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Originally posted by The W
Hi Ebenech. You have to check one thing before firing up the motor after modification.
First, I don´t really have an idea how much CR will be with TC pistons + semi chambered or flat head.
There´s 2 valve pockets per piston - whereas Anglia pistons are completely flat - no pockets, nothing.
They are more like Pinto ones. And these Anglia ones (Hepolite 18400) were quite popular with the rally
boys here in Finland but I know some tuners used TC ones with pretty good results.
Personally I don´t have experience about TC pistons.
So now there should be at least 6 mm from deck to piston in TDC to achieve approx. 10,3:1.
Even one mm less will be raise CR a lot which causes a lot of extra heat and possibly detonation.
If you don´t use forged pistons anything more like 11:1 will be hazardous for cast pistons - they might melt.
So don´t get too greedy with CR - altough it brings some more torque and some extra bhp.
Also check the valve tolerance if using a high lift cam.
And one more thing - don´t expect smooth tickover - it will be pretty lumpy. But if all is in tune it´s a one helluva
screamer!
I quess all Cortinas, Capris and even Transits had semi chambered head from 68 to 70.
Pistons were bowled but mostly unpocketed but there´s a rumour that 1100-1300 Escys got flat type head by that time and
only 1600 and 1300 GT & 1600 GT´s got semi chambered ones.
Actually, I ripped one 1600 GT Capri -69 in parts years ago - still got its cyl.head, semi chambered one.
No GT markings anywhere, just a T3 cast...
First, I don´t really have an idea how much CR will be with TC pistons + semi chambered or flat head.
There´s 2 valve pockets per piston - whereas Anglia pistons are completely flat - no pockets, nothing.
They are more like Pinto ones. And these Anglia ones (Hepolite 18400) were quite popular with the rally
boys here in Finland but I know some tuners used TC ones with pretty good results.
Personally I don´t have experience about TC pistons.
So now there should be at least 6 mm from deck to piston in TDC to achieve approx. 10,3:1.
Even one mm less will be raise CR a lot which causes a lot of extra heat and possibly detonation.
If you don´t use forged pistons anything more like 11:1 will be hazardous for cast pistons - they might melt.
So don´t get too greedy with CR - altough it brings some more torque and some extra bhp.
Also check the valve tolerance if using a high lift cam.
And one more thing - don´t expect smooth tickover - it will be pretty lumpy. But if all is in tune it´s a one helluva
screamer!
I quess all Cortinas, Capris and even Transits had semi chambered head from 68 to 70.
Pistons were bowled but mostly unpocketed but there´s a rumour that 1100-1300 Escys got flat type head by that time and
only 1600 and 1300 GT & 1600 GT´s got semi chambered ones.
Actually, I ripped one 1600 GT Capri -69 in parts years ago - still got its cyl.head, semi chambered one.
No GT markings anywhere, just a T3 cast...
