14-10-2013, 09:30 AM
Hmm, tbf, I really wouldn't expect it to be an issue with chamber design - they're both dished pistons and from looks, they aren't vastly enough different to cause issues IMO.
I'd expect since it's only light, that's possibly signs of a failing fuel pump or it briefly running lean - get an EGT gauge on there and make sure you have wideband o2 readings, that way you might pick up if it does it with new pistons, I don't think a change to 2.0 8vT pistons will save it detting again...
EDIT: Just realised - you're running a 1.9 head on the 2.0 8v bottom end - the bore on the 1.9 is 83mm, you've got an 87mm oversize 2.0 bottom end - that could be combined with the slightly odd 16v pistons to cause det... The combustion chamber in the head of the 1.9 is going to be a good bit different than the 2.0 head... Who built this engine out of interest?
I'd expect since it's only light, that's possibly signs of a failing fuel pump or it briefly running lean - get an EGT gauge on there and make sure you have wideband o2 readings, that way you might pick up if it does it with new pistons, I don't think a change to 2.0 8vT pistons will save it detting again...
EDIT: Just realised - you're running a 1.9 head on the 2.0 8v bottom end - the bore on the 1.9 is 83mm, you've got an 87mm oversize 2.0 bottom end - that could be combined with the slightly odd 16v pistons to cause det... The combustion chamber in the head of the 1.9 is going to be a good bit different than the 2.0 head... Who built this engine out of interest?
