Volvo 740 Turbo with "shaved" housing with a hole in it ?

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circuit slave

Hi everyone I started another thread in which I lost turbo pressure.
Well, it turns out that the 2" aluminum foil-type hose which goes from
under the airbox to the back down by the exhaust I assume was very old
and had holes. I replaced it and have boost but the problem I noticed
is the Turbo housing was shaved with some type of tool and a hole was
made?

To relieve pressure? Why would they have done that? I mean maybe
that's why I dont' have full boost turbo power and maybe why the guage
is somewhere around 10 o'clock when I'm not even moving?

I was going to plug it with JB Weld, but now I'm afraid. I mean I
don't want to blow up the thing. Do you think the previous owner had a
pressure problem so they did the mickey mouse job and relieved the
pressure by shaving the metal housing and alowing a hole for pressure
relief?


Any suggestions are appreciated. Thanks !
 
circuit said:
Hi everyone I started another thread in which I lost turbo pressure.
Well, it turns out that the 2" aluminum foil-type hose which goes from
under the airbox to the back down by the exhaust I assume was very old
and had holes. I replaced it and have boost but the problem I noticed
is the Turbo housing was shaved with some type of tool and a hole was
made?
Click to expand...

Can you get a picture? I can't think of any hole that should be in the
turbo housing, where exactly is it?
To relieve pressure? Why would they have done that? I mean maybe
that's why I dont' have full boost turbo power and maybe why the guage
is somewhere around 10 o'clock when I'm not even moving?
Click to expand...

As I said earlier, the guage is supposed to sit around 10 o'clock when
the car is not running. Black is vacuum, yellow is boost, the place
where they meet is atmospheric pressure, if the guage is not pointed
there when the engine is off then it's broken.

I was going to plug it with JB Weld, but now I'm afraid. I mean I
don't want to blow up the thing. Do you think the previous owner had a
pressure problem so they did the mickey mouse job and relieved the
pressure by shaving the metal housing and alowing a hole for pressure
relief?
Click to expand...

Did something wear on it and make a hole? Or is it on the exhaust side?
Perhaps the car ran lean and overheated the exhaust housing, melting a
hole in it.
 
No, James. The ACTUAL TURBO CHARGER housing was shaved down (grind the
metal down on one the left side) and a whole was created. I believe
its a Garrett (it's got a metal little label that's all greasy)

So maybe that's why I've had the leak all this time? But the hose I
replaced helped. I mean I accelerate and such.

Now by "exhaust side you mean after the intercooler and AMM, right?
Because I mean the ACTUAL TURBOCHARGER housing, if that makes sense.
 
I took some pictures of it. All it looks like is picture the "donut
housing" of the turbo charger and shaved down one side. It looks
really weird. I can email you the pics.
 
I think you will find that James may be querying whether your car was fitted
with EGR (the hole being on the manifold just above the turbo mount, should
have a metal tube going to the EGR valve) that caused the PO a problem so he
removed it.

All the best, Peter.

700/900/90 Register Keeper,
Volvo Owners Club (UK).
 
circuit said:
No, James. The ACTUAL TURBO CHARGER housing was shaved down (grind the
metal down on one the left side) and a whole was created. I believe
its a Garrett (it's got a metal little label that's all greasy)

So maybe that's why I've had the leak all this time? But the hose I
replaced helped. I mean I accelerate and such.

Now by "exhaust side you mean after the intercooler and AMM, right?
Because I mean the ACTUAL TURBOCHARGER housing, if that makes sense.
Click to expand...


Yikes, that's definitely a problem. By exhaust side, I mean the exhaust
turbine housing, as opposed to the compressor housing. The former is
cast iron and will be all rusty, the latter is aluminum and facing the
front of the car.

Are your engine mounts completely shot? Only thing I can think of is
maybe the turbo has been rubbing against something but I've never seen
that happen.


You can see a good picture here of a T3
http://www.servia.fi/~professi/AdvHTML_Upload/files/timon_tiomi_012.jpg


As well as another showing the inside, with the compressor and turbine
blade assemblies joined to the shaft running through the center
cartridge. The wastegate actuator is also visible.

http://www.lanciadelta.org/images/garrett.jpg
 
Peter said:
I think you will find that James may be querying whether your car was fitted
with EGR (the hole being on the manifold just above the turbo mount, should
have a metal tube going to the EGR valve) that caused the PO a problem so he
removed it.
Click to expand...


I've never encountered a Volvo with EGR, I don't believe they used it in
the US market. None of the manifolds I've ever seen have had any unused
holes in them. The tube I'm referring to is a corrugated aluminum hose
which connects a sheath over the exhaust manifold to the airbox, the
purpose being to draw heated air into the intake when the engine is cold
to accelerate warmup. There's a wax thermostat in the airbox which
operates a flap valve to close off this tube, if it gets stuck open and
hot air is drawn in once the engine has already warmed up then the air
mass meter can be damaged.
 
Yeah, I've opened the airbox when I changed the air filter. I saw that
flap that flaps open/closed. I accidentally "touched it" (because the
car is so old and never maintained, touching can damage :P) and part of
the flap crumbled. Where is the thermostat in there?


