I did some searching and someone on an old thread from the prior site tested a 1.6 on a dyno up to 235* and at least claimed to confirm that the 1.6 does not pull timing at higher temps. They said the 1.8 ECU was smarter but I never did find evidence that it in fact alters the timing at higher temps either. Lots of speculation all around the interweb though.
Ack! Bad info, in my opinion! The 1.6 abso-posi-lutely retards timing and costs you a few T and HP somewhere in the 200-210F range coolant temp range, as measured at the back of the cylinder head.
With all the goofy "Autometer-type" coolant temp installations, you might see a bogus 235 in a sensor mounted in a heater hose next to the cherry red header, but this is misleading.
Over 220F is risking head warpage fubars that will increase leakdown and reduce power. I dont know whether the valve job or the headgasket sealing is the main effect of the root cause of overheating, but 220-230F is the range at which permanent unpleasantness infiltrates the cylinder head.