Turbo Leak 671 TI

[John Dickson]

I need some assistance in determining where this turbo is leaking. Is it a seal or a gasket beneath the clamp? Does this look familar to any of you? What would be my next course of action for repair? Thanks for the help!
John

 

[Genesis]

That is a NASTY exhaust leak and has been going on a while (or is fairly extreme)

Its difficult to know exactly where it is coming from, but you need to find it pronto. With the carbon all over the intake side and relative lack of it on the pipe outbound my guess is that it is in the seal between the exhaust housing and the center section, but its hard to know for sure. The way I find these is to start with a dead cold engine, have someone start it and spray a soapy solution on all the joints - you'll see bubbles where the leak is. This has to be done on a COLD engine and immediately on start as that part of the exhaust gets hot FAST and will evaporate off the solution before it can bubble (putting cold water on hot cast iron is a great way to have it crack too.) If its the center section to exhaust housing that is leaking it is a near certainty that erosion has occurred on the mating pieces and the turbo needs reconditioning or replacement. You can use Sikaflex on the exhaust flange to pipe joint (I do UNLESS there is a high-temp gasket in there) but I wouldn't attempt it on the hotside center-section to housing joint as any that gets mobile in there could cause the turbo to grenade under load.

The potentially-very-bad news you may have a MAJOR problem in your airbox. Pull those inspection covers and have a look. Some gunk is not serious but if it is up to the level of the ports on the liners (or worse is partially obstructing them) you've got big trouble and there's a decent chance that significant internal damage in the form of excessive wear has already occurred. There are no safe ways to clean the airbox short of a teardown; the "boxed-in" situation arises when you have gunk in the ports or above their level and yet the engine is running ok - you're damned if you try to clean them and liberate some of it or get it in the cylinders, and you could be damned if you don't and it breaks free and goes in there.

The blanket involved needs replacement too, while its not oil (immediate fire risk) the soot does fairly serious damage to the insulation quality of the blanket. Turbo blankets are relatively cheap (~100 or so); change it once you find and fix the leak.

Get some pictures of the airboxes and liner ports up here.

 

[Banshee36]

happened to a buddys boat. try a new clamp, but check the flanges, they may be eaten up.
JW

 

[Angela]

Karl, where do you find turbo blankets for $100 or so? I'd like to have four new ones at prices like that!

 

[MikeP]

The circular clamps used on these turbo installations are a poor way to connect things together and, as noted, should be checked. I have rebuilt turbo's in the past and it's not really difficult though considerable care needs to be taken. Turbo rebuild kits used to be readily available but I haven't done one in years so I don't know if they still are. But they should be for these common AirResearch units if you are interested in doing it yourself.

Seems like a lot of soot from the engine to me also but, of course, if it's been deposited over a long period of time, it may not be an issue...

Re those turbo blankets - Count me in on those $100/set.

Two years ago I priced them from some company recommended here (can't remember what company at the moment) and got a quote of something like $1500. So I'm definitely interested in the $100 buck versions!

 

[Bugsy]

Karl, where do you find turbo blankets for $100 or so? I'd like to have four new ones at prices like that!

Contact Joaquim Cartaya 305-266-9897

A few years ago now but for 692's I got turbo blanket G5; turbo sweep G8 and special strip G8 all for $170.00

He's at 8221 SW 13th Terrace
Miami

I was looking for a "deal" on replacement Walker filters in FLL (didn't get one) but they knew Joaquim.

 

[Bugsy]

Add...that was one side, of course.

 

[SKYCHENEY]

You can clean the blankets. Spray them with Soot-Out and then rinse them off and let dry. That is the least of the worries here. You first have to get that leak fixed. Since it appears not to be just be an outlet leak that you could seal with Silkolene and a new clamp, the turbo will probably have to come off. As long as you have it off, take to a turbo shop and have it rebuilt. The last one of those AR turbos that I took in was about $400 for the rebuild.

 

[John Dickson]

Thanks for the comments guys... took the top of the intercooler off, its pretty caked up. Will pull the airbox covers and take some pics too. I am winter stored in water inside (in Michigan) so I cannot start engines till spring when the doors open. I would like to have the turbo repaired this winter if I need to - it still spins fine - I will also check the whole exhaust side for leaks too as I have quite an "exhaust spray pattern on the port fuel tank 2 x 3 ft pattern (out board of the turbo).