Looking at that pic---I don't know which side is which, hehe. But Okay,
well, interested, here are the pics !

http://i29.photobucket.com/albums/c300/circuitslave/56bfbefc.jpg

http://i29.photobucket.com/albums/c300/circuitslave/17edccea.jpg

http://i29.photobucket.com/albums/c300/circuitslave/KIF_0569.jpg
 
I see, well, the whole is on the compressor side, as you can see.
 
circuit said:
I see, well, the whole is on the compressor side, as you can see.
Click to expand...


Crap! That's sure the first time I've ever seen THAT happen! That's a
Mitsubishi turbo, same one I have in my '87. It's pretty clear that the
aluminum hose has ground a hole in the compressor housing from years of
rubbing, it's no wonder you're losing boost and getting funny sounds.
Try patching it up with some JB Weld, just don't get chunks inside the
turbo. A better solution, if you're able to do this, is to remove the
housing and take it to a welding shop and have them TIG the hole closed
but removing it with the turbo on the car is a real pain, there's not
much wrench access.
 
James, I think it was intentional--there's no way that could have
happened with rubbing.

I'm looking into it---FYI, the Volvo was a single owner--my uncle and
it's been like that for years. And his son (who let's just say is had a
somewhat drifty life) told him "Dad, I know a guy who fix turbo
charger's for like $75."

It's steel, no way that could have happened, IMHO.
 
Would JB Weld hold up to the heat generated by a Turbo at full boil?

I think not.
 
The hole was hidden by that aluminium pre heat hose. Looking at the
car --everything looks fine no obvious signs. I don't know, not to
jump to conclusions, but it just looks devious.
 
Without pulling the turbo, what else would work? Muffler bandage
maybe?

I replaced the pre heat house, as you can see in the pic, but the hole
was blocked by the old house, that's why it makes me suspicous.
 
circuit said:
James, I think it was intentional--there's no way that could have
happened with rubbing.

I'm looking into it---FYI, the Volvo was a single owner--my uncle and
it's been like that for years. And his son (who let's just say is had a
somewhat drifty life) told him "Dad, I know a guy who fix turbo
charger's for like $75."

It's steel, no way that could have happened, IMHO.
Click to expand...


It's aluminum, and it's definitely a hole rubbed in it, look at how it
lines up there, I'd bet money that's what happened. I have the exact
same car with the exact same turbo, there's no hole there and absolutely
no reason to have one. Aluminum is soft, my alternator has a gouge
rubbed in it from the plastic cable sheath rubbing on it over the years,
even steel will wear like that if a bit of oily road grit gets in there,
it's the same way you can polish scratches out of metal or glass with a
cotton cloth and some abrasive powder.
 
Would JB Weld hold up to the heat generated by a Turbo at full boil?

I think not.
Click to expand...


Not on the exhaust side certainly, but on the intake it might, it'd be
iffy though. Best solution aside from replacing the housing would be to
weld it.
 
I'm sorry, my bad. Yeah, aluminum. Well, it's on the intake side, so
couldn't JB weld work?

I talked to my other uncle who says, well, it's not like it's on the
exhaust side, so it might work.

I'd get it welded but--well, It's my daily driver and if it's from
wear, it's been like that for years, so a month or two isn't going to
make a difference I think.
 
FYI for clarification the turbo lacked power since about 2002. I
thought I lost power, but I never really had it to begin with, hehe.
 
circuit said:
I'm sorry, my bad. Yeah, aluminum. Well, it's on the intake side, so
couldn't JB weld work?

I talked to my other uncle who says, well, it's not like it's on the
exhaust side, so it might work.

I'd get it welded but--well, It's my daily driver and if it's from
wear, it's been like that for years, so a month or two isn't going to
make a difference I think.
Click to expand...


Well patch it with something, with a boost leak like that you're burning
a lot of extra fuel since it's metering the air before the leak and
fueling accordingly. You'll burn up your catalytic converter driving it
like it is.
 
Would JB Weld hold up to the heat generated by a Turbo at full boil?

I think not.
Click to expand...
JB Weld is spec'd for up to 500F. http://jbweld.net/products/jbweld.php I
doubt the compressor side gets much above 300F and the pressure is
insignificant.

The way I'd do it is to clean the surface with brake cleaner and JB Weld a
piece of metal over it - I'm concerned the JB Weld might crack if you try to
bridge the void with it. A coin that is slightly larger than the hole will
conform to the curved surface reasonably well. JB Kwik or a small bead of
the putty equivalent will hold the plug in place without the need to come up
with a fancy clamp; you'll just need some patience to hold it until it
sets - about five minutes. Then mix some JB Weld to apply around and over
the plug. Epoxies harden best when hot, so the car should be drivable within
an hour or so if you don't wind it up too much.

BTW, I would expect noticably better performance and fuel economy from
repairing the hole. It is having the same effect that any other hole in the
boosted side of the intake has: it draws more air through the AMM than the
engine is really using, which convinces the ECU to inject fuel to match. I
don't know how it got this way, but you'll be a lot happier when it is
fixed.

Mike
 
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