I happened to remove the air intake from the turbo and got an unpleasant surprise. The vane blades look rough-chipped along the edges and I'm wondering if I need to replace the unit. The bearings seem ok with no play but it seems likely if nothing else the unit is out of balance due to erosion of the wheel.
I see replacement cartridge units are available, seems like it should be a straightforward install as shaft, wheels and bearings are in a pre balanced unit. Wouldn't be comfortable doing a component level repair but if this assembly could slip in might be an easy fix. Anyone have any thoughts on this?
I've already gone thru the air intake system checking for potential leaks and found none but resealed everything anyway. Last oil analysis was good so no idea what caused the wear on the vanes. Would appreciate any thoughts as zero experience with turbos here.
Chuck,
Are the chips on the edges at the far end away from the middle? If so, are there any marks on the turbo housing? Chips on the face of the blades? How about a photo?
Pulled from another site: "The best way to check for bearing problems or contact between the housing and turbo wheels is to remove the intake or exhaust plumbing from the turbo (which ever is easier) for a peek inside. Any sign of scraping on either the turbo blades or the housing means the bearings are shot and the turbo needs to be replaced or rebuilt. You should also spin the turbo by hand to feel for any roughness or binding. If it doesn't turn freely, repairs are in order.
Other problems to watch for are cracks, nicks or chips in the turbo wheel blades, and/or "eroded" (worn) blades. A turbo is a very delicately balanced assembly. Most automotive turbocharger wheel assemblies are balanced to within .001 oz.! A broken blade, worn blades or even nicked blades can be enough to throw the assembly out of balance. The turbo may still spin freely, but the imbalance will prevent it from reaching maximum rpm and eventually pound the shaft bearings out-of-round. There's no way you can rebalance the rotating assembly, so if there is any indication of damage, the damaged parts must be replaced."
Turbo can be send out for repair or a new one purchased off ebay. Not very expensive for a new one but would not pay anything close to list price.
Pierce
You can also stick a rod on a dial indicator through where the oil supply opening is to check for play while moving the shaft up and down with your fingers at either end.
Pierce
Bottom line, is YES, replace it ASAP. With eroded blades, it is likely unbalanced.
If larger vanes come off, that metal is "eaten" by the engine-- not worth taking a chance on!
Sounds unanimous then, new turbo. Looks like a new turbo cartridge from Holset is around $700, and can buy a new turbo complete for around 1300 so will probably go for a new unit. I appreciate the help even if it's not exactly what I wanted to hear. Here's a picture of existing:
Chuck,
Have never seen blades like yours that had a filter ahead of it. Would check your air cleaner installation as this would not be considered normal wear. Like Brett said, you can imagine if even a small part of a blade broke off. Out of balance can take out a seal, cause oil to be introduced into the intake, spike the EGT and burn a hole in a piston.
More than likely, a small piece would go out the exhaust but if it happened to get between the cylinder wall and the piston, it could score the wall or cause the compression ring to stick. Either one, a bad deal.
Betting you can get a factory new turbo complete for around the $700 price if you look a little. Years ago, I was buying smaller Rotomaster turbos (Rajay) for just over $225 new. In case you are wondering, the only difference between an automotive turbo and one for an aircraft is the inspection they get plus the factory spends more time balancing them before assembly. Then they get the yellow tag and more $$$.
Pierce
Chuck,
Check this page: cummins turbo 8.3 | eBay (http://www.ebay.com/sch/i.html?_odkw=cummins+turbo&_osacat=0&_from=R40&_from=R40&_trksid=p2045573.m570.l1313.TR2.TRC1.A0.H0.Xcummins+turbo+8.3&_nkw=cummins+turbo+8.3&_sacat=0)
New turbos for a Cummins 8.3 starting at about $250. Looks like an exact match OEM Holset for yours at $889.
Pierce
I had my turbo rebuilt at a local Fuel Injection/Turbo shop in San Diego when I lived there about 5 years ago. I think it was about $400. I did because I thought I heard the bearing starting to make noise. Looked brand new after rebuild - included cleaning up the leading blade edges. I was pleasantly surprised to see much stronger pedal response from a stop. I guess I didn't notice it declining as it happened over a long period time and I probably wrote it off as just carrying more weight (on the coach that is...not me :) )
You might check with local shop to see what they can do. Either way I hope you find a nice performance surprise too.
you remember where and what?
John, I would be interested to know what shop in San Diego you used also.
If you could find the info I'd sure appreciate it.
Richard B
No, there is a big markup on turbos. Using Rayjay/Rotomaster turbos, we never had a single failure. While that was a few years back, you just have to do your homework on the different brands out there. Lots of forums that cover Cummins turbos and the various manufactures. You just have to make sure the turbo matches the engine and it's RPM range.
