Help - Should I replace this turbo?

belfert · September 07, 2019, 05:13:41 PM

I disconnected everything from my turbo this afternoon in preparation to replace the turbo. I happened to spin the turbo today and it spins great now with no detectable play. It wouldn't even make a single revolution earlier this year when the bus had not been run all winter. I ran the bus this morning and let it sit about four hours before working on the turbo. I suspect enough oil was in the left in the turbo now so it spins fine now.

Would you still replace this turbo? I have a Reliabilt turbo ready to go in. My biggest issue is trying to get the nuts off the manifold studs. I need a 6" extension to get to the bottom nuts and I couldn't budge things with a 1/2" ratchet. I have an impact, but I've been warned that might break the studs off. I can't get an impact to the top two nuts and not sure I can even get a socket in there.

I did notice the clamp holding the two halves of the turbo together is loose and I will fix that if I don't replace the turbo. It will take me about two hours to put everything back together if I replace the turbo or not. I have a new boost pressure sensor I will install.

chessie4905 · September 07, 2019, 06:44:59 PM

Turbo should spin freely with a touch of drag. You should not have ANY looseness when you try to wiggle the shaft side to side or up and down. The fins should be free of differences between each other or any chips or corners missing. There should be no scar or gouge marks in housings. You need to inspect fins and on both ends of turbo. If all that passes muster and all clamps or housings bolts are tight with no air or exhaust leaking, your problem is not the turbo. Make sure you don't have an out of sight exhaust leak at the exhaust piping or flange to the turbo. Make sure there isn't an air leak from turbo to engine intake. Make sure you are getting full throttle and you don't have fuel filters that are partially restricted. Make sure you don't have a restricted air filter.

belfert · September 07, 2019, 07:22:54 PM

Mine is all electronic so I am getting full throttle. My Silverleaf shows 100% engine load when the throttle is fully depressed. My issue is low turbo boost. I just back from a 1,500 mile trip and the boost never went above 13.6 PSI per the Silverleaf even at 100% engine load. It has gone a little higher on previous trips, but not above 15 PSI or so that I recall. I have have been told it should go higher. Fuel filters had 4,000 miles at beginning of trip.

There might be a little bit of play, but I thought it is normal to have a small amount of play? I can't tell if the fins on one side are worn a bit, or if I don't know what I am looking at. I am going to compare my new turbo with the old one.

I would just replace the turbo in a heartbeat if I could get the nuts off the studs. I really don't want to break a stud and need to have the bus towed to a shop. I already bought the turbo and can't return it. (I paid $450 for a genuine Reliabilt turbo on Ebay back a few months ago.)

chessie4905 · September 08, 2019, 04:35:41 AM

Can you remove the turbo along with the manifold? Comparing the play and the condition of the fins along with the new one.
As a side note, be sure the turbo is the right replacement. Both housings should be same number with same A/R.

belfert · September 08, 2019, 04:56:37 AM

I brought my engine serial number to the local Detroit dealer and they gave me a quote for the turbo including the part number. Their price was sky high so I used that part number to buy a new turbo. I would hope it is correct.

chessie4905 · September 08, 2019, 05:54:53 AM

A little more info for you.

https://www.thetruckersreport.com/truckingindustryforum/threads/detroit-s60-low-turbo-boost.200637/

luvrbus · September 08, 2019, 07:55:14 AM

Before I start replacing turbo I first check the play and a little movement from side to side doesn't affect one ,then for leaks, restrictions both on the intake and exhaust on electronic engines the boost sensor and hose for splits or bad connections. Turbos work on temperature and gases if the engine is not making the exhaust temperature (EGT) which should be over 700F+ for the 11.1 at full throttle then you have a major problem no new turbo will cure it.FWIW the 3 pieces manifold on the 60 series can be a problem and not cheap to replace around $2000.00 from Detroit

belfert · September 09, 2019, 04:48:36 AM

I decided there is no way I was going to get the nuts off the studs to replace the turbo so I gave up on replacing the turbo.

The repairs I made definitely helped. I am now maxing out at 17 PSI again instead of only 13 PSI. I still think it should be higher and I will replace the turbo next year.

buswarrior · September 09, 2019, 05:29:49 AM

Be sure to store that fresh turbo properly.

Don't need it rusted up lying in a puddle someplace.

Happy coaching!
Buswarrior

Scott & Heather · September 09, 2019, 02:05:29 PM

When I had low power issues on my DDEC II 8v92 I checked the boost and realized I was making 9psi max. I knew that was bad. I sent the turbo out to a rebuilder cliff recommended in Arizona. When I came back, I installed it and now I'm getting 26psi max boost. It's a night and day difference. I didn't have shaft play, and my old turbo did spin freely, but the fins were a little tired and just didn't do the trick anymore.

Geoff · September 09, 2019, 03:02:27 PM

As I remember, the fins were rubbing on the housing. That'll certainly slow down a turbo!

Quote from: Scott & Heather on September 09, 2019, 02:05:29 PM
When I had low power issues on my DDEC II 8v92 I checked the boost and realized I was making 9psi max. I knew that was bad. I sent the turbo out to a rebuilder cliff recommended in Arizona. When I came back, I installed it and now I'm getting 26psi max boost. It's a night and day difference. I didn't have shaft play, and my old turbo did spin freely, but the fins were a little tired and just didn't do the trick anymore.

DoubleEagle · September 09, 2019, 04:51:41 PM

As I remember it, the fins were broken and banged up a bit, and you were lucky to get 9 psi.

belfert · September 10, 2019, 03:26:51 AM

The original reason I thought the turbo needed replacement was because of the relatively low boost and it wouldn't make a single revolution when spun by hand. It turns out the reason it was so hard to spin was that it had sat all winter so no oil left in turbo bearings. After I made a Labor day trip it spun just fine. The fins look just fine and no discernable play in things. It isn't hitting the housing or anything that I can tell.

I will still replace the turbo since I bought a Reliabilt one already.

chessie4905 · September 10, 2019, 03:54:15 AM

Did you replace the boost sensor?

belfert · September 10, 2019, 04:40:33 AM

Quote from: chessie4905 on September 10, 2019, 03:54:15 AM
Did you replace the boost sensor?

Yes. It is a new Detroit part. I am getting the same PSI as I have been getting historically. The old sensor was actually labeled GM.