Engine System Tubing & Assemblies

Precision tubing and fabricated assemblies for everything around the engine. Intake, exhaust, cooling, charge air, and fluid routing. The parts that have to fit right, seal tight, and hold up.

Overview

One Engine, Dozens of Tubes. We Make Them All.

A leak means a field failure. A misaligned tube means an install problem that backs up production. Contamination inside a pre-engine part means a dead turbocharger. Engine system tubing doesn't leave room for close enough.

H-P builds the full engine-side package under one roof. Intake, exhaust, cooling, charge air, and fill. That means fewer vendors to manage, fewer part numbers to track, and components that actually fit together on the first install.

What Ties It All Together

SAE J 1726 Cleanliness

Particle-controlled cleaning on every engine-side tube. Strict contamination control on pre-engine parts.

Compound Bending

Multi-plane bends that route through tight engine bays while protecting internal surface quality.

End Form Variety

Marmon beads, flares, expansions, SME beads, threaded ends. The right connection for every point in the system.

Prototype Through Production

Sample parts for fit checks before committing to production volumes.

By Application

What We Build Around the Engine

Air Intake Tubing

Everything upstream of the engine has one job: deliver clean air. A particle that gets past the filter and into the turbo or combustion chamber doesn't come back out quietly. That's why intake tubing runs through our SAE J 1726 cleaning program before it ships, and why the bends have to be smooth inside even when the routing is tight outside. Typically aluminum for weight and corrosion resistance, with welded mounting brackets.

Exhaust Tubing & Assemblies

Post-engine tubing fights heat, thermal expansion, and constant vibration. A weld that cracks under cycling fails in the field. An end form that doesn't seal against the DPF or muffler connection creates an exhaust leak that shuts down a machine. We build for that. Marmon beads, expansion slots, and custom end forms designed for the actual connection points, not generic fits.

Aluminized carbon, stainless, and aluminized stainless handle the heat. Bellows go into assemblies where thermal movement and torsion need to go somewhere that isn't a crack.

Exhaust tubing assembly with marmon beads and end forms in aluminized steel

Charge Air & Turbo Tubing

Pressurized air to and from the turbocharger. A boost leak kills performance. A contaminant kills the turbo. These parts run strict contamination control, and the sealing at every connection point has to hold under pressure that the engine is actively generating. Marmon beads and flared ends, typically on 1D bends.

The inner wall matters as much as the seal. One wrinkle disrupts the flow path, and the turbo feels it as lost efficiency.

Charge air cooling tubes with 1D bends for turbocharged engine systems

Radiator & Coolant Lines

A coolant leak on a piece of heavy equipment isn't a minor repair. It's downtime. These tubes route through tight spaces in smaller diameters, carry fluid under pressure, and have to seal at every connection for the life of the machine. End forms are typically SME compliant beads.

Aluminized carbon steel coated on both sides is the standard. Coolant corrodes from the inside, weather corrodes from the outside. The dual coating handles both directions.

Radiator coolant lines in aluminized carbon steel with dual-side coating

Fill Pipes

Fuel, oil, and fluid fill pipes. Simpler geometry than the rest of the engine-side package, but tight tolerances at the connection point. A threaded end that doesn't seal is a fluid leak on an engine. The end forming has to be precise enough to hold a screw-on cap tight through vibration and thermal cycling for years. Carbon steel or aluminum, smaller diameters.

Engine fill pipe with precision threaded end forming

Materials

Materials We Run

Material choice affects weight, corrosion resistance, and service life. If you are balancing cost against durability against operating environment, we will walk through it with you.

Carbon Steel

1006 – 1026

Stainless Steel

304, 316, 409, 439

Aluminum

6061, 6063, 5052

Aluminized Steel

1006 – 1010

Specialty Alloys

Ask our engineers

SAE J 1726 Cleanliness Standard. All engine-side tubing goes through our particle-controlled cleaning program. Pre-engine parts (intake, charge air, coolant) are cleaned to SAE J 1726 standards.

Markets

Where This Work Goes

From off-road equipment to power generation, these parts end up in machines that cannot afford downtime.

Heavy Equipment

On/Off-Road Vehicles

Power Generation

Agriculture

Construction & Mining

Military & Defense

Specialty Vehicles

Forestry & Logging

FAQ

Common Questions

We bend engine system tubing from 3/8" OD up to 8" OD on CNC machines, and up to 10" OD on NC equipment. Most engine-side parts fall in the 1" to 4" OD range. The best process for your part depends on geometry and tolerances.

SAE J 1726 is a cleanliness standard for tubing used in engine systems. Our cleaning program removes internal particles, oils, and contaminants that could damage turbochargers, injectors, or other sensitive engine components. Pre-engine parts (intake, charge air, coolant) go through this as standard. Post-engine parts like exhaust can also be cleaned to spec when required.

Yes. Many customers receive intake, exhaust, coolant, and charge air parts together in a single kit, packaged for their assembly line. Kitting reduces part numbers, simplifies receiving, and cuts picking time.

Marmon beads, expansion slots, flares, flanges, SME compliant beads, threaded ends, and custom profiles. The right end form depends on what the tube connects to and the operating conditions.

Yes. Most engine tubing programs start with prototyping. We produce sample parts for fit checks and testing before committing to production tooling and volumes.

Cleanliness, tight packaging, and end form variety. A general bent tube needs a cut and a bend. Engine tubing needs particle-controlled cleaning, compound bends that navigate around other components without wrinkling, specialized end forms at every connection point, and leak testing. Higher standards because the consequences of failure are higher.