The Atlas Copco QAS 70 steps up to 56 kW prime power (70 kVA) using an Isuzu 4JJ1X 3.0-liter engine, while maintaining the same 67 dBA sound level as the smaller QAS 25 and QAS 45. The 110-gallon integral fuel tank provides over 25 hours of runtime at 75% load.
The Leroy Somer LSA 42.3 L9 alternator delivers ±0.25% voltage regulation with AREP excitation. Multi-voltage switching covers 120V single-phase through 480V three-phase. DEF is required for Tier 4 Final compliance via the 7.4-gallon DEF tank.
The QAS 70 steps up to the Isuzu 4JJ1X 3.0-liter engine — a larger displacement than the 2.2L 4LE2 series used in the QAS 25 and QAS 45. Despite the power increase to 56 kW prime, Atlas Copco maintains the same 67 dBA sound level through improved enclosure engineering and vibration isolation. The 110-gallon fuel tank is sized proportionally for the higher consumption rate, delivering competitive runtime in the 50-70 kW portable class.
The QAS 70 is the largest Isuzu-powered model in the QAS lineup. Above this output level, Atlas Copco transitions to John Deere engines starting with the QAS 125, which brings longer 500-hour oil change intervals but a different parts ecosystem.
The QAS 70 occupies a sweet spot in the Atlas Copco portable lineup — enough power for most medium commercial and construction applications, while still using the compact Isuzu platform that keeps the unit manageable for transport and setup. The Isuzu 4JJ1X is a proven industrial engine with a well-established parts supply chain outside of Atlas Copco's own network.
That parts availability matters, because Atlas Copco's after-sale service is the brand's biggest weakness. Owners consistently report unreturned service calls, travel charges exceeding $311/hour, and multi-week waits for factory parts. For QAS 70 owners in Northern California, OnPoint provides local maintenance and repair service — we work on the full QAS lineup and stock common consumables for the Isuzu-powered models.
Engineering specifications
Acoustic
Sound @ 7m, 75% load
67 dBA
Enclosure
Sound-attenuated
Fuel system & runtime
Integral fuel tank
110 gal
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Get pricing & lead time on the Atlas Copco QAS 70
Tell us about the application — kW, voltage, application, install timeline — and we'll respond within one business day with budgetary pricing, lead time, and any sizing notes.
Adjust load percent and tank size to estimate runtime. Pre-filled with this model's spec where available.
Estimate runtime on this tank
Estimated runtime
34.0 hours(1.4 days)
Fuel consumption ≈ 3.24 GPH at 75% load. Estimate based on industry-typical 1800 RPM standby curves (≈0.07 GPH/kW at full load). Actual consumption varies by engine, ambient temperature, fuel quality, and tuning.
Service intervals
Manufacturer-recommended intervals for the Atlas Copco QAS 70 under standby duty. Field intervals may differ based on load profile, ambient conditions, and fuel quality.
Oil & filter
Every 500 hours or 12 months
Air filter
Every 500 hours
Fuel filter
Every 500 hours
Major overhaul
≈ 20,000 hours
Common failure modes
What we've seen fail on this platform. Use as a service-planning reference, not a diagnostic — actual failure modes depend heavily on duty cycle and maintenance history.
Component
Symptom
Typical hours
Severity
Fuel filter
Restricted fuel flow, hard starting, power loss
500+
minor
Starting battery
Failed start or slow cranking after extended storage
4,380+
minor
Coolant hoses
Weeping at clamp joints, low coolant warning
5,000+
minor
Frequently Asked Questions
What is the prime and standby rating of the Atlas Copco QAS 70?
The QAS 70 delivers 56 kW prime power and 60 kW standby power. It is rated for continuous variable-load prime operation in portable applications.
What engine does the Atlas Copco QAS 70 use?
The QAS 70 is powered by an Isuzu 4JJ1X 3.0-liter inline-4 turbocharged-aftercooled diesel engine running at 1,800 RPM. The 4JJ1X is the largest Isuzu engine used in the QAS lineup — above this model, Atlas Copco transitions to John Deere engines.
What are the service intervals for the QAS 70?
Oil changes are due every 500 hours or 12 months, whichever comes first. Air filter and fuel filter replacement intervals are 500 hours. Major engine overhaul is specified at 20,000 hours under normal operating conditions.
Is the Atlas Copco QAS 70 EPA Tier 4 Final compliant?
Yes. The QAS 70 is EPA Tier 4 Final and CARB compliant, legal for operation throughout California. The 4JJ1X uses DEF and SCR aftertreatment to meet Tier 4 Final — a 7.4-gallon DEF tank is integrated into the unit.
How does the QAS 70 differ from the QAS 95?
The QAS 95 transitions from Isuzu to a John Deere 4045 HFG04 4.5-liter engine, delivering 76 kW prime — 36% more than the QAS 70. The QAS 95 also uses a larger 166-gallon fuel tank vs. the QAS 70's 110 gallons, and noise increases slightly to 69 dBA.
What fuel does the Atlas Copco QAS 70 use?
The QAS 70 runs on diesel with DEF (diesel exhaust fluid) required for SCR aftertreatment. The integrated 110-gallon diesel tank provides over 25 hours of runtime at 75% load. A separate 7.4-gallon DEF tank supports the Tier 4 Final aftertreatment system.
Who services Atlas Copco generators in Northern California?
OnPoint Generators provides local service and maintenance for Atlas Copco QAS units across the Bay Area and Northern California. We stock common consumables for Isuzu-powered models including the QAS 70 and offer faster response times than the Atlas Copco factory service network.
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