Flywheel Bolt Kit Buying Guide for Honda and Acura H2B Swaps

Quick answer

For most Honda and Acura H2B swaps, buy a complete flywheel bolt kit that matches your flywheel and crank flange thickness, includes the correct bolt length for full thread engagement, and comes with a torque lubricant. If you are reusing OEM bolts or mixing hardware, stop and measure first; the wrong length can strip the crank flange or leave the flywheel loose.

An H2B swap mixes a Honda B-series engine with an H-series transmission, so the flywheel and clutch hardware rarely bolts together like a factory combination. The flywheel bolts are one of the few parts that must be correct on the first try, because a loose or broken bolt can destroy the crank flange or send the flywheel into the bellhousing.

This guide covers what actually matters when you buy a flywheel bolt kit for an H2B swap: bolt length, thread engagement, lubricant, and whether a dedicated kit is worth it over sourcing hardware piece by piece.

Why H2B swaps need their own flywheel bolt decision

In a factory Honda setup, the flywheel bolts are matched to a specific engine and flywheel combination. An H2B swap changes the stack-up: you may run an H-series flywheel, a B-series flywheel with an adapter, or a custom flywheel, and each has a different flange thickness. That changes how much bolt shank sits inside the crank.

Too short, and you lose thread engagement, which risks pulling the threads out of the crank under load. Too long, and the bolt can bottom out before the flywheel is clamped, which feels tight with a torque wrench but leaves the flywheel loose. A kit made for the swap removes most of that guesswork.

• Measure your flywheel flange thickness and compare it to the bolt length under the head.
• Check that the bolt threads fully into the crank by hand before final torque.
• Never assume a bolt that fits one H2B combo fits another; adapter plates vary.

What to look for in a Honda flywheel bolt kit

Grade and material matter, but so does the finish. A grade 8.8 or higher steel bolt is common for this job, and a coating or plating helps resist corrosion in the bellhousing where moisture and clutch dust collect. Titanium is an option if you want weight savings and corrosion resistance, but it costs more and is not necessary for a street car.

The kit should include the correct number of bolts for your flywheel, plus washers if the flywheel requires them. If the listing does not state bolt length, grade, or thread pitch, treat that as a missing specification and ask before buying. You cannot infer those from a photo.

• Look for a stated grade, such as 8.8 or higher, or a named material like titanium.
• Prefer kits that include a torque lubricant so you do not guess at friction values.
• Confirm thread pitch and length in writing before you order.

Lubricant and torque: the step most people skip

Flywheel bolts are torque-to-yield or torque-to-spec depending on the design, and friction changes the clamp load for the same wrench reading. A dedicated lubricant, like the ARP Ultra-Torque included with some PLM kits, gives you a consistent friction coefficient so the torque spec actually produces the intended stretch.

If you use engine oil or anti-seize instead, you are changing the friction and therefore the clamp load. That can leave the flywheel under-torqued or over-stretched. Use the lubricant the bolt maker specifies, and apply it to the threads and under the bolt head unless the instructions say otherwise.

• Apply lubricant to both the threads and the underside of the bolt head for consistent torque.
• Do not mix lubricants between bolts in the same flywheel.
• Torque in a star pattern in stages to seat the flywheel evenly.

Kit versus piece-by-piece: which makes sense

Buying individual bolts, nuts, and washers from a hardware store is possible, but you have to match grade, length, thread pitch, and finish yourself. For a one-off swap, that is a lot of measuring and a real risk of a wrong-length bolt. A pre-assembled kit is usually cheaper than sourcing each piece separately and removes the matching work.

That said, a kit only helps if it matches your specific flywheel and crank flange. If you are running a custom flywheel or an adapter with unusual thickness, measure first and confirm the kit's bolt length works. If the kit does not list a length, ask the seller before you buy.

• A kit is the better default for a standard H2B swap with common flywheel combinations.
• Custom or adapter-based setups may need a specific length; verify before ordering.
• Keep the leftover lubricant packet for future clutch jobs.

Decision rules for H2B flywheel bolt selection

• Match bolt length to your flywheel and crank flange: Measure the flywheel flange thickness and compare it to the bolt length under the head. You want full thread engagement without the bolt bottoming out in the crank. If the kit does not state a length, ask before buying. No stated length means no purchase until you confirm it.
• Use the specified lubricant, not whatever is on the shelf: ARP Ultra-Torque or the lubricant included with the kit gives a consistent friction coefficient. Oil or anti-seize changes clamp load at the same torque reading. Apply to threads and under the head. If the kit includes lubricant, use it; if not, buy the lubricant the bolt maker recommends.
• Choose grade and material based on use, not marketing: Grade 8.8 or higher steel is the practical baseline for a street or track H2B swap. Titanium resists corrosion and saves weight but costs more and is not necessary for most builds. Do not pay for titanium if you have not confirmed fitment. Fitment first, material second.
• Buy a complete kit unless you have a custom stack-up: A kit saves you from matching grade, length, pitch, and finish yourself and is usually cheaper than sourcing each piece. For custom flywheels or adapters, verify the included bolt length against your measured stack-up. Standard swap: kit. Custom stack-up: measure and confirm.

Product facts that affect your decision

• PLM Pressure Plate Bolts For Honda & Acura - Set of 6 Pieces - ARP Ultra-Torque Lubricant: Set of 6 bolts with 1 x ARP Ultra-Torque Lubricant #100-9908, for B-Series, D-Series, H-Series, F-Series, and K-Series four-cylinder Honda/Acura applications. These are OEM-spec bolts, not OEM bolts. This is the pressure plate side of the job, not the flywheel-to-crank bolts. If you are refreshing clutch hardware at the same time, the included ARP lubricant gives you a known friction value for consistent torque.
• PLM Header Assembly Hardware Bolts Nuts: Includes 2 bolts and 2 nuts (4 nuts for the long version), 8.8 grade or higher, short bolt is 2 3/8 inches and long bolt is 3 1/2 inches. Fitment is for PLM headers with slip-fit collectors on B-Series, K-Series, and D-Series. Not a flywheel part, but a good example of why length matters: the short and long versions exist because flange thickness changes. Apply the same logic to flywheel bolts and measure your stack-up.
• PLM Titanium K-Series Header Manifold Stud Kit K-Series K20 K24: Complete set of 5 titanium studs, nuts, and washers. Also fits K20C1 FK8 FL5 turbo and downpipe. Titanium fasteners resist rust and corrosion. If you want corrosion resistance and weight savings on exhaust-side hardware, titanium is an option. For flywheel bolts, titanium is not required, but the same corrosion-resistance reasoning applies in a damp bellhousing.

Who this is for

Best for

• Honda and Acura H2B swaps using a common B-series or H-series flywheel combination
• Builders who want a complete, matched set of flywheel bolts and lubricant instead of sourcing hardware individually
• Street and track cars where consistent torque and corrosion resistance matter

Not for

• Custom flywheel or adapter setups where bolt length has not been measured and confirmed
• Builders who already have the correct OEM bolts in good condition and a known torque spec
• Anyone expecting a kit to fit without checking thread pitch and length against their crank flange

Pick a flywheel bolt kit that states its length, grade, and lubricant, then verify it against your actual flywheel and crank flange before you torque anything. That one measurement prevents the most expensive H2B swap mistakes.