sparkplug wrenches are metric. Always have been.

That's strange...I have spark plug sockets (have a rubber thingy to hold the
plug) marked 13/16 and 5/8. I think I bought the 13/16 when I owned a '63
Mini-Cooper.
--
Ken Lyons '97 Brilliant Black/'90 Classic Red
Inside the Beltway
[Remove the first two digits to reply]

"Ken Lyons" > wrote:

> "Lanny Chambers" > wrote
>> All sparkplug wrenches are metric. Always have been.
>
> That's strange...I have spark plug sockets (have a rubber thingy
> to hold the plug) marked 13/16 and 5/8. I think I bought the 13/16
> when I owned a '63 Mini-Cooper.

There are a lot of metric wrenches that are almost the same as SAE
sizes, for example 13mm and 1/2", 11mm and 3/8", etc.

Both 13/16" and 5/8" correspond closely to metric sizes and since plug
wrenches are hex rather than 12 point, they can be a little loose w/o
damaging the plugs.

Look he
http://www.vaughns-1-pagers.com/scie...conversion.htm



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XS11E > wrote:

> There are a lot of metric wrenches that are almost the same as SAE
> sizes, for example 13mm and 1/2", 11mm and 3/8", etc.

Oops, that's 11mm and 7/16", of course. I shouldn't try to do stuff
from memory...


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wrote:
> Have a 2000 Mazda Protege ES.... built in Japan.
>
> I'm going to attempt to change the spark plugs myself
> but have no idea if the actual plugs themselves in this
> vehicle require a metric wrench!
>
> If one buys say Autolite or whatever plugs.... is the
> hex head on them metric as well and therefore requires
> a metric spark plug wrench?

The MX-5 needs a 10mm spark plug socket (the smallest of the three
common sizes), and I expect the Protege is the same.

"Zog The Undeniable" > wrote in message
...
> wrote:
>> Have a 2000 Mazda Protege ES.... built in Japan.
>>
>> I'm going to attempt to change the spark plugs myself
>> but have no idea if the actual plugs themselves in this
>> vehicle require a metric wrench!
>>
>> If one buys say Autolite or whatever plugs.... is the
>> hex head on them metric as well and therefore requires
>> a metric spark plug wrench?
>
> The MX-5 needs a 10mm spark plug socket (the smallest of the three common
> sizes), and I expect the Protege is the same.

Miata uses a 16mm (5/8 ") socket. You will need a socket made for spark
plugs.

Chas Hurst wrote:

> Miata uses a 16mm (5/8 ") socket. You will need a socket made for spark
> plugs.
>
>
Spark plug socket dimensions don't refer to the distance across the
flats, which could well be 16mm - they refer to the thread size, and the
flats are always the same size for a given thread. No idea why.

"Zog The Undeniable" > wrote in message
...
> Chas Hurst wrote:
>
>> Miata uses a 16mm (5/8 ") socket. You will need a socket made for spark
>> plugs.
> Spark plug socket dimensions don't refer to the distance across the flats,
> which could well be 16mm - they refer to the thread size, and the flats
> are always the same size for a given thread. No idea why.

Spark plug sockets are dimensioned like every other socket-acroos the flats.
What dimension does the 10mm you posted correspond to? The threads on a
Miata plug are 14mm.

Chas Hurst wrote:

> Spark plug sockets are dimensioned like every other socket-acroos the flats.
> What dimension does the 10mm you posted correspond to? The threads on a
> Miata plug are 14mm.
>
>
It must be a weird British convention then:

http://www.spark-plugs.co.uk/pages/p...ance_tools.htm

Spark plug spanners (and *only* spark plug spanners) are sized by the
thread major diameter here. A bit of Googling suggests the rest of
Europe uses the actual across-flats measurement, so maybe the US does
the same. You learn something new every day!

I can always post a picture of one of my car's NGK BKR6E11-IX plugs
sitting in a "10mm" socket...