1.0 n 1.2 heads

W

welsh_micra

is there any differnce between heads except the camshaft?

ive put ma gas flowed head from a 1.0 on a 1.2 block with a 1.2 carb will it go any better?

thanks scott
 
Well according to bob the 1.0 head has a smaller combustion chamber therefore raises the compresion ratio. Tried and tested to give great results!
 
doesn't the 1.0 head have a helical inlet though (unlike the 1.2) creating a 'whirl pool' air & fuel mix?

...i'm a novice in this area so I cant say what the pros & cons are...but I think this is another difference (from archived posts)...may be somone whith more expertese than me can comment on this
 
I think Bob has some dyno results of the diferent heads if I remember correctly. I had a 1l and a 1.2l heads on a flow bench a few years ago. I forget the CFM's now but the 1.2 head out flowed both a standard and a ported 1l head. Better flow doesn't necesarily mean more power, but It's a good indication. The 1.2 head has very straight ports which isn't so good but they are a lot larger than the 1l. I would imagine that the way forward would be a 1.2 head but carefully ported to encourage swirl. If you are still running the stock manifolds I would imagine there would be little difference in power between the heads. If I have time in the next few days I'll post up some pics of my garage ###ui processed head, they appear to have worked on the combustion chamber and unshrouding the valves as well as the usual porting.
 
surely the best of both worlds would be a 1.2 head with 1.0 valves (because i'm assuming they'd be shorter to stop them hitting the pistons) and a 1.2 carb (or better). And maybe port and polish it yourself while its off.

Thats purely a guess, i can't guaruntee any of that would work, i'm not advanced enough yet! :p
 
Well i will have fitted bobs ported head 1l by feb, think the main down fall of the 1.2 is the low 9.0:1 compresion ratio, fitting this head along with reprociled cam, arnolds exhaust manifold an bobs inlet with su carb will be perfect.
 
its not 9:1 its 9.5, you really want at least 10.5:1 or more to get good power from N/A. Everything about the MA design restricts its power, of an otherwise very good engine.
 
having around 40 thou skimmed off a 1.2 head will give you around 10.5 cr

slyboogie said:
surely the best of both worlds would be a 1.2 head with 1.0 valves (because i'm assuming they'd be shorter to stop them hitting the pistons) and a 1.2 carb (or better). And maybe port and polish it yourself while its off.

Thats purely a guess, i can't guaruntee any of that would work, i'm not advanced enough yet! :p
Click to expand...

ma10 and ma12 use the same length and size valva's
 
Oh right i wont refer to the sources that say its 9:1 anymore then. Think when its done i'll get the compresion tested so we have some figures.

Adding to bobs dont they use the same cam too?

Adding to bobs dont they use the same cam too?
 
Wrenchable said:
Oh right i wont refer to the sources that say its 9:1 anymore then. Think when its done i'll get the compresion tested so we have some figures.

Adding to bobs dont they use the same cam too?

Adding to bobs dont they use the same cam too?
Click to expand...


there not alot between then,you wouldn't notice any differents
 
You cant do compression tests to establish compression ratio. It has to be measured.
 
Ed said:
its not 9:1 its 9.5, you really want at least 10.5:1 or more to get good power from N/A. Everything about the MA design restricts its power, of an otherwise very good engine.
Click to expand...

the fact that the webbers and exhaust manifold i fitted proves how much power is hiding it what can only be described as and otherwise amazing piece of jap engeneering

i think if we were to break it down into order of where the most power is hiding the main culprits clogging up the works are

1. inlet manifold
2. Exhaust
3. head/internal engine components

i think playing with the head before sorting out the inlet/outlet would be pretty worthless
 
speedle

valid points on the manifolds (very poor design !)
but i had 2 or 3mm skimmed off my 1.2 k10 (think it was 3mm but not sure) and it felt much quicker
but the belt idler was maxxed out and like ed said it retards your valve timing (top sprocket would need advancing)
 
oh i agree that it can help frank of that there is no doubt, however you can see up to 20bhp gains from changing the inlet alone i dont think any amount of head work could achieve that figure.

at least the german documentaion that came with my webbers says it gives you 70ps (69.7bhp) from a standard 1.0 ma10 :p believe that when its on the rolling road
 

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