Combustion Chamber Volume 149/161 Head

[FB_MAD]

Can anyone tell me the combustion chamber volume for a 149/161 kidney shape small chamber head??

Or.... compression ratio with a 149/161 head on a 179??

Or........................ a chart with the combustion chamber volumes of various red heads and I'll work it out meself??

Did have a chart 'ere at home with various head volumes years ago but wouldn't have a clue where it is now.

And I'm too lazy to go and cc the head meself so hoping someone already has the figures to save me the trouble.

Cheers,

Terry.

[oldjohnno]

As far as I know 149, 161 and 173 are 45.4 cc.
The 179, 186 and 202 are 53.5 cc (except the XU1 which has the smaller 45cc chamber) and also I think the 202 EFI has a smaller chamber  too.

[FB_MAD]

Thanks Oldjohnno,


Based on that I'm looking at around 9.6 to 1 ( or so ) comp ratio with standard chamber 149 Yella Terra head on flat top pistoned 179.

Thanks for taking the time to reply...... appreciated,

Cheers,

Terry.

[oldjohnno]

You're welcome. The figures actually came from an old post of Dr Terrys. At the risk of teaching you how to suck eggs, here is the formula - maybe someone else will find it useful. (One cubic inch equals about 16.39cc)

CR=(D + V + DC + G + CC) / (V +DC + G + CC)

CR = Compression Ratio

D = Displacement of one cylinder

V = Piston Volume (will be a negative value with a domed piston)

DC = Deck Clearance Volume

G = Gasket Volume

CC = Combustion Chamber Volume