Hi Scotty! Today I took my intake manifold off to replace the spark plugs since I suspect it's part of the reason for occasional misfire, and I found the valve in cylinder is partially opened, as indicated by the picture, is this normal? Because 2 years ago I replaced the timing chain, don't know whether they did a bad job. BTW, the car model is 2008 nissan sentra base model, 2.0 L
I also attached few pictures for my pistons, seems to have bad oil control ring due to the pattern on cylinder wall, considering this is a 16 years nissan, may be normal.
Thanks in advance for any and all feedback!
Ethan
the valves are supposed to be open.
See our FAQ for troubleshooting misfires
Thanks for reply, but it seems only cylinder 1 has the valve opened, could you tell where can i get more information about this design? I searched a while and found someone said it will be fully closed after the compression stroke, but don't know whether it's true. Thank you in advance!
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Thank you so much, I watched how engine works, and learned the reason behinds.
I found the valve in cylinder is partially opened, as indicated by the picture, is this normal?
Why would you think otherwise? It's hard to tell from the picture - is the valve burned, chipped, or fracturing?
Thank you for the reply, now I realize it's because my knowledge about how engines works is wrong before I post the question. And it's hard to tell from the picture, but the surface of the valve is shiny, although a little bit black, so I think it's in a good condition.