Head CC

[matt_vaughan]

Which small block 8v heads have more and less CC, please also relate to age.

Does the later 1200 have larger CC than early (12ST and 12NV relative)

I need a head with a larger CC than a 1200 ST, was thinking C14SE...dont worry about ports, thats not a problem :D

Thanks

[Stuart]

the non egr 1.6 head I have is approx 38cc

[Stuart]

my sig site will let you calculate the rough CC of the head based on cylinder capcity and comperssion ratio

[matt_vaughan]

I dont have the ST head to measure to compare though thats the problem. Could do with a list of head CC measurements or similar that could help me decide which head to go for.

*goes out to find haynes manual*

[matt_vaughan]

Stuart I misread your second post. Used your various calculators and using a standard 1.2 head on the engine I'm building I get a CR of approx 11:1, not sure if thats too high.

[Stuart]

what are you trying to achieve?

[matt_vaughan]

Avoiding having to pocket pistons on a High Comp 1400

[garyc]

dont you pocket pistons to stop valves hitting them. you will probably find that once you measure stuff loads will need skimming from the head and block to get the cr up anyway.

[mowgli]

dont you pocket pistons to stop valves hitting them. you will probably find that once you measure stuff loads will need skimming from the head and block to get the cr up anyway.

the use of 1200 pistons without pocketing them will create a high compression engine..

PMC originally did the conversion & there was a writeup in CCC magazine, which was the inspiration for me to do my conversion back in the early nineties. they machined the pistons & actually had a photo of them in the article. I worked it out properly & valve clearance was not an issue as the valve cutouts are the same on a 1200 piston as on a 1300 piston.

[burgo]

c14se has a very small combustion chamber

[Stuart]

depends on the cam lift at tdc.... what cam are you planning on using

[matt_vaughan]

Kent AST1 Road Sports

6.24mm Cam Lift
10.55mm Valve Lift
270 Degree

Dont mind having the pistons pocketed if needed, its the proper way to do it I'm sure, but if I can avoid it using a different head then I would rather do it that way.

[Stuart]

you will be fine with that cam and not needing pocketing.

[matt_vaughan]

Was more thinking about compression to be honest...do we rekon 11:1 is relatively safe...??

Bear in mind the whole idea of the engine is it's a High comp 1.4 lol

[Stuart]

imho I dont see it as a problem... others might.

Dont forget CR is a static figure which will vary with throttle opening/cam timing/duration etc. so in some cases a high static CR is kinda irrelevant/a bonus lol

[matt_vaughan]

Sod it then, I'll slam the high comp stuff together. I'll keep it all in mind though. Mowgli had pocketed pistons and his engine lasted well so it might be an idea sometime in the future should it be rebuilt at any point.