fiestaturbo.com

[karls rs1800]

someone has just posted a reply and mentioned pinking anyone know what they mean??

[Sphinx]

I think its 'slang' for detonation.

[karls rs1800]

what you mean the engine is going to blow up??

[jonosi]

what you mean the engine is going to blow up??

is it not when your fuel/air mixture is not set correctly thus meaning your engine isnt running at its best ?

[ianFRST]

pinking is detonation.

more common in turbo cars, you can actually hear the noise it makes when the engines at high rpm due to not having enough fuel / or the ignition is slightly out

[Project_XR2i_Trackcar]

in lamens it mean its detonating out of time to what it should be.

Usually down to the fuel/air ratio being wrong or lower octane fuel.

Not too sure about fords but, Subaru engines, in particular jap imports are renound for it due to the lower RON rating available in UK. (jap = 100 RON, UK = 95 NUL or 98.6 optimax). My STi5 used to have a knock (another term for detonation/pinking) link fitted so i could monitor if it was detting, if it did i backed off.

End result is piston melt down

Prevention is higher octane fuel by adding an octane booster or adjust the AFR (air fuel ratio) through a remap.

[Raymondo]

i beleive people call it pinking because that is the noise it makes when detonating

[MotorcyclesFish]

It's when the compression in the cylinder overpowers the natural stability of the fuel (in laymans terms), causing it to ignite prior to the spark plug's pulse, in an uncontrolled manner. This pre-detonation is damaging to the engine and piston, mainly because it's effectively trying to work against the piston being as it's gone off too early, causing nasty vibrations and pulses through the piston and crank/rod assembly. A piston that's had pinking on it will look like someone's been firing a bb gun at it for about a day.

Pinking sounds like someone's dropped a biro behind your dash, or maybe like a cup full of ball bearings rattling around the engine bay.

Causes of it are basically early ignition of fuel - so that's either the spark is too far advanced, actually causing pinking itself, or that the compression is overcoming the fuel's threshold for auto-ignition, either too high a CR or incorrect mixture.

[Sphinx]

Its also worth adding that the higher the octane of the fuel, the more 'stable' it is. Although 100 ron will squeeze a few more bhp out of a jap car thats designed to run on it, once lower octane is put in, its less stable and the compression of the engine causes it to ignite before the spark.

[PaulC]

To add to it, you'll notice pinking much more when labouring the engine... for example being in the wrong gear going up a hill. The sound will be much more noticeable.

[FezzR]

this is one of "those" subjects that everyone knows about but in practice few people really know whats going on or what theyre actually describing.

Grant has the best description so far but i would change the use of the term "pre - detonation" to "pre-ignition"

one very important thing that everyone is failing to mention is temperature though.
pre-ignition occurs due to excess temperature in the cylinder, weather it be wrong AFR raising the overall temps of the complete cylinder heating the combustion gases and fuel so that when compression occurs the engine effectively runs like a diesel and auto-ignites due to the compression not from a spark as others have said.

relating back to the Scoobies the main reason for piston melt down is because the turbo is sat on cyl. no 3 (IIRC) heat ratiated from turbo heating the cylinder, combinded with other factors usually like fuel quality etc

[FezzR]

google is always useful too define:detonation

[John ox]

i thought only very old cars had the pinking problem because of the fuel used ?

[FezzR]

i thought only very old cars had the pinking problem because of the fuel used ?

i think you are refering to the unleaded / leaded fuel differences when they did away with leaded fuel
if so this is down to the fuels inability to hold off auto-ignition, as mentioned above. Again this is down to temps in the cylinder

[lucasdemoley]

My si has done this when I was stuck in traffic and it overheated, then I kaned it up a hill and didnt notice the temp. On many motors it can be down to the heat. If you have ever uses a 2 stroke engine alot on like a chainsaw or strimer if its being used for quite a long time you can hear it doing it very obviously due to it just overheating.

[~S1~]

Pinking, Pre-ignition and detonation are three seperate things.

First off, people should realise that the combustion process involves burning the fuel air mix in a controlled manner, it does not explode.

Pinking- Caused by over advanced ignition which gives the spark too early in the cycle. The combustion process is trying to work against the upward movement of the piston. Noise is like a "tinkling" sound. Used to happen a lot in my first fiesta, 1.1L Mk1 when labouring the engine.

Pre-Ignition- Similar to pinking but is the mixture is ignited before the spark is created, often by carbon deposits in the chamber that glow red hot. Same sound as pinking.

Detonation- Is when the mixture literally explodes instead of a controlled burn. It can be caused by a number of factors including too high boost pressure if a turbo or too high compression ratio, lean fuel/air ratios etc. The temperature within the combustion chamber reaches extreme levels which causes the mixture to explode. Detonation causes great damage to pistons, heads etc.

[karls rs1800]

well just thought i'd tell you that i ran out of petrol last week then thats when the pinking noise came. plus i have noticed that the temp gauge on the dash works sometimes when it wants to but sometimes it goes up then goes down to the mark at the bottom when you turn the engine off. plus i have noticed lately that it bellows out a lot smoke since i ran out of fuel.
could any of these factors have caused the pinking?? and how can i sort the pinking noise out???

[lucasdemoley]

well just thought i'd tell you that i ran out of petrol last week then thats when the pinking noise came. plus i have noticed that the temp gauge on the dash works sometimes when it wants to but sometimes it goes up then goes down to the mark at the bottom when you turn the engine off. plus i have noticed lately that it bellows out a lot smoke since i ran out of fuel.
could any of these factors have caused the pinking?? and how can i sort the pinking noise out???

SOuns to me like you just picked up the cr*p that was at the bottom of the fuel tank, and by the sounds of it this was maybe quite abit. jst an idea.