How much shaft play is to much??

[IN 05 NT]

2-3 mm seems too much....

but remember...you do need a lil bit of movement between,........as then oil pressure will elliminate the movement,

remember a rebuild is round $500....so is it really worth it?

blake

[wilbo666]

well the manual says to replace teh turbo when it has 0.18mm of radial play

the seller says anything bigger than that, you can safely assume that the bearing is well used ... and 2-3mm of total movement =totally rooted.

While I'm not saying that it isn't rooted....the radial run out measurement is taken from the center of the shaft not the ends, worth noting that!

Cheers
Wilbo

[thechuckster]

While I'm not saying that it isn't rooted....the radial run out measurement is taken from the center of the shaft not the ends, worth noting that!

goes to have aother look at the manual page.....

mmmm ... i wonders how one would do that measurement with my old RB20 turbo?

mine has more axial play (e.g. worn seals) than radial movement - tho the radial movement could just be a symptom of the seals being worn.

the shaft rotation feel the same whether the shaft is pushed inwards and rotate or pulled outwards and rotated.

My old T04/3 turbo(which copped the red-hot-turbo-overheating episode) had a huge of axial play, you could pull it forward so much that the compressor wheel was grinding on the housing...

[wilbo666]

goes to have aother look at the manual page.....

mmmm ... i wonders how one would do that measurement with my old RB20 turbo?

Same way I'd imagine, up the turbo oil drian hole.

I found the silvia serivce and repair manual when I went looking for specs for T25Gs...might be able to find the same for the RB20?

mine has more axial play (e.g. worn seals) than radial movement - tho the radial movement could just be a symptom of the seals being worn.

I thought axial play was related to the thrust bearing, not really the seals per say...

I'll be honest and say that I don't know a whole lot, but my general thoughts these days are that if the wheels don't hit the housings, the axial (thrust) movement is within spec, the turbine doesn't look massivly caked with carbon and the compressor outlet isn't an oily mess that the turbo is prbly ok

Note I said I don't know that much tho!

My old T04/3 turbo(which copped the red-hot-turbo-overheating episode) had a huge of axial play, you could pull it forward so much that the compressor wheel was grinding on the housing...

That's shagged

Cheers
Wilbo

[thechuckster]

from memory, i couldn't see the shaft thru the bearing housing ... but i'm not taking the blower off to check this assumption

i think i have a sylvia maintenance manual in PDF form too... now i know why i downloaded it

yes, the axial measurement is directly measuring the thrust washer... but i think it also tells you about the condition of both thrust washer and the seals - as once one fails, the other follows shortly afterwards ;-)

...

and .. yes, the old red-hot-turbo would have been surprise to the fool who tried to use it next ... am not sure where it ended up - hopefully in the bin.