Reinforced ARP bolts for OEM rods HONDA L15

The Honda 1.5 L15A and L15B7 engines concerned

This kit is for the 1.5-litre Honda four-cylinder engines with codes L15A, L15A1, L15A2, L15A4 and L15A7 (1,497 cc, 78 to 120 hp), and for the turbocharged L15B7 of the Civic X (1,498 cc, 170 to 205 hp). Since 2001 they have powered the Jazz, City, Airwave, Mobilio, Freed and Partner, then the Civic X and XI, CR-V V and HR-V, as well as the Honda GAC Fit and City and the Everus S1.

Whether naturally aspirated or turbocharged, a 1.5-litre engine that is revved higher or boosted harder loads its rods more: inertia forces follow engine speed, and only the rod bolts hold the cap. ARP does not publish the part number or the diameter of the original rod bolt; the kit replaces it with ARP2000 bolts without washer.

Reinforced ARP bolts for connecting rods

At every engine revolution, the rod and piston assembly pulls on the rod cap, and only its bolts hold it against these inertia loads. The original ones are intended for stock power and for a single installation.

In place of the original bolts, the kit brings ARP bolts without washer: ARP recommends tightening them by measuring stretch, and the instruction sheet gives a torque only for an installation without a gauge. Material: ARP2000, an alloy steel developed by ARP, heat treated to 220,000 psi tensile strength, with threads rolled after heat treatment. Against classes 10.9 and 12.9 of original fasteners, between 150,800 and 176,900 psi minimum, the margin is 24 to 46%.

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.

Source of the torque and stretch figures: ARP 208-6301 instruction sheet, in the revision applicable at publication. The manufacturer's instruction sheet prevails in the event of any difference. Read the ARP 208-6301 instruction sheet

No thread locker is called for by the ARP instruction sheet for this kit: the bolts are fitted with ARP Ultra-Torque grease, on the threads and under the head.

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

Tightening to stretch means setting the preload on how much the bolt actually stretches, rather than on a torque affected by friction. With the bolt fitted, the dial gauge is placed on both its ends and the bolt is tightened until the stretch given in the table is read. It is the safest method on a highly tuned engine.

Technical guide

Torque and stretch figures are only valid with ARP assembly grease, applied to the threads and under the head.

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 rod bolt that lets go on an L15A or an L15B7 does not stop at itself: the rod leaves the block and takes the piston and the crankshaft with it. A set of ARP bolts costs a fraction of a full rebuild of the bottom end.