A dreaded problem for many owners of the Corsa VXR/SRi and other vehicles with similar Z16LEx engines is the piston 4 failure. While this is known to occur on some standard engines, the chances of this can be dramatically increased through poor tuning. Normally if caught early enough the single piston can be replaced with an OEM piston for a cost effective repair.
You can recognise signs of piston 4 by the feeling of power loss, rough idle and poor cold starts; and you can confirm this with a compression test.
We recommend addressing the issue as soon as signs start, if left too long damage to the engine bores can occur and the only option then is to rebore the cylinders to accept over sized pistons or replace the entire bottom end.
We recommend that all Z16LEx engines that are tuned above 205bhp are fitted with uprated injectors to ensure adequate fueling in order to protect the pistons. Many owners want to improve their confidence in their engines safety and opt to have a full engine rebuild with fully forged pistons and rods to strengthen the engine.
Corsa SRi 1.6T
Astra SRi 1.6
Engines which are effected: