How to Install a Flywheel Bolt Kit on a Honda/Acura H2B Swap

Quick answer

Clean the crank flange and flywheel mating surfaces, apply medium-strength threadlocker, and torque the flywheel bolts in a star pattern to the spec for your specific bolt kit and crank. If you don't have the kit's published torque value, use the factory service manual spec for the engine your crank came from, not a generic number. Re-check torque after the first heat cycle.

An H2B swap mixes an H-series block with a B-series transmission, so the flywheel and bolt hardware don't always come from the same service manual. That's where most flywheel bolt problems start: guessing the torque instead of confirming it.

This guide walks through a clean install you can do on jack stands, with the engine and transmission separated. It covers surface prep, threadlocker, the torque sequence, and the checkpoints that tell you something is wrong before the car is back on the ground.

Confirm your bolt kit and crank before you touch anything

Flywheel bolts are not universal. Bolt length, thread pitch, and head style vary by crank and by kit, and an H2B build can pair an H-series crank with a flywheel designed for a different application. Lay the bolts next to the flywheel and confirm they thread in by hand for several turns before you commit to the install.

If the bolt bottoms out or grabs after a turn or two, stop. Forcing it strips the crank threads, which turns a 30-minute job into pulling the engine. If your kit doesn't list a torque spec, use the factory service manual value for the crank you're using and treat that as your number.

• Checkpoint: bolts should thread in by hand until the head is close to the flywheel. Any resistance means wrong pitch or dirty threads.

Clean and degrease the mating surfaces

The crank flange and the flywheel's mounting face must be bare metal, dry, and free of oil. Brake cleaner on a lint-free rag works well; avoid paper towels that shed fibers into the bolt holes. Any oil film between the surfaces lets the flywheel shift under load, which shows up later as vibration or a loosening bolt.

Run a thread chaser, not a tap, through the crank bolt holes to clear old threadlocker and debris. Blow the holes out with compressed air and confirm nothing is left sitting at the bottom, since trapped debris can stop a bolt short of full engagement.

• Common mistake: spraying brake cleaner directly into the bolt holes and leaving the residue. Wipe, then dry.

Apply threadlocker correctly

Medium-strength threadlocker on the threads is standard practice for flywheel bolts, and it's cheap insurance against backing out under vibration. A small drop on the threads is enough. More is not better: excess liquid can hydraulic-lock in a blind hole and give you a false torque reading.

Keep threadlocker off the flywheel face and off the underside of the bolt heads. If the head is meant to clamp dry, lubricating it changes the clamp load at a given torque value. If your kit specifies a lubricant or sealant instead, follow the kit's instruction over general advice.

• Checkpoint: one drop per bolt, threads only. If you see liquid squeeze out around the head, you used too much.

Torque in a star pattern, in stages

Snug all bolts by hand first, then torque in a star or crisscross pattern rather than going around the circle. Two or three stages, such as half spec then full spec, seats the flywheel evenly and prevents the flange from cocking to one side.

Use a calibrated torque wrench and hold the flywheel still with a proper flywheel holder or a pry bar against a ring gear tooth, not through the friction surface. Work up to your confirmed spec and stop there. Over-torquing stretches the bolts and can distort the flange.

• Common mistake: torquing in a circle. It can pull the flywheel off-center and create runout.

Verify runout and re-check after the first heat cycle

With the bolts torqued, check flywheel runout with a dial indicator on the friction surface. If runout is out of spec, pull the flywheel and inspect for debris, a burr, or a bent flange before reinstalling. A flywheel that isn't seated flat will not fix itself once the transmission is bolted up.

After the first drive or heat cycle, re-check the bolts if you can access them. Threadlocker cures under heat, and any bolt that moved during the first cycle will show up now rather than at redline. If a bolt was loose, remove it, clean the threads, and redo the install rather than simply re-torquing it.

• Checkpoint: zero movement on re-check. Any bolt that turned means the install needs to be redone.

H2B flywheel bolt install steps

1. Step 1: Confirm bolt fit and torque spec: Thread each bolt into the crank by hand and confirm several full turns of engagement. Identify the correct torque value from your bolt kit or the factory service manual for the crank you're using. Checkpoint: any bolt that won't thread by hand is the wrong pitch. Stop and sort it out before installing.
2. Step 2: Clean the crank flange and flywheel face: Degrease both mating surfaces with brake cleaner and a lint-free rag, then chase the crank threads and blow the holes clean. Common mistake: leaving oil film or debris, which causes runout and loosening.
3. Step 3: Apply medium-strength threadlocker: Put one small drop on the threads of each bolt. Keep it off the flywheel face and off the underside of the bolt heads unless the kit says otherwise. Checkpoint: no squeeze-out around the heads. Too much threadlocker can cause a false torque reading in a blind hole.
4. Step 4: Torque in a star pattern in stages: Snug all bolts by hand, then torque in a crisscross pattern in two or three stages up to your confirmed spec, holding the flywheel with a proper holder. Common mistake: torquing in a circle or in one pass, which can cock the flywheel.
5. Step 5: Check runout and re-check after the first heat cycle: Measure flywheel runout with a dial indicator, then re-check bolt torque after the first drive or heat cycle. Any bolt that moved on re-check means the install comes apart and gets redone, not just re-torqued.

Parts that pair with an H2B drivetrain build

• Precision Works Engine Mount AWD Bracket - K-Swap EG Civic DC2 Integra: This bracket converts Precision Works K-Swap engine mounts into an AWD engine mount kit, and by adding the rear bracket you can mount an AWD transmission into an all-wheel-drive setup. If your H2B build is going AWD rather than front-wheel drive, the mount side of the job changes along with the drivetrain, so plan the bracket and mount kit together before you set final driveline angles.
• PLM Power Driven T3 Twin Scroll Turbo Manifold S2000 F-Series F20C F22C: The manifold is built from 304 stainless steel with CNC machined flanges, a 1/2-inch-thick flange, 8-gauge schedule 40 pipe, and a T3 twin scroll design for Honda F-Series F20C and F22C engines. If your swap is turbocharged, the manifold's flange thickness and material affect how it seals and how it handles heat cycling, which is the same logic that applies to keeping your flywheel hardware properly torqued and seated.

An H2B flywheel bolt install comes down to three things: the right bolts for your crank, clean dry mating surfaces, and a torque sequence you can actually verify. Get those right and the flywheel stays put. If you're still choosing drivetrain hardware for the build, sort out the mount and bracket side before the engine goes back in.