Leaking hot side 3B turbo?? (2 Viewers)

[Awl_TEQ]

@Dougal , @gerg , @yotahed

What do you guys think?

I am concerned about an exhaust leak apparently coming from between the Hot side and the center section of my turbo. I wiped off the soot seen on the charge side the other day and it came back right away. I am down 5psi on boost without any change to fuel. This is likely why. And how do I remedy the situation? Can I laser cut a thin (0.010"-0.040") stainless washer/gasket and install it in the shoulder recess where they joint together.

the bolts are tight and the assembly is snug

disregard the oil weeping from the drain

 

[Dougal]

That's minor and I think they all do that to some extent. It's just a close fit with no actual seals (other than rust) between the turbine housing and centre section.

I would look on the compressor side and air filter first.

 

[Awl_TEQ]

Everything on the compressor side seemed tight but I'll check again. Maybe I can blow a bit of shop air in there and find a leak

 

[gerg]

Does it spin freely? Egts up as your boost is down? Loosing that much boost should drive your egts up quite a bit. An exhaust leak is not quite as bad as a boost leak, although it is curious as to why it's leaking there. Any chance you can spray soapy water on it when it's cold with your throttle pulled out to see where exactly it's leaking? Might be a crack forming. Diesel exhaust has the ability to create a lot of mess with a fairly insignificant pinhole leak. I have a couple and there anoying, but nothing much comes from them. Have you ever tried presurizing your turbo and charge pipe to look for leaks? Can be done with some plumbing rubber hose adaptors and an airline fitting on a PVC end cap. Then I use a smoldering piece of oiled rope that smokes to search for boost leaks. I honestly think your loss of boost and the small exhaust leak are possibly unrelated, but hard to tell right now.

Check if it spins easy
Look for leaks....everywhere.

 

[yotahed]

If you are worried about it, drop the housing off the rear and clean both sides, looking for chips and cracks. Smear a coat of exhaust flange sealant(not a lot) and bolt back together, tightening evenly as you go. If it still leaks, its likely the hotside is from a core Turbo(rebuilt) and the flange is worn out/corroded.

 

[Awl_TEQ]

Ok, finally had time to take a look at this issue.

@gerg , she spins freely, my EGT gauge quit. New one is on order.

@yotahed , Turbo was shiny new when I bought it. Has maybe 30k on it on two different engines.

Here is what I did: I removed the inlet silicone elbow and taped up the opening with duct tape. I poked my shop air blow gun thru the tape and gently pressured up the intake. No discernible leak in the charge pipe or intake manifold that I could see or hear. As I was doing that I noticed there was some play between the center section and the exhaust side. All the bolts were tight, though not very tight. I tried to tighten them first and only one of the six moved at all.

So I decided to pull the whole assembly off the truck and see whats going on. Much easier on the bench. I removed the hot side housing and couldn't see anything abnormal at first.

I started cleaning the assembly and dealing with the oil leaks when I noticed that the hot side housing would move a little over .100" up and down (relative to when it was mounted in the truck) but not hardly any movement horizontally. So I checked the circular shoulder joint where the two pieces mate. The hot side was nice and round. Its clean and no cracks are visible.

But the center section is definitely the issue. You can clearly see that the flange is worn away on the bottom half when mounted. I measure about 0.100" missing. Makes sense.

First thing that jumps to mind - is the impeller hitting the housing? Yep. Just starting to.

 

[Dougal]

That is odd. It's a lot of wear on that lip and it must have been moving a lot for a long time to do that.

What is the make/model of the turbo? Is a new bearing housing available? Simply bending/tweaking the clamp plates would ensure it can't move again. But it's a concern that it could move in the first place.

 

[Awl_TEQ]

So the plan is... driving the Matrix to work tomorrow for starters. I bought the turbo from Alamo. They are in the building next to us at work. I boxed all the parts and I'll go see them tomorrow. I'll see what the options are then. New center section and have them re-assemble? I can likely fix the center section. We do that sort of thing at work often. Build up with weld and turn down to size on the lathe. As long at there is something to hold on to in the chuck. Alamo would still need to re-assemble for me.

But. While we are talking turbo assembling. Is this the turbo I want? I bought this unit based on a thread where @Dougal was pontificating about how the CT26 was too big for the 3B and a smaller unit was better. He was pushing some garrett unit, can't recall which. Here is the tag on my unit:

I don't know enough about turbos (that's why I'm posting plenty of experts online). I recognize the 042, something to do with the turbine size. No idea what 0911 is. Maybe just the date, Sept 2011? I dunno.

So here is the deal - this turbo started with a 10psi waste gate. It never opened. Not even once. I know because during an inspection I found there was zero soot in the waste gate. So I removed it and gained some room from the firewall with a custom down pipe. See photos below. I ran it at 7-10psi after that for a while. Blew that 3B up with a failed #3 rod bushing. Mounted it on another engine and ran 10psi for a while. Rebuilt the first engine and swapped that back in with the turbo. Increased compression, better exhaust, better header and tight new motor allowed an easy 15-17psi still with no waste gate. I like 15psi max. It's enough for me. No black smoke, decent power. I drove to Pismo and on the way back is when I started noticing the decrease in boost.

I know this turbo works. But can I get boost sooner?

 

[Awl_TEQ]

That is odd. It's a lot of wear on that lip and it must have been moving a lot for a long time to do that.

What is the make/model of the turbo? Is a new bearing housing available? Simply bending/tweaking the clamp plates would ensure it can't move again. But it's a concern that it could move in the first place.

I believe I didn't have it tight enough. Either that or the hard mounted air cleaner wasn't allowing enough flex and was push/pulling on the intake every time the motor flexed. Prolly both. I should check the motor mounts.

 

[Dougal]

To get more boost you need a smaller turbine housing. Ask Alamo while you're there.

Stripping and reassembling turbo CHRA's is no problem. Just mark the alignment of the shaft, wheel and nut before you start. Reinstall in the same alignment. And beware of left hand threads!

 

[gerg]

I'm thinking you don't have a flex pipe on the down side of the exhaust. This could allow exhaust movement to translate repeated stress onto the center section. Braded exhaust is cheap and plentyful on eBay. Well worth the addition if you don't have one. Good to see you caught it jus before the Big Bang.
Cheers
g

 

[Awl_TEQ]

Gerg- There is a flex just out of view of the pictures above. A six inch stainless (inside and out) 2.5"Ø. Also the inlet on the compressor from the air filter has a 90° silicone elbow and a silicone coupler with a bulge type design to allow some flex. You can see in the fist pic of post #6 my inlet piping.

I walked over to Alamo a while ago and showed them the wear. The option we chose was a reman bearing section they had in stock and to have them swap the rest of the components over and check it all over for more wear. They called me back after checking the turbine to let me know it did indeed mill itself to a smaller diameter so they are also supplying a new turbine now. Cost was reasonable. $150 for the center section and hourly for the labor. Don't know the cost on the turbine yet. Bush/bearings may be replaced too depending on wear.

 

[gerg]

Ahh well what can you do. Maybe it was just abit loose and opened up after time? Glad you caught it.
g