Qwkswede's 1992 244 daily driver. Back to my rolling roots.

qwkswede said:

Whats the BLPT? pressure test?

Click to expand...

boost leak pressure test, sorry. that was the evoM creeping back to the surface

I did some leak checking last night.

• I was able to isolate the intercooler and also the pipes leading into and out of. I stuffed a spray can in the hose end near the throttle body and clamped it, and plugged the idle valve pipe. Then I used a 2" cap with a hole and inserted into the pipe near the turbo outlet. I pumped up to 10psi of regulated air from my compressor. The intercooler held 10psi no problem. No hissing sounds anywhere. Hoses blew up nice and firm, etc.
  PASS
• I reconnected the intake tube to the thottle. I inflated the tubing again at the turbo side intercooler pipe. I seem to get some small leakage through the cylinders and can hear it in the crankcase. But the pipes and clamps and even the intake manifold gaskets all seem silent. I think thats a pass.
  PASS
• I did not pressurize the turbocharger itself. And I'm a bit suspicious of that. I did a better job sealing and tightening the clamp at the compressor housing outlet when I replaced that connection. And there might have been some gain there. It does seem to be running slightly better. But I still hear a hissing while driving under boost that I can't hear while pressure testing, or revving idling. Maybe I'll work on plugs and pressure for that section tonight.
  MAYBE A LEAK

I tugged at the wastegate rod, and there is some preload on the gate. I remember putting about 1/2 of the hole diameter preload on it when I was working there. It seems the same still.

Thanks for the reminder. My wastegate bracket is on the loose side.

You could very well have a leak between the manifold and turbo. That would sound like an exhaust leak, however.

Also, did you ever run it with the downpipe disconnected from the rest of the exhaust?

IAC hoses good? Saw you plugged them on the first part. I split one of those a few months ago, car was way gutless, and that split only showed up around 12-15psi. WG sounds about right.

Fuel pressure good under heavy throttle/boost?

qwkswede said:

I did some leak checking last night.

• I was able to isolate the intercooler and also the pipes leading into and out of. I stuffed a spray can in the hose end near the throttle body and clamped it, and plugged the idle valve pipe. Then I used a 2" cap with a hole and inserted into the pipe near the turbo outlet. I pumped up to 10psi of regulated air from my compressor. The intercooler held 10psi no problem. No hissing sounds anywhere. Hoses blew up nice and firm, etc.
  PASS
• I reconnected the intake tube to the thottle. I inflated the tubing again at the turbo side intercooler pipe. I seem to get some small leakage through the cylinders and can hear it in the crankcase. But the pipes and clamps and even the intake manifold gaskets all seem silent. I think thats a pass.
  PASS
• I did not pressurize the turbocharger itself. And I'm a bit suspicious of that. I did a better job sealing and tightening the clamp at the compressor housing outlet when I replaced that connection. And there might have been some gain there. It does seem to be running slightly better. But I still hear a hissing while driving under boost that I can't hear while pressure testing, or revving idling. Maybe I'll work on plugs and pressure for that section tonight.
  MAYBE A LEAK

I tugged at the wastegate rod, and there is some preload on the gate. I remember putting about 1/2 of the hole diameter preload on it when I was working there. It seems the same still.

Click to expand...

the way I've done mine (and some folks will try to seal it up and let it sit over night, that's a bit excessive imo) is plug the exhaust to catch any potential cylinder blow through, put a cap on the compressor inlet and air the whole thing up to like 25psi or so and listen for leaks. you will hear some escaping into the breather system, but if you're looking for leaks I've found that soapy water in a spray bottle goes a long way to identifying leaks. the first time I did it on my 940 I discovered that:
1) idle air hose split on the backside down at the bottom, and only opened up in boost
2) the blow off valve was leaking around the seal (vband was loose and it needed some rtv encouragement)
3) the charcoal canister lines were shot

the idle air hose I would have eventually figured out, but the other two would have probably persisted

gsellstr said:

IAC hoses good? Saw you plugged them on the first part. I split one of those a few months ago, car was way gutless, and that split only showed up around 12-15psi. WG sounds about right.

