Alfa 156 jts Oil problem...

[GabAlfa]

Hi all,
Hope someone can help or maybe I can help someone. I have be an Alfa driver pretty much all my life. I have recently acquired a 2004, 156 jts (74,000 kms) and discovered the following;
Down on power, burning oil, burning fuel excessively as proven by the spark plugs, black carbon build up in base, core and arch (not oily).
carried out compression test - 150 psi (dry) 250psi (wet). I think that is good compression, please let me know otherwise.
took cam cover off and hold and behold discovered Cam lobes worn - replaced them with 147 TS, had a spare set lying around...yes, they are the same, and they work !. just need to have a thread machined on the end of the exhaust cam shaft for the HP fuel pump spindle.
Also replaced the variator and variator half bearings (intake cam) and half bearing for exhaust cam, they were scored.
Also replaced all 16 valve lifters/tapets.
Re-assembled. Put fresh Castrol Edge 10-60W oil and bang ! Power is up, fuel consumption is better but still blowing out smoke, doesn't seem blue, more like black.
Oil consumption seem excessive to me (100 ml to 100km's) this is city driving, short trips. Noticed the temperature does not rise quickly, possible thermostat issue (open all the time). Can take about 20 minute to reach 70-80 degrees.  I live in Queensland so no winter here...
Checked spark plugs and burning right to me, slight black grey on base but grey white in core and arches (NGKR6EK twin arch spark plug).
Also discovered that the Cat Converter core (honey comb material) has been damaged as I discovered bits in the muffler (assuming due to excessive fuel burning and heat from inadequate intake and exhaust aperture). Have not experienced the Motor control system failure alert and checked the codes with the ECU Multiscan and only error code is P0443 - Evaporative Control Valve which I replaced (had one lying around) and still get the error. This one beats me, not sure but I'm not too worried about it.
So... my mystery is where is the oil going ? If it was the valve stem seals leaking surely I would see oil build up on the spark plugs. Compression is good as I can see. Is it the Cat converter causing issues ? Anyone have any suggestions or silver bullet !!
Alfa forever !! "Your not a true petrol head until own an Alfa"

[poohbah]

Sorry to ask the obvious, but you didn't mention it in your post - I presume the first thing you did was check the ground and underside to make sure its not just leaking somewhere?

My '99 V6 has only done just over 100k, and I had it serviced 6 weeks ago (including cambelt change) - all was good, til it suddenly started dropping oil. Lucky I noticed pretty quickly, turned out to be coming from dodgy oil switch.

I should add, I had a Fiat 85s Regata (facelift 131) in the early 90s that drank oil like Russian sailor on shore leave, had no obvious leaks, blew no blue smoke or showed any obvious signs of where it was going until the crank seized ...

[bazzbazz]

A/ Your Thermostat is stuck open and needs replacing. This causes the car to run rich all the time which eventually causes poisoning of the cats and their eventual destruction.

B/ Your Cats have been poisoned and have started to disintegrate, they NEED to be replaced. See above.

C/ Compression should be around 200 dry (but this is dependant on the kit you use and other factors). The standard oil rings in the JTS are particularly known for wearing & cracking, which would explain your oil usage and the sooty plugs.

Just out of curiosity is plug #1 more fouled/damper than the rest.

Fix the Thermostat, fix the Cats, then see how you're traveling.

Baz

[GabAlfa]

Thanks BazzBazz for the response and advise. Bit surprised that compression is that high on a dry test. I should add that it was a cold engine the dry test. The spark plugs look and feel all the same across cylinders. Compression test the same across all cylinders, give or take 2-3 psi. I think your right the Thermo needs replacing and the cat as well. Just not sure if that will reduce the oil consumption..

Thanks Poobah for your response. No sign of oil leaks on floor or base of engine. It's clean. Bit concerned about your old fiat.
I also checked the oil breather and not blocked, just a bit of oil as expected and valve spring all good.

Ciao

[poohbah]

At least that rules one thing out then. Hopefully you find the root cause soon.

As for the Fiat, it probably would have run forever except that neither me nor the missus (it was her daily driver) were particularly "disciplined" when it came to vehicle maintenance - being in our early 20s at the time and having no experience at all of maintaining what was then a comparatively exotic creature (at least relative to our more humdrum previous conveyances!)

Pity, because it was generally a great little car (except for the occasional electrical gremlin) and was head and shoulders above anything else in its class in terms of style, comfort, and performance for the price.

[bazzbazz]

Just not sure if that will reduce the oil consumption..

Oh it may not, but until you fix those first, your just wasting your time trying to solve it. Bit like trying to paint a horse pink inside a burning stable being over run by hungry polar bears . . . its a bit hard to try and work out which is causing who to shit themselves all over the floor.

Baz