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This ARP performance fastener, stud, bolt, tool, or assembly is the 84.0mm Ring Compressor. Confirm the exact engine or vehicle application, thread size, length, material, strength series, included quantity, installation lubricant, tightening sequence, and current ARP torque specification before ordering.
Key Features
- Exact 84.0mm Sizing: Matches BMW M50 M52 M54 bores precisely for secure ring compression without gaps or slippage.
- Tapered Design: Gradual slope applies even pressure to prevent ring cocking breakage or distortion during piston insertion.
- Steel Construction: High-strength material handles high-pressure assembly and repeated professional use.
- Knurled Grip: Textured exterior provides firm hand control in tight engine bays.
- Works with OEM and aftermarket 84mm pistons no special adapters needed.
- Yes the 84.0mm size matches M54B30 bore exactly for E46 330i and similar models.
Fitment
| Years | Make | Model | Application |
|---|---|---|---|
| Universal or specification-matched application. Verify every dimension, interface, load or operating requirement, and listing note. | |||
Specifications
| Brand | ARP |
|---|---|
| Manufacturer Part Number | 901-8400 |
| Product Type | Tools |
| Condition | New |
| Configuration | 84.0mm Ring Compressor |
| Exact 84.0mm Sizing | Matches BMW M50 M52 M54 bores precisely for secure ring compression without gaps or slippage |
| Tapered Design | Gradual slope applies even pressure to prevent ring cocking breakage or distortion during piston insertion |
| Steel Construction | High-strength material handles high-pressure assembly and repeated professional use |
| Smooth Bore Surface | Polished interior avoids scratches on rings or pistons for clean reliable sealing |
| Knurled Grip | Textured exterior provides firm hand control in tight engine bays |
| Q | Will this fit BMW E46 330i M54 engines? A: Yes the 84.0mm size matches M54B30 bore exactly for E46 330i and similar models |
| Method | UPS Ground or USPS Priority |
| Availability | In stock - ships same or next business day |
| Packaging | Protective cardboard box 4 x 4 x 3 inches |
| Weight | 0.8 lbs |
| Key Features Exact 84.0mm Sizing | Matches BMW M50 M52 M54 bores precisely for secure ring compression without gaps or slippage |
What's Included
One new ARP tool in the exact configuration and quantity identified by this listing. Brackets, wiring, air lines, fittings, switches, fasteners, fitting kits, fluids, covers, and accessories are included only when expressly stated for this exact part.
About ARP
Automotive Racing Products manufactures high-performance studs, bolts, nuts, washers, wheel hardware, assembly tools, and installation lubricants for engine, drivetrain, chassis, and racing applications. Thread dimensions, material, preload method, lubricant, torque, and included quantity remain exact-part specific.
Important Disclosures
- California Proposition 65 warning applies. Review the current manufacturer warning before handling or installation.
Related Parts
- Shop all ARP products
- ARP 4.055in Ring Compressor
- ARP 4.110in Ring Compressor
- ARP 4.2125in Ring Compressor
Frequently Asked Questions
How do I confirm the 84.0mm Ring Compressor fits my application?
Match the exact engine family or vehicle, component location, thread diameter and pitch, under-head length, material, strength series, and every current ARP application note.
Can I reuse the factory torque value with this ARP hardware?
Not automatically. Use ARP's current instructions for the exact part, material, lubricant, tightening sequence, and preload method. Factory torque values may be based on different hardware and friction.
What is included with this ARP kit?
Only the studs, bolts, nuts, washers, lubricant, and tools expressly listed for this exact part number are included. Verify the required quantity before disassembly.
Installation Instructions
- Confirm ARP part number 901-8400, the complete application, and every required supporting component before beginning work.
- Clean and inspect all mating threads and components, then verify thread engagement, length, washers, nuts, lubricant, and required preparation before assembly.
- Follow ARP's current tightening sequence, lubricant instructions, torque or stretch method, and any retorque procedure for this exact part.
- Verify clearance, preload, fastener seating, and normal component operation before returning the vehicle or engine to service.
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