Fuel pressure good under heavy throttle/boost?

Click to expand...

linuxman51 said:

the way I've done mine (and some folks will try to seal it up and let it sit over night, that's a bit excessive imo) is plug the exhaust to catch any potential cylinder blow through, put a cap on the compressor inlet and air the whole thing up to like 25psi or so and listen for leaks. you will hear some escaping into the breather system, but if you're looking for leaks I've found that soapy water in a spray bottle goes a long way to identifying leaks. the first time I did it on my 940 I discovered that:
1) idle air hose split on the backside down at the bottom, and only opened up in boost
2) the blow off valve was leaking around the seal (vband was loose and it needed some rtv encouragement)
3) the charcoal canister lines were shot

the idle air hose I would have eventually figured out, but the other two would have probably persisted

Click to expand...

I too had a split idle air hose. It's easy enough to spot it when the car idles well enough but the boost performance (and very rich mixture) suffers significantly and gets progressively worse.

qwkswede said:

I did not pressurize the turbocharger itself. And I'm a bit suspicious of that. I did a better job sealing and tightening the clamp at the compressor housing outlet when I replaced that connection. And there might have been some gain there. It does seem to be running slightly better. But I still hear a hissing while driving under boost that I can't hear while pressure testing, or revving idling. Maybe I'll work on plugs and pressure for that section tonight.
MAYBE A LEAK


I tugged at the wastegate rod, and there is some preload on the gate. I remember putting about 1/2 of the hole diameter preload on it when I was working there. It seems the same still.

Click to expand...

Careful with pressurizing the turbo's compressor side - there will always be some leakage past the internal piston ring seal (behind the compressor wheel). Unless you have a carbon-faced seal turbo but that's unlikely since they are normally only needed when used with a draw-through carb setup.

Still, might be valuable to pressurize the compressor housing to check for leaks at the backplate which should be easy to fix by tightening the clamp bolts. Or replacing the o-ring there, if this turbo has one.

To check wastegate preload, if you have a mityvac or other regulated air pressure source with a gauge, pump the wastegate actuator up to your peak boost pressure. Put a dial indicator on the end of the actuator rod right where it connects to the crank, lined up parallel to the actuator rod. You should see ~1mm (0.040") of actuator movement at your desired boost pressure. Just a rule of thumb but works well on most old-school internally wastegated setups.

If you see more than 1mm of movement, you should adjust the rodend inwards to increase preload on the actuator.

I think its cam timing. Verify that your crank pulley has not slipped. Then re-verify that your cam timing is right. Just my two cents

-sam

I never did run this car with an open downpipe. It has always had a cat and muffler in the exhaust.

The IAC hoses seemed OK at 10 psi when I had the entire intake system pressurized. Though I'm running slightly higher boost in real life. Seeing about 11-12 psi on the data logs. So maybe I'll give that another go tonight with higher pressure and a tailpipe plug and pressurizing at the compressor inlet. That should get the entire system full of air. I have never had to be quite so meticulous about small leaks, its not usually that critical.

But if I have my hands in there, I may as well replace hoses and clamps until it is sealed up tight.

I am still suspicious of this too. I'll get to it this weekend, just one thing at a time.

Though with LH2.4 running the engine, the idle IGNITION timing was about 10-12 degrees. And thats triggered from the rear of the crankshft. So if it has slipped, it is only a tiny bit. Ignition timing was at least in the ballpark.

Should I just knock the crank pulley and balancer loose to get a look at the timing belt cog pulley and the crank shaft key?

RoadRacer4Life said:

I think its cam timing. Verify that your crank pulley has not slipped. Then re-verify that your cam timing is right. Just my two cents
-sam

Click to expand...

^yeah may not be a bad idea, and it's easy enough to do.

qwkswede said:

Should I just knock the crank pulley and balancer loose to get a look at the timing belt cog pulley and the crank shaft key?

Click to expand...

