What is this telling me?

[BrazilianZ28Camaro]

The clean area of the chamber is the absence of fuel.

have to be careful with that statement... fuel does wash carbon away

Then probably our gas is a total junk , because everytme I tried to clean exaust ports, valves and chambers with gas, nothing happenned.

I submersed valves in gas and the carbon was still there after several days.

I think a hot chamber would do the gas cleaning even harder due vaporization, but its JMHO.

[MadBill]

As an aside, be interesting to hear how tight the squish was, to cause such significant contact...

[lorax]

Then probably our gas is a total junk , because everytme I tried to clean exaust ports, valves and chambers with gas, nothing happenned.

I submersed valves in gas and the carbon was still there after several days.

I think a hot chamber would do the gas cleaning even harder due vaporization, but its JMHO.

The fuel wash never allows the carbon to develop to start with.

[BrazilianZ28Camaro]

The fuel wash never allows the carbon to develop to start with.

I respect your opinion Lorax, but then I wonder how intake ports sometimes get sooty due reversion? The constant fuel flow there would keep the walls clean right?

Looking at the chamber pic again, its suggest the majority of the intake charge is following the shortest path to the depression path (spark plug side of the of the cylinder,or exaust valve seat due overlap suction) like we do know it should, then I believe the fuel is being almost totally directed to the center of the chamber due the fact the valve windown is also much bigger there than the valve to chamber wall windown.

The carbon indicate where in the chamber the "raw" fuel is being deposited by the intake charge and due the lower chamber wall temperature needed to combustion (hopefully), after the spark, this same fuel is partially burned and partially "melted" on the chamber building carbon.

Sorry I haven't chemical base to explain why this happen or if even correct. JMHO again

I'd luv to learn more about this also.

[TMSJoe]

Here are some piston pictures. The blurry side shot is showing the burned oil by some of the lateral gas ports. The others, from the top, show the dome cleaned off by the intake valves. They also show the imprint of the head under the spark plug.

It is my belief that the fuel is being thrown against the chamber wall and washing the buildup away. The heads have a vain on the roof that I feel is separating the fuel from the air. Maybe not. That is why I'm looking for other opinions.

I have seen the car run at the race track and I feel it is rich. The car seemed to leave a blackish cloud on the launch. Not oil blue. However when we leaned it out it ran slower. BUT that run also skated on the launch. So it wasn't a conclusive test in my eyes.

The cam is @.050 276/280-R6. installed @102 ITC With 1.6 rockers. This cam was faster than the 281/282-R12 that was in it. I have no information on install info on this cam.

[TMSJoe]

Could also be a weak ignition/electrical system. How was the motor running overall. Missing? Popping? Surging?

From the stands I heard a "flutter" at the top of 1st gear. Also the cam swap improved everything but the 1/8 MPH. I feel the engine is being over revved.

No matter what the owner will not sleep until the engine pulls past 8000 RPM. So I plan to put a bigger intake on it and cam it for what the customer wants.

[af2]

Could also be a weak ignition/electrical system. How was the motor running overall. Missing? Popping? Surging?

From the stands I heard a "flutter" at the top of 1st gear. Also the cam swap improved everything but the 1/8 MPH. I feel the engine is being over revved.

No matter what the owner will not sleep until the engine pulls past 8000 RPM. So I plan to put a bigger intake on it and cam it for what the customer wants.

Joe, throw some spring at it and watch it help.

[CREngines]

What fuel are they running in that?

[lorax]

What fuel are they running in that?

X2 That was my next question, and what is the timing, and has the timing(TDC) and advance been verified?

[JoePorting]

Could also be a weak ignition/electrical system. How was the motor running overall. Missing? Popping? Surging?

From the stands I heard a "flutter" at the top of 1st gear. Also the cam swap improved everything but the 1/8 MPH. I feel the engine is being over revved.

No matter what the owner will not sleep until the engine pulls past 8000 RPM. So I plan to put a bigger intake on it and cam it for what the customer wants.

Are there any contact marks on the pushrods? They could be binding on the heads causing the high rpm valve float.

[TMSJoe]

I'll look at the pushrods. I don't know what fuel other then race fuel from the track. Don't know the timing other then the pointer is accurate.

Any opinions on the port design? I'm not liking the swirl thing.....

[MaxFlow]

Bad cam events for heads. Carb out of whack, valve bounce..oil in chamber,

[JoePorting]

Lots of people are making good power with those heads. It's not anything to do with the port.

[Strange Magic]

From the looks of the piston as well as the heads, it doesn't appear that anything is hitting. It just has a tight quench. There is a distinct difference between missing carbon and missing carbon from the head interfering with the dome or quench area of the piston. The difference is in how it will look. A satin/brushed clean look doesn't mean it's hitting, although a spot that looks almost chrome would be an indication of contact. The pictures are not clear enough and close enough to determin this.

Your tune up is not so good and your consuming oil as well.

[lorax]

From the looks of the piston as well as the heads, it doesn't appear that anything is hitting. It just has a tight quench. There is a distinct difference between missing carbon and missing carbon from the head interfering with the dome or quench area of the piston. The difference is in how it will look. A satin/brushed clean look doesn't mean it's hitting, although a spot that looks almost chrome would be an indication of contact. The pictures are not clear enough and close enough to determin this.

Your tune up is not so good and your consuming oil as well.

I tend to agree, Its not hard with an aluminum head, specially if its not well wormed up, and the mixture is that rich, for the flame to get squelched in a tight quench. Cooling the mixture is what it does. In a case where it tight, plus rich and cold, it can do the job quite well,
I don't see it hitting on the plug side because the head is carboned up on the quench pad, even if the pistons isn't. for the far side, its little harder to tell from the pictures, but I have my doubts as well.