John has excellent advise about rebuild shops. There is not much to a turbo and bead blasting the hot side makes it look like new. With a few new parts, it is as new again. The secret is matching the many vane options on the hot side with just as many vane options on the intake side to make gains over stock or just replacing with the same parts for OEM performance. I tried my hand at compressor mapping but was never as good as the guys that do it all the time. They also have lots of tips and can give one lots of insight into turbo care and feeding. With so many pickups being chipped now, many owners want more PSI so change turbos to do it. Adding more fuel makes more heat and more boost does the same. Really important to accurately know your EGT as it is critical once the turbo and fuel system has been modified from stock.
With the turbo close to the exhaust manifold like on a inline engine like a Cummings, the rule of thumb is 10 degrees cooler on the post turbo side for every pound of boost compared to exhaust manifold EGT. An example would be a 8.3 with 20 psi of boost would indicate 200 degrees cooler post turbo compared to an EGT probe into the exhaust manifold (called pre-turbo). A Detroit like ours has over three feet of pipe between the exhaust manifold and the turbo mounted on top so the difference would be a lot more. In a perfect world, the pistons would have senders mounted on the crown as this is the part that will be damaged. Modifying for more horsepower makes it super important to know exactly what the temperature is as it exits the exhaust port.
Rebuild shops can also check for any faults from the air cleaner to the turbo that might lead to vane damage. Some of our coaches have quite a few feet of intake pipe/hose between the filter and the turbo intake.
John, I forgot to post my boost on the 6V-92TA. At fuel cutoff at 2110 RPM, the Pro-Link sees 19.6 psi between 2000 and 6000 feet elevation. Going to wrap the exhaust and blanket the turbo and will check it again after that. Probably should have recorded supply fuel pressure too but forgot as the reader was on my lap.
Pierce
I'm finding an exact match turbo hard to come by. Wish I was able to decode the assembly number but apparently the compressor side impeller is a rare bird. I am able to get a new unit complete or a cartridge assembly from Holset, thru one of their distributors. Have looked longingly at ebay specials at a fraction of the price.
Need to move the coach a couple hundred miles and get out of this sandbox for a while. Once I do,think I'll pull the turbo, inspect it and most likely order a cartridge assembly from Holset. That looks like it will replace all moving parts without issues of reassembly or balance, reuses the housing, at around half of new unit cost. I've talked to several Houston rebuilders but none have all parts in stock.
When I replaced my fuel pump I ordered one thru Cummins rather than an Ebay part. When I opened the Cummins box, stamped proudly on the pump was "made in China." :o I'm hoping not to pay six times the ebay cost for a part from Holset and find it comes from the same aftermarket mfg.
Chuck,
The automotive parts business is very competitive and they source from the least expensive supplier with a good track record. Chinese pet food is a real no-no, HF tools can be marginal and they can't build a cutting edge jet engine so they have to rely on the Russians. On the other hand, almost all Apple products (until the new plant opens here) are made in China and are not only are they aesthetically and functionally on top of the world but rarely give trouble. Just depends on the plant organization, management, target market, etc. If the pollution and building bubble doesn't cause major problems there, watch out. Probably too late to say "watch out."
While you are waiting, do research on turbos with online forums. A lot of the turbos you see on ebay may come from rebuild shops as volume keeps their turbo cost down and profit margin up compared to smaller shops with smaller orders. Call the suppliers/rebuilders and send the best and highest resolution photo possible of the photo you posted to a rebuild shop(s) for advice on the damage shown. They can tell you how far you can drive it and how soon it will need replacing. I can only guess. Good to make phone friends with one of the tech guys rather than sales. You seem pretty knowledgeable about mechanical stuff so should not be too hard to get them to buddy up and talk shop with you.
No idea about Holset as have had experience with KKK, Garrett Air Research and Rayjay/Rotomaster turbos.
Some forum advice on turbos has to be taken with a grain of salt as a lot of users are really young super macho guys with their chipped PUs and are talking nothing but s____.
Pierce
Chuck,
There has to be a heat cycle life for these turbos.
What quality of NDT testing is done during the reconditioning of a turbo charger?
It would be interesting to see what kind of failures (blade loss?) reconditioned units have compaired to new units.
With an exchange unit you don't know what it came off of. Was it run at a lot of full throttle, high temperature high RPM?
Without that history I would go for a new one.
JD
John,
The blades/vanes are new along with the bearings and seals in the replacement cartridges. The only thing left in a turbo is the body for the hot (cast iron) and compressor side (aluminum). They are very simple devices and not like the other accessories on an engine and have only a common shaft with vanes at each end riding on a couple of bearings. Turbos with waste gates are only slightly more complicated with the waste gate a simple bolt on item. That's why new turbos on ebay are so inexpensive.
