Reinforced ARP bolts and nuts for OEM rods VW EG PG G60

The Volkswagen 1.6 EG and 1.8 G60 engines concerned

This kit covers two Volkswagen 8-valve four-cylinder engines: the naturally aspirated 1.6-litre of 110 hp (EG, 1,588 cm³), fitted to the Golf I GTI and Cabriolet, the Jetta I GLI and the Scirocco from 1976 to 1982, and the supercharged 1.8-litre G60 of 160 hp (PG, 1,781 cm³), fitted to the Corrado G60, the Golf II GTI G60 and the Passat B3 and B4 G60.

This ARP kit replaces the original rod bolts of the EG and PG engines, whose reference is not published. ARP describes it as a set of bolts to be pressed into the rods, for water-cooled Volkswagen engines.

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.

Made in 8740, this kit goes in in two stages: the bolts are pressed into the rods first, then the nuts are tightened. The ARP instruction sheet recommends checking the stretch; with no gauge, it gives 54.2 Nm. These bolts are made from 8740, a chrome-moly steel brought to 180,000 psi tensile strength by ARP's heat treatment; the threads are rolled afterwards. For comparison, classes 10.9 and 12.9 of original fasteners have a minimum of 150,800 to 176,900 psi. The 8740 bolts hold up to 9,500 rpm (calculated estimate).

Technical specifications

According to the ARP instruction sheet, the bore of each rod must be chamfered widely enough to take the radius under the bolt head, before the bolts are pressed in.

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.

The values above come from the ARP 104-6002 instruction sheet applicable at the date of publication; it is authoritative in the event of any difference. Read the ARP 104-6002 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

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 bolt threads and to the bearing face of the nuts.

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?

On a prepared Golf GTI, Scirocco or Corrado G60, each rod bolt takes inertia loads on every turn, and the failure of a single one wrecks the rod, the piston and the block. An 8740 kit protects this weak point for far less than rebuilding the bottom end.