A $4-$stroke S$.$I. engine has six cylinders, each cylinder has $10-cm$ bore and $15-cm$ stroke. The engine is coupled to a brake having a torque radius of $45-cm.$ At $3000$ rpm $,$ with all cylinders operating the net brake load is $370$ N $.$ When each cylinder in turn is rendered inoperative, the average net brake load produced at the same speed by the remaining $5$ cylinders is $260$ N $.$ Estimate the indicated mean effective pressure of the engine. With all cylinders operating the fuel consumption is $0\mathrm{.}35k\frac{g}{m}in$; calorific value of fuel is $43M\frac{J}{k}g$; the cooling water flow rate and temperature rise is $70k\frac{g}{m}in$ and $12C$ respectively. On test, the engine is enclosed in a thermally and acoustically insulated box through which the output drive, water, fuel and air connection passes. Ventilating air blown up through the box at the rate of $15k\frac{g}{m}in$ enters at $23C$ and leaves at $65C.$ Draw up a heat balance of the engine on minute basis stating the items as a percentage of the heat input. $($Take$,$ specific heat of water as $4\mathrm{.}18k\frac{J}{k}g-k$ and specific heat of air as $1\mathrm{.}005k\frac{J}{k}g-k.$