mine knocks at idle when cold and warm,worse when cold! goes totally under load or anything above 2,000 revs.. have been told its piston slap by a garage.. first sounded like an end to me but that wouldnt disappear like this does..clueless but going to take it to extreme scoobies see what they say

 

mine knocks at idle when cold and warm,worse when cold! goes totally under load or anything above 2,000 revs.. have been told its piston slap by a garage.. first sounded like an end to me but that wouldnt disappear like this does..clueless but going to take it to extreme scoobies see what they say thats a 93 classic jdm

 

I think you may have got that around the wrong way chap !

It's the bore that is larger than the piston, resulting in it slapping
on the sides, when it gets hot the piston/ring expands creating a tighter
fit.

Rob

 

Piston slap is usually more pronounced under light load (blipping the throttle or gentle acceleration) Your description is very akin to the cambelt tensioner noise. It may not be, but worth bearing in mind.
JohnD (old fella from Romford!)

 

What is the cambelt pre-tensioner noise? I just had mine serviced and they said it was leaking and is due to be replaced.

However for the past couple of weeks prior to the service I have noticed a tapping noise when accelerating from 1000RPMS to 3000RPMS. Sounds like tappets or a slight fluttery noise.

Is this a pre-tensioner leaking noise compared to piston slap?

Cheers