l008com
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- May 25, 2015
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So I finally had time today to take this apart again. I took the head off hoping to find a bad gasket. But sadly, it looked fine. The piston and cylinder walls also looked fine. Of course I couldn't see the state of the piston ring from here, it looks like I'd have to remove the motor and take it apart from the bottom to get eyes on the rings. Not sure I'm going to go that far with this.
Also the valves look ok too. Things are a little dirty but it doesn't look that bad to my inexperienced eyes.
So I guess the question is, is a bad piston ring the only thing that would be causing blow-by at this point? Or could it still be something else? If it is highly likely to be the ring, what are the odds that it is damaged, vs just gunked up and dirty?
Also the valves look ok too. Things are a little dirty but it doesn't look that bad to my inexperienced eyes.
So I guess the question is, is a bad piston ring the only thing that would be causing blow-by at this point? Or could it still be something else? If it is highly likely to be the ring, what are the odds that it is damaged, vs just gunked up and dirty?
l008com
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- May 25, 2015
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Ok maybe finally on to something!
I took the valves out, inspected everything. They both seem to have clean rings around them, and they seem to be seating very well into the cylinder head.
HOWEVER the intake valve does seem to be a little sticky! I don't know how much stick is "normal" for valves, but the exhaust valve is definitely much free-er moving than the intake. Its not sticking around the ring though, it's sticking on the shaft. It looks like the intake valve's stem goes through a gasket or seal of some kind and the exhaust does not, thats probably whats causing the sticking, and hopefully that is the cause of the misfiring and blow-by.
But without any obvious gunk to clean how, how do you loosen up a valve like this? OR am I barking up the wrong tree, and is this a totally normal amount of "stickiness" that the spring and combustion will fully eliminate when it's running?
Edit: In the video, the springs are removed, so the exhaust is closing fully by gravity, and the intake is not.
I took the valves out, inspected everything. They both seem to have clean rings around them, and they seem to be seating very well into the cylinder head.
HOWEVER the intake valve does seem to be a little sticky! I don't know how much stick is "normal" for valves, but the exhaust valve is definitely much free-er moving than the intake. Its not sticking around the ring though, it's sticking on the shaft. It looks like the intake valve's stem goes through a gasket or seal of some kind and the exhaust does not, thats probably whats causing the sticking, and hopefully that is the cause of the misfiring and blow-by.
But without any obvious gunk to clean how, how do you loosen up a valve like this? OR am I barking up the wrong tree, and is this a totally normal amount of "stickiness" that the spring and combustion will fully eliminate when it's running?
Edit: In the video, the springs are removed, so the exhaust is closing fully by gravity, and the intake is not.