What can i do to stop my 325i sport pinking/pinging?

[oakey]

My 325i sport has recently started pinking/pinging.
i would be very grateful if anyone knows how to sort this problem on these cars or if anyone knows the cause of the problem?
cheers

[oze30]

hi octane fuel will hopefully prevent this.\

Not too sure, but could it be the timing?

[M5pilot]

It is very rare for these cars to pink.

You need to identify exactly why this is happening.

Where are you based?
Sal

[oakey]

im based in surbiton, surrey. the car has recently (2000 miles ago) had a 2.7 conversion. It only does it in when i accelerate hard at the end of the revs in every gear apart from first. It also kicks out a nasty bit of smoke each time it makes the noise. seems to be getting worse slowly.

[M5pilot]

Stop driving it hard as of immediate effect.

The compression sounds like it's too high or your not getting enough fuel.

Who did the conversion? Has it been remapped or chipped?

Can you give more details about the 2.7 build please - which pistons, compressions ratio, head work etc etc.

Sal

[oakey]

the car was remapped during the conversion. i do not know the compression ratio. No head work was done. The work was done by bexley motor works in kent. The car seemed fine at first. There was apparently slight scoring on the camshaft bearing journals-could this have anything to do with it?
thanks

[maxfield]

I don't suppose it does it with the a/c on but i wouldn't of thought you would have this time of year.

[oakey]

the pistons used were custom JE pistons. this is all i know

[oakey]

have not got a/c.

[maxfield]

Ok my dads M3 sometimes pinks when a/c is on.

[carpmart]

I would agree with SAL, compression seems too high!
Did you have a skim at the re-build?
Are the pistons domed?
What head gasket have you fitted, particularly thin ones can increas CR quite a bit!
Do you use 'super' unleaded? If not worth using as it is a higher octaine.
Are you just noticing this as you are starting to drive it hard after the re-build or has it been happening all the time?

[320Touring]

As sal says, the m20 only needs 91octane to run right.

they dont have knock sensors as standard, so cant advance or retard the timing to take advantage of the higher octanes.

[oakey]

no skim at the rebuild
think an elring gasket was used
dont know whether the pistons are domed or not.
the garage say its probably because it was very hot in the summer when they mapped it and now it has cooled down alot. they said to use only high octane fuel and if it keeps doing it to take it back and change the mapping.

[M5pilot]

I suggest you take it back to Jags and Nigel and get them to rectify the problem.

I had my car done there a few years back and there was a real bad hesitation in the rev range which they fixed straight away once told.

In the mean time use 99 octane fuel until the car is booked in.

Mapping in a hot workshop can be a problem but with their new "super fan" I doubt that's going to be a problem.

Take it back and while your there tell Nigel to get a hair cut.

Sal