Reinforced ARP bolts for OEM rods OPEL VAUXHALL X14 Z14

The Opel and Vauxhall 1.4 16-valve engines concerned

This kit is for the 1.4-litre 16-valve four-cylinder Opel and Vauxhall engines with codes X14XE and Z14XE (1,389 cc, about 90 hp). Between 1994 and 2009 they powered the Corsa B and C, the Tigra and the Astra F and G, as well as the Holden Barina and several Chevrolets sold in South America.

Even without changing the camshaft, a small engine that is revved higher loads its rods harder: inertia forces follow engine speed and the original rod bolts are what hold them. ARP does not publish the part number of these bolts; the kit replaces them with 8740 bolts of M9 diameter.

Reinforced ARP bolts for connecting rods

Few parts of the bottom end work as hard as the rod bolt: at every revolution, it is what stops the cap from pulling away under the inertia loads of the rod and piston assembly. The original bolt is designed for stock power and is single-use.

The original rod bolts give way to ARP bolts in 8740, M9 diameter, preferably tightened by stretch, the method ARP recommends, or to the torque in the instruction sheet if no gauge is available. 8740 is a chrome-moly steel that ARP heat treats to 180,000 psi tensile strength, with threads rolled after heat treatment. As a reference point, standard engine fasteners mostly belong to classes 10.9 and 12.9, i.e. 150,800 to 176,900 psi minimum strength. The 8740 bolts hold up to 9,500 rpm (calculated estimate).

Technical specifications

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 109-6003 instruction sheet, revision in force on the day of publication. Should any difference appear, the official instruction sheet takes precedence. Read the ARP 109-6003 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.

Once the fasteners are fitted, the ARP instructions call for the big ends to be checked and resized by a machine shop.

Measuring bolt stretch

With the stretch gauge, you read directly how much the bolt stretches during tightening: the dial gauge sits on both ends of the fitted bolt, and tightening stops when the stretch reaches the value in the table. Friction no longer comes into play, hence a more consistent preload on a heavily stressed 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?

When a rod bolt gives way on an X14XE or a Z14XE, the rod, the piston and the block go with it. A set of ARP bolts in 8740 holds inertia forces better than the original ones, at a price far below that of rebuilding the bottom end.

Matching connecting rod bearings

New bolts, new bearings: find below the connecting rod bearings suited to this engine.