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Compression Ratio

Posted: Fri Dec 10, 2004 9:38 am
by donhailo
Please help me, I´m confused.
Can anyone help me with the correct capacity of the combustion chamber and the correct compression ratio of a 1098er?! The blue BL-Workshop Manual says 32cc and a compression ratio of 8,5:1. But when I take this capacity (32cc) and use it with the formula given in David Vizards book, I end up with a cr of 9,5:1.
Any ideas?, thank you very much, Donhailo

Posted: Fri Dec 10, 2004 10:12 am
by brixtonmorris
i think thats 8,5 to 1 corresponds to a 948cc ohv i think the 1098 engine has 9,5:1 ratio

Posted: Fri Dec 10, 2004 12:33 pm
by grainger
in the haynes manual it says 'high compression - 9.5 - 1' so you must have got it right i reckon, well done

grainger

compression ratios

Posted: Fri Dec 10, 2004 7:03 pm
by Willie
The high compression 1098 engine (10MA-U-H........) is 8.5-1
The low compression 1098 (10MA-U-L.....) is 7.5-1. The capacity
according to the workshop manual is 32cc The heads are identical
on both high and low compression engines. The amount of dish of
the pistons determines the compression ratio. In order to arrive
at your 9.5-1 compression ratio you would need to fit the head from
an Austin or Morris TRANSVERSE engined car which have a capacity
of 26.1cc (NOT the 12G295 head).

Posted: Fri Dec 10, 2004 7:51 pm
by grainger
sorry :oops: ... ignore me ... got me foot in me mouth as usual ...

gr