Spark Plugs (Hot or Cold) W221-S500-2006 UK Spec

[kalakov222]

Once again, I have gone back to the books to revive my memory about spark plugs.
As I understand, Hot Plugs ie ones with numbers 7 onwards or so run hotter, thus better suited for regions where climate is cold year round e.g. northern Europe, Moscow, Siberia, Canada etc, so that the Combustion Chamber gets hot quickly and remains hotter.

Conversely a 'Cold Plug' designated by its number 5 etc would run cooler thus more well suited to all year round warmer climates.

Can anyone please comment to confirm or rectify my understanding.

 

[Wearsafoxhat]

I think the hot and cold plugs is more to do with heat dissipation within the engine, (performance engines) than climate but could also be wrong.
Not all manufactures use the same scale though, some have low numbers as cold and some have them as hot.

Back to the books eh.


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[alexanderfoti]

Yes as above, every 100hp, go one step colder.

So fit the standard plugs onto your car and you will be ok.

 

[Wighty]

I never knew any of that

 

[pgh13]

I think the hot and cold plugs is more to do with heat dissipation within the engine, (performance engines) than climate but could also be wrong.
Not all manufactures use the same scale though, some have low numbers as cold and some have them as hot.

Back to the books eh.


Sent from my iPad using Tapatalk

I think you're right. I can remember discussions in magazines back in the 60s saying that using the wrong heat range could result in burnt pistons. You'd want a colder plug if you were tuning the engine for more power or possibly a hotter plug if the engine was burning oil to help keep it clear of deposits.

Good explanation here from NGK

http://www.ngk-sparkplugs.jp/english/techinfo/qa/q03/index.html

 

[RhodieBill]

Just think of it as: (As in Performance).

Hot Engine = Cold Plugs.
Standard Engine = Medium - Hot Plugs.

And just be careful as some Manufacturers Higher Number = Colder the Plug and others the other way around!

This Article might shed some light: https://www.gsparkplug.com/shop/spark-plug-heat-range

 

[kalakov222]

I think the hot and cold plugs is more to do with heat dissipation within the engine, (performance engines) than climate but could also be wrong.
Not all manufactures use the same scale though, some have low numbers as cold and some have them as hot.

Back to the books eh.


Sent from my iPad using Tapatalk

apologies for the vague post, I am referring to Bosch plugs nomenclature.

 

[kalakov222]

I think you're right. I can remember discussions in magazines back in the 60s saying that using the wrong heat range could result in burnt pistons. You'd want a colder plug if you were tuning the engine for more power or possibly a hotter plug if the engine was burning oil to help keep it clear of deposits.

Good explanation here from NGK

http://www.ngk-sparkplugs.jp/english/techinfo/qa/q03/index.html

thank you, will review.

 

[kalakov222]

Just think of it as: (As in Performance).

Hot Engine = Cold Plugs.
Standard Engine = Medium - Hot Plugs.

And just be careful as some Manufacturers Higher Number = Colder the Plug and others the other way around!

This Article might shed some light: https://www.gsparkplug.com/shop/spark-plug-heat-range

thanks

 

[LostKiwi]

Also the numbering scheme is manufacturer dependent. Some a lower number is colder, some it's hotter.
As above a colder plug transfers heat away from the tip and into the cylinder head more efficiently. Too hot a plug will lead to pinking and detonation in the chamber, too cold a plug will lead to plugs fouling (being unable to burn off residues).