Marks on cylinder wall, valves too big?
Marks on cylinder wall, valves too big? Pulled apart the engine yesterday to investigate a tapping noise that's been annoying me for awhile now. On cylinders 5 and 7, at the very top, there is a mark/groove that's been worn into the cylinder wall. It looks almost like the exhaust valve was touching it, but the valves didn't have any visible wear. The motor is a stock bore 5.3L, with 799 heads. The intake valves are 2.00", and it had six 1.59" exhaust valves and two 1.55" exhaust valves because they jackass I bought them from put in the wrong valves. I don't think these valves are too big for the cylinder though. NONE of the other cylinders have this mark, just 5 and 7. Luckily, the mark is just above where the rings get to so I hope there is no ring damage. Cylinder walls look money.
On first start up there was a screeching/tapping sound that started after about 5 minutes, and only lasted on for the first drive. Then a tapping noise began a hundred miles later or so that sounded like a lifter, hence the tear down I'm doing right now.
#7:
#5:
On first start up there was a screeching/tapping sound that started after about 5 minutes, and only lasted on for the first drive. Then a tapping noise began a hundred miles later or so that sounded like a lifter, hence the tear down I'm doing right now.
#7:
#5:
Last edited by Ferocity02; Dec 7, 2012 at 05:05 PM.
The groove isn't very deep, I could barely feel it with my fingernail. I'd guess its only a few thousandths deep. I took a file to lightly work the raised area down, should work out.
So are 2.00 and 1.59" valves too big for a 5.3L?
So are 2.00 and 1.59" valves too big for a 5.3L?
how far bove the ring travel is the mark? If you have some room, I'd almost (carefully) touch the mark with a grinder so the valve won't touch anymore. Even .020 clearance would be good.
Well, the valves were the wrong size, 1.59 instead of 1.55. Once I get the right valves in there it should be fine. But I didn't know 2.00 and 1.59 were too big for 5.3l bore. And its weird that only these two cylinders had marks. Perhaps its due to minute errors in casting tolerance and mahining tolerance.