I would pull the spark plugs and stick a long skinny screwdriver in the #1 spark plug hole. Gently turn the crank by hand till you get the screw driver all the way to the top. Rock it back and fourth till you find the middle and it should be obvious then check your mark on the crankshaft

-Sam

^^^ and check the mark on the crank gear as well, make sure it hasn't slipped on the crank, if the nub snapped off.

Don't forget that the outer section of the crank pulley can spin on the inner if the rubber damper part is worn out. This can cause wrong readings off of the crank pulley.

I'm not finding much wrong, but eliminating things is good I suppose.

I ran a more thorough pressure test last night with the tail pipe plugged, and applying pressure into the compressor inlet. I did find some small leaks around the IAC hoses. I tightened the clamps up and those stopped. The turbo was nicely sealed everywhere. I'm not sure how much those tiny leaks affect performance at 11-12psi that I'm running, but the car does feel a bit better. It might be placebo though.

On to the camshaft timing. I tried to locate TDC on the crankshaft as close as possible by touching the #1 piston through the spark plug hole. It seems my error to feel that is about + or - 1 crank degree. That seems close enough for this exercise. And with that accuracy the camshaft timing mark is lined up on the cover nub. Its close, definitely not off by a whole tooth, or even 5 degrees. The camshaft roll pin was in good shape too. I checked that when I did the cam swap. So that seems to be set up as advertised.

One other thing that came to mind is valve lash. When I installed the cam, I checked the lifter clearances and they were all at the tighter end of the recommended range. Could my lash be too tight and bleeding cylinder pressure? I'm stretching here and nothing was way out of range. But maybe just some valve seat wear allowing the valves to settle deeper into the pockets. I might have my friends the local Volvo shop go through the valve lash. They have the collection of shims needed to make small adjustments.

I will post up some datalogs I recorded last night too. You can clearly see the slow boost ramp up. So I'm starting to think I might start looking for things there again. Maybe this is just a big lazy Garrett on an automatic car with a tight converter.

Full boost at 3600 rpm. . .
This is a 2nd gear pull where boost has a time to build. If I open the throttle in 1st gear, I don't hit full boost until I'm into 2nd gear. Does this seem weak to anyone else?

<a href="https://picasaweb.google.com/lh/photo/1jI-P-zKqtU97rQ3I4X0h9MTjNZETYmyPJy0liipFm0?feat=embedwebsite"><img src="https://lh3.googleusercontent.com/-_rstLc7iPRc/VQG2hPWdutI/AAAAAAAAJqI/WUSsscbAzRw/s640/slowboost.png" height="369" width="640" /></a>

Is that with a .48 turbine housing?

I haven't been able to confirm that. Did these turbos ever come on Volvos with a .63? I assume it is a .48.

harribert said:

Is that with a .48 turbine housing?

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Anyone know their Volvo turbos from this angle?

There was a larger hotside on some of the 7's. Even so, I'm rocking a .63 on my 2871r and it's damn quick to spool.

Something definitely doesn't seem right.

How does it respond to the wastegate line being unhooked and rolling into it?

Valve clearances can have a little affect on things. How's the vacuum at idle? Stable?

gsellstr said:

There was a larger hotside on some of the 7's. Even so, I'm rocking a .63 on my 2871r and it's damn quick to spool.

Click to expand...

Apples and oranges...an old journal bearing T3 and a ball bearing GT28R are two totally different animals. Wheel dimensions and aero design are totally different. Bearing system is completely and fundamentally different. Turbine housing gas passage design is unrelated.

Think of A/R as a ratio (because it is one ). Area over radius. It's a measure of a housing's "nozzleness" - the smaller the value, the more nozzling action it performs - and a smaller nozzle will increase gas velocity, all else being equal.

You can have two turbines with identical A/R ratios but if the turbine wheels are different dimensionally or in aero design, or if the turbine housing cross sectional area at the beginning of the volute (scroll) is not equal, then you can't necessarily draw any correlation in performance. Without talking about two housings in the same family on the same turbine wheel it's pretty much futile to compare A/R.