Exhaust Leak

[JHumphries]

I have an exhaust leak at the turbo where the downpipe attaches. Exhaust is bypassing the turbine and blowing out at this point. I believe this is causing my lack of power and poor mileage due to a lack of drive pressure for the turbo.

What kind of seal is used here? Is it possible I could replace that?

I would like to use this opportunity to put on an exhaust brake as well as the smaller turbine housing. I just have to convince my wife of all of this (she controls the money).

 

[PToombs]

If it's leaking where the pipe is attached you're not losing any drive pressure. It's leaking after the turbine. What do you have for an air filter? If it's exposed it may be plugged with soot from the leak.

 

[cerberusiam]

The seal from turbo to downpipe is a v-band clamp and, yes, they fail and the connection leaks.



Thats not going to affect power generation as its after the turbine. Power loss is almost always the result of fueling\air issues. Check\change air and fuel filters first then continue if the power loss is still evident.



Location will make a differnece this time of the year with blended winter mixes. If you are in a colder area thats one possibility.



I assume this is the turck you just got in your sig? How many miles and any history on it? Just been this route with 3 trucks and both ended up being lack of fuel and VE issues.

 

[JGrefenstette]

If you hadnt said "downpipe", what you described sounds exactly like the turbo/manifold gasket. Typically youll get a loose bolt and itll cause the gasket to blow out. depending on how bad its blown out it usually sounds just like a head/manifold gasket blown out. youll see the tell tale soot on surounding surfaces where ever its blow. If that IS the gasket your refering to... . YES it can be replaced and its a simple and inexpensive job. shouldnt have to remove oil lines from turbo, just take intake tube off and downpipe clamp off, remove the four mount bolts that go into manifold flange and lay the turbo back, clean both surfaces, slide new gasket in, and put it all back. If i was you id replace the bolts, or clean em real good with a wire brush and paint em up with anti-seize. Those bolts torque to 24ft. lbs, new bolts, or your old ones aint in to bad of shape, id make sure you got a accurate wrench and get em more like 30ft. lbs.



If this is not where your exhaust is leaking from, hahah ignore everthing i just said, sorry to waist your time. just go get you a new v-clamp and call it a day. Hope this helps.



-Jimmy

 

[JHumphries]

I assume this is the turck you just got in your sig? How many miles and any history on it? Just been this route with 3 trucks and both ended up being lack of fuel and VE issues.

This is the W350 in my signature. I bought it in Denver two years ago. I live across the water from Seattle.

The truck has ~180k on it. I don't know if anything has been done other than replacing the injection pump and deleting the muffler.



As far as the exhaust brake goes, I forgot I would have to change the exhaust springs. Can that be done without pulling the head? On a gasser, I can pressurize the chamber via the spark plug hole. Obviously that won't work here!

 

[cerberusiam]

As far as the exhaust brake goes, I forgot I would have to change the exhaust springs. Can that be done without pulling the head? On a gasser, I can pressurize the chamber via the spark plug hole. Obviously that won't work here!

Yeah, you can change the springs without pulling the head. The CTD is an interference engine, run the cylinder to top dead center and the valves will hit the piston when they are open if the timing is not correct. You could pressurize the cylinder thru the injector hole if needed but I don't think they will drop enough at TDC that you can't get them back.

 

[Greenleaf]

... . they won't go far when at TDC. Pretty easy to do, but need to plan the operation and have the tools ready and maybe a set of new collets. You will loose a few.



A modified spring compressor from Genoe's Garage will make it real, real easy. I had some serious problems with the compressor as sold. Too much stuff is in the road.

 

[JHumphries]

Okay, so after paying attention while driving, I have the following information concerning my lack of power:

The engine pulls strong under boost until ~1800 (rough guess, I have no tach)

Then it lacks power until it starts to de-fuel, then it really falls on its face.

When I punch it while cruising, I can hear the turbo spool up, but the power doesn't go anywhere for several (15 to 20) seconds and it very slowly builds up.

This is my second Dodge Diesel as evident by my sig. Although it has been a few years, and the truck was in much better condition, I don't remember the boost coming on so slowly, or falling off so soon. My old truck pulled all the way to redline and then very rapidly fell on its face instead of fading off.

 

[cerberusiam]

A smaller exhaust housing will help of course but maybe not as much as you think of there are other problems.



It sounds like you are just running out of fuel. Have you adjusted the star wheel, fuel pin, power screw, etc? Checked fuel pressure as the engine revs?



Same problem on my son's 93, started loosing the top end and no black smoke. Checked fuel pressure and it was 2 psi at idle and zero after that. Added fuel pump and made it much better then the IP started giving up.



Pyro will tell you a lot about fueling, gauges are invaluable when ti comes to tracking these problems.

 

[JHumphries]

I ordered a tach, pyro and boost gauge from Geno's yesterday. When those come in I will check the readings on those.

 

[PToombs]

I had another thought, or 2! Is the exhaust pipe mount still on the bell housing? If that is gone, or not used, the down pipe will break at the flange, causing the leak you describe.

2nd thought, you may have a boost leak, which won't let the aneroid open the fuel enough to let it run good. Check the small metal line which goes from the head to the AFC (aneroid) housing on the injection pump. These are known to break, and if it is, the truck will run like a dog.

 

[JHumphries]

It sounds like you are just running out of fuel. ... Checked fuel pressure as the engine revs?



Same problem on my son's 93, started loosing the top end and no black smoke. Checked fuel pressure and it was 2 psi at idle and zero after that. Added fuel pump and made it much better then the IP started giving up.

How do you go about checking the fuel pressure? Also what numbers am I looking for? I would assume the Banjo bolt where you bleed the system?

 

[cerberusiam]

How do you go about checking the fuel pressure? Also what numbers am I looking for? I would assume the Banjo bolt where you bleed the system?

Yeah, the bleeder between the filter and IP is a good place to tap a gauge.



Like Pete said, the aneroid boost reference line is a problem at times.

 

[JHumphries]

https://www.turbodieselregister.com...203516-fuel-delivery-problem.html#post1961251



This post mentions a tapped fitting from Geno's. The only thing I can find listed (1/8 inch) is for 24 valve engine and newer.

Are these parts useable on our 'old' engines?

If they are not, where can I get one?

Can I drill and tap my current banjo bolt?

 

[PToombs]

Yeah, that's the one. Don't pay attention to what it says, it fits. You'd think that after so many years they'd correct that huh? You don't want to try tapping yours, the head on the Geno's one is twice as thick as the stocker for strength. I tapped mine, won't go thru that again! That sucker is made of "super hardium"! I thought I was going to break the tap off in it. You can't go wrong for $7.



Just pull the bleeder banjo, and put that one in.

 

[RSchwarzli]

Anwers to two of your above questions:



Valve springs: Easy to change, no head removal, and it took me about 2 hours including valve lash adjustment.



Exhasut leak - I did have a leak at the downpipe to turbo. Did not effect the power, but I could hear it leaking. I did get a new V clamp and it did NOT fix it. Ended up having to drop the downpipe again and looked at the turbo and saw it was pitted. Ended up fixing it by using sanding the a bit off the flange with just the disk of a grinder so it was no longer pitted. Put a new clamp on and bingo!





Now carry on with the fueling questions...

 

[MLee]

Checker had a tool rental that was free and that is what I used for the valve spring replacement. It had a knob on top that wound down and was a close area tool and worked good on my 95. Just have a good strong magnet close by to pull the collets away and be careful to not loose one of those little buggers. I used the TDC on each cylinder and it worked good. The valves would only drop about 1/4" or so, i think.