Curious your thoughts on combustion burn pattern
 

300 miles on new build. Two cylinders (4,6) down on power from the get go. Bad rings. This I know. What surprised me was how much different the cylinders look from each other insofar as the combustion pattern on them. Take a look.

I understand in a N/A application, the end cylinders tend to take on less fuel than ones closer to the carb, but I'm seeing a good difference between the end cylinders..and I'm not sure its due to a lack of fuel. Further investigation is needed of course, but wanted to post in parallel. Some things to know.

- I did lean the engine out 2nd pass down the track (to the point where it was breaking up), but only at higher RPM and I rectified that with jets right after. 10 passes at the track, and the rest is street driving.

- Number 8 ignition lead was loose when I got home from the track...probably like that for the last two passes, and then the 5 or so minutes to load and unload the trailer. That was the last time this ran.

Passenger head - You can see the end chamber (8) looks a lot darker than, the number 4 chamber. To me, 4 looks ideal. 8 doesn't even look like a fuel distribution problem, its looks more like a burn problem, so probably a result of the loose lead/lack of ignition, yeah?

https://lh3.googleusercontent.com/6R...R2M=w1520-h580

Here is a close up of cylinder 8.
https://lh3.googleusercontent.com/cn...Y7Q=w1520-h580

Chamber 8 closeup
https://lh3.googleusercontent.com/XY...Zck=w1520-h580

Chamber 4, close up
https://lh3.googleusercontent.com/if...0PQ=w1520-h580

Move over the other side of the engine, and cylinder 7 here, looks like its doing half the work! Normal to be this light in color? There is very little carbon buildup as you can see.
https://lh3.googleusercontent.com/42...4y8=w1520-h680

All pistons were polished to a mirror like finish prior to assembly.

I'm sure more mileage would tend to average out how these cylinders look and there probably isn't anything to worry about, but thought Id run it by and see if I'm overlooking anything.

Thoughts?

All the chambers except #8 look good to me. # 6 is a little dark. Piston tops look normal too except #8 looks like it was washed down with unburnt fuel.

Swirl patterns are different between left and right hand ports in a paired intake port wedged chambered Head.
combine that with heads that might have a tad too much port area for the motors cid and rpm range and these clockwise and counter clockwise swirl patterns effect the burn rate and of course the timing advance needed per left and right hand ports.

Sounds good Gents. Thank you. Not much I can do except run it out, so back together it goes, and see how it does.

Almost looks like that #8 piston is "kissing" the combustion chamber. Also what is that mark on the piston top at about the 2:30 position?

Its a close squish, but there is no contact. Everything turns and feels very smooth.

I believe what you're seeing at 2:30 is a piece of carbon. Went to look on block thinking 'how could I miss that?' and its gone from that spot. There are some other pieces floating around. I'll clean them all up when the rods come out.