Hi All
Have registered with AMCE and can sign in--cant post or reply--Whats up with that?

Hope my written description makes sense---not real good with writing!

The problem
Have D6C 76A5795(1964)we bought new.
After realizing turbo was not working reached down exhaust and it will not turn.

Pulled turbo where could get wrench on shaft.
tapped it opposite rotation and it now turns free with some scraping noise in one spot.
Exhaust housing still on(intake removed)

Pulled exhaust housing and found the plate(1S2098)
and nozzle(8N7940)to be binding the exhaust impeller.
Measuring stack up clearances the nozzle and plate
are not properly clamped-to much clearance.

More studying and it looks like RUST forming between housings under clamp(flange mating area) has pushed housings apart. ????????

Removing the rust(?) looks like it will allow proper clamping of the nozzle piece between the bearing housing and exhaust housing although this will be less than original clearance it should be ok(?)


Should I use sealer on the rusted mating surface?
What kind of sealer?

The next thing is how is this assembled where plate and nozzle are in proper position?(plate floats and has rotation stop)

Cat I-Form 31778 installing turbo or turbo nozzle
is apparently the instructions for this procedure.
Anyone have copy of this?

Has anyone had this problem(rust) before?

Going to surf around on the site forum--looks great!

Thanks
David

Hi and welcome:)
Don't have the Form 31778......but do have the service manual for the 76A.
Turbocharger is a Schwitzer 4D......Clearance between impeller and compressor back plate is 0.020 - 0.022.
Any rubbing of the impellers are the "kiss of death" in terms of balance.
About the only thing I can think of that would stop the rusting and survive the heat would be the generous use of high temperature anti-seize ( the aluminum color/based stuff)

David, I think it's time for a rebuilt turbo. Check your oil pressure too, should be betweem 30 and 50 psi low to high idle. If you free up that one it may blow up and dump it's cookies into the cylinders. More expense.
Later Bob

David - It takes a few days for Joe to complete the registration process on ACME, as all new registrations have to be checked individually to weed out scammers and spammers. Joe runs numerous forums, and is a busy lad, but you'll get full posting ability shortly, I'm sure.

Your turbo sounds like its pretty sad, and Bob's advice is wise. Turbos run at extremely high speed, and need to be within those very precise specification parameters. The shaft just runs on plain bronze bushings, but there's piston ring seals as well, behind the impeller and compressor turbines, that need to be in good shape.

As the turbos wear, the bushings wear, and this allows the impeller or compressor turbine to come into contact with the housings. The piston rings wear and allow oil to escape into the intake or exhaust, leading to excessive oil consumption.

The impeller and compressor turbines can get out of balance relatively easily, and this leads to turbine or compressor wheel failure. This means they can lose chunks off the wheels, and if the compressor turbine loses chunks of metal, it will go through the engine, with resultant severe piston/valve/head damage. The turbine and compressor can spin at up to 100,000 RPM, so precise balance is critical.

If you send your turbo in for repair .. as it stands, without major damage .. the repair cost will generally be less, than if you wait until the compressor or turbine wheels commences to hit the housings and creates damage to both.
Once that happens, you're up for turbo housing replacement, as turbo repair shops will not re-use housings that have been damaged by contact with compressor or turbine wheels.

The corrosion is just a pointer to possibly more problems deeper in the turbo. Just cleaning the surfaces and re-assembling the turbo, possibly won't cure all your problems, and I'd advise the cheapest route, is to send it in for complete overhaul.

Hi Guys
Thanks for info!
Would have never thought that I would find this type of forum on the net!
FANTASTIC!!

Looks like Joe is busy man!
People like that are what makes life better for all.

Magnet
Oz brings up the next peice of info that would be handy.
The bearing clearance(shaft to bearing) movement at the end of shaft(or impeller base?) in the up down or let right directions.

If this checks within specs then will go with it.
$$$$$$ is big problem now after major and long illness.(lots better now!)

The machine is very low hours and has spent most of its life under a shed.
It was last used in 94-95!

I think that the rust pushed housings apart while it sat allowing plate and nozzle to fall and jam turbine(while it sat stored)--I think that the turbo never even turned as there are no marks---other than in the carbon/soot(from the scraping while turning by hand). after cleaning with rag no sign of contact.

The oil pressure pegs the gage cold and drops back slightly at hot idle.
The numbers are gone so don't know the real reading.

I know I am taking a chance using like is but think its gona be ok.

About 10 to 20 hours work and then shortly will be able to replace turbo!

Bearing clearance specks will let me make sure!

Am going to check price on reman turbo---might surprise me.
Are there any re builders that I should avoid?
(poor track record)


Recently learned that modern machine opperaters work in air/heated cabs!
With stereo!
Whats the world coming to!!

Thanks!
David

Don't have specs David, the bushings for the shaft are free to move in the housing aswell as on the shaft. This is to share the surface speeds of high RPM's. Therefore the shaft will move up and down slightly, it should spin freely aswell. Look for any pieces broken off the impeller or turbine. If okay, get everything else cleaned up and assembled tight. If you have too much wear you will hear the impeller or turbine squeeking as it contacts the housing. If all is good so far, pour some oil into the top of cartridge where lube line connects. Put line back on and fire up the engine. Run at low idle and then at high idle. Listen for squeeks as you rev engine up (impeller/turbine hitting housings). Then load the engine as listen. If you don't hear any squeeling or squeeking it should stay together. Check or replace air cleaner elements and look for a clean exhaust under load.
Later Bob

Well, if it happened while sitting, chances of recovery are pretty good.
Here are the specs.....had to do a little cut and paste due to the file size limitation of the BB that wont allow posting of a full page that is legible.

Magnet, Bob, Oz:)

Your help is fantastic!
One of the few times the this internet thingie has provided me with real and useable info!

Once the turbo is solved and back on and checked out have on hyd cyl has to be resealed.

Have discovered some rust on track adjuster shafts but think I can live with that for a few hours with a case of grease!---pisser as the pins/bush/rails have about 90% remaing.


Life is good:cool:

David

David, don't worry about the rust on the adjuster cyls. They seal on the inside, that's where the piston is. Just clean them off and oil before collapsing the adjusters if you have to. The dozer cyls should have some shims under the square packing gland. Take out the bolts pry it forward and remove some then tighten back up. Your machine chould have the stacked chevron seals.
Later Bob

David - The overhaul instructions for the Schwitzer 4D turbo are in the D6 Service manual .. Section 2A-10, Group 271.1 ..
Unfortunately, this section is missing from my D6C service manual, and the only other format I have, is microfiche .. so I have nothing that I could offer to scan, for turbo dis-assembly/re-assembly right at present. I haven't found Form 31778 yet, that could take a while .. and when I do find it, it will likely be on fiche, too ..