Description

FIAT Kobelco SK350, SK330 Technical Manual

If you’re turning wrenches on a FIAT Kobelco SK350 or SK330, you already know the aftermarket specs are garbage. This Technical Manual is the factory print — 843 pages of OEM test procedures and tolerances you check with a gauge, not a guess. I’ve seen too many guys chase a main relief valve leak because some third-party data sheet had the wrong pressure. That doesn’t happen when you work off the original.

Hydraulic Pressure Specs and Test Conditions

Page 13 of this manual breaks down the hydraulic oil cleanliness standard (NAS 9 or less) and the exact measuring conditions. You need the oil temperature at 50°C (122°F) within a ±5°C window. Water temp on the radiator surface at 75°C (167°F). The manual tells you to measure in H mode unless it says otherwise. That’s the kind of detail that stops you from pulling a pump that isn’t bad.

What Does This Manual Cover for the SK330 and SK350?

Everything from pilot primary pressure (5.0 MPa / 725 psi at G pump port a1) to the main relief valve setting at 34.3 MPa (4970 psi) on the boom up circuit. Boost pressures, overload relief, travel circuit pressures — all listed with high and low tolerances in the table. If you’re rebuilding the swing system, the RH swing relief is 29.4 MPa (4205 psi) and LH swing is 23.0 MPa (3335 psi) with their own +6.0 MPa tolerance. That data isn’t in any aftermarket reprint I’ve seen.

843 Pages of Factory Data

You’re not getting a condensed version. 843 pages means the manual covers engine speed modes (H, B, S) with exact idle and full-throttle rpm values. The track link revolution test times (34.3–31.1 seconds for 3 revolutions in 1st gear STD). Cylinder operating times — boom up 2.7–3.3 seconds, arm out 2.9–3.5 seconds, bucket digging 2.7–3.3 seconds. Each number comes with a tolerance range. That’s how you diagnose a weak seal without throwing parts at it.

Read the Measurement Conditions Before You Start

The manual prints a note: “The mode is already ‘S’ mode when power is thrown. Unless otherwise specified, measure it on ‘H’ mode.” That single line has saved me two hours of re-diagnosis. If you skip setup conditions, you’ll get false readings. The book also specifies measuring with the air conditioner off. Small things, but they make the difference between a fix and a warranty comeback.

Engine Speed Modes: H, B, S Explained

H mode high idle is 2100 rpm (+30/-70). B mode low idle is 1700 rpm (+30/-70). S mode high idle drops to 1900 rpm (+30/-70). Decel at 1050 rpm. These are not numbers you guess. Set your tachometer, check the multi-display, and compare. If your machine won’t reach spec, you’ve got a governor issue or a fuel restriction. The manual gives you the baseline.

Related Manuals

• Kobelco SK350 2007 Service Manual
• FIAT Kobelco SK330, SK330LCVI, SK330NLCVI Workshop Manual – 1302 Pages Factory S
• FIAT Kobelco W80 2004 Technical Manual – 46-Page OEM Factory Specs

For background on how these systems work theoretically, you might check Wikipedia’s article on Manual Transmission and Manual Transmission — the fundamentals of torque transfer apply to any machine with a gearbox.

FAQ

Does this manual include torque specs for the main relief valve?

Yes. The main relief valve pressure for the ATT circuit is 34.3 MPa (4970 psi) with a +0.7/-0.5 MPa range. The boost pressure is 37.8 MPa (5480 psi).

Is the manual in Imperial units?

Yes, all values are in psi.

How does this manual handle the “S mode” vs “H mode” test conditions?

The manual specifies that unless otherwise noted, measurements should be taken in H mode. It provides separate engine speed expectations for H mode (1000 rpm Lo idle, 2100 Hi idle), B mode, and S mode. You need to set the display accordingly. It also notes that the mode defaults to S when power is thrown. This kind of detail is why OEM manuals matter. If you skip that note, your hydraulic pressure readings will be off by more than 10%.

Can I use this manual for the SK330LCVI model?

This manual covers the SK330 and SK350 base models. For LCVI variants, check the FIAT Kobelco SK330, SK330LCVI, SK330NLCVI Workshop Manual – 1302 Pages Factory S which includes the LCVI-specific systems.

If you’ve been fighting aftermarket PDFs that leave out the test conditions or round torque specs, you already know the value of a real factory manual. Access the Factory Manual and get the data that matches the machine on your lift.