just thinking about the theoretical compression ratios in the H series motors, ie 1.6L pistons in 1.3L block gives 7.8:1 tc and 1.3L pistons in 1.6L block gives 11:1 tc, and wondered if a 1.3L crank and pistons were to be used in the 1.6L block effectively destroking to 1.3L, would the theorectical compression ratio be too low given that the 1.6L block is around 10mm taller deck height?
in theory using a crank with a shorter throw would give you lower compression and a more revable motor but you would need longer rods to make up the 10mm difference otherwise you wouldn’t have any squish and you would lose a lot of efficiency
has anyone actually confirmed that the block is actually 10mm taller on the hde with them side by side ?
or is it all just word of mouth as a lot seems to be
i am going by word of mouth from a few people, that’s why asking on forum rather than fb, so there is record of it as well as deciding which way to go
I have an HC, HE and HD block and can confirm that the HE and HD are 10mm taller. They run a different cam belt, and cam belt cover because of this.
As for running a 1.3 crank in a 1.6 block, probably not a good idea. The only similar thing I recall was as a kid my dad had an old Ford Cortina with an Essex 3.0 V6 that some numpty had rebuilt with a crank from the 2.5l motor - it ran terribly and could hardly get up a hill near our house. Once the correct crank was re-installed it was reasonably quick.
Yep exactly what JC said