Pierce
Pierce,
That sounds OK!
What about the oil passages? I guess they are in the housing?
Can you clean them out?
Coked up oil passages would be bad on the bearings.
JD
Depending on the amount of coke, oven cleaner and a scotchbrite pad will usually do the trick with a mototool used to get stubborn deposits off. If the seals are held in place by a snap ring, the groove will need to be clean too. Tools to work on a turbo may be found on ebay. Just noticed a used tool kit for $200.
Here is a good site from Garrett. They make the turbo used on our Detroit Diesel 6V-92TA engines. This page shows what the bearings look like and have links to everything you might want to know about turbo including a size selector. See at: Oil & Water Lines | Turbobygarrett (http://www.turbobygarrett.com/turbobygarrett/oil_water_lines)
Pierce
Found the receipt:
PCE Diesel
Authorized Cummins Dealer
2255 National Ave.
San Diego, CA 92113
619-687-0035
Total was $450, ($111 parts/$320 labor/$19 in taxes and hzd waste) on Jan 8, 2008
Looks like they are not at this address anymore. Here's a link to their locations ("diesel and motors" location?): PCE Propulsion Controls Engineering : Contact Us (http://www.pcediesel.com/contactus/index.shtml)
FYI: Sometime ago I uploaded the "Turbo Technician's Guide" from Detroit Diesel in an album: http://www.foreforums.com/index.php?action=media;sa=item;in=2251 (http://www.foreforums.com/index.php?action=media;sa=item;in=2251)
Has some photos of what needs to be replaced and what doesn't but it shows some pretty extreme (and obvious) conditions. It might help you take notice of things you might not notice otherwise. These are obviously a little different from Cummins turbos but I think all the concepts are the same.
P.S. I pulled the turbo off the engine and dropped it off, so the labor is purely the turbo rebuild.
John,
Nice PDFs! I have the factory DDEC II troubleshooting manual. It's much to large to upload but let me know if you would like a CD.
Pierce
Thanks John, I will bookmark that
Dave,
Thanks for the boost numbers. I don't get the 19.6 psi max until I hit 2100 RPMs. Think I will pull the rubber intake boot and take a look at the blades. I have zero exhaust leaks. Now that I read your 2450 RPM, that sounds like Detroit numbers for a big HP sport fisherman engine. Our fire engines were all 71 series mid-engine installations with the radiator fan right behind the cab. We ran 2400 on some, 2300 on the first conversions. They would make an incredible noise at 2400 spinning the radiator fan. No headphones could cancel the noise if sitting next to the engine in the jump seats. Pumping at max RPM with the engine, fan, 1000 GPM pump was louder than a rock concert.
Our 6V-92TAs have the blower bypass valve. Wonder if that makes a difference in boost readings? Need input from other owners.
Another forum member PMed me and said his 92 series Eagle only saw 8 psi boost on the hills. That seems really low.
Pierce
Our 3208 does 14 psi, and as far as I can tell that is spot on for that engine. The 8.3 spools up a lot more, and the variety of stock boost levels covers a pretty wide spectrum...
Pierce The by pass on out 92 series work just like a waste gate, that is my understanding. When I installed my gauge i asked the Bus guys on another board and was told for a mechanical 8v92 that 5 to 10 # was what i was to expect. I went through my system and made sure i did not have any leaks. So that is the extent of my knowledge on Turbos, On my Eagle i took the # of it and was told that Turbo was rated for 435 HP. I talked to the shop Boss here at work and he said the the Electronic motors of 92 series might have a little higher boost. That's it that's all I know :D
The blower bypass should open at 5 psi, on the 8V-92 that gives about 35 hp gain at crankshaft. HP is result of fuel injector size, timing and turbo, proper combo will provide a very happy motor. My sperence is on mechanical DDC babes, Any version of DDEC is pure snake oil to me. ;D
Dave I knew there was someone out there that could answer that I tried to get a hold of Clifford but I;m sure he's out working on something lol
I have a VMS II and I typically see a maximum of 21 psi during high rpms, full load - usually just before shifting. I don't know if this is the pressure before or after the blower. (i.e. turbo only or turbo+blower). I also have a very small exhaust manifold crack I need to get after soon. I have only had the VMS for about 18 months so I don't know what's normal long term.
My engine is 300 hp. Is it fair to assume a 350 hp engine should generate higher boost?
Might be interesting to compare turbo part numbers. Mine is 23503262 (s/n TF222)
There is also the configuration sticker on the valve cover (photo attached). It shows "1092" for the Turbo.
I also attached photos of the other stickers. Shows some interesting info.
@Pierce: Thanks for the offer - I hope I never need it!
Andy,
A waste gate dumps any excess pressure overboard or to make less noise, back into the exhaust system downstream, in other words, the excess is wasted hence the word "wastegate." Turbos with wastegates get boost at lower engine RPM but would produce more pressure than the engine was designed for so the wastegate keeps the boost pressure constant once the design pressure has been reached by dumping the excess. It also reduces turbo lag. Did your 8V-92 have a turbo?
Our blower bypass just routes the pressure around the blower lobes and back into the plenum chamber where the aftercooler is. The gain for our engines should be about 25HP.
Dave, we don't have to worry about changing injectors or changing the timing for more horsepower as a change in the DDEC II ECM firmware just keeps the injectors open longer for more fuel and will change the fuel and timing as the RPM, boost pressure, temperature, and altitude dictate. Don't know the setup on the 500-535 HP ladder trucks and boats as far as injectors go. The 500 HP 6V-92TA ladder truck engine on the YouTube dyno only had a single turbo. The DDEC is the big reason our engines don't smoke with a clogged air cleaner. The boost sensor sends the pressure to the ECU and it just keeps the fuel turned down. Smart! That's why electronic diesels get better fuel mileage, smoke less and are easier to hotrod (if you have the right engine serial number or go to a marine Detroit shop). A lot of boats use two turbos as the turbine/compressor wheel mass is less so they spool up faster, get more HP sooner and get the boat up on a plane faster.
Keeping the same turbo body but changing the turbine and compressor wheels can easily change the amount of boost pressure it puts out.
My 300SD has a wastegate that keeps the boost from exceeding about 15 psi. I plugged the line to the wastegate so it never opens. Running great at well over 400,000 original hard miles so must not have hurt it. My turbo kits were non-wastegate and only gave about 7 psi as the engines didn't have the HD parts the factory turbo engines have. (oil squirters, hollow dome pistons, different valves, different connecting rods, etc.)
Now for a short story. I was on the way home from Minneapolis St. Paul in a partially wrecked Ford PU with a mechanical turbo engine (for my SOB). I came across a Dodge PU fueling just past Salt Lake City. He had a long goose neck aluminum trailer behind and on the freeway on ramp, he left me like I was tied to a tree. Lots of black smoke. I still can't believe how fast it was. Several hours later as I was pulling into Winnemucca, NV, he was stopped on the freeway with his hood up looking at the engine. Guess you can give a diesel too much fuel and boost.
Pierce
Mine goes to just under 20 psi just as it shifts. No cracks in the manifold. Will check my turbo part number and let you know if different. Expect the ECU is controlling the amount of fuel so less horsepower but turbo is the same. That's why a Detroit dealer can plug in the ECU and with a firmware change, get an instant 350 HP on your engine. When I turn on my Pro-Link 9000, it reads the DDEC type, RH or LH rotation and the horsepower (350 HP). 350 HP is the maximum EPA limit for that engine in a vehicle other than a fire truck so a dealer can't go any higher unless they have the serial number from a fire truck engine.
I like your valve covers. Mine don't have the raised letters. Bummer for the evening!
Pierce
Wow you guys know your stuff, Thanks for all the info going to take me awhile to digest it all.
Don't feel too bad, I'd rather have the extra 50 hp!
Your trans was the power limitation. Trans is nominally rated at 780 pound feet. Original 89 300's were rated at 277 and 840 torque.
Customers buddies were on them saying they had 300hp.
At the unihome seminar on oct 87 I met the Detroit and Allison rep and I mentioned this issue.
So we agreed to rerate the engine to 300/820. Allison guy liked it as it put less strain on his trans.
You may be able to change yours back to the 89 specs. In a side by side race the 89 was noticeably faster.
The two reps just told Foretravel the change was required.
Sorry marketing the product was the key. Lost a lot sales because of the 277 hp rating. Buddies razzed the owners.
John,
Thanks for the PDFs. I will print them out and add them to my manuals. How do you manage to keep your engine so clean? My engine could use a good cleaning! I think mine was a result due to the disintegration of the insulation under the bed. I removed most of it today as it was falling off in big pieces and probably not very effective. Don't want that stuff touching a red hot turbo. Pierce's pics showed what could happen as it easily burns!
I found an excellent troubleshooting checklist for DD6v92 turbos from Diesel Pro Power. It's a quick reference for some situations and can help you in determining the health of your engine by looking at the exhaust. It's in pdf format and is a one page printout. I printed one and added it as the first page to the DDEC II troubleshooting manual that Pierce sent to me on a CD.
http://www.dieselpro.com/FreeResourcesPDF/Dieselpro_DD_6v92_turbo.pdf (http://www.dieselpro.com/FreeResourcesPDF/Dieselpro_DD_6v92_turbo.pdf)
Jerry