TOMEI Main Stud & Crank Cap Ladder Kits | 4A-GE / 4A-GZE 16V (AE86 Corolla / AW11 MR2 / AE92 Corolla)

TOMEI 4AG Main Stud & Crank Cap Ladder Kits

For 1983–1987 Toyota Corolla AE86, 1987–1991 Toyota Corolla AE92 coupe, 1984–1989 Toyota MR2 AW11, 1983–1987 Toyota Sprinter Trueno AE86, and 1987–1991 Toyota Sprinter Trueno AE92 coupe equipped with 4A-GE / 4A-GZE 16V engines.

Overview

TOMEI 4AG main studs and crank-cap ladders reinforce the lower end of Toyota 4A-GE and 4A-GZE 16V engines in 1983–1987 Corolla AE86, 1984–1989 MR2 AW11, and 1987–1991 Toyota Corolla Levin / Sprinter Trueno AE92 coupes and 1988–1991 U.S.-Market Corolla GT-S AE92 coupes. The main studs improve main-cap clamping consistency, while the ladder pieces increase support across the crank-cap area for high-RPM and performance engine builds.

Choose the ladder set for additional cap support, the studs for reinforced clamping, or the complete matched package for both. Ladders require compatible longer main fasteners, and oil-pan or baffle modification may be necessary.

Key Features

• Designed for Toyota 4A-GE / 4A-GZE 16V bottom-end reinforcement
• 8740 chromoly main-stud construction
• M10 × P1.25 main-stud thread specification
• Ten main studs, ten nuts, and ten washers in main-stud-equipped configurations
• Five special heat-treated crank-cap ladders in ladder-equipped configurations
• Supports more consistent main-cap clamping and increased crank-cap rigidity
• Available as ladder-only, main-stud-only, or complete matched configurations

Bottom-End Reinforcement

High engine speed and increased cylinder load place additional stress on the crankshaft, main bearings, main caps, and fasteners. The stud-style fastener system provides a more consistent clamping arrangement at the main caps, while the ladder system adds structural support across the crank-cap area to help control deflection under demanding engine operation.

The complete configuration combines both upgrades for builds where main-cap clamping and crank-cap rigidity are being addressed together.

Vehicle Fitment

Toyota Corolla — AE86

• 1983–1987: Trueno (JDM) / 4A-GE 16V
• 1983–1987: Levin (JDM) / 4A-GE 16V
• 1985–1987: GT-S (U.S.-Market) / 4A-GE 16V

Toyota MR2 — AW11 / MK1

• 1984–1989: JDM / 4A-GE 16V
• 1985–1989: U.S.-Market / 4A-GE 16V
• 1986–1989: JDM Supercharged / 4A-GZE 16V
• 1988–1989: U.S.-Market Supercharged / 4A-GZE 16V

Toyota Corolla / Sprinter — AE92 — Coupe

• 1987–1991: Corolla Levin / Sprinter Trueno (JDM) / 4A-GE 16V
• 1987–1991: Corolla Levin / Sprinter Trueno GT-Z (JDM) / 4A-GZE
• 1988–1991: GT-S coupe (U.S.-Market) / 4A-GE 16V

Fitment Notes

• Crank-cap ladders require longer main fasteners with adequate engagement. Factory main-cap bolts are not compatible with the ladders.
• Ladder-equipped configurations require sufficient No. 5 ladder clearance at the oil pan and baffle; these components may need modification.
• The main-stud clamping arrangement requires bearing clearances suited to the reinforced fasteners.
• Factory AE86 SR5 4A-C and AE92 SR5 4A-F / 4A-FE engines are not covered. Engine-swapped vehicles require the compatible 4A-GE / 4A-GZE 16V configuration.
• Intended for off-road competition use.

Product Specifications

Brand: TOMEI
Product Type: Bottom-End Reinforcement
Engine Family: Toyota 4AG 16V
Main Stud Material: 8740 Chromoly
Main Stud Thread: M10 × P1.25
Main Stud Quantity: 10 in stud-equipped configurations
Crank Cap Ladder Quantity: 5 in ladder-equipped configurations
Ladder Construction: Special Heat-Treated Cast Iron (FC)
Primary Purpose: Main-Cap Clamping & Crank-Cap Reinforcement

Which Configuration Should You Choose?

Crank Cap Ladder Set – 5 Ladders — Best for adding cap support to a build with compatible main studs

Choose the ladders when your engine already has suitable longer main fasteners and you want additional crank-cap support. Factory main bolts are not compatible.

Main Stud Set — Best for improving main-cap clamping without adding ladders

Choose the stud set when your build calls for reinforced main fasteners but not the ladder system. It includes ten studs with their nuts and washers.

Complete Main Stud + Crank Cap Ladder Set — Best for addressing clamping and cap support together

Choose the complete set when you need both upgrades and want the matched TOMEI components in one configuration.

ARP 8740 Chromoly Main Stud Kit — Best for a studs-only build using ARP fasteners

Choose the ARP alternative when your compatible 4A-GE 16V build calls for ARP main studs without crank-cap ladders. This is not a claim that the ARP kit is compatible with TOMEI ladders.

Our Recommendation: Choose the complete TOMEI set when both upgrades are needed, ladders alone when compatible studs are already part of the build, or a studs-only option when added ladder support is unnecessary.

Available Configurations

Crank Cap Ladder Set – 5 Ladders

Includes:

• (5) TOMEI crank-cap ladders
• Main studs are not included.

Main Stud Set

Includes:

• (10) 8740 chromoly main studs
• (10) 12-point fastening nuts
• (10) washers
• (4) 6-point assembly nuts
• (1) ARP molybdenum assembly lubricant

Complete Main Stud + Crank Cap Ladder Set

Includes:

• (5) crank-cap ladders
• (10) main studs
• (10) 12-point fastening nuts
• (10) washers
• (4) 6-point assembly nuts
• (1) ARP molybdenum assembly lubricant