You may remember that I shared some information on a couple of ABB VTC 254-13 turbos sent in for overhaul and repair, one of which was cracked. If you missed it, you can check it out here.
We’ve continued work on this overhaul and we’re now completing the rebuild, during which we came across another challenge which the OEM had solved (though on a different model).
One of the turbochargers required a new turbine wheel and shaft with a new compressor wheel.
These parts were ordered and balanced, but when our engineers went to remove the compressor wheel to fit the rotor assembly, we came across a problem.
If you haven’t worked on these turbos before, ABB advises the following:
• The compressor wheel extraction tool is to be screwed in until it reaches the bottom of the impellor end
• Connect hydraulic hand pump
• Hydraulic oil passes down the tool and expands the compressor wheel allowing removal of impellor from the turbine shaft
The tool they refer to looks like the picture below.
The manufacturer doesn’t give any value for the pressure needed to remove the impeller wheel, so it is down to the engineer’s feel to get it right.
For this rotor assembly, even with the interference fit, the compressor wheel needed considerable force to remove it from the shaft.
Talking to ABB experts we found that this was such a problem on VTC304 models that they have redesigned the tool.
Even when using OEM tooling, it is worth checking they are the latest versions, just as you’d check you were using the latest version of engine (or turbo) parts.
If you have any questions regarding correct tooling, let me know, we’d be happy to help.