Engine in good condition???

giannicsl

giannicsl

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hi boys,
an advice.
these spark plugs were fitted new to an m90 engine.
after 600 km they were dismantled.
according to your analysis and experience, is the engine in good condition?
or what kind of problems can you see from the burning of candles?
the number 5 spark plug is completely dry and perhaps the injector is not working well.
thanks for your opinions

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Looks like oil in the middle plugs rather than carbon soot from overly rich mixture.

Do you get any oil smoke on hard acceleration, which means worn rings? How about when you do the engine braking test (start over 4500 rpm, coast down in gear to 2500rpm then open throttle), which means valve seals and guides?
 
After only 600km (left to right)...

If they all looked like 1 and 6, I'd suspect the engine was due for an overhaul soon.

If they all looked like 2 and 4 I'd suspect the engine was OVERDUE for an overhaul.

#3 is definitely in big trouble :(. Bad/broken rings or valve guides

I agree that #5 is getting no or very little fuel.

I would probably do a compression and leakdown test just to make sure, but I'd guess that motor is not in very good condition (and has some fuel delivery problems).
 
Based on first impressions, I would concur with the other opinions in this thread regarding the need to overhaul. Whether that involves a valve job or a rebuild of the engine's lower half is unknown. However, without additional data, spark plug readings are only one indicator of engine condition. You never described how your engine ran or, for that matter, what kind of driving you attempted: driveway, traffic or the autostrada? As noted, a compression test and/or a leakdown test is never a bad idea.

An out-of-tune engine could easily foul plugs and fail to burn off deposits left from poor maintenance or non-use. You mention “injector.” It does not take much to cause a fuel injected engine to run poorly. Low fuel pressure, dirty injectors, failing pressure sending unit, improperly adjusted idle potentiometer. The list is long. An engine that had been sitting for a long time could suffer from sludged/sticky piston rings (oil) and cause some fouling. Contaminated and thinned oil might suck past valve seals and guides. To the extent possible, and if not already performed, I would consider ensuring that the engine is in proper tune, including a valve lash and ignition timing check, fresh petrol und oil, followed by a long spirited drive.

BTW, although the exact Bosch spark plug heat range is not clear to my eyes, they "generally" appear to be correct. Same with electrode gaps. And, while this should probably not matter, have you commingled spark plugs made in Russia with plugs made in Germany? o_O

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thank you very much for your replies.
the engine is not mine,
but I can say that it is an engine that has been stopped.
compression
looks to be good, but there are also other mechanics who said it is in need of new piston seals ...
definitely has fuel management problems ...
maybe the fuel pump even if new is not suitable ...
when you put new candles it is fine, it does not smoke.
shortly after it starts to go to 5 cylinders ...
is a Ljtronic from 1980.
2 times out of 4 if it does not start immediately you have to change the spark plugs ...
the spark plugs that are shown in the photos were put on new and have about 400
American miles ... made in the extra urban road,
mountain...
country...
in just one day ...
I can't add any more clues
p.s.
new water temperature sensor.
often and before changing the spark plugs it was necessary to unplug it.
 
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