theoretical combinations - may take a bit of reading!!

[mikey14sr]

Being cooped up in the truck for a couple of nights has resulted in this;

Based on the specs in the haynes bible, and on the assumption that piston heights + volume left in the cylinder are the same in all the engines fitted to the nova (excluding 1.0), using the formulae CC divided by CR = HV, I have come up with the following combustion chamber volumes;-

12ST = 130cc
13SB = 140.97cc
14NV = 147.76cc
C14SE = 138.9cc
'93on C14SE = 141.73cc
E16SE = 159.8cc
C16SE = 163.06cc

Based on the above, as discussed many times in 1.4 tuning posts -

14NV block + 12ST head = CR a bit high or
1389 / 130 = 10.68:1

14NV block + C14SE head = best comination or
1389 / 138.9 = 10:1 but only with a pre '93 head as post '93 =
1389 / 141.73 = 9.79:1

And the combo I will be using on my own motor is -

14NV block + 13SB head =
1389 / 140.97 = 9.85:1

I just hope this is of some help to you all, it has just been something to do for me!!!

[burgo]

you have no idea how helpful that is mate nice oneone

[mikey14sr]

And I've just remembered reading about a 1 litre turbo which had about 150 brake in an old cars +car conversions mag. He'd used a 1.2 block, sleeved down for metro pistons with an E16SE head which works out as this -

998 / 159.8 = 6.24:1 - no wonder he was able to run 18psi of boost!!

[Nick]

wow nice one

too tired to understand that

so it's gone in one ear and come straight out the other.

http://www.punchstock.com/image/photodisc/6874833/comp/os27036.jpg

[Aragorn]

there are differences in the pistons too tho

sr and sri pistons are different for instance but they are same bore etc due to different compression ratio

[Snowface]

think you can ru on an 11.0 cr or even 11.5 cr if you use 97/98 ron petrol.

my c/r is fairly high.

slight skimmed 1.2 head on a 1.3 block that has also been skimmed.

[Snowface]

isn't the combustion volume in the 1.2 head 120cc?

i.e. 10:1 cr, so 1200 / 10 = 120cc?

[mikey14sr]

CR for the 1200 is 9.2:1 which gives 130cc, and as I stated, and Aragorn pointed out, this is based on piston crowns/TDC heaights being the same across the board, which we now know that they are not.

Unfortunately I dont have space to keep one of each engine so I cant play around with plasticine and get trully accurate figures