In the early 1990s the B-series engines etched their names deep into the roots of the sport compact world. With the strong cult following that ensued, there seemed to be no end in sight for these DOHC monsters. Then something happened: The infamous Honda camp gradually began to loose its popularity as engine supplies decreased and prices increased. At the same time, drifting took hold of the motorsports world and Honda took a backseat to rear-wheel-drive sleds from Nissan and Toyota. Over the last few years Honda's piece of the compact performance pie has shrunk. In the latest market survey released by the Specialty Equipment Market Association (SEMA), Honda's market share has decreased from over 70 percent in the late-'90s to less than 40 percent. Despite its loss of the market share, the compact performance industry continues to grow.
While Honda and Acura enthusiasts saw doomsday on the horizon, engineers in Japan stepped up to the plate and delivered a whole new powerplant, the K20A and K24A (otherwise known as the K series). It seems Honda is getting its second wind. The K-series engine swap has rekindled old and spawned new interest in the Honda scene.
First ImpressionsWhen you peer into the K-equipped hood, the most obvious deviation from the B series is the engine's 180-degree rotation. The K's engine and transmission is the mirror opposite of the previous four-cylinder engines. The crank also rotates in the opposite position. Visually, it's disorienting to see a Honda or Acura with an engine that leans rearward, an intake that has been moved to the front of the engine and an exhaust that sits toward the rear firewall. The radiator hose and heater hose outlet positions have also flipped positions from its predecessors. Other changes include changing the positions of the power steering pump, A/C compressor and alternator.
What advantage does a K-engine swap have over previous models? For starters, the engine's new rearward position improves the front-to-rear weight ratio. It also uses the latest variable valve timing, i-VTEC, and a variable intake cam gear called VTC, which helps with emissions. Other improvements include a segregated, chain-driven oil pump and one-piece crank girdle, which reduces the chance of crank walk at higher engine speeds or when producing an abundance of horsepower.
The most enticing improvement comes by way of factory-rated horsepower. In stock trim, the most recent RSX Type-S boasts a 2.0-liter 200-hp engine. With minor bolt-ons and tuning, it's not uncommon to see 240 hp. In order to extract similar performance from a B series, you'd have spend thousands of dollars and reduce the engine's overall reliability. The same reasoning applies to the Prelude's 2.2-liter H22, another popular Honda swap. Why shoehorn a heavier engine into a Civic, alter the handling and affect the front-to-rear weight ratio when you can sport a K series that weighs virtually the same as a B18C? Grab a Coke from the fridge and ponder that for a while before you continue reading.
K-Series Engine SwapsBy reading on, we're assuming we've piqued your curiosity, and you want to know how to put some grunt under your hood. Arizona-based manufacturer, Hasport, has been swapping Honda and Acura engines for over 10 years. A month after the K20 and K24 engine was introduced, Hasport began fabricating custom mounts. Currently Hasport has mount kits for nearly every Civic chassis-from the 1988 EF, to the present-day ES-and the 1995 to 2001 DC2 Integra, which uses the same mount kit as the EG Civic. Also in the works are kits for the 1990 to 1993 DA Integra, 1990 to 1993 Accord and 1994 to 1997 Accord. "Most likely the Accord mount kits will come for either the RSX/Civic transmission or the TSX/Accord transmission," said Brian Gillespie, Hasport's R&D product development and marketing director. All mount kits are CNC-machined using T6061 billet aluminum and come in three polyurethane options from street to full race.
It should be noted that swapping a K into an older chassis, such as the EG or EK Civic, can have a number of unique problems caused by two main factors: the K engine's orientation and electronics. Due to engine-design variance, each K transplant is addressed differently.
K-series FrankensteinsDie-hard Honda and Acura fanatics will recall the first LS-VTEC engine was pieced together by a group of skillful mechanics a few years back. For mere pennies, the B18A head was discarded and replaced with its B16A counterpart while using the same 1.8-liter block. The final outcome was a Frankenstein motor with quick rpm response and exceptional torque, something the B16A lacked. Like the B and H series that proceeded it, the K series also has interchangeable parts. And unlike the B and H series, you don't need to modify the K's oiling system to get the VTEC to work when bolting on the Type-S or Type R VTEC head.
As an example let's take the 2.4-liter 160-hp K24 block, from the Honda CR-V, and swap the head with a RSX Type-S upper half. With that combination, drop in the motor and tune it using popular fuel managements, such as the Hondata K-Pro. It's not unusual to see a gain of 50 or more hp and loads of torque due to the 2.4-liter displacement. Compare the costs incurred to make this Frankenstein to those needed to swap in a 210-hp B18. Exactly!
Incompatibly IssuesThere are some incompatibility issues to address when considering K swaps. One such problem arises when the RSX Type-S head is mated to an Accord block. The head's piston dome clearance causes the valves and head to come into contact with one another. The issue can be resolved, however. "Slap some Acura TSX rods and pistons in that same Accord block while using the Type-S head and you'll get better overall performance than a factory TSX engine," Gillespie stated. Other problems arise from the K series' dimensions. While its diameter is miniscule compared to the H22, its height poses a problem. The K24 gets most of its extra displacement by increasing its stroke from 86mm to 99mm.This increased stroke means the block sits .75 of an inch taller than even the already-tall H22. This can create some clearance problems.