How to build a "reliable" lsvtec/b20vtec

25 de octubre de 2024 Ennio Delacruz

If you’ve been scouring the forums for answers on building a solid LS VTEC or B20 VTEC engine, you’ve probably noticed the same questions pop up repeatedly. That’s why I’ve put together this guide. My goal is to provide a reliable, all-in-one resource on the essentials for building these engines—so you can stop searching and start building. Keep in mind, this is a general guide that covers intermediate-level steps. Anyone with a bit of mechanical knowledge and patience can follow along.

Essential Parts and Tools for a Reliable LS VTEC/B20 VTEC Build

Starting with the basics, here are the essential parts you’ll need. These components are critical for durability and engine health:

ARP Rod Bolts (LS/B20): These provide extra strength for the connecting rods.
ARP Head Studs (GSR/ITR): Ensure these are specifically for the GSR/ITR models; avoid B17 versions.
New Head Gasket: For B18A/B (81mm bore) or B20 (84mm bore) engines. Use a multi-layer steel (MLS) or aftermarket option suitable for your bore.
ACL Bearings (LS/B20): Reliable bearings to handle the increased load.
Piston Rings: Hastings or OEM rings will do the job for stock and aftermarket pistons alike.
Valve Seals: Use OEM seals for B series engines.
22T Water Pump (DOHC VTEC): Reliable water flow for performance engines.
Timing Belt: Go with the OEM P72 GSR/ITR belt.
P72 Oil Pump (DOHC VTEC): Choose a 1996+ pump for improved flow.
Magnetic Oil Drain Plug: Important for catching metal shavings during break-in.
Spark Plugs: Choose NGK V-power BKR6E for stock LS pistons, BKR7E for 10.0-12.0:1 compression, or R5671A-8 for compression over 12.0:1.
Adjustable Fuel Pressure Regulator: Needed for stock ECU and injectors.

Additional Tips: “Same” parts mean they share Honda/Acura part numbers across compatible models.

Additional Preparations for Performance and Reliability

For a truly reliable setup, also consider:

Shotpeen LS Rods: Increases rod strength.
Cylinder and Rod Honing: Recommended when using ARP rod bolts.
Rotating Assembly Balancing: Ensures smooth high-rev performance.

Complete these steps to enhance durability in your hybrid engine.

Building for Power: Performance Upgrades

If power is your primary goal, add these components:

2.5-Inch Exhaust: A full setup, including headers, catalytic converter, and muffler.
Hondata or PasswordJDM Intake Manifold Gasket: Reduces intake air temperature.
Adjustable Cam Gears: Necessary even for stock cams, as LS VTEC timing can be slightly off.
Higher Compression Pistons (P30 or P73): OEM or aftermarket forged pistons for more power.
Performance Cams and Valve Springs: Consider Skunk2, Rocket Motorsports, or Toda for high-rev reliability.
High-Quality Intake Manifold: ITR, AEBS, Skunk2, and JG provide a good range of options.
310cc Injectors: Essential for fuel demands at higher power levels.
Cylinder Sleeves (for 84mm bore): Reinforces the block to handle increased pressure.

Torque Specifications

Using the correct torque specifications is essential for reliability. Here’s a quick list for common components:

Fuel Filter Bolt: 25 ft/lbs
Crank Pulley Bolt: 130 ft/lbs
Cam Gear Bolts: 41 ft/lbs
Cylinder Head Bolts: 22 ft/lbs (first), 63 ft/lbs (second)
Rod Bearing Caps: 23 ft/lbs (for ARP rod bolts, follow ARP’s guide)
Oil Pan Bolts: 8.7 ft/lbs

Always have a reliable torque wrench and follow Honda’s specified sequence for each component.

Assembly Tools and Prep

Before you start, gather these tools and supplies:

Assembly lube, RTV, and 30W ND oil for break-in.
Full set of metric wrenches and sockets in 3/8” and 1/2” drives.
Torque wrenches (both inch-lbs and ft-lbs).
Spark plug socket and extensions.

At minimum, you’ll need a Haynes or Chilton manual, but a Helms manual is ideal for in-depth guidance.

Choosing the Right Cylinder Head

When choosing a head, the two main options are B16 and GSR:

B16 Heads: Offer a bolt pattern compatible with ITR intake manifolds, giving more flexibility with aftermarket options.
GSR Heads: Have “quench pads” in the combustion chamber, which can aid in detonation prevention and combustion efficiency.

For high-power builds over 200whp, you’ll need stronger cams and valve springs, so factor in any costs and potential trade-offs when selecting your head.

Building the Block

The LS/B20 blocks are reliable with a few upgrades:

Forged Pistons: Stock pistons are weaker under high compression; forged pistons are ideal for builds where reliability is a priority.
ARP Rod Bolts: LS rod bolts are a known weak point, so upgrading to ARP bolts is a must.
Aftermarket Bearings and Rings: ACL bearings and Hastings rings have been used successfully in high-performance builds.
Rotating Assembly Balancing: Adds high-rev stability, helping the engine run smoother.

Final Steps and Tips for Assembly

Head Installation: Set the block to TDC and install the head with ARP studs, torquing to their specifications.
Install the Timing Belt: Make sure both the crank and cams are aligned, and follow a systematic tensioning process.
Fuel and Ignition Setup: Proper injectors, a tuned ECU, and high-quality spark plugs are essential for reliable power delivery.
Break-in and Oil Changes: Follow a rigorous break-in schedule, starting with 30W non-detergent oil. Change oil at intervals of 20, 100, 500, and 1000 miles before switching to synthetic.

Conclusion

Building an LS VTEC or B20 VTEC engine is a rewarding project when approached correctly. With the right parts, a keen eye on torque specs, and consistent attention to detail, you’ll have a reliable and powerful engine that reflects the hard work you’ve put into it. For any questions, a Helms manual or consulting a reputable engine builder will be invaluable for ensuring a quality build.

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