Dear Abhilash,

I suppose you are asking about heat transfer efficiency in FIN case, as there are lot of other parameters to describe the efficiency of IC engine namely Volumetric eff, mechanical efficiency etc.

A lot of work has already been done and published. I can pass along some suggestions (books, research papers) if you want. 

The following infrormation may be useful for your studies

The peformance of IC engine gets effected with the type of the cooling system. With improper cooling sysems- 1) the performance of lubricating oil in between liner and piston gets affected casuing metal to metal contact causing increase of friction power. 2) In case of SI engine, hot sources will be fomed  (temps more than  SIT of uel) causing detonration, 3) expansion of piston causing siesure of piston in cylinder 4) increase of temperatures of engine valves leading to drop in volumetric efficiency

In case of air cooling, fins are provided on the circumfrence of engine cylindee as well as cylinder head.. For evaluating fin performance, two parmeters are to be considerad 1) fin efficiency, 2) effectivenss The efficiency of fin forms a criterion for judging the relative mertis of fin of different geometries of materials. An improvement in fin effectiveness occurs when the fin is made from a meterial of high thermal conductivty  such as copper and aluminium alloys. Although copper (k= 385 units) is superior to aluminium (k= 225 units) regarding thermal conductvity yet fins are generally made of aluminium because of their additional advantage related to lower cost and weight. . Increase in the ratio of perimeter to the cross sectional area also brings about improvement in the effectivess of fin.This explains the preferance for fin closely spaced  fins. The lower limit  on the pitch distance is governed by thickness of boundary layer that develops on the fin surface. A high value fo film coefficient has an adverse effect on heat dissipatoin. Use of fins would be better justifified under conditions for which the convective coefficient is small, when the fluid is gas rather than a liquid. 

You can refer the following literature 

Abstact v;This study presents the results of computational numerical analysis of air flow and heat transfer in a lightweight automobile engine, considering three different morphology pin fins. A numerical study using Ansysfluent® (Version 6.3.26) was conducted to find the optimum pin shape based on minimum pressure dropand maximizing the heat transfer across the Automobile engine body. The results indicate that the dropshaped pin fins show improved results on the basis of heat transfer and pressure drop by comparing otherfins. The reason behind the improvement in heat transfer by drop shape pin fin was increased wetted

surface area and delay in thermal flow separation from drop shape pin fin.

Ref:MAXIMISING THE HEAT TRANSFER THROUGH FINSUSING CFD AS A TOOL

Sanjay Kumar Sharma1

and Vikas Sharma2

International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.2, No.3, August 2013

wireilla.com/engg/ijmech/papers/2313ijmech02.pdf

2) review paper on different materials of fin IC engine performance 

Heat Transfer Augmentation of Air Cooled 4 stroke SIEngine through Fins- A Review Paper

Prof. Arvind S. Sorathiya,, Manankumar B. Joshi,, Prof. (Dr.) Pravin P. Rathod3

 International Journal of Research in Engineering & Advanced Technology, Volume 2, Issue 1, Feb-Mar, 2014

www.ijreat.org/Papers%202014/Issue7/IJREATV2I1003.pdf

3) review paper on geometry of fin on IC engine performance 

An Effect of Different Parameters of Fins on Heat Transfer of IC

Engine- Review Study

Prof. Arvind S. Sorathiya,, Hiren P. Hirpara,, Prof. Dr. P.P. Rathod3

IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE)

e-ISSN: 2278-1684,p-ISSN: 2320-334X, Volume 11, Issue 3 Ver. I (May- Jun. 2014), PP 63-71

www.iosrjournals.org/iosr-jmce/papers/vol11-issue3/.../J011316371.pdf

It's better to start with the textbook. Heat exchanger and/or heat transfer book are required. For heat transfer textbook with sufficient info you need, I'll recommend "An Introduction to Mass and Heat Transfer--Principles of Analysis & Design by Stanley Middleman John Wiley & Sons, Inc. 1998"

To increase rate of heat transfer. When heat transfer rate is more the combustion chamber temperatures are low thereby formation of Nox is less.

Generally the efficiency of fins depends on the geometry that is fin surface area. As the fin surface area increases that increases the heat transfer quantity. Tapered fins are most suitable but it is difficult to manufacture. The material of the fins are very important. That decides the heat transfer, generally the materials of the fins should be of high thermal conductivity. The materials like copper, aluminium or alloy of these materials are most suitable for heat transfer.