The boat and likely the turbo too are twenty three years young. Would you recommend rebuilding the turbo anyway at this point? Whats the process for removing the bolts from the flange? They look pretty corroded.

Will also tear down the intercooler for cleaning. Guess the airbox inspection will tell the bottom line :-(

 

[Genesis]

Take the turbo off and look at the exhaust flange on your collector and the turbo.

It looked to me like the leak wasn't at the flange as the V-clamp there wasn't covered in it - which means odds are the leak is at the center-housing to exhaust housing joint. That's a crappy deal as those are nearly impossible to successfully reseal in the field - I'd either swap the turbo for a rebuilt or take it to a turbo shop and have them do it. Odds are there's erosion damage to the sealing surfaces and the tolerances involved are tight. You can rebuild these yourself but IMHO its not worth it. Using Sikaflex there can be done but its not safe due to the risk of the material getting loose in the exhaust side and impacting the wheel with catastrophic results.

If the leak is at the flange between the collector and turbo you can clean that up and seal with Sikaflex. It smokes like hell the first time it gets hot - it basically "cooks" into a seal. Works really well. But like I said, I doubt the problem is there due to the lack of soot on the clamp at the joint.

If the intercooler is caked with soot it has to be cleaned (that's not difficult; brake cleaner sprayed on the air side - out of the boat please! - will remove it easily); the bigger problem is potentially in the airbox. Let's see what 'ya got - if you're lucky the deposits aren't serious and you can just leave that alone, clean the intercooler and either have the turbo rebuilt or replace it with a rebuilt unit.

If there is no gasket on the outlet from the turbo to the collector use Sikaflex when you reassemble, and ALWAYS use new "V" clamps. NEVER NEVER reuse those on the hot side - if you have one break while the boat is running you're done as the entire engine room will be filled with soot immediately and there is a significant risk of an engine-room fire; the exhaust gas can exceed 1000F.

 

[SKYCHENEY]

John,
Take your turbo to Michigan Turbo in Grand Rapids. They will either rebuild or exchange. Most likely you will just get hit with their minimum charge which is $400, I think.

http://www.michiganturbo.com/

 

[John Dickson]

Genesis - Thanks for the comments, should be to the boat this coming weekend for the airbox inspection and pics. Will post. Is the collector the pipe from the manifold to the turbo housing? Is there a procedure for the flange bolts? Looks like they've been on there for awhile.

Sky - Thanks for the turbo referral, I'll give em a call and ship it as I am in Shelby Twp. north of Detroit.

John

 

[Genesis]

No, the collector is the exhaust pipe coming out of the turbo and going to the showerhead and then out of the boat.

For the flange bolts my recommendation is to use a shitload of PB Blaster and BE PATIENT. If you try to force them you WILL break the studs. The steel anneals over time with the extreme temperature changes and the nuts tend to seize on the stud; if you crank on it you'll snap 'em. Spray with PB, wait an hour, try to loosen with moderate force, if no joy spray again, wait another hour, etc. You may take a couple of DAYS to get them off this way, but they will come without breaking.

The bad news is that if you break one or more studs you're in for fun. The only solution then is to drill them out and the flange is prone to break as the hot pipe is cast iron and that stuff is quite brittle. If you break the flange you're buying a new hotpipe, and while they're not terribly expensive they can be VERY hard to find. If you find yourself having to drill the studs center-punch the stud and drill a pilot hole 1/2" deep or so with a very small carbide bit so the drill doesn't jump on you. I have about a 75/25 record on being able to drill those out if necessary without breaking the flange - if you do break a stud and manage to drill it successfully consider removing the other studs (PB Blaster will allow you remove them if they're intact, again, taking your time), drill the threads (carefully - again, if the drill grabs you can snap the cast iron) and then use the turbo bolt and nut sets that Caterpillar has - they make a special high-temperature bolt set for turbos that is IMHO a much better solution and avoids this nonsense in the future. I've never broken a stud taking my time, but I've fixed a half-dozen of these for friends over the years who have snapped 'em by being impatient. Oh, and if you do snap a stud it is GUARANTEED to break flush with the flange or worse - just slightly proud (much harder to drill!) but not high enough to get a tool on it - you know Murphy, right?

