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There is not enough pressure in the LPO for the plungers to lift against the valve spring pressure - not even close at the highest cold psi.
The LPO only fills the cavities. When the lifter is raised towards the valves, a check valve closes off the oils escape and locks the plunger in the lifter so the valve can open. LPO only eliminates the slack in the valvetrain when the lifter is on the base circle and the valve is fully closed.
An issue you have taking the stem heights in that manner is the rocker box is a wedge, so each "row" of valves will measure differently. You can compare all the lower exhaust valves to one another. You can compare all the valves in the center (2 per cyl) to each other. And you can compare the top valves by the intake ports to one another. Your wide swings are due to the rocker box being a trapezoid, not a rectangle.
Ok. So when I do the math on the spring retainers, I get a a difference of 0.165" to 0.173" difference between the uphill retainer and the middle of the cylinder retainer of the intake valves. Which is not that far off from the 0.158" difference between the two intake valve stem heights. So I guess these two different measurements are not that far off from each other.
So where does that leave me? Am I back to having bad rings on number 6 cylinder to account for 225psi compression test as per the dealer I took it too? Or do I still have a valve stem that is too high so that when the engine is running I have an intake valve that is not closing completely? And how do I account for the dealer telling me I have an intake valve leaking? I'm at my wits end trying to figure this out. Thanks, B.
I'm not sure Jack. I will call them tomorrow to find out exactly what procedures they did to come up with a leaky valve. Because I'm not finding that. Which brings me back around to bad rings. I may buy a leak down tester to try more testing.
With a stage 1 cam, do I need fly cut pistons? I know what I have read is no. But...... You know how things go on the net. B.
Stage 1 and stage 2 cams do not need piston work unless the block has been excessively decked. Most OE blocks have a piston protrusion of 0.028-0.032". The OE max spec is 0.354"
I originally had a whacked-out crankshaft grind with my reman. When Zeb builds motors, he uses reduced height pistons to make sure for the higher lift cams.
Ok got it. If I end up pulling mine I will do one of two things. One, just do a re-ring kit. Or two, do a short block swap. Money is tight so I will have to do some self reflecion on which way to go. I think part of my diagnostic problem is how I'm applying air pressure. I am using a scuba tank with 3500 psi in it and tapping into the low pressure port to apply air to the cylinder. Which is 150 psi. BUT, I don't think I'm getting enough volume of air to make a definitive test. I can hear air leaking past the rings, but without a leak down test tool I can't determine what percentage is leaking past the rings. B.
I've always had home or shop compressors, so I can't say what the lowest volume is needed. You can rent pancake compressors from Home Depot reasonably if you don't know someone with a pancake. The leak-down tester (don't get a Harbor Freight, it has the wrong size orifice and low pressures) can be made easily for those of us with pneumatic equipment and supplies. You need a regulator, two gauges, and a means to generate a 0.040" or 1mm orifice between them. The orifice changes depending on bore size, but our size should be that.
When the dealership did the test, they could have had a little carbon between the valve and seat. Most people I know pop the valve a few times with a dead-blow hammer to make sure it's seated.
Well, finally got a leak down tester and a small compressor. Got to testing this afternoon. The leak down tester is showing a 30% air leak. I can hear the air coming out through the head and nothing past the valves. So a short block is in order. Sucks. B.
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