ARP reinforced crankshaft main studs for Toyota 2JZ-GE 2JZ-GTE

The Toyota engines concerned

The 2JZ is Toyota's 3.0-litre inline six-cylinder petrol engine (2,997 cm³, 86 mm bore, 86 mm stroke), built from 1991 to 2007 as the naturally aspirated 2JZ-GE and the twin-turbo 2JZ-GTE. It powers the Toyota Supra (JZA80) and the Lexus GS300 (JZS147), among others.

As standard, the crankshaft is held by main cap bolts (Toyota reference 90910-02104), tightened to torque and then by angle: 44 Nm, then 90°.

Reinforced ARP studs for main bearings

On a crankshaft, the main caps are what hold the shaft against the loads passed on by the connecting rods. If their clamping force drops, the cap shifts slightly on its parting line at every cycle: the mating faces become indented, then the bearing bore goes out of round.

This kit replaces the original bolts with ARP 8740 steel studs, with their nuts and washers as the ARP instruction sheet lists them. On the 2JZ, each stud is first threaded into the block by hand, the caps then go on over the studs, threads and washers are coated with ARP assembly lubricant, and the nuts are finally torqued in three passes. The tension in the stud is higher and more even, and the block no longer takes the rotating load at its thread. Material: 8740, a chrome-moly steel that ARP specifies at 200,000 psi tensile strength. Factory-fitted fasteners usually belong to classes 10.9 and 12.9, with 150,800 to 176,900 psi minimum tensile strength. On this six-cylinder engine, the 8740 studs in M10 are rated for 1,400 hp at most (calculated estimate).

Technical specifications

Tightening torque

No torque is applied to the stud as it goes into the block: it is screwed in by hand. To secure the studs permanently, ARP instruction sheet 203-5405 allows a Loctite thread locker, provided the nuts have reached their final torque before the product cures.

Follow the cap tightening sequence recommended by the manufacturer when bringing the nuts up to torque; the kit's instruction sheet details each step.

Stronger fasteners change the clamping force: the size and roundness of the main bearing bores are checked after installation, and the bores are line-honed if necessary, using the final fasteners and lubricant.

The torque figures above come from the ARP 203-5405 instruction sheet, revision applicable at publication. The official instruction sheet is authoritative in the event of any difference. Read the ARP 203-5405 instruction sheet

Technical guide

All the torque values on this page assume ARP assembly grease; with engine oil they are no longer correct.

The ARP brand

Coming from the aerospace industry, Gary Holzapfel founded ARP (Automotive Racing Products) in the early 1970s to put an end to engine failures caused by weak fasteners in motorsport. The company designs and manufactures thousands of part numbers in California, in several material grades depending on the application.

Advantages over the original bolts

Criterion	Original main bolts	Reinforced ARP studs
Tightening	Bolt screwed straight into the block	Three torque passes, steady build-up
Threads in the block	Loaded by the turning bolt at every tightening	Stud screwed in by hand, no torque
Refitting the caps	Cap held by hand while the bolts go in	Cap guided by the two studs

When studs become necessary

• Power increase from a turbo, supercharger or higher boost
• Stroker crankshaft or higher rev limit
• Complete bottom end strip-down
• Bearing bores or block threads already fatigued
• Intensive motorsport use

Vehicle compatibility

OEM reference: 90910-02104

Why is it the most cost-effective solution?

As original equipment, the main bolts are tightened by torque then angle and stretch for good. In 8740, the ARP studs, reinforced and stronger, hold the caps against clearly higher connecting rod loads: less risk of a fastener-related bottom end failure, and therefore a costly repair avoided.

Consider the crankshaft main bearings

A bottom end rebuild calls for new bearings. We offer the tri-metal crankshaft main bearings that match these engines: