Paging the internal combustion diagnosticians

Saab 9-5 [2.3-litre petrol] low-pressure turbo. 110,000 miles, replacement
turbo at 70,000. It has started blowing off blue-ish smoke from the exhaust
when changing up 2>3, 3>4 and 3>5. It's not worse when giving it welly, and
happens on even the gentlest of changes. No differnece if the engine is
cold or hot. As the revs drop for the change, there's a small billow of
smoke. It doesn't do it if you by-pass 3rd gear, and it doesn't do when
changing down, as the revs increase. Any ideas of its cause?

 

Rings.

 

You've got his number?

 

are you using thinner oil than is recommended for this engine?

 

Rings more likely. IMHO

--
Catman MIB#14 SKoGA#6 TEAR#4 BOTAFOF#38 Apostle#21 COSOC#3
Tyger, Tyger Burning Bright (Remove rust to reply)
Alfa 116 Giulietta 3.0l (Really) Sprint 1.7 75 TS 156 TS S2 166 V6 2.5
Suzuki Bandit 600
Triumph Sprint ST 1050: It's blue, see.
www.cuore-sportivo.co.uk

 

Nah, it'd be guides if it happened on over-run, as the manifold is under
a higher vacuum, the oil is sucked [1] through the guides.

[1] for the pedants, I know it isn't really sucked in.

 

Or both. I wonder if there is any suggestion of 'pinking' under load.
This can be caused by valve guide/seal wear. Had it on my old Manta
GT/J. On lifting the head to have them done, however, it was found that
there was also heavy bore wear. It lasted a few thousand miles more with
no pinking but ever increasing smokiness.
--

+-------------------------------------------------------------+
| Pete Fisher at Home: |
| Voxan Roadster Gilera Nordwest Yamaha WR250Z |
| Gilera GFR Moto Morini 2C/375 |
+-------------------------------------------------------------+

 

Classic sign of worn valve guides or (and this is the good news) simply
knackered valve stem oil seals. If it's only seals you might be able to
do them in-situ, depending on access.
--
Dave
GS850x2 XS650 SE6a

Teach a man to fish and he and his pikey mates will have the
river cleaned out in a day.

 

How do you remove the seals without removing the valve springs?



--
Beav

VN 750
Zed 1000
OMF# 19

 

Piston to tdc, lock crank, fill with compressed air, depress spring,
remove collets, remove spring, replace seal and reassemble.

HTH


DD

 

TY. That was what I was always taught.

--
Catman MIB#14 SKoGA#6 TEAR#4 BOTAFOF#38 Apostle#21 COSOC#3
Tyger, Tyger Burning Bright (Remove rust to reply)
Alfa 116 Giulietta 3.0l (Really) Sprint 1.7 75 TS 156 TS S2 166 V6 2.5
Suzuki Bandit 600
Triumph Sprint ST 1050: It's blue, see.
www.cuore-sportivo.co.uk

 

Yup, me too

It'd be worth a compression test. Run a dry test first, and then squirt
a little oil into the cylinders and run it again. If the pressures
increase significantly, then suspect worn rings.

 

How do you accomplish a reverse of "bash on spring cap with socket"?

Personally, I think if you've gone to the trouble of removing the cam, then
a few more bolts to remove the head wouldn't be a bad thing. No hammers
needed and no need to hope Heath Robinson can help.



--
Beav

VN 750
Zed 1000
OMF# 19

 

Not in the least. Probably because it's a load of old bollocks. Filling the
cylinder with oil may be a better idea, but they're all daft idea's anyway.
A valve stem and seal job should be accompanid by a bore check and a
possible ring job, so the head should be off.


--
Beav

VN 750
Zed 1000
OMF# 19

 

Why disturb the head when you don't need to? No point in it - just a
quick repair and back on the road (maybe to the auction house or
dealer).
--
Dave
GS850x2 XS650 SE6a

Teach a man to fish and he and his pikey mates will have the
river cleaned out in a day.

 

There's plenty of times it's nothing more than just the seals.
--
Dave
GS850x2 XS650 SE6a

Teach a man to fish and he and his pikey mates will have the
river cleaned out in a day.

 

Indeed there is, but a high mileage bike isn't likely to be one of them.

It's a real **** when you do one job only to find you've got to start all
over again too.


--
Beav

VN 750
Zed 1000
OMF# 19

 

So how do you replace the valve springs again?


--
Beav

VN 750
Zed 1000
OMF# 19

 

Oh come on, there should be at least one "fnaar" in there.

 

With a doofer. I can tell you've never done this.
--
Dave
GS850x2 XS650 SE6a

Teach a man to fish and he and his pikey mates will have the
river cleaned out in a day.