The block is the basis of any engine in order to perform and last. A used, seasoned engine block is better to start off with because it has already been heated and cooled and stressed to form a dimensionally stable start.
After cleaning and inspection for a good core, you must start with checking and align honing, or cutting a fresh line bore because everything from here on is based directly on main bearing saddles being straight and true.
Now, since the line bore is correct, you can measure and deck the block (and I mean deck). First you must make sure the block is square to the main bearing journals and that the length of stroke on #1 is the same as #6. Besides, the deck of every engine has warpage; and if the block has been cut for counter bore shims, you must sleeve the bore and take it back to the original specs. This will ensure proper liner projections. Then double-check the upper bore with the lower bore so when you cut for upper press fit liners, they will fit right. The final work on the block is to true up the camshaft journals with the long hone to ensure no cam bearing problems miles down the road.
The highest stress part of your engine converts rotating weight to reciprocating motion (up and down motion) into torque and horsepower. With all well seasoned crankshafts the first step in inspection is to magnafluz the metal for cracks. After you’re sure the crank is worth spending time and money on, proceed to the crank straightener. All cranks have bend. Some can be just polished to be true, but the rest have to be ground. Next is to drill out the oil passages and chamfering the oil holes. After all, the only way the rods get oil is the main journals in the crankshaft. Depending on end horsepower, there is an advantage on offset grinding. By just offset grinding the rod journals, you can change the stroke length resulting in more cubic inches. Last but not least, a reciprocal motion of the crank must run free of weight differences, balancing counterweights, taking away unneeded metal to keep all the journals the same.
Remember, the rod is what holds the piston to the crank. In one reciprocating motion, the crank is trying to shove the rod and the piston through the head. On the other hand, the power stroke is trying to throw the rod out the oil pan. Keeping this in mind, the term used to recondition rods is called “rod resizing”. This means to make sure the big ends are the same size, the small ends are the same size, and the length from the big end to the small end is all the same (six or eight or twelve depending on what you are working on). The next main problem with rods is the reciprocating weight factor. The rods must all weigh the same both on the small and the large end then the total must be the same on all.
Aluminum pistons expand twice the rate of steel and are the weakest link when it comes to horsepower. We use a thermal-barrier coating called ceramic to protect the dome of the piston to stop cracking and melting. The TBC coating spreads heat evenly across the piston surface, resulting in more complete and efficient burning, resulting in increased miles per gallon. We also use a Poly Moly™ coating called Teflon® for piston slap on the liner and to take away piston skirt drag. To say the least, we balance all pistons to weigh the same, and the combination of the two can gain more horsepower and use less fuel to do it.
Now just review compression ratio. In order for a high horsepower engine to live and be efficient, you must have the right combination of compression ratio, fuel, air and timing. Remember, the higher the horsepower on the turbo charge engine, the lower the compression ratio to gain volume displacement and lower internal pressure for less wear on rod bearings the increased manifold pressure and volume of power will overcome or compensate the lower compression.
The camshaft engine timing is the main source of the engine. Using high boost pressures and volumes of air flow, the exhaust cam lobes must be increased to allow the exhaust gases to exit the engine and spin the turbocharger or turbochargers. So, you must understand, a turbocharged engine lives on exhaust exit. The more exhaust exits and the easier it exits, the more boost you get.
Likewise, the more you advance timing, the more response you get and the cooler the engine runs, the harder it is on the upper rod bearing. The more you retard timing, the more boost you get. The more power and torque, the more heat you get by holding the compressed gases in the combustion chamber.