hi all,
thanks for all your help. i have replaced the bottom rubber elbow from turbo finally.
while the pipe was off i had a mooch at the props.
there is tiny minimal lateral play in the shaft. i wud say less than a mm play.
is this anything?
the blades seem in fine condition.
thanks once again

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THIS IS MY 4. THERE ARE MANY OTHERS LIKE THIS ONE, BUT THIS IS MINE.
red st185, running 10 psi all gears, powerflow cat back, and air filter. oh and fab scoop splitters

The shaft should move up and down and side to side. There should be no movement you can "feel" in and out.

Sounds pretty normal to me

_________________
Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
_______________________________________
Turbocharging - the replacement for displacement

I thought it was the other way round Kris - ok for a bit of in & out, but no up/down, left/right movement as this means the blades stand a chance of contacting the walls of the housing?

Cheers,
Mark

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Mark - 94 Red Jap ST205 WRC - Gone but not forgotten
'06 Blue Merc E320 CDi v6
'89 Mica Blue MR2 Mk1b restoration project
"Don't make me come over there"

Hi Mark,
in & out indicates the thrust bearing is fubarr. a little up and down on a turbo is normal as theoil in teh bearings will not be under pressure and hence you can squeeze the oil out of place easily. Strangely I understand Ball bearing turbos actually have more play than the simple floating oil type.

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JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

Ah cool - ta for clearing that up for me m8 Maybe I knew that at some stage before and just forgot - damn but my memory is a mess these days

Cheers,
Mark

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Mark - 94 Red Jap ST205 WRC - Gone but not forgotten
'06 Blue Merc E320 CDi v6
'89 Mica Blue MR2 Mk1b restoration project
"Don't make me come over there"

indeed - just tell yourself that you are learning more than you are forgetting m8 - you will not remember what it is that you forget anyway Thats what I do

_________________
JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

shud there be no vertical play whatsoever?
my seems as though it is sat in its bearings. with the minimal of wiggle.vertical and hosrizontal

_________________
THIS IS MY 4. THERE ARE MANY OTHERS LIKE THIS ONE, BUT THIS IS MINE.
red st185, running 10 psi all gears, powerflow cat back, and air filter. oh and fab scoop splitters

A little bit of vertical play is OK.

In summary:-

Up and Down = OK

In and Out = Bad

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GT4DC Events Co-ordinator
1996 ST205 UK

I find this guide most useful
http://members.aol.com/mr2mkii/turbo.htm

By the way, what he says broadly correct. If you can actually feel any movement on the shaft then the turbo is out of spec

However, as above a perceptible amount of radial motion is taken up in the oil. In/out means a worn thrust bearing which is far more likely to result in a blade/housing issue than up/down movement

It has to be born in mind, as has been said earlier, some of the play in the shaft / bearings is taken up through heat and oil pressure.

I dont want to come over as a smart Aleck but I worked in the ball / roller bearing industry for 22 years at RHP / NSK initially as a tool room apprentice moving on to design office and eventually as QA manager.

To be blunt there is a lot of crap written about bearings (plain and ball / roller) and tolerances, by people using the bullshit baffles brains approach.

If I had to I could calculate the the precise required amount of radial and axial internal clearance for any bearing given material types, speeds, loads and temperatures. Given the amounts of radial and axial play plus the above information I could calculate the clearances under various operating conditions.
Not wanting to lecture anyone but if anyone ever wants to talk balls ! or bearings then drop me a pm.

ps
I still have friends in the industry should further "help" be required.

pps
Despite what I said at the beginning it sounds like a lecture, sorry.

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Forever in search of knowledge (especially GT4 related)

lecturer lol

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THIS IS MY 4. THERE ARE MANY OTHERS LIKE THIS ONE, BUT THIS IS MINE.
red st185, running 10 psi all gears, powerflow cat back, and air filter. oh and fab scoop splitters

Sorry

Kris and Sirius said it best
In and out is bad.

_________________
Forever in search of knowledge (especially GT4 related)

dt4 - please feel free to post some interesting stuff - after all were all here to learn.

I have heard from some places that a rollerbearing turbo is not particularly suitable for a roadcar application. Is this true? If so do you know why?

Cheers

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GT4DC Events Co-ordinator
1996 ST205 UK

Roller bearings are great load bearers and are typically used where radial loads are high.
They are poor for high speed applications though as the high rolling contact area is prone to over heating (as the load increases this gets worse)

Like many things though compomises have to be made
The loads involved may force the designer to go for a roller bearing, the temperatures due to speed and operating temps and ability to get a supply of lubricant to the contact areas may suggest ball bearings. The actual space that is available for any rolling elements may mean the only viable option are needle rollers.

I think Cototeboy on the OC is trying to source parts for a DIY rebuild just so he can have a go not because he believes its a DIY job.
He cant find catalogue bearings that fit and are capable of withstanding the speed / heat / load.
To be honest I dont think he will.
I have contacts in super precision bearings in the UK, Switzerland and Japan and could probably track bearings down if I was given a referance but to be honest there is a case of "stick to your knitting"
Welders weld
Engine mappers map
Turbo rebuilders ............
I worked in Japan for a short period of time in a super precision factory and the materials and processes used for this type of product make the manufacture of the "industrial" bearings (gearbox / hub / clutch etc) seem rough and ready.

_________________
Forever in search of knowledge (especially GT4 related)