Fiat Palio 1242 8V.
I had taken the exhaust header off and found a lot of carbon in the second exhaust port in the cylinder head. The other 3 ports have a brownish colour.

The carbon is dry(is not oily). The valve stem is also dry.

The spark plug of that cylinder also has more carbon on it than the rest(not a lot), however, the carbon on the electrode looks slightly wet and the first 2 or 3 threads(closest to the electrode) have an oily substance on them.

There does not seem to be any mis-firing.
I swapped the fuel injectors and there was no change.
Compression test results are as follows:
1> 195 PSI
2> 210 PSI
3> 200 PSI
4> 200 PSI

Could this cylinder be burning oil, running rich or does it have something to do with the spark plug?

The engine has just been rebuilt and has done only 300km.
Everything in the engine is new.
The ignition coils and spark plugs are about a year old and are Fiat genuine.

New pistons and rings as well?
Cylinders honed?
If so, wait until the engine reaches about 4-5000 km, and everything is "run in".
Until that time, oil consumption is considered normal in a way.

Thanks for the reply!
Yes, pistons and rings are new.
Cylinder sleeves installed and honed.

Is it normal that its only the second cylinder that's making so much carbon?
The other 3 cylinders seem to be fine.

Just give it some more time/ km's...

(Btw, are you sure it was clean after the rebuild..?)

Yes. I had cleaned all the ports with a flap wheel. They were absolutely clean and shiny. In fact, I had polished the exhaust ports. They were almost mirror finish.

Here are the pictures of the exhaust ports 1-4.

The second port has a lot of carbon in it and is completely black in color.(Note that the port floor has less carbon on it because I wiped some of it off to see if it was oily)


1,3 and 4 are brownish in color with a lot less carbon

Kunal said:

Here are the pictures of the exhaust ports 1-4.

The second port has a lot of carbon in it and is completely black in color.(Note that the port floor has less carbon on it because I wiped some of it off to see if it was oily)


1,3 and 4 are brownish in color with a lot less carbon

Click to expand...

Please have a look at the above pictures and let me know whether this is normal or something is wrong.

Kunal said:

Please have a look at the above pictures and let me know whether this is normal or something is wrong.

Click to expand...

seems " acceptable" - do more hours and see how it goes..,
removing spark plugs will give enough evidence periodically = no need to remove the exhaust manifold--

incidentally,
double check there is an excellent seal with a gasket between head and manifold :idea:

Charlie

How is fuel and oil consumption.?

Peter Pick-Up said:

How is fuel and oil consumption.?

Click to expand...

Fuel and oil consumption seem to be OK.

Hard to tell.
You'd be amazed about the dirt build up in any engine in a short period of time.Just recently I changed an injector gasket in my Alfa GT jtd Diesel engine.
I ONLY run premium fuel and synthetic oil in that engine, I always drive long distances at high speeds.
Still there was massive carbon build up, it surprised me....but didn't concern me much, it's just the way modern engines run, I guess...!!

I guess that's normal for a diesel engine.

But, since mine's a petrol engine and the carboin build up is ONLY in one port, its worrying me a bit.

I just hope it's not oil from a valve seal!