Cylinder head advice

[daveeeeee]

Ok, i have aquired an ma10 with brand new valves and head skimmed. i also have the head of an ma12, it is ported inlet and exhaust, three angle valve seats and a high lift cam. However it has been skimmed 64thou! some of you will probably know this head it blonged to AMY originaly i believe. now i'm not sure witch to use, i was thinking of putting a rev lomiter on the car and limiting it to 6000rpm or so as i dont think it will go much further without the valves hitting the pistons, howerver it has been proven that the k10 still has power to give past 6000rpm. so what to do? i'm quite unsure whether to use the ma12 head as it may have been blowing headgaskets often, thats just a hunch anyway.

cheers

 

[frank]

daveeeeee

you need to measure the combustion chamber cc really, in both heads and aim for a compression ratio of about 10.5:1
then use the best bits to make 1 good head imo
and i doubt you,ll get valve bounce, unless the cam has very steep opening/closing angles
and you,ll lose some c/r if the cam has a long duration

 

[whipit]

60 thou just sounds rediculous, if you want that high a compression ratio you may as well get the bottom end done to take advantage and change the pistons to increase compression.
sure you know this any way, try using 2 head gaskets or a spacer.

 

[daveeeeee]

brings up the old subject of what head is better. from what i've seen on the site the ma12 head is more efficient for running higher power, so i'm thinking the ported head will work better with the bike carb settup than the ma10 head.

 

[whipit]

oh yeah that old argument, i personaly prefer a ported ma10 head over a ported ma12 head simply because the flow isn't as direct which helps to atomise the fuel with the air, yet the ports are the same size.
think we really need a rolling road test with both cars having the same compression ratio rather than i hijack this thread any more.

 

[AMY]

So my old head lives on, it was just a 40thou skim originally, it's a good port and valve job on that head, i'd go with it rather than a 1l head any day. Is there an adjustable pulley on it? I'm not to sure about what has been done to it since I sold it. Ideally you want to get it on a RR and mess with the cam and ignition timing. If you want a 1l head I have that garage ###ui ported and processed head here that i'm waiting for anyone to make me an offer on. Anyone?

Bloody swear filter, that's garage f ukui aka Phoenix power

 

[Ed]

Well I can tell you that the ST head is closer to the MA12 than the MA10, and that makes by far the most power from any Ma series engine...

 

[daveeeeee]

grrrr, i do think that the ma12 is a better head but its the sheer amount its been skimmed that really worries me. what gains will i be looking at through using this head? and the ported ma10 head you have amy? roughly anyway

oh and it does not have an adjustable pully.

 

[whipit]

yeah its gonna be ed, its injection. fuel and air dont need to mix as much as carb. sorry not taking the pee mate.