Question on combustion chambers?

[Jeff]

Recently tore down sbc, out of a jetboat that I built this past summer. It had 18 hard hours, but was having lifter noise at around 6000rpm,the reason for the tear down.
Question on the chambers , is that 1,3,5,7 look very rich, well 2,4,6,8 chambers are not as sooty, plugs are even whiter, how can one bank run richer than the other on a single plane set up?Might be a dumb question, but I do not know .

Kind of new to this board, came across it awhile back, and saw that some very smart people hang out here. Have never realy gotten the chance to get into the tuning end of engines ,or reading the internal parts as good as I think I should know. For the last 14 years I have been running my own machineshop/engine building place and having good luck building engines for some of the tracks in the area, asphalt and dirt both.Thats why I feel a little foolish asking my question, but have never worked with anyone that could point things out, as to why they look the way they do. ( like the way the burn on the piston should look ) If any of this makes sense.

[bill jones]

-If you still have the sparkplugs and you know exactly which cylinders they came out of---I'd cut the threaded ends off so that you can look at the porcelains from the side---to view the dark circular rings that should be encircling the porcelain near the little internal sealing gasket.
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-then lay those out in relation to the cylinder position and to the carburetor position---then look at the rings and see if the 1357 side shows obviously wider rings than the 2468 side.
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-I would also suspect there could very well be a water flow problem where 2468 isn't getting near the water as 1357 so the 2468 could be running hotter or maybe even the head dries up for some reason at WOT.
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-I have seen some manifolds where the carburetor mounting stud holes are drilled wrong/not perfect---and the carburetor could be shifted to the left.
-And there's the possibility that the carburetor boosters could be twisted crooked also.
-any goo or obstructions in the left side main air bleeds would cause those booster to run rich.
-or an air leak near the top of the meter block gaskets could be allowing air into the right bank fuel circuits and leaning them out.
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-Poor valve stem seals on that one head could also make those cylinders LOOK rich.

[MadBill]

First thought would be a problem with the left side of the (presumed) Holley 4 bbl carb, e.g. jet size. (including one drilled out but not re-numbered, been suckered on those before) Next, plugged air bleed, etc. Third, massive gasket vacuum leak affecting entire right bank (unlikely) Fourth, heavy oil/PCV leak to left bank masquerading as fuel rich. Fifth, oil drainback or guide problem on left bank. Last shot: cooling problem, too much on left or too little on right.

<EDIT> posted before I saw The Other Bill's post. Nice to see great minds thinking much alike!

[Unkl Ian]

My first idea was different jets side to side ,

could also be a loose jet.

[Jeff]

Thanks, I will look at the seals today, have to open up the drain back holes some, but both sides. Went for a ride with the customer and did notice he has trouble getting the water valves right for temp, temp fluctuated from 120 to 165. Lake superior is a cold lake.
I have some pic's but did not know how to attach.

[SchmidtMotorWorks]

What kind of intake manifold is it?

If it is two plane I think you can rule out fuel related cause.

Cooling sounds probable to me, maybe an upside down head gasket?

[automotive breath]

....Question on the chambers , is that 1,3,5,7 look very rich, well 2,4,6,8 chambers are not as sooty, plugs are even whiter, how can one bank run richer than the other on a single plane set up?....

This may be a shot in the dark. Did you check to see if one bank of pistons are coming closer to the head than the others, it is possible the block was decked wrong at some point in the past. I have even seen someone put a different thickness head from one side to the other. A difference of 0.005” to 0.010" or more from bank to bank would produce the described burn.

[Jeff]

Have not compared deck height side to side , but block has not been decked. Did get a chance to pull apart the heads, found one bad intake seal on 5. Have not got the carb in the shop, but it is a holy not sure of the #. Also cut # 7 & 8 plug need to cut a couple more, but they are burning diffrent. The heads are set of Pro Comp, 1st time I have ever used any.
Thanks for all the ideas.