So my 8v92 has been suffering from low boost and we are now monitoring it constantly and it's constantly low. Where the hot side clamps and connects to the cold side has a leak so it's all black there and the top of the engine bay above the turbo is black with soot. The soot has actually been coming into the coach through the access hatches and turned my carpet under there black. I resealed the hatches with spray foam so that problem is resolved but the turbo still needs RR. The fins are fine, there isn't any play in the shaft and it spins freely, but that leak between the hot and cold side is causing me to lose some boost and I need to resolve it.
What kind of money am I looking at to replace or rebuild the turbo?
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You don't need a rebuild. You just need to take the clamp off where it is leaking, clean the mating surfaces, and reclamp it. At the most, you may need a new clamp.
Scott. try Geoff method it may work for yu, but the TV8513 turbo on those engines were bad about warping the mating surface on the turbine side and most the time they need to be machine if it has been leaking for very long.A good rebuilt TV8513 with the 1.23 A/R cost around $750.00 watch the crap on Ebay,I buy my turbos from Tom @ www.turboresource.com (http://www.turboresource.com) in Lake Havasu good luck
When I say clean the mating surfaces of the exhaust, you may have to use a file to get the plack buildup off the exhaust lip. Scott, you have a good mechanical aptitude. Look real close at the surfaces that mate together with the clamp.
--Geoff
Geoff,the way I read it Scott is talking about where the turbine housing mount to the center plate but I could be wrong
these clamps ?
(https://cdn.shopify.com/s/files/1/0865/6152/products/465745-9001_3__clipped_rev_1.png?v=1456961421)
If you are doing this yourself, when reassembling, use a little antiseize on the castings where the clamps ride to help them tighten and pull the pieces together. Use only a small amount to avoid excessive smoke when they first get hot.
What is the number on your turbo ?
Tv7512 ar .96 ?
Awesome responses guys thank you. I will take a photo today. I don't know the turbo number but I can try to figure that out too. Arrow is pointing to the area that appears to be leaking and there is a lot of soot on the hot part of the turbo housing right there. I've replaced the clamp but it didn't change anything: (https://uploads.tapatalk-cdn.com/20180202/85e556ea2d9d3558ac3e20b1fda50299.jpg)
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Since you bumped the HP up to 500 your turbo should be a TV8513 with 1.39 AR ,that clamp looks a little short to,when the clamp is tight there is about 1/8 to 1/4 inch gap.
That looks to be a after market turbo ,take the numbers and call Tom @ Turbo Resource and see what you have
If at first you don't succeed...
I like luvrbus observation, the mating surfaces may have an issue.
Did you disconnect the piping before trying your new clamp? The piping can hold it jigged wrong?
If this requires any further screwing around, it's a diminishing return game...
trade it in for a fresh one, and reset that clock completely?
happy coaching!
buswarrior
Guys that is not Scott's turbo! He has used someones photo as an example to demonstrate what he was talking about that is a photo iof a new or rebuilt turbo.
Scott if it were me, I'd go ahead and use Clifford's suggestion and get a turbo from Tom and replace it now during your down time.
I'm pretty sure you won't be disappointed.
Yes you can do as Geoff suggests for less $, but the same amount of work. (well actually twice the labor if you still end up replacing it afterwards!)
;D BK ;D
Those shouldn't be the normal leak points. If you clean or reclamp in that location, you should always loosen, at least exhaust pipe connection first, as if it is causing a bind, it will be difficult to get that location sealed, especially because of the small diameter compared to exhaust outlet diameter. On some mountings, you may need to loosen intake pipe also for same reason.
I used to rebuild turbos when I worked for DDA. Part of the process in rebuilding is getting the exhaust buildup off the exhaust half of the turbo. In a shop, you should have a bead/sand blaster cabinet to remove the exhaust deposits off the center housing of the turbo. In Scott's situation, cleaning the mating surfaces of the exhaust pipe and turbo with a file is a DIY solution.
It could very well be that the flange on the exhaust is worn out or broken. There are new exhaust flanges available.
I do not understand the posts telling Scott to buy a rebuilt turbo. There are two many people on this board that don't mind spending other people's money. Scott has another mouth to fed. I am all for the cheapest solution.
Quote from: Geoff
I used to rebuild turbos when I worked for DDA. Part of the process in rebuilding is getting the exhaust buildup off the exhaust half of the turbo. In a shop, you should have a bead/sand blaster cabinet to remove the exhaust deposits off the center housing of the turbo. In Scott's situation, cleaning the mating surfaces of the exhaust pipe and turbo with a file is a DIY solution.
It could very well be that the flange on the exhaust is worn out or broken. There are new exhaust flanges available.
I do not understand the posts telling Scott to buy a rebuilt turbo. There are two many people on this board that don't mind spending other people's money. Scott has another mouth to fed. I am all for the cheapest solution.
Yes by telling Scott
"If it were ME, I'd replace the turbo with a rebuilt one!" I suppose I am helping spend his $. But I did say if it were ME, and I also understand the difficulty of R&Ring that turbo no an 8V92 in an MCI in tight quarters (MCI are not as easy to get to as a RTS or GM) and the fact that Scott likes to do things once and be done with them not re-do and re-do things if it doesn't work the first time.
But yes Geoff you are correct it's his $ and I should not have pointed out IF IT WERE ME I'd rather spend the $ and only do it once!
Thank you for pointing that out and have a GREAT SUPER BOWL WEEKEND!
;D BK ;D
Super Bowl? Wife is pumped for the Kitten Bowl on Sunday on Hallmark channel.
Scott asked the price and I gave it to him what he does with it is his business,lol he is never going to be happy till he sees 25 to 28 lbs of boost on that 8v92.
FWIW I have never had much luck cleaning the 2 machined mating surfaces to stop one from leaking but he may have good luck who knows,it does get old in hurry removing that turbo 2 or 3 times trying to stop a leak ???
Normally those clamps never come loose nor do the mating surfaces "wear out". Was the clamp loose originally from a previous repair? How did it become loose enough in the first place? Is the exhaust hanging and causing extra load on that joint? There may be other details to tend to as well.
The Tv 8513 is bad about about the mating surfaces I have 6 of those laying in the shop with bad mating surfaces I need to get machine ,those are a good size turbo the DDEC's use and the center has been a problem over the years for me anyways.
With the steel seal ring MCI uses on the exhaust pipe that goes inside the turbine housing make even it worse,I cut those out and clamp it to the outside of the turbine housing with a V band JMW
The turbo does not need to be removed from the engine to file the turbo flange. Like I said earlier, it could be the exhaust pipe flange could be bad, and those are available at struck parts store.
Unlike most of us, Scott's bus is key to his employment.
He cannot afford to be screwing around with things over and over, nor will he find any pleasure in doing so. On the road, he has a schedule to keep.
Sunday service won't wait for a Monday arrival.
And word spreads that you are unreliable. That is the death of any ministry.
All this figures prominently in the advice to cut the loss and replace with fresh.
Happy coaching!
Buswarrior
LOL all mute anyways Scott probably has one ordered as this goes on
Quote from: luvrbus on February 03, 2018, 09:59:26 AM
LOL all mute anyways Scott probably has one ordered as this goes on
If Scott ordered a rebuilt turbo without looking at his old one, I guess I'm in the wrong business. I better get religion and learn to sing! No offense intended!!
--Geoff
Lol. I haven't ordered anything yet Geoff.
I actually appreciate the cheapo fix suggestion from Geoff if it might work I might try it once. I'm maxing out on a full hill climb with a brand new air filter at 14 psi of boost at sea level if I'm lucky. I've never ever ever hit 20 psi. The turbo clamps are not loose nor broken. I did replace the one in question because I thought that would fix the issue but it didn't. That being said, I am partially in the camp of just replacing the turbo with a rebuild for $750. That's very doable for us. You guys are absolutely right, my tours ebb and flow but when they are flowing I can be dinking around with stuff I have to get it fixed and done right which is why I opted not to weld my air tank in my recent rust hole issue I posted about. I just called Luke and had him ship out a new tank and had it put in. Done and done.
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When everything is according to Hoyle the DDEC 8v92 with get up to 25+lbs of boost on a hard pull
Scott, I have a 91 Prevost with an 8V with only 86K original miles and the absolute most I have ever seen on the boost guage climbing the hills to Branson is 17. I have no turbo leaks showing and, like you, a new air filter less than 1000 miles ago. I hoped for more but it has just never been and right now, there doesn't seem to be anything wrong with the engine. I do need to pull the radiator and have it rebuilt but otherwise she purrs like a kitten (I mean roars like a lion).
I know what it is like to feed mouths, so maybe this could help you decide .
Rob
91 Prevost
Missouri
Rob, thanks for the data point. What is yours set at? Ken uploaded the 500hp program to mine and then added some fuel beyond that. I should be somewhere in the 550 hp range. So I should be getting full boost
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wrong post, sorry!
Scott
Mine is set for 475 hp, a lot less than yours.
Rob Missouri
Scott, you should see in the mid 20s psi boost. My 6V92TA will produce 25 psi at full load at full rpm.
JC
I had Tom build a turbo 2 weeks ago for a 6v92TA with 9G90's I got 31 psi @ 2000 rpm under a good load between Laughlin and Golden Valley climbing the pass not to shabby
Nice. I'd love to see that!
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Scott,yesterday Eddie picked up a manifold for his 8v92 DDEC 2 he was getting 15 lbs of boost with a broke manifold in 2 places with a blown gasket on a 450 hp 8v92 engine