What AMBAC International makes

AMBAC International is a manufacturer and remanufacturer of diesel fuel injection systems and related power and fluid components. Its core products are injection pumps, fuel injectors, injector assemblies, common-rail fuel pumps, and matched engine components for heavy-duty commercial, industrial, and defense engines. The company describes itself as a relationship-based manufacturer that produces customized quantities from prototype through small-batch runs, engineers and manufactures matched components, and works to tolerances measured in microns.

Alongside finished fuel-system parts, AMBAC runs a precision machining shop built around machining, grinding, and honing for low-to-medium-volume programs. Its published capability envelope covers parts from 0.25 to 18 inches, around 6 inches in diameter, in ferrous and nonferrous metals, stainless, and alloys, from forgings, castings, billet, and bar. Production volumes run from 100 to 50,000 units a year. The company also offers reverse engineering, product design, design for manufacturing, and program management, and it remanufactures complex mechanical assemblies for OEMs that would rather outsource the teardown-and-restore work. An aftermarket brand, ZillionHD, handles distribution of remanufactured and replacement fuel-system parts.

Ownership and history

AMBAC is one of the oldest continuously operating fuel-injection manufacturers in the United States, and it is employee-owned. The lineage traces to 1910 and the American Bosch operation in Springfield, Massachusetts, which produced magnetos and, from the 1920s, diesel fuel injection systems for the emerging truck and off-road industry. Through the World War II era the plant supplied a large share of the electrical and fuel-system parts used by US military vehicles, aircraft, and ships. The business passed through several owners over the following decades, including the American Bosch-ARMA holding structure, and many of its original fuel-system designs are still referenced by OEM engine makers today.

The modern company operates from Elgin, South Carolina, at 910 Spears Creek Court, and its current federal corporate entity, AMBAC International Corporation, was incorporated in 1987. Today AMBAC is an employee-owned company run on open-book principles, where employee-owners see the financials and share in the results. Chairman and CEO Robert Isherwood, who has led the company for roughly seven years, describes it as a factory that builds people as well as parts, and credits the shift to employee ownership with a financial turnaround at the Elgin plant completed around 2018.

Certifications and quality

AMBAC holds ISO 9001:2015 certification and posts a downloadable certificate on its own site. On its defense capabilities page the company lists ISO 9001, small-business status, and DoD-approved supplier standing, and notes that Cybersecurity Maturity Model Certification (CMMC) Level 3 is in development rather than in hand. The company runs a full engineering, metallurgical, and measurement lab function, plus heat treat and supply-chain support, to control quality on the machined and assembled parts it ships. Buyers evaluating AMBAC for regulated programs should confirm current certificate dates and any PPAP requirements directly, since the public certificate page does not list an issue date.

Defense programs and known customers

AMBAC's clearest documented customer relationship is with the US government. The company is a registered federal contractor under CAGE code 01843 and UEI D3NUKCV62FL5, with a primary registration in engine-equipment manufacturing. In April 2026 the Defense Logistics Agency issued a justification to buy the AVDS-1790 diesel injection pump directly from AMBAC as the actual manufacturer, covering up to 992 units at a standard unit price of $12,380. The AVDS-1790 is the air-cooled V12 diesel used in M60 tanks, M88 recovery vehicles, and related heavy armor, so being the approved source for its injection pump is a meaningful sole-source position. AMBAC has also held US Army contracts for fuel injector assemblies.

On its defense page the company says it has been recognized by the US Marine Corps, the Israeli Defense Forces, and the Republic of Korea Army, and that it received a Raytheon Epic Award as a global top supplier. Those recognitions are the company's own statements. Beyond defense, AMBAC serves aerospace and industrial engine OEMs and the heavy-duty trucking aftermarket, though it does not publish a named commercial customer list, which is normal for a components manufacturer working under OEM programs.

Sourcing evidence

AMBAC appears in US customs import records with a light footprint: three recorded ocean shipments, the most recent in September 2026, from metal and machine suppliers in India. That is consistent with a US-based manufacturer and remanufacturer that builds and restores parts domestically rather than importing finished goods, so most of its activity would not show up in import bills of lading. Because the import sample is small, no shipment trend is charted here.

These figures come from US ocean-freight customs records only. Air, truck, and rail movements, and most domestic sourcing, do not appear, and manifest product descriptions are noisy. Absence of a record is not evidence of absence. The federal contract facts above come from public government award records.

Frequently asked questions

What does AMBAC International make?

AMBAC International manufactures and remanufactures diesel fuel injection systems and related engine components, including injection pumps, fuel injectors, injector assemblies, and common-rail fuel pumps. It also provides precision machining, grinding, and honing, complex assembly and test, reverse engineering, and remanufacturing of mechanical assemblies for heavy-duty commercial, industrial, and defense engines.

Who owns AMBAC International?

AMBAC International is an employee-owned company, described on its own materials and third-party profiles as 100% employee-owned and run on open-book management principles. It is led by Chairman and CEO Robert Isherwood. The business traces its lineage to the American Bosch fuel-injection operation founded in 1910.

Where is AMBAC International located?

AMBAC International is headquartered at 910 Spears Creek Court in Elgin, South Carolina, near Columbia. Its manufacturing, engineering, and remanufacturing operations are based there.

Is AMBAC International a defense contractor?

Yes. AMBAC is a registered US federal contractor under CAGE code 01843 and is a DoD-approved supplier. In April 2026 the Defense Logistics Agency approved buying the AVDS-1790 diesel injection pump directly from AMBAC as the actual manufacturer, and the company has held US Army fuel-injector contracts. The AVDS-1790 powers M60 tanks and M88 recovery vehicles.

What certifications does AMBAC International hold?

AMBAC holds ISO 9001:2015 certification, with a downloadable certificate posted on its website. It also identifies itself as a small business and a DoD-approved supplier, and lists CMMC Level 3 as in development. Buyers should confirm current certificate dates directly.

How big is AMBAC International?

AMBAC is a small business, with roughly 40 to 60 employees based on public professional-network estimates. It qualifies as a small business under the applicable federal size standards and does not publish revenue figures, which is typical for a privately held, employee-owned manufacturer.

Last verified September 27, 2026. Is this your company? Request a correction.