mx5cartalk.com

The car didn't overheat until it had to have a bottom end refresh recently.

Now it goes beyond the centre marker by lap 3 of a session even when only using 6,500rpm and 10psi compared with 7,500, 12 psi and no overheating ever.

Nothing else seems to have been changed, so wondering if it has the correct head gasket.

It's the usual SE non-VVT BP4W head with a coolant re-route.

What's the correct head gasket?

when rebuilding my sons vvt engine for his clubman,pretty sure we used an early model(na8) metal head gasket,because he already had a reroute.his build is here viewtopic.php?f=57&t=60342 ,you can send him a message to find out exactly which.It has stock compression ratio (never did actually measure it though it should be 10ish to 1) and around 280hp at the wheels.he drives it to work every day and no troubles so far.
Mick

Based on info available on Mazda-speed.com, a 94-00 head gasket (BP26-10-271) is required when doing a reroute with the SE head.

You may like to search the same site for implications of doing a reroute with SE head and retaining the standard SE head gasket.

While you're at it you should also check threads regarding the accuracy of the OEM temperature gauge. If your standard gauge has moved hotter than half way I'd suggest that you get the head checked for hardness next time it's off.