DART Head Stud Kit Toyota 2JZ 1/2" (S220)

Technical Specifications

Manufacturer reference: DART 66140117
Series: S220 (Steel 220,000 psi)
Application: DART Iron Eagle 2JZ engine block with 1/2" threading
Stud thread size: 1/2" (12.7mm)
Nominal tensile strength: 220,000 psi (1517 MPa)
Kit quantity: 14 studs + 14 12-point nuts + 14 washers

Block compatibility:

• DART Iron Eagle 2JZ reference 31011011 (1/2" head studs version)
• Bore: 86mm standard (88mm max)
• Deck height: 8.625" (219.08mm)
• NOT compatible with OEM Toyota 2JZ block (11mm threading)

Materials & Manufacturing

S220 head studs:

• Premium steel sourced exclusively from US mills
• Nominal strength 220,000 psi tensile strength (1517 MPa)
• +120% clamping force increase vs stock TTY bolts
• Made in USA (Rogersville, Missouri)

Ultra-precise manufacturing process:

• Individual vacuum heat treatment (full-time metallurgist supervision)
• Individual straightening post-treatment to eliminate deformation
• Centerless grinding (exceptional concentricity ±0.001" / ±0.025mm)
• Post-heat-treat thread rolling for optimal strength (vs cut threads)

12-point nuts:

• Cold forged in-house
• Vacuum heat treated
• Better torque distribution, multiple engagement angles

Washers:

• Hardened parallel washers
• Double-disc ground
• Uniform load distribution, accurate torque reading

Black Oxide finish (Mil-S-13165): Anti-corrosion protection, professional appearance

Installation & Torque Specifications

IMPORTANT - DART Iron Eagle Block Only: This kit is designed EXCLUSIVELY for DART Iron Eagle block reference 31011011 with factory 1/2" threading. DO NOT use on OEM 2JZ block (11mm threading).

MANDATORY Lubrication:

• Recommended lubricant: ARP Ultra-Torque Assembly Lube
• Alternative: High-temperature molybdenum
• Application: Stud threads + under washers + under nuts
• NEVER install dry (risk of galling + false torque reading)

Torque specification:

• Final torque: Consult DART/Point One specific documentation
• Method: Progressive tightening in 3 passes (30% → 60% → 100%)
• Sequence: Center to outside (cross pattern)
• Control: Stud elongation measurement recommended (stretch gauge)

Engine break-in:

• First 100 km: No aggressive RPM/boost increase
• Re-check torque: After 500 km with cold engine
• Periodic verification: Every 10,000 km or before competition

Compatibility & Applications

Compatible with:

• Engine block: DART Iron Eagle 2JZ 31011011 (1/2" head studs)
• Cylinder heads: OEM 2JZ-GTE / 2JZ-GE / aftermarket (Titan, HKS, Brian Crower)
• Head gasket: Cometic MLS 1/2" studs, HKS MLS 1/2" studs (1.0-2.0mm)
• Dowels: Modified head dowels for 1/2" clearance

Retrofit on OEM 2JZ block NOT RECOMMENDED:

• Block cracking risk
• Retrofit cost: $800-1200 USD machining
• Requires: Drilling + tapping 1/2" block, head boring, specific gasket

Performance applications:

Street/Track (800-1200 HP / 1.5-2.2 bar):

• S220 1/2" studs sufficient
• Cometic MLS 1.3mm head gasket
• Head preparation: Resurfacing + leak test

Race Extreme (1200-2000+ HP / 2.2-3.5 bar):

• S220 1/2" studs validated
• Cometic MLS 1.5-2.0mm head gasket
• Head preparation: Resurfacing + O-ring grooves
• Possible upgrade: Point One H260 (260,000 psi) for ultimate builds