Turbo Shaft Play of Journal Bearing Turbos
Often times we have customers ask us about turbo shaft play, certain shaft play is totally normal on journal bearing turbos while some excessive play should be considered as a failed turbo. This does not apply on ball bearing turbos as ball bearing turbos do not have shaft plays.
For a new journal bearing turbocharger, a little side to side play is perfectly normal as the space between the shaft and bushing would be taken up by oil pressure during turbo operation. However, a brand-new journal bearing turbocharger should have zero forward and back (from compressor end to turbine end) play. If it does, there’s a high probability that the turbo has some machining errors.
When you have shaft play on a used turbocharger and would like to diagnose whether it’s within acceptable parameter or it has failed. Here are some tips for you as well. Same as the above mentioned method, using your fingers to grab on the shaft nut of the compressor and see if it has a forward and back play, if it does even on a miniscule scale, then there’s a great chance that continuing to run the turbo the compressor wheel blade will grind on the compressor housing, causing the whole turbo to fail.
Turbochargers have very tight tolerances, therefore we consider forward and shaft play more than 1mm as excessive shaft play, this will generally lead to turbo failure as the turbocharger continues to run.
Now you know how to check on your turbocharger for shaft play, do not panic when you feel slight side by side shaft play.