|
Apart from everything else, sparkplugs have a heat range, an ideal range where they are designed to operate at, and diffrent motors need diffrent heat range plugs.
NGK plugs are colder the higer number you go, and hotter for the lower numbers, other plugs can be diffrent though.
Generaly a Turbo needs a colder plug, because the engine runs hotter, meaning you need a colder plug to work properly in the temprature that the motor runs at. (a colder plug can tolerate a higher heat range)
It's not quite that simple, but explaining more just makes it more complex.
A standard Volvo usualy runs like a BP5ES or BP6ES, the Turbos need a BP7ES and even a BP8ES if your upping the boost a lot, otherwise the plug can melt or just start to missfire at speed.
If you want to see a motor that runs real hot, try a rotary, they use anything from a 9 to a 14.
Some motors have piston slap, generaly it's just the piston moving around in the bore, as the motor heats the piston expands and most of the time it goes away, even modern day engines tend to do it.
It can be a sign though of a worn engine, if it does it when hot it's not such a great thing.
But I'm only guessing as to what the noise is in your case, it's hard to know what something is without hearing it.
I know my engine has some slap when cold, but I also know there is another noise I can't yet find, noises drive you mad when you don't know what they are.
Mechanics use a simular device to what a doctor uses when trying to find out what noises are, the good old stescope, allthough the ones in the auto stores often have a probe so you can stick it into areas you think the noise is comming from.
--
Veronica, my 85 760Ti
|
