4G63 Engine Building Basics 101
4G63 Engine Building Basics 101
Confused by all of the options for your 4G63 based project? Need to build the engine but having a hard time determining what you can build. Unfamiliar with what terms like “stoker” and “de-stroker” mean? Don’t be alarmed, the options are endless and as a result, we can’t cover them all here, but we will try to shed light on some of the general benefits and detriments of the major options and give an idea on how they came to be and what they are used for.
To start out, one must understand the fundamental differences of materials and tolerances use to build engines. MAPerformance uses two terms to differentiate between the power holding capacity of any given engine within the 4G63t power plant, “Stage 1” or “Stage 2.” These designations are given to engines that can hold certain amount of approximate power, but imply the components and techniques used to assemble them with the understanding that an increase in power will result in an increase in the heat and stresses imparted to the internals that are being used to control that power level. A “Stage 1” engine will have tighter tolerances in ring gaps, and bearings with focus on materials that weigh and wear less. A “Stage 2” engine will have looser tolerances meant to accommodate more expansion resultant of higher heat, and higher oil pressures generated by higher RPM use.
Should I build my engine to handle more power than I expect to need, to build in room for future power growth?
Many customers ask this question, and while the truth is, “Sure, build the engine to handle as much power as you want,” the fallacy is that the larger scale build will generate an engine that will last longer. The “Stage 1” engine has a valid place and purpose to be used. An engine which tighter piston to wall clearance and less ring gap will not typically destabilize the piston on start up which is a common forged piston cold start artifact. Forged pistons expand under heat, but also contract during cold. When a piston warms up, it is expanding until it reaches running temperature but until that happens, the larger piston to wall clearance will allow the piston to rattle in the bore… it is subtle and sometimes silent, but it is a side effect that will wear the bore of the block out faster. As a general rule, we recommend that customers build an engine to suite their power goals for the maximum life expectancy.
What is a stroker and what are de-stroker engines?
Many engines in common use today use components based in both 4G63 and 4G64 geometries. Since the 4G64 block is essentially the same, except 6mm taller, and the geometry of the internals is compatible, many people choose to rely on components or similarly sized components to achieve hybrid builds of varying displacements.
The illustration above highlights the critical locations of measurements used to determine the piston requirements, but the basic builds use either the 4G64 or 4G63 block with either the 100mm 4G64 crank or the 88mm 4G63 crank. The factory rod length is 150mm for these engines but many times 156mm rods are used to change the rod ratio as well. These combinations are further bolstered by the use of various aftermarket crank solutions which, in combination with the correct pistons or, in some instances, custom pistons, to complete a shortblock assembly.
What combination is best and why should I choose it?
This is a trendy topic and quite frankly, dependent on technology and tuning advancements so there is never a clear stand out winner but the main choices tend to boil down to the following displacements. Here are some pro’s and con’s of each:
2.0l 4G63 engine
Pros: High revving with good rod ratio
Cons: For Evo applications, blocks can be hard to source and no extra displacement for more exhaust energy
2.3 4G63 based “Stroker” engine
Pros: Easy displacement that bolts in where the 2.0l goes without any modifications
Cons: Rod ratio is shorter which creates more side load stress on pistons, creating greater wear on cylinder bore. 4G63 blocks are scarce.
2.4 4G64 based engine
Pros: Big displacement with minimal rod ratio loss for longevity of bore. 4G64 block cores are easy to come by and vastly less expensive.
Cons: 6mm taller block requires that the head be degreed into the bottom end which will require more installation expertise and adjustable cam gears for EVO applications.
There are a myriad of variations of these engines that all attempt to increase either revolutions holding capacity or displacement, all with the intent of holding more power by creating more exhaust energy to feed a larger turbo. Which ones is best for you? That will depend on how the above can affect your use of the car and long term goals, but what we can tell you, is that we can help build you and recommend you specific configurations to keep you and your car happy. Feel free to reach out and we can offer our professional opinion, and don’t forget to dream big!