Reinforced ARP bolts and nuts for OEM rods HONDA ACURA B16A B17A B18

The Honda B16A, B17A and B18 engines concerned

This kit is intended for the Honda B16A, B17A and B18 engines, 1.6 to 1.8-litre four-cylinders with twin overhead camshafts and 16 valves, which ARP lists with the M9 thread: they are found in the Civic IV to VI, CRX II and III, Integra, Capa, Domani and Orthia, as well as the Acura Integra.

The original rod bolt of these engines is a Honda bolt, part number 13204-P72-003; the kit replaces it with an ARP2000 bolt of M9 diameter, pressed into the rod and then tightened with a nut.

Reinforced ARP bolts and nuts 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.

The bolts are pressed into the rods and each takes a nut; ARP asks for tightening to a stretch figure measured with a gauge, and gives a fallback torque when no gauge is available. 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. The ARP2000 bolts hold up to 10,250 rpm (calculated estimate).

Technical specifications

Before the bolts are pressed in, the ARP instructions require a check that the chamfer at the top of the rod bore is large enough to clear the radius under the bolt head.

Tightening torque and stretch

For this part, ARP favours tightening to a measured stretch, the key to an exact preload; torque is given only when no gauge is available. The figures in the table assume ARP lubricant.

Figures taken from the ARP 208-6401 instruction sheet, revision in force on the day of publication. Should any difference appear, the official instruction sheet takes precedence. Read the ARP 208-6401 instruction sheet

The ARP instruction sheet does not require a thread locker for this kit; only ARP Ultra-Torque grease is applied, on the bolt threads as well as on the bearing face of the nuts.

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

All the torque and stretch values on this page assume ARP assembly grease on the bolt threads and on the bearing face of the nuts; engine oil does not replace 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

OEM reference (rod bolt): 13204-P72-003

Why is it the most cost-effective solution?

On a tuned engine, the rod bolts see ever greater tensile loads: one that gives way destroys the rod, the piston and the block. The ARP2000 bolts in this kit remove that risk for a fraction of the cost of a bottom-end rebuild.

Matching connecting rod bearings

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