Introducing myself.
looking for a decent forum on turbochargers .
"Hypergear" has blown me away with his milled Center core !!
i have a turbocharger that operates in a marine environment with ceramic ball bearings.
Got it apart ATM to replace compressor wheel due to corrosion .
the turbine side has a ceramic ball bearing with 8 loose balls.
they are black/grey so seem to be Si3N4 material, 7/64 size (See pic)
turbo is an IHI RHF5 model. A/R is 0.614 so it's pretty small.
The core housing does not allow the bearings/guts to be removed.
fair to say it's a core replace not repair.
Hard to see the compressor end bearing, it's a lot smaller ( 5.11 mm shaft bore)
Seems to be a lot smaller bearing/bush arrangement.
Anyway the bearings are not worn and seem to be in good condition,
except ii could only find 5 of the 8 installed. Initially I thought I had lost them,
but the remaining 5 were installed 90 degrees apart.
i remembered the guy I Purchased this from, said he had pulled apart turbo to service it.
Appears in the process he lost 3 of the balls, so just put it back together and here I am
200 hours later with it rotating fine !
so have purchased new balls same size and material for $1 each.
In the process I found synthetic sapphire and ruby balls for $4 each.
Ceramic ball turbos precautions are not to allow impact on housing and to store horizontally.
the ruby/sapphire would be more resistant to impact and are also another 5 times harder than ceramic.
Ball bearing turbo cores have a restrictor in the oil inlet. Couldn't take a photo for you guys,
but inlet hole in the Center housing is probably not much more than 1/16 inch.
This agrees with the beginning of this thread , that one large ceramic bearing is used
on turbine end, and a smaller sleeve/bearing on the compressor side.
well at least for IHI turbos.
