Originally Posted by tracknut

I have a F350 that has a complet miss in # 8 cylinder with no compresion the rest of the engine has 410 to 420 psi don't if the blowby is to much or not. Engine is now on the floor. Haven't had time to take apart yet. Should I pull the left head or the injector thanks Jeff

Originally Posted by ernesteugene

...Keep in mind that cylinder #6 fires and then immediately cylinder #8 fires so that during the same 1/2 (180 deg) revolution of the crankshaft both rear cylinders on the driver's side bank are trying to lift the rear surface of the head from the block at nearly the same time!...

Originally Posted by ernesteugene

Here's a "triple whammy effect" theory as to why cylinder #8 might be the most vulnerable to burnout.

1) Cylinder #'s 1, 2, 7, & 8 receive less air flow during their intake strokes than do cylinder #'s 3, 4, 5, & 6 due to the taper in the intake plenums. I've drawn this conclusion from my engine model, and from several reports on "dusted engines" which clearly showed that most of the dusting damage occurred in the center 4 cylinders. BTW, your #2 which shows some damage is also one of the outer 4 that receives less air flow!

2) Cylinder #'s 8 & 6 are in the process of filling at the same time, i.e., during the same 1/2 crankshaft revolution, and they both fill from the same intake plenum, and that means that #8 gets even less air flow than do the other outside cylinders.

3) Cylinder #8 has the injector with the fuel cackle issue, and it seems to me that this "water hammer" effect that causes the knocking noise from the #8 injector might mean that the ICP and therefore the fuel rate is a little higher for #8.

Combining the least amount of air flow with perhaps the most fuel would certainly make #8 the most problem prone! I'd sure like someone to start a pole (which I don't know how to do) and see if #8 has caused significantly more issues than a random sampling of 1/8 would suggest if all cylinders failed equally.

Originally Posted by Tenn01PSD350

The driver side is notoriously the hottest across the board on the 7.3. I have proven this out with my IR thermometer as have others, so this is pretty much fact as far as I am concerned.

It is also compounded by the fact that the rear most cylinder manifold tubes are the hottest. So the #8 starts out as a potential problem, and only gets worse with the firing order and what Gene spoke of with how the intake plenum lends itself to poor air flow to the outer cylinders. The front cylinders are only saved by the fact the exhaust goes back on the manifolds and carries that heat there.