Checking crankshaft timing mark
04-23-2015, 08:51 PM
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Checking crankshaft timing mark
Hi,
Working on