pinking ??

boomy · Post by **boomy** » Mon Jul 11, 2005 7:54 am

Not sure what this is, but any help appreciated:

I have noticed recently that when my car get warm ( 30 mins plus of driving ), especially in the hot weather like yesterday, it starts to make like a tinckling/metalic sound under power....if I am bumbling along on a straight road it is fine, but try and climb a hill and its starts loosing power and making this strange noise...

...

It was REALLY hot yesterday and I was bombing along through the Dorset countryside for over an hour

before it started...

Someone said it was 'pinking', but I thought this would happen straight away, not after so 1/2 hour...what can I do to find out the cause...??

Cheers, Mark

impmad2000 · Post by **impmad2000** » Mon Jul 11, 2005 8:57 am

Yes that sounds like pinking to me. It can be brought on by either by advanced ignition timing or by hot spots in the cylinder head. Causes for hot spots include slightly weak running or incorrect temperature spark plugs. I have also had this caused in a badly smoky engine where i believe peaks in the carbon build up in the cylinder head were hot enough to cause pre ignition.
Does the car "run on" after killing the ignition ? This indicates self ignition from hot spots.
Good luck
Tim

davidppp · Post by **davidppp** » Mon Jul 11, 2005 10:00 am

I agree..sounds typical.

And oil in the upper cylinder can cause it in itself..ie without necessarily producing carbon deposits.

The first and most important check is cooling..I would go so far as to remove the shroud to look for anything over the cylinders..I have often found stuff like paper , straw, all stuck in a gooey mess.
Also check the timing is not retatrded..full throttle mixture is not easy to check without a portable Oxygen meter..or a rolling road..but is not usually too weak if the car is running well.

The detritus inside the shroud may sometimes have been cuased by eg mice!
But I'm sure its usually just blown in there..and stuck..

Than, use Redex as usual, while splashing out on the highest octane juice you can find..pref with lead in..

It is, annoyingly, sometimes necessary to take off the heads to sort this..

Kind regards
David

boomy · Post by **boomy** » Mon Jul 11, 2005 10:32 am

Thanks guys...

No it doesnt run-on after being switched off...

I always use unleaded; but would it be better to try LRP ??

When I use it on the daily run to and from work ( 7 miles each way ) it NEVER does this, only when it gets pretty hot...

I will have a poke around inside the shrouds etc when I get home..

Thanks again...