How much turbo movement is normal?

[BrentN]

Hey all,
I am still trying to track down the tinny noise that I am hearing. I pulled my air inlet hose off my turbo yesterday to check the impeller blades.

I can move the blade assembly from side to side to where it will contact the housing. Question: How much sideplay is normal? I get a little bit of endplay...but not much.

If someone can clue me in I would appreciate. I really dont want my turbo coming apart.

[gmctd]

Axial or radial play should not result in impeller wheel or blades contacting the housing at any point.


Full-floating sleeve bearings will give impression of excess play when cold - do same test when engine is hot, immediately after shutdown, so bearings will have normal oil interface.

Fan must not contact housing at any point.

[kowsoc]

Also the impeller shaft becomes fairly hot during operation which causes expansion and further "tightening" of the bearing. I would check the heat sheild for the source of the noise, loose bolts, cracks, bends, etc....

[DA BIG ONE]

A compressor wheel (usually the first to hit housing) hitting the housing makes a squeeling noise. The hollow tinny sound you mention may very well be the heat shield mentioned in previous post.

[gmctd]

Check serpentine belt idler mechanisms and pulley bearings.

Check Vacuum pump, alternator, and ps pump bearings.

Check fan clutch and ater pump bearings.

Give harmonic balancer and access drive pulley a close scrutiny while you're at it

[BrentN]

Just a follow up on this earlier post...If you can move the compressor side impeller of the turbo from side to side (with engine off of course) REPLACE IT IMMEDIATELY. Had I done a little more homework it would have avoided the complete failure of my turbo and potential further damage to my engine.

From the time I inspected it, until it failed was about 18 hours..

I will post a follow up when I get my rebuilt turbo installed.

[ 10-04-2004, 07:29 PM: Message edited by: BrentN ]

[kowsoc]

I have a 94 and 96 and they both have shaft movement from side to side. I have been told that some clearance is necessary to allow for the expansion of the shaft from heat of operation. Without some clearance the bearings would sieze. :eek:

[gmctd]

If the shaft does not have radial movement - side-to-side, up-down - then you've also got problems.

The shaft bushings are floating, meaning they spin inside the housing as the shaft apins inside them, allowing the 100,000 and upwards rpm.

Necessary to make pressure at low volume - Boost - from high volume at high velocity.

Trick is, as posted above, the fan - wheel and blades - must not touch the housing at any point.

Axial play - front-to-rear - against thrust bearings should be minimal, same deal - turbine and compressor wheels must not touch housings.

Seemingly exces radial play at cold will decrease with oil pressure and heat.

Again, fan and turbine wheels must not touch housing at any point.

Word up, dudes.....