Reinforced ARP bolts for OEM rods FORD Q7DA QQDA QQDB QQDC QQDD CSDA CSDB CGBA CGBB CHBA CHBB

The Ford engine concerned

This kit is designed for the Ford Duratec HE 1.8-litre four-cylinder petrol engine (1,798 cc, 83.0 mm bore, 83.1 mm stroke) found in the Focus II, Focus C-MAX, C-MAX and Mondeo III, built between 2000 and 2012.

On this engine the kit takes the place of the original rod bolt: ARP describes it in its instruction sheet as a set for the "Ford 1.8L Duratech" and gives the tightening method to follow.

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 kit is supplied in ARP2000; the ARP instruction sheet calls for stretch-measured tightening and, without a gauge, a torque of 61 Nm. These bolts are made from ARP2000, an ARP-specific alloy steel heat treated to 220,000 psi tensile strength, with threads rolled once the treatment is complete. Classes 10.9 and 12.9 of standard fasteners start at 150,800 and 176,900 psi: ARP2000 exceeds them by 24 to 46%. The engine speed allowed by the ARP2000 bolts goes up to 10,250 rpm (calculated estimate).

Technical specifications

According to the ARP instruction sheet, the bolt seat in the rod cap must be chamfered generously enough that the fillet under the bolt head does not land on the edge.

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.

The values above come from the ARP 251-6202 instruction sheet applicable at the date of publication; it is authoritative in the event of any difference. Read the ARP 251-6202 instruction sheet

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

The ARP instructions for this kit require the big ends to be checked and resized once the fasteners are fitted: this job belongs to an equipped 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

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

The ARP brand

Founded in the early 1970s by Gary Holzapfel, who came from the aerospace sector, ARP (Automotive Racing Products) was born to put an end to fastener-related engine failures in racing. Its thousands of part numbers, designed and manufactured in California for the cylinder head, the main bearings and the connecting rods, come in several materials depending on the application and are recognised for the consistency of their manufacture.

Vehicle compatibility

Why is it the most cost-effective solution?

A 1.8-litre Duratec HE built to rev higher or to take boost loads its rod bolts harder on every cycle. When one lets go, the rod, the piston and the cylinder block are often lost with it: the price of an ARP2000 set stays well below that of a rebuild.