LB7: Boost leak..? How to find

[McRat]

It will leave a groove in the hsg you can feel with your fingernail. Turbo failures under 500rwhp are actually fairly rare, but they do happen.

Really sounds like you need a Dmax guy to listen to it. Got a feeling it's not boost related if boost is AOK.

 

[John Noonan]

It will leave a groove in the hsg you can feel with your fingernail. Turbo failures under 500rwhp are actually fairly rare, but they do happen.

Really sounds like you need a Dmax guy to listen to it. Got a feeling it's not boost related if boost is AOK.

Pat,

The problem is I have not taken the housing off, who can send me a LB7 engine manual online so I can see what else is involved?

J

 

[Turbo Buick 6]

You don't need to take the housing off to see if its hit. If you spin it and gently push to the side while spinning you will hear it hit if its bad. Also check for thrust play....thrust is bad.

 

[John Noonan]

You don't need to take the housing off to see if its hit. If you spin it and gently push to the side while spinning you will hear it hit if its bad. Also check for thrust play....thrust is bad.

From the pictures I have posted it will require further removal of the part that bolts to the intake/compressor side of the turbo..that is why I want to see the manual for help..I have taken it apart about as far as I am comfortable without a manual.

I did mark the blades and housing with a marker to see if it hits however I need to drive it tonight or tomorrow and see if the blades remove the ink from the Sharpie pen.

John

 

[Turbo Buick 6]

From the pictures I have posted it will require further removal of the part that bolts to the intake/compressor side of the turbo..that is why I want to see the manual for help..I have taken it apart about as far as I am comfortable without a manual.

I did mark the blades and housing with a marker to see if it hits however I need to drive it tonight or tomorrow and see if the blades remove the ink from the Sharpie pen.

John

I could be wrong as I don't have a LB7 but I thought it was just a couple nuts or bolts to take the intake horn off.

 

[John Noonan]

I could be wrong as I don't have a LB7 but I thought it was just a couple nuts or bolts to take the intake horn off.

From what I see it is a wire harness cover, wires and other "stuff" on the motorcycle boards I can get PDF free online manuals, do they have that for Michelle's truck?

John

PS, thank you for trying..I am very happy to have some help.

J

 

[McRat]

Pat,

The problem is I have not taken the housing off, who can send me a LB7 engine manual online so I can see what else is involved?

J

Naw, I meant once the 45 deg intake horn is off (3 x 10mm bolts?) you can see the compressor wheel and inducer bore. That's where it hits normally. Radial play is about .030", thrust play is about .005 max.

If I had engine manuals, do you think I'd be on my 4th engine? :rofl:

PS - I'm a LLY/LBZ guy. In the bike world, it would be a Harley guy giving a Kawasaki guy help. General info AOK, but best advice would come from the LB7 owners.

 

[Turbo Buick 6]

I looked in the TSB section and the closest thing I could find was turbo removal, but they are showing the turbo coming out with the horn on it so that doesn't do much good.

 

[John Noonan]

Thanks guys, I don't want to pull the Turbo or as the dealer called it 10 times the "Blower" :hifinger:


John

 

[John Noonan]

So what is the part called that I have pointed to with the screwdriver blade?:coolspot:


John

 

[Turbo Buick 6]

So what is the part called that I have pointed to with the screwdriver blade?:coolspot:


John

EGR maybe I've never played with an LB7

 

[John Noonan]

EGR maybe I've never played with an LB7

I am wondering if the EGR Valve "Exhaust Gas Recirculation Valve" is causing it, Tomorrow I will drive the truck and see if the impellers hit the housing, if it does what information do I look up for a replacement turbo?

John

 

[Turbo Buick 6]

I am wondering if the EGR Valve "Exhaust Gas Recirculation Valve" is causing it, Tomorrow I will drive the truck and see if the impellers hit the housing, if it does what information do I look up for a replacement turbo?

John

Is it your turbo??? I don't know, but the only way to check it is to pull the horn and check play. It may not hit but have a lot of thrust. I just redid a turbo for my car that didn't hit but had .125" thrust and wouldnt make over 15 lbs of boost. Slapped a new thrust plate in and bam....I made the 22 lbs the wastegate was set at.

 

[John Noonan]

Is it your turbo??? I don't know, but the only way to check it is to pull the horn and check play. It may not hit but have a lot of thrust. I just redid a turbo for my car that didn't hit but had .125" thrust and wouldnt make over 15 lbs of boost. Slapped a new thrust plate in and bam....I made the 22 lbs the wastegate was set at.

Well I will hope to have a manual online or I guess I can take several pictures as I go to make sure were all of the hoses, separators, etc go so if it is the turbo I will make sure to put it back without any "extra" parts..

John

PS. Nobody LQQking has an LB7 manual online..?

J

 

[maxaholic]

Taking the horn off is a pita. But the only hard part is the bottom bolt. Trust me you cannot get any of the wiring screwed up, as they all have seperate connectors. Go slow take your time and you will get it off.

 

[John Noonan]

Max,

Thanks however can anyone tell me what the "thing" is I have in the pictures with the hose running to it?

Also what is a good turbo to install if this one is going out?

John

 

[McRat]

So what is the part called that I have pointed to with the screwdriver blade?:coolspot:


John

IIRC, that's EGR actuator you are pointing to. Most LB7's do not have EGR, only a few do. California trucks 03-04? were one.

You should block/disable EGR anyhow (for racing purposes only of course), to increase engine life and performance.

I do not remember all the specifics about LB7 EGR, perhaps do a search or start a new thread.

 

[McRat]

If you want to replace the charger, and you aren't planning on seriously racing the truck, I'd suggest a HTT turbo kit. It is gated like OEM, and will improve performance, yet not negatively affect towing. I made 674rwhp with one, and ran 11.77 ET, but you would want to keep it under 350rwhp with a stock trans. Should you decide to go Mustang hunting later, you would have a charger that could do the job.

 

[Trippin]

John,

Give me a call and I'll do my best to get you the "manual" info you need. It is not online anywhere, but I can print and fax or possibly convert individual pages to pdf for you.

Perhaps you can stop by on your way to El Mirage and I'll have a listen. We are not to far out of the way. Right next to the 5 freeway at Magic Mountain Parkway.

Guy

 

[John Noonan]

Well I took it apart down to the turbo (no pictures at this time) and determined from inspecting the side to side play on the impeller shaft and the lack of contact on the housing that the turbo is OK, that is the good news. The bad news is now I have a truck tore down and still have yet to find the pressure "leak sound"

Guy at So Cal Diesel was very very helpful in assisting me in ruling out what the sound could be from, I am now going to attempt to find a "EGR Blocker" shim to see if that si the problem as most other parts have been ruled out.

Anyone here have a shim/blocker they can send me (I am willing to pay for it) so I can see if that is the problem?

Also I spoke with Pat (again very helpful) and since the EGR assy has soot on it that may in fact be the problem and if it is then the shim/blocker would not remedy the problem if the vale assy is leaking both ways?

I am looking for a used LB7 EGR assy (I know one of you have one laying around if you have not already thrown them away) and the EGR Blocker/Shim..

I am going to also post a wanted as as well.

Thanks to everyone for trying to help us out with our stock towing truck


John