Oil Leak in intake tube and Spark Plugs

[archyman]

Some results after the compression test on semi hot engine full throttle and no distributor:
cylinder 1: 12,5 bar
cylinder 2: 12,5 bar
cylinder 3: 13,5 bar also a bad spark plug from this cylinder(covered in black)
cylinder 4: 12,5 bar

Ok, so i was pretty confused because i know for sure that this engine is 9.3 bar
The mechanic who made the test showed me the servicing software for the model and there it showed that for the model the normal compression is between 9.3-12.7 atmospheres.
He concluded something i did not exactly understand. The segments are obviously fine, but the increased pressure is due to worn valve rubbers Probability?
Anyway if anybody can translate this info it would be great.

[BETEK]

The normal compression for d14 is 12.7 bar the 9.3 bar is the minimal allowed.
Maximum variation between cylinders must be 2.0 bar if bigger need service or lower than 9.3 bar,

I suppose your test numbers is for dry compression test. Because with wet test, numbers are always bigger.

The cylinder 3 bigger compression can be from oil leaking from valve stem seals, from carbon deposits, excessive fuel being injected to the cylinder.
I think the cylinder 3 injector inject more fuel and run reach the cylinder that creates carbon deposits with result high compression.
Or weak ignition on cylinder 3 creates bad fuel burning=carbon deposits
Or the valve stem seals on cylinder 3 are worn and oil comes into cylinder.

See for carbon deposits on cylinder 3 piston also post some high quality photos from spark plugs.
Spark plugs reading gives many information for each cylinder http://www.gnttype.org/techarea/engine/plugs.html

[archyman]

Great article!
The test was dry indeed.
I've checked the distributing cables and they are OK. If the problem is running rich on third cylinder isn't it more likely to loose compression due to wash of the oil and low lubrication etc??
It seems very possible that oil is leaking in the cylinder..the spark plug seems just like if that was the case.
Is there a way of diagnosing it without opening the head?

[BETEK]

If the problem is running rich on third cylinder isn't it more likely to loose compression due to wash of the oil and low lubrication etc??

To loose compression the piston rings, cylinder wall, or valves must be worn to loose compression.
Maybe the problem is somewhere in injection or firing system and build carbon deposits because you said that engine does not consume any oil.
Are there any carbon deposits on cylinder 3 piston?
OR maybe just faulty compression test for cylinder 3.

It seems very possible that oil is leaking in the cylinder..the spark plug seems just like if that was the case.

What type of black colour is the spark plug on cylinder 3? Oily or with carbon deposits? Photos from spark plugs will help for diagnosis.

Is there a way of diagnosing it without opening the head?

We are trying

[saxophonias]

is this difference so big to create any worries at all? I see very consistent numbers. I am not an expert but i doubt there will be equal numbers even in a new engine.

[BETEK]

is this difference so big to create any worries at all?

The numbers are normal I can say even optimal for the age of the car except the cylinder 3.
The maximum compression must be 12.7 bar and not bigger. The cylinder 3 has 13.5 bar of compression.

[archyman]

Are there any carbon deposits on cylinder 3 piston?
OR maybe just faulty compression test for cylinder 3.

What type of black colour is the spark plug on cylinder 3? Oily or with carbon deposits? Photos from spark plugs will help for diagnosis.

Cant't really say if there are carbon deposits inside the engine itself, i guess i will have to open it to find out which is not good for now.
The spark plug seems black and deffinetly dry not oily. It's really not that much, but is different from other spark plugs. The inside of the sparks stays white on the other, here is black.(seems like the CARBON FOULED type from the site)
Here are some pics:

[BETEK]

The spark plug looks like that has been overheated from the colour of insulator (insulator glazing). Maybe lean fuel-air mixture.
The cause for this spark plug on cylinder 3 might be from bad ignition or bad working fuel injector.
I can't say that is heavy carbon fouled.

The spark plugs are NGK BKR6E-11 or BKR5E-11?

[archyman]

The spark plug is NGK-R BKR6E , L9Z5 - Made in..France

[BETEK]

BKR6E is with 0.9 mm gap (tip-eletrode distance)
BKR6E-11 is with 1.1 mm gap
OEM civics use to have 1.1 gaped spark plugs like this one in the photo.



A narrow gap may give too small and weak a spark to effectively ignite the fuel-air mixture, but the plug will almost always fire on each cycle. A gap that is too wide might prevent a spark from firing at all or may misfire at high speeds, but will usually have a spark that is strong for a clean burn.
From Wikipedia: http://en.wikipedia.org/wiki/Spark_plug