The nuts are castellated and should not be reused in any event as they will not properly lock a second time. For obvious reasons (1000F temperatures!) you can't use Nylocks or similar. Some guys use high-temp anti-seize on the studs on re-install; I find it doesn't really make much difference down the road if you do or don't but it probably doesn't hurt - either way you're going to take your time and use lots of PB on subsequent removal.

Once you get the studs out the flange surface should be checked to make sure its true and not eroded; minor imperfections can be cleaned up with a flat sander; stuff a rag in the pipe so dust doesn't go back into the engine. Make real sure you're not sanding the flange out of true!

When you reinstall the new turbo check the drain pipe on the bottom for the oil and make sure it is not obstructed in any way (it must drain freely to work properly), and use a new gasket on that connection. If the oil feed line hasn't been changed in five years or more, change it now and use the proper hose for it. On the first start make very certain the turbo has oil before you allow the engine to fire as the bearing HAS TO be flooded before the turbo is allowed to spin. Hold the STOP and crank until oil pressure is achieved so as to insure that the bearing has oil before the engine is started for the first time.

That's pretty much it - its not a difficult job, just one that requires patience with the flange bolts to avoid making the job take about 5x as long

 

[MikeP]

When dealing with recalcitrant fittings, TIGHTEN them first rather than trying to loosen them. This will usually break the bond and allow them to be removed with little drama. It only requires the slightest bit of fastener tightening movement to break the bond - if it moved at all, then that's sufficient. If fittings are badly corroded, you may need to tighten a fraction/loosen a turn or even less, tighten it again, loosen to a bit beyond where it was before, and repeat this process until the fitting is removed. It takes far less torque to tighten a fitting than to loosen it if there is any corrosion/whatever and all you need to do is break that bond.

Personally, I have had very mixed luck with any of the penetrants as far as releasing badly seized fittings but they do work fine IF the penetrant can actually penetrate through the corrosion. I know a lot of folks swear buy various brands like PB, Kroil, etc but I haven't found any of them to work any better (or worse) than MMO or WD 40 and I have never seen a boat without WD40 on board!

 

[MikeP]

Sorry - should have added this to the previous post...

One of the best ways to handle seized nuts is with a nut splitter. If access permits, it's the easiest and fastest way to deal with them. Takes maybe a minute to break the old nut without damaging the threads at all. Afterwards, wire brush the threads and install a new nut. Obviously, if you are dealing with bolts, this won't work.

We worked on many old engines and, in many cases, we'd use a nut splitter without even trying to loosen some of the nuts. You could tell by looking at the fittings that it wasn't worth the trouble to try and remove the old ones and we wanted new fittings anyway...

 

[John Dickson]

Ok, got some pics of my airboxes
due to limitations I will post in several posts
here are the first three

 

[John Dickson]

Here are the last three cylinders, actually 4, 5, 6 going to forward from aft

 

[John Dickson]

Ok, check out number 5 in the previous post, looks like it could be missing a ring. Here also is the intercooler and turbo vanes

 

[Genesis]

Airboxes don't look bad. The parts of the skirts I can see look ok, and there's no carbon obstructing the ports. The oil film in there is normal. Believe me, I've seen some NASTY airboxes in the past. The way to check the rings is to roll the engine by hand until you can see them in each individual port, then press on them with something wood like a skewer stick. They should have a "spring" to them - if they don't they're broken somewhere in their circumference.

The intercooler is badly fouled as is the turbo compressor wheel. Since you're going to R&R the turbo anyway, that's no big deal. The Intercooler should be removed and the air side cleaned - brake cleaner (several cans) will do the job quite well. Its a hella-messy job - don't even think about trying to do it in the boat.

Looks like you dodged serious damage and have some cleanup work to do - I'd clean the intercooler, replace the turbo, and run the boat.

 

[captddis]

Take some pics of the rings, It looks like a broken and missing ring in the pic. The airboxes are nasty. The soot has mixed with the oil in the airbox and made the black mung.. I would consider kits at this point. If you do kits, remove the blower and clean the airboxes until a white rag passes through and comes out white. Check the exhaust side turbine for damage from the ring. Good luck.