JTS valve failure - Alfa Romeo Forum
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(Post Link) post #1 of 16 Old 17-07-14 Thread Starter
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JTS valve failure

Just for your information, a tragedy I just met. My 156 2.0JTS started to run with 3 cylinders after a highway trip and gave several fault messages, like cylinder 3 misfire. The new ignition coil and plugs did not help and further investigation showed there were no compression in cylinder 3. After one and half day of dismantling the root cause was found and just like expected, a burn exhaust valve in cylinder 3. Not a nice job at all, when there is no space behind the engine and the wire sets are what they are without "service plugs" to help dismantling. Anyway, now the head is ready to be taken in machine tooling.
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156 2.0 JTS and EX 159 sw 2.4JTDM Q-tronic
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Just a scratch.


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(Post Link) post #3 of 16 Old 24-07-14 Thread Starter
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I get the cylinder head back from workshop tomorrow. One new valve and others machinered, quides ok. Does anybody know if the tightening torque with new head bolts is really 20Nm/40Nm/90deg/90deg/90deg ?
Sounds a lot for me.
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From the workshop manual: engine torques, so 20Nm/20Nm/90°/90°/90° (I think).
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Just out of interest what mile/km has the car done and what fuel grade 95 98 octane.
Did you have any issues with the injectors?
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(Post Link) post #6 of 16 Old 29-07-14 Thread Starter
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jts

hi,
It's 147tkm driven, approx. 90 miles. always 98 octane used.
There have been no issues with injectors, and in workshop they thought that the Bosch injectors have been reliable. Yesterday I got the head back on block, but there are a lot of wires and pipes waiting for putting on their places still. I was close to nervous breakdown when installing the plastic intake box when there is really no space enough... On the other hand putting it under hood together with the head will make installing all wires even more difficult.

I'm rather sure accumulation of carbon in intake (direct injection) and in combustion chamber (oil consumption) are the root causes to the failure. unfortunately I don't have any idea what to do for these features.

Some pictures before and after. Everything cleaned, one new valve, others machined, guides were OK.
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Last edited by vesku; 29-07-14 at 06:20.
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As a matter of my personal interest, when was the car made or first registered, preferably the date of manufacture as reported by eper?

The reason I ask is that the GTV never got the early euro3 version of the JTS engine only the later euro4 version. I understand it was only the earlier engines that had the inlet coking up problem. I would like to think that my engine is not likely to suffer from this.
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(Post Link) post #8 of 16 Old 29-07-14 Thread Starter
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the exact manufacturing date I don't know now, but put between plates in 7/2003
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the exact manufacturing date I don't know now, but put between plates in 7/2003
Thank you for that, registered July 2003 is very likely to be one of the last of the euro3 engines. I would dread having something like that happen to my engine, which is definitely euro4.
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The only thing I can suggest is to run a cleaner in the fuel every third or fourth tank of fuel. possibly use a 10w 60 oil may help with consumption a little.
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10W60 is the only oil recommended for the JTS engine. My own JTS @82,000 miles uses little oil, I used just over 1 litre for the 2,500 mile trip around France last month.

The JTS engine does not have an EGR valve, it uses 'internal' EGR by the cam timing allowing exhaust gasses to re-enter the engine FACTfile - Alfa GTV.

The main part of interest is:
'The use of stratified charge only at speeds around idle speed, however, allows the 2.0 JTS unit to use a conventional catalytic converter system. This result is also made possible by a more extensive use of exhaust gas recirculation, which reduces the production of nitrogen oxides (NOx). Because Alfa Romeo engines are fitted with variable valve timing, exhaust gas is recirculated to the intake on the 2.0 JTS directly between the intake and exhaust valves (internal EGR).'
The camshafts fitted to the euro3 engine and the ECU were changed for the euro4 engine, thought to rectify the coking up of the inlet tracts.

I was recommended to use injector cleaner on a regular basis by ALFA TUNER, it does make a noticeable difference.
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Yes sorry the 10w60 is the recomended oil
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(Post Link) post #13 of 16 Old 31-07-14 Thread Starter
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Hi,
I've used 10W-60 oil, Selenia or Valvoline, rather thick oil in finnish winter indeed...
There is no variable timing in JTS cams like was in TS.
I have not found reliable root cause why many JTS engines burn so much oil. Plenty of possible reasons have been listed, like oval cylinders, flat pistons, narrow piston rings etc etc.
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So dies that mean the GT JTS is the latter euro 4 engine?
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Quote:
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There is no variable timing in JTS cams like was in TS.
The JTS has variable valve timing controlled by the variator as does the TS. Alfa Romeo 156 Variator The JTS engine has an improved oil feed to the variator which results in less variator problems than the TS.

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So dies that mean the GT JTS is the latter euro 4 engine?
No idea about the GT JTS. The GTV JTS uses the same 55184599 euro4 Catalytic Converter as the later 156 JTS, it never had the earlier 55180214 euro3 Catalytic Converter as fitted to the earlier 156 JTS , so it is reasonable to conclude that there was never a euro3 GTV JTS.
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(Post Link) post #16 of 16 Old 01-08-14 Thread Starter
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You are right, I didn't recognize that thing when the workshop put the lifters, springs and shafts back.

But, now the engine is running again. It took several minutes after the first start before the lifters got oil in and took backlash away. I already was afraid I have to open the lifters but then the noise disappeared. I changed the oil twice and the first 50km went without error codes.
What a job for an old man like me, who is used to more simple motors and more space under hood!
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