Dont know if it's pinging

[nupes]

[color=#000000:post_uid0]Hi all,
Can anyone help me out? I think my car is pinging but Im not sure. When I go up a hill in 2nd, 3rd and 4th gear at about 2.5k to 5k I get a rattling, shuddering, electrical pinging? type sound on the right side where the alternator sits. My mate sez that pinging sounds like marbles in a coke can, it sounds a bit like that.
The reason I think its pinging is because when I fill it up with 91 RON the noise is lower sounding, when I fill with 98 RON optimax, the noise is quieter, less obvious and a bit higher pitched.
I recently took it in for a major service and they replaced spark plugs (with NGK iridiums) but still makes the sound.

Is there any sure fire way of knowing whether it is pinging or not?

Much Appreciated

Nupes[/color:post_uid0]

[BigMal]

[color=#000000:post_uid1]Take it straight to the mechanic to take for a drive round the
block. If you have a timing light make sure the motor is set
at 10deg. Keep filling the motor with 98 till you get it fixed
but really having a mechanic reset the timing should only
cost $20-30 and pinging does damage the motor so get it
done quick. Try getting petrol from a BP as they are all
corporate sites not franchises so the chance of getting
bad petrol from them is a lot less.

Regards

Mal[/color:post_uid1]

[nupes]

[color=#000000:post_uid0]OK Thanks Mal,
I'll try it out. Do you think its worth getting a compression test as well? Maybe one of the cylinders is out

Cheers

Nupes[/color:post_uid0]

[BigMal]

[color=#000000:post_uid1]Once you show it to the mechanic he will work it out for
you. Hopefully not that severe. If it was bad fuel you
may need to drain the tank or run some metho in it to
get water out. Anyway the mechanic will set you straight.

Regards

Mal[/color:post_uid1]