Description

Cummins 155B, 220B, 270B, 330B, 370B Technical Manual

You’ve got a 155B or a 370B on the stand, and some aftermarket PDF tells you the fuel rate is “about X.” That’s a good way to overshoot a prop curve and melt a piston. I’ve seen it. This is the factory Cummins 155B, 220B, 270B, 330B, 370B Technical Manual – 118 pages of OEM data that Cummins Marine printed for real mechanics who don’t guess. Page 2 gives you the 155B power ratings: 112 kW (155 hp) at 2800 rpm, High Output rating, bore & stroke 102 mm x 120 mm (4.02 in x 4.72 in), displacement 3.9 L (239 in³), weight 390 kg (860 lb). That’s not a generic spec. That’s the factory number you run a piston-to-valve clearance against.

If you’re rebuilding a 220B, 270B, 330B, or 370B, you need the same level of data. The manual gives each model its own page – 155B on page 2, 220B on page 4, 270B on page 6, 330B on page 8, 370B on page 10. No mixing. No “see previous model.” Each engine gets its own table of dimensions, rotation direction, and rated speed. That’s how you avoid ordering the wrong injector pump gasket.

Fuel Consumption and Prop Curves – Page 2 Example

Page 2 shows the 155B fuel consumption along the prop curve: at 2800 rpm it burns 28.8 L/hr (7.6 g/hr). At 1200 rpm it drops to 3.4 L/hr (0.9 g/hr). Those numbers assume fuel at 35° API gravity and 29°C. You need those curves to dial in the correct propeller pitch. One knot too much load and you’re running continuous overload. The manual explains that High Output rating is for pleasure use under 300 hours per year, with full power limited to one hour in eight. Respect that or you’ll be pulling the head off a 330B before the warranty ink dries.

Does This Manual Cover the 220B and 270B?

It does. The table of contents lists 220B on page 4 and 270B on page 6. Each entry includes the same type of technical data: power ratings (crankshaft power, propeller shaft power after gear losses), rated speed, rotation, and dimensions. You’ll also find the engine configuration – in-line 4-cylinder for the 155B, others may be 4 or 6 depending on model. The manual doesn’t skip pages. It goes from 155B straight through 370B, then continues to the 450C, 4B, 6BT, and larger marine diesels up to QSK 19. That makes this book useful beyond just your immediate engine family.

3 Reasons to Stick with OEM Documentation

First, aftermarket manuals omit the small-print notes that keep you out of trouble. For example, the rating definitions on page 2 specify that propeller shaft power is 97% of rated power after gear losses. A generic book skips that and you end up with an oversized prop. Second, OEM torque values are not republished by third parties – they change with bolt batch numbers and sealant updates. Third, the wiring and fuel system diagrams in OEM prints are drawn to scale with actual connector pinouts. You can’t rely on a scanned copy from 1999. This file is the original OEM PDF from Cummins. Cummins FD40 Technical Manual – OEM Parts Catalog 434 Pages covers parts breakdowns if you need that level of detail, but for engine specs this is the one.

118 Pages – Why Page Count Matters

118 pages sounds thin compared to some full shop manuals. Don’t let that fool you. Every page is dense with rating tables, fuel consumption charts, and engine dimension drawings. Each model gets its own spread. The manual also includes performance data for related marine engines like the 6BTA 5.9-M2, C Series, and KTA 19-M. That’s 30+ engine variants in one document. The OCR excerpt shows the full range of bookmarks: 155B through QSK 19. If you’re working on a Manual Transmission coupled to one of these engines, the flywheel housing dimensions and rotation direction are critical to alignment. This manual gives you those numbers.

Who Needs This Manual

If you own a boat with a Cummins 220B or a generator with a 330B, this is your baseline. Home garage enthusiasts need the factory fuel consumption data to avoid buying too much propeller. Professional mechanics need the exact crankshaft power – not the brochure number – to verify compliance with ISO 8665. And if you teach marine diesel maintenance, the rating definitions alone are worth the access. Pair this with Cummins NTA-855-L4 1986 Technical Manual – OEM Army Specs if you’re dealing with older military-grade engines, but for these smaller marine models, this 118-page book gives you the numbers that keep you from pulling a cylinder head twice.

Source Authenticity – No Aftermarket Reprint

This file comes from the official Cummins archive – bulletin number 4000167, Rev. 6/01, printed in the U.S.A. The original PDF includes the Cummins footer and the note “All data subject to change without notice.” That’s not a disclaimer; it’s a reminder that you must check the latest intranet curves for production updates. The manual also references CPL 0741 and curve M-90197 for the 155B. You won’t find those part numbers in a Chilton book. If you’re pairing this with a Manual Transmission retrofit, confirm the engine rotation (counterclockwise facing flywheel) matches your transmission input. The manual specifies that for every model.

Frequently Asked Questions

Does this manual include the 370B fuel system diagrams?

It gives the power and fuel consumption for the 370B on page 10, but not full fuel system schematics. It is a technical manual, not a service manual.

What torque values are listed for the 155B cylinder head?

The manual provides engine specifications – bore, stroke, displacement, weight, and power ratings. Torque values are not in the sample pages; they would appear in the service manual for that engine family.

Can I use this for the 450C or the 4B 250?

Yes. The manual covers the 450C on page 12 and the 4B 250 on page 14. You get the same type of ratings and dimensions for those models.

Is this a reprint of a newer version?

It is the original 2001 PDF from Cummins Marine. Rev. 6/01. Not a scan of a scan. The file is watermarked and contains the original page layout.

You’ve got the engine on a stand and you’re ready to rebuild or repower. Don’t chase specs from a forum. Access the Factory Manual and get the exact numbers Cummins intended for your 155B, 220B, 270B, 330B, or 370B. One file, 118 pages, and zero guesswork. Cummins QSK23 QSK60 QSK45 QSK78 QSX15-G Technical Manual | Factory Specs covers the big inline engines, but for these marine four- and six-cylinder models, this is the document you need between the gasket set and the flywheel.