ARP Main Stud Kit for Honda B16A (Civic Si & Del Sol)

ARP Main Stud Kit for Honda B16A - Part #208-5402

The B16A is happiest at the top of the tach, and that's exactly where the factory main bolts give up their margin. Whether it's the B16A2 in a 99-00 Civic Si (EM1), the B16A3 in a del Sol VTEC, or a JDM B16A swap in an EG hatch, the ARP main stud kit is the right way to anchor the crank in a bottom end that will be revved hard or boosted.

What It Is and Why It Works

Main studs clamp the caps more accurately than bolts. The stud threads into the block hand tight, so when you torque the 12-point nut the fastener stretches on a single axis and the torque reading reflects real clamp load instead of thread friction. The block threads also see less wear, which is worth caring about on a 25 year old aluminum block that may get freshened more than once. ARP machines these studs from 8740 chromoly heat treated to 200,000 psi, thread rolled after heat treat, and the kit covers the B16A's 2-bolt main arrangement with 10 studs, nuts, hardened parallel ground washers, and ARP assembly lubricant in the box.

Specs

Fitment

Also fits JDM B16A engines commonly swapped into EF, EG, and EK chassis. The fitment follows the engine, not the car it came in.

What to Know Before You Buy

Treat main studs as part of a machining plan. ARP notes that an align hone of the main bores may be necessary after installation, because the studs pull the caps down harder than the stock bolts and can distort the bores slightly. Install them on a bare block, torque the caps, and have your machine shop check bore size and alignment before the crank goes in. Skipping that step on a swap-meet block is how guys end up chasing oil pressure. If the block is at the shop anyway, this kit plus rod bolts and bearings is the cheap part of the build. For the B18C VTEC engines use 208-5403 instead, and for the non-VTEC B18A/B18B use 208-5404.