Reinforced ARP bolts for OEM rods HONDA K20A

The Honda K20A engines concerned

This kit is intended for the Honda K20A engines, four-cylinder units of 2.0 litres with twin overhead camshafts, 16 valves and i-VTEC valve timing: Civic Type R (EP3) and Civic 2.0i Sport.

It replaces the original rod bolt with an ARP2000 cap screw, without washer, which threads into the connecting rod and clamps the cap.

Reinforced ARP bolts for connecting rods

At every revolution, the rod bolt takes the pull of the rod and piston assembly, which tries to force the cap away through inertia. As original equipment, it is sized for stock power and is replaced at every strip-down.

This kit replaces the original rod bolts with ARP2000 screws, tightened to a stretch figure, the method ARP recommends for this part, or failing that to torque. ARP2000 is an alloy steel developed by ARP and heat treated to 220,000 psi tensile strength; its threads are rolled after heat treatment. Standard engine fasteners commonly fall into classes 10.9 and 12.9, i.e. 150,800 to 176,900 psi minimum strength: ARP2000 sits 24 to 46% above that.

Technical specifications

Tightening torque and stretch

ARP gives priority to stretch control for an accurate preload; the torque in the table is used only when no gauge is available. Torque and stretch figures in the table apply with ARP lubricant.

Figures taken from the ARP 208-6003 instruction sheet, revision in force on the day of publication. Should any difference appear, the official instruction sheet takes precedence. Read the ARP 208-6003 instruction sheet

Assembly is done without thread locker, as the ARP instruction sheet calls for none: ARP Ultra-Torque grease is applied to the threads and under the head of each bolt.

According to the ARP instructions, the big ends must be checked and resized with the fasteners in place; plan a visit to a machine shop.

Measuring bolt stretch

Stretch measurement supplements torque tightening and gives the most accurate preload. It is done with the bolt in place: the gauge, fitted with a dial indicator, bears on both ends of the bolt and shows the stretch achieved, to be brought to the value in the table above. This avoids the variations caused by friction, which matters on a highly stressed engine.

Technical guide

Tightening is done with ARP assembly grease, on the threads and under the head: the torque and stretch figures in the table were established with it.

The ARP brand

ARP (Automotive Racing Products) came into being in the early 1970s, when Gary Holzapfel, who came from the aerospace industry, decided to tackle the engine failures caused in motorsport by inadequate fasteners. Today the brand produces thousands of part numbers in California for the cylinder head, the main bearings and the connecting rods, in materials suited to each application, with manufacturing known for its consistency.

Vehicle compatibility

Why is it the most cost-effective solution?

A K20A from a Civic Type R revved higher or fitted with forced induction asks its rod bolts to hold inertia loads that the original hardware was not sized for, and a broken bolt destroys the rod, the piston and the block. ARP2000 bolts cost little compared with rebuilding a K20A bottom end.

Matching connecting rod bearings

To complete the bottom-end rebuild, we offer the connecting rod bearings intended for this engine.