Cylinderheads

Cylinder Head

There is a very interesting and thorough discussion by Steve Cecchele at the turbo124 forum.

Combustion chambers

Here are a few of the combustion chambers that Fiat tried over the years. It's not even close to complete, it's just what I happen to have photos and measurements of right now, so if you have more to contribute, please do. Some reworked chambers would be nice too...

US-spec 1300

Casting: 128AC0C000040/4 4315419 Width across combustion chamber (not counting cylinder recess): 78mm

This one came from a US-spec '74, and has the circular recess that lowered the compression of the US-spec 1300 for emissions reasons. The combustion chamber doesn't extend all the way to edge of the cylinder bore so the valves are significantly shrouded.

US-spec FI 1500

Casting: 138AE2A00 4430881 Width across combustion chamber (not counting cylinder recess): 86mm

This is a ten-bolt 1500 fuel-injected head. The exhaust valve is larger and the combustion chamber extends the full width of the cylinder bore so the valves are much less shrouded.