TOMEI Main Inner Bearing Set - Nissan RB26/RB25

Tomei began operations in 1968 as a race car tuner in Japan. Over the last 40 years Japan has emerged as one of the leaders in automotive research racing and culture. Tomei products have been utilized in nearly every motor sport imaginable. Tomei’s racing heritage means their research and design team have first hand knowledge of the extreme demands racing puts on an engine. Using only the highest quality materials means that Tomei’s products can handle the intense strain and heat a purpose built engine will experience whether it be on the street or the track. Tomei’s attention to detail is second to none. All of their products are thoroughly researched and engineered to achieve optimal efficiency. Because of even miniscule differences in measurements can cause catastrophic engine failure all Tomei products fall within strict tolerances. Tomei machines all of their engine components to enhance airflow and ensure proper fitment and seal.

When tuning engines for higher power output and high RPM the bearings are subjected to extreme load conditions. These harsh conditions require the bearings to be able to cope with excessive loads and stress conditions. The TOMEI Competition Bearing series are designed for fatigue resistance durability effective lubrication and resistance to scoring. Designed for use on engines that will be outputting 1000 HP and at over 10000RPM. These advanced designed bearings are suitable for the serious professionals in mind whom need results.

Materials:

• OVERLAY （P76 Material）
  The P76 material is used for it's superior abrasion and fatigue resistance. The elimination of the tin flash plating improves the heat transfer through the bearing.
• F781 Material
  The F781 material is used on connecting rod bearings for high performance engines. It has a hardened steel backing to improve the support of the bearing lining and assist bearing retention in the housing.
• The combination of these material enhancements optimize bearing performance under high loads and temperatures.

Crush:

• The Competition Bearing Series are designed with an increased crush (i.e. extra bearing length of typically 0.100-0.175mm). The extra crush improves the retention of the bearing in it's housing.
• Crush Height: The crush height is based on the bearing being a fraction longer than the housing seating so that a small section protrudes above the rod bore parting surface. When the rod halves are drawn together the inserts touch before the halves thus forcing the inserts tightly into place.

Eccentricity:

• The wall thickness at the crown of the shell is thicker than the wall at 3/8" down from the parting face. These Competition Bearing Series have an increased amount of eccentricity to compensate for the bearing housing bore elongation in extreme conditions and to help create an effective hydrodynamic oil film.

Notches:

• The Notches help with bearing alignment during fitment. They do not hold the bearings in place during operation that is the function of “Crush”.

Bored Surface:

• The bore bearing surface finish method helps promote effective oil flow and to maintain adequate lubrication for both the bearings and other moving parts.

Oil Grooves:

• The design of the oil grooves on the lower main bearing shell is always a trade off between oil supply to the Conrods and the bearings load carrying capacity. These TOMEI Competition Bearings generally have a 3/4 groove to give optimum balance of oil flow whilst keeping optimum load carrying capacity.

Please note: Prices are for a set of 6 upper and 6 lower bearings each in grade and size specified please refer to the chart below for information on bearing grades and sizes.