pbskids

Due to the EU’s Global Data Protection Regulation, our website is currently unavailable to visitors from most European countries. We apologize for this inconvenience and encourage you to visit www.motortrend.com for the latest on new cars, car reviews and news, concept cars and auto show coverage, awards and much more.MOTORTREND.COM
 |   |   |  4 Piston's K-Series Billet Cylinder Head
Subscribe to the Free
Newsletter

4 Piston's K-Series Billet Cylinder Head

The next level of performance for the high-powered K-crowd

Mark Gearhart
Apr 8, 2019

Images by 4 Piston Racing

If you're looking to go full tilt on your next K-series build, 4 Piston Racing's gorgeous billet cylinder head should be at the top of your parts wish list. Designed for max-effort, naturally aspirated, alcohol drag race engines, the 4 Piston's billet head is designed to increase power beyond 11,000 rpm. Yeah, you read that right! For big boosted engines that are approaching 100 psi of boost, 4 Piston is already hard at work on a standard port version that will offer racers increased rigidity and reduce deflection issues.

  |   4 Piston is known the world over for its record-breaking cylinder head and engine building services. The company has taken everything it knows about naturally aspirated Honda drag racing and put it in its new billet K24 head.

"The billet is not going to fit 80 percent of the applications; that's just the reality," says Luke Wilson of 4 Piston Racing. "Most applications are going to want a standard K-series casting with a good CNC port job."

  |   4 Piston Racing K Series Billet Head CNC Grooves

While the OEM Honda castings offer sufficient performance for smaller-displacement endurance and drag race engines, they limit power when trying to turn stratospheric engine speeds. The OEM casting and its water jackets have been scrutinized and tend to be the limiting factor in making more than 500 hp in 165- to 170-plus-ci race engines. This is where 4 Piston's billet head really shines.

"To continue carrying rpm, we needed to work without the constraints of these water jackets," Wilson explains. "So, we designed this billet piece to give us the freedom to put whatever port shape we wanted into the cylinder head. The valve angle is changed, which allows us to not only have a better approach angle with the port, but it also gives us flexibility with camshaft centerlines that we don't have with the OEM cylinder head. The rigidity of the head also allows us to have a better head gasket seal with bore sizes that push the limits with the OEM casting."

  |   4 Piston Racing K Series Billet Head Valveseats

Valve diameter comes standard in 40 mm, though 39 mm is an option for those who want to try more aggressive cam centerlines. Exhaust valve sizing is 30 mm and titanium valves are typically requested to keep the weight out, while stainless is also an option. The seats used are copper beryllium on the intake and the exhaust side, however, a nickel aluminum bronze option is also available.

  |   4 Piston Racing K Series Billet Head CHE Valveguides

CHE valve guides are situated at the nucleus of the custom-spec PSI valvesprings. A Ferrea retainer, seat, and lock combination holds the valvespring in place and spring pressures are dictated by end-user camshaft selection.

4 Piston currently has just one port package, but it can customize the head however the customer desires. The valve angle change is based around one port design for naturally aspirated drag racing, but a turbo port without the valve angle moved is also available. The head is currently offered without water jackets, and the crew is working on a design with water on the exhaust side.

Is this sexy billet head the right fit for your bolt-on K-swap that sees local meets and the occasional car show? Probably not the case, though it's certainly show-worthy. If you're looking for the most efficient, naturally aspirated K24 head on the market, or perhaps you're tired of trashing head gaskets regularly on your big-boost setup, this may be your answer.

  |   4 Piston Racing K Series Billet Head 4 Piston Racing Valvecover
  |   4 Piston's house hatch—dubbed "Carrott"—has served as an R&D platform for its billet head program. Real-world testing brings about real-world results.

Intake valve size options:
38 mm - 420 cfm at .650
39 mm - 438 cfm at .650
40 mm - Proprietary

Exhaust valve size options:
30 mm - 280 cfm
31 mm - 290-plus cfm

Combustion chamber:
47 cc - 52 cc available

  |   4 Piston Racing K Series Billet Head CNC Grooves
  |   4 Piston Racing K Series Billet Head Engine
  |   4 Piston Racing K Series Billet Head

Sources

4 Piston Racing
Pittsboro, IN 46167
317-440-6777
By Mark Gearhart
21 Articles

BROWSE CARS BY MARKET

MORE HOW TO

It was a short six years ago that we featured Tommy Fitzgibbon's amazing reverse-head H22-powered 1995 Honda Odyssey LX minivan, and as much as we'd like to say every story has a happy ending, life just isn't like that.
Bob HernandezMay 14, 2019
Through years of research and development, careful component selection, and expert assembly, the 4 Piston Racing team has no problem churning out an over-the-counter, quadruple-digit hp long-blocks
Evan PerkinsApr 4, 2019
Looking better and feeling better with HFP and Acuity Instruments' upgrades inside and out in our project 2018 Civic Si.
RodrezMar 22, 2019
To date, only the CTR, Accord, and RDX have been outfitted with Honda's turbo K20C1, all of which behave quite differently due to a multitude of factors.
Micah WrightMar 13, 2019
Quickjack has the ideal solution to make garage life much easier
RodrezMar 11, 2019
Join Our FREE

Sign Up today for our FREE Newsletter and get the latest articles and news delivered right to your in-box.

Sponsored Links

SEARCH ARTICLES BY MAKE/MODEL

Search
CLOSE X
BUYER'S GUIDE
SEE THE ALL NEW
NEWS, REVIEWS & SPECS
TO TOP