Uprated main bearing studs ARP RENAULT Clio RS Megane RS F4R

This kit of uprated main bearing studs for the RENAULT F4R engine contains 10 ARP studs and 10 ARP nuts.

You will find the fitting instructions in the "Download" tab above.

Below (click on the image) are the tri-metal main bearings for the F4R engine:

Gary Holzapfel came from the aerospace industry and set up ARP (Automotive Racing Products) in the early 1970s to answer a major problem in motorsport: engines destroyed by bolts and studs that were not strong enough. At the time no manufacturer was able to meet that need. ARP now offers thousands of part numbers across several ranges and product types, including head bolts, main bearing bolts and con rod bolts. Depending on the application, ARP offers several ranges, that is several materials, of fasteners:

• 8740: a chrome-molybdenum steel with standard strength properties, perfectly suited to prepared engines. This steel offers a tensile strength of between 1240 and 1447 N/mm2.
• ARP2000: stronger than 8740, the ARP2000 alloy withstands clamping and tensile loads of up to 1516 N/mm2. This range is widely used on track and drag cars and can be used with hydrogen.
• L19: a treated high-grade steel offering tensile and fatigue strength well above the 8740 and ARP2000 ranges. Its tensile strength reaches 1792 N/mm2. This material is more prone to corrosion, so it must be kept oiled and away from moisture. Hydrogen is not recommended with this range.
• CA625+ (Custom Age 625 Plus): this "super alloy" has far higher technical properties while resisting corrosion and oxidation. Its tensile strength reaches 1930 N/mm2.

All ARP fasteners are designed and manufactured in the United States. Production starts with cold or hot forging, then a heat treatment that varies with the range, followed by shot peening to remove any irregularity. Precise grinding then gives perfect concentricity before the thread is cut. Finally comes the finish, with a coating such as black chrome-molybdenum oxide, or polishing of the stainless steel, depending on the product range.

Every kit comes with assembly lube and instructions setting out:

• the installation steps
• the tightening torque
• the tightening procedure