Originally Posted by ITRSPORT

Exclusive pistons and connecting rods have been developed for the Type R. The high-pressure die cast piston crown has been reshaped to increase the compression ratio to 10.6:1 and valve pockets deepened to accommodate the increased valve lift and duration of the Type R. The piston skirt is coated with molybdenum to minimize friction and allow it to withstand high-rpm operation, while specially designed oil paths have been machined into the underside of the piston to provide additional lubrication to the piston pin.

Extreme care was taken in the forging and machining of the connecting rods to ensure each engine of a precisely matched set of connecting rods. Like in the GS-R, the rods are constructed of special high-strength steel for a rigid yet lightweight component. Extremely accurate machining of the Type R connecting rod minimizes variation between parts. Connecting rod bolt elongation has been strictly controlled for uniform fastening force. This is achieved through manually assembling each and every connecting rod for the Type R, and the result is a significant reduction of fastening force variance.

The combination of lightweight pistons and connecting rods helps to reduce reciprocating inertia and enhance throttle response significantly.

Piston Summary:

* High-pressure die cast piston crown has been reshaped to increase compression ratio from 10.0:1 up to 10.6:1
* Valve pockets deepend to accommodate the increased valve lift and duration
* Piston skirts were made ligher in order to lessen the inertial mass
* Piston skirts coated with molybdenum to minimize friction and allow it to withstand high-rpm operation (also used in the NSX)
* Injectors installed on the underside of the pistons allow for improved cooling, and prvent the pistons form getting "burned-in"
* Combination of lightweight pistons and connecting rods help reduce reciprocating inertia and enhance trottle respnse significantly

Connecting Rod Summary:

* Connecting rod bolt elongation has been strictly controlled for uniform fastening force
* Manually assembled for the Type R to reduce fastening force variance
* The specially designed rods have the letter "R" molded onto them
* Rods are constructed of special high-strength steel to withstand higher rpm's and are still lighter than GS-R connecting rods

ENGINE BLOCK AND CRANKSHAFT

The Type R utilizes a pressure die cast aluminum alloy block with cast-iron cylinder liners for light weight and maximum rigidity. Its highly rigid crankshaft is made of forged, high-strength steel with eight full balance weights to reduce vibration at high rpm by 20 percent. The journals of the crankshaft also feature a special micro-polished surface finish for reduced friction and increased durability.

8-Weight, Fully-Balanced Crankshaft:

* Balancing weights were added to number 1 and 4 wich reduces vibration at high rpm by 20 percent
* The journals of the crankshaft also feature a special micro-polished surface finish for reduced friction and increased durabilty
* Attachment point of the connecting rods to the crankshaft uses a new, adjustable connector that allows the mechanics to manually adjust the connection using a micrometer so they can compensate for the stretching of the connecting rod bolt
* Intake lift was increased from 10.6mm to 11.5mm
* Exhaust lift was increased from 9.4mm to 10.5mm
* Intake opening timing was increased from 10 to 15 degrees before piston apex
* Closing timing was increased from 40 to 45 degrees after the piston reaching base
* Exhaust opening timing was increased from 40 to 45 degrees before the piston reaching base
* Closing timing was increased from 7 to 10 degrees after piston apex
* These timing alterations allow the valves to remain open longer and cause more air to enter the combustion chamber

CYLINDER HEAD, VALVES, SPRINGS, AND CAMSHAFTS


Cylinder head design for the Type R is a double overhead camshaft, four-valves-per-cylinder configuration which incorporates the exclusive VTEC system. The Type R engine utilizes the latest combustion technology to provide a combination of fuel efficiency and power. Because of the low surface-to-volume area of the chamber, minimal surface area is exposed to the heat of combustion and more heat is retained in the expanding gases, resulting in increased thermal efficiency. And the generous "squish" area around the combustion chamber yields increased gas turbulence, faster flame propagation, and even better efficiency.

Extensive modifications of the cylinder head were undertaken improve performance. This also involves hand-polishing of the intake and exhaust ports near the valve seat area. In addition to hand polishing the ports to improve flow, special lightweight intake valves are also fitted. These valves feature a thinner shaft to reduce weight and increase flow. The head of the valve is also lightened to further reduce valvetrain weight. These modifications net a 12 percent weight reduction of the intake valves, allowing the engine to rev higher. These lighter intake valves help extend the rpm range of the Type R engine by an additional 200 rpm.

Special high-performance dual intake valve springs with an oval-shaped cross section are utilized to allow the use of high-performance camshafts for increased flow at high rpm. The unique oval shape allows a stronger valve spring to be fitted in the same area as a conventional spring. Conventional dual high-performance valve springs are used on the exhaust valves. Camshafts fitted to the Integra Type R are longer duration with higher lift to help increase engine breathing and top-end horsepower. At high engine speeds, valve lift on the intake side is increased by 0.9 mm, and on the exhaust side by 1.1 mm, compared to the GS-R. The valve timing is extended an additional 10 degrees on the intake side and 8 degrees on the exhaust side.

Exclusive lightweight valves:

* 12 percent weight reduction
* Valve shaft width was decreased from 5.5mm to 4.6mm
* The angle of the valve seat opening was tightened from 60 to 45 degrees
* Valve heads are lightened to reduce valvetrain weight
* Weight recduction allows engine to rev 200 rpm's higher

Camshafts are longer duration with higher lift:

* Increase engine breathing and top-end horsepower
* During high engine speeds, valve lift on the intake side is increased by 0.9 mm, and on the exhaust side by 1.1 mm, compared to the GS- R
* Valve timing is extended an additional 10 degrees on the intake side and 8 degrees on the exhaust side

Hand-polished Intake and Exhaust Ports:

* Intake and Exhaust Ports are hand-polished near the valve seat area to improve air flow
* Originally only two of the best mechanics at Honda port and polished the manifolds by hand. At this time only 25 engines a day could be created. During the last several production years 5 mechanics have been working full time on port and polishing in order to increase production.

Special high-performance dual intake valve springs:

* Oval-shaped cross section to allow the use of high-performance camshafts for increased flow at high rpm
* Non-cylindrical, "flat" springs in order to keep the spring height near-stock, and still increase rebounding power

The use of a surface-oriented crystal bearing material was pioneered in Formula One racing and has been adapted for use in the Type R engine. Unlike the surface of conventional bearing material, the crystal bearing surface has molecules oriented into a pyramid shape. This surface traps a layer of oil and holds it far better than conventional bearing surfaces, reducing friction and enhancing reliability.