actually the 1.6 comes in 8v and 16v, the one normally fitted to 306's is the 1.6 8v, the TU5, the 1.4 being the TU3
Block - same physical size, some extra allowances for sensors around the oil filter, larger flywheel iirc
bore and stoke are different - (1.4 = 75mm bore x 77mm stroke) (1.6 = 78.5mm bore x 82mm stroke)
1.6 16v has an extra idler pulley for the cambelt, the 8v block wasn't even drilled/tapped to accept the bolt for this
heads - lots of differences, there are 2 basic kinds of each, the 1.4 came with Spi (single point injection) and later ones were Mpi (multi-point injection), different cams / cam bearing journal sizes for each (depending on what peugeot felt like that morning) you can also get bigger valves on some 1.4 Mpi heads iirc from the 106xsi and Ax GTI
on the 1.6 side there are roller and non-roller rocker type heads, again different camshafts, bigger valves, more valves (16v) different port spacing, (earlier heads sometimes have inlet ports like this - 00-00, later ones will invariably have the spacing more like this - 0-0-0-0)
there are a few very minor changes other than these, but plenty to be thinking about
lol slow-writing fail
Block - same physical size, some extra allowances for sensors around the oil filter, larger flywheel iirc
bore and stoke are different - (1.4 = 75mm bore x 77mm stroke) (1.6 = 78.5mm bore x 82mm stroke)
1.6 16v has an extra idler pulley for the cambelt, the 8v block wasn't even drilled/tapped to accept the bolt for this
heads - lots of differences, there are 2 basic kinds of each, the 1.4 came with Spi (single point injection) and later ones were Mpi (multi-point injection), different cams / cam bearing journal sizes for each (depending on what peugeot felt like that morning) you can also get bigger valves on some 1.4 Mpi heads iirc from the 106xsi and Ax GTI
on the 1.6 side there are roller and non-roller rocker type heads, again different camshafts, bigger valves, more valves (16v) different port spacing, (earlier heads sometimes have inlet ports like this - 00-00, later ones will invariably have the spacing more like this - 0-0-0-0)
there are a few very minor changes other than these, but plenty to be thinking about
lol slow-writing fail
Project: Formula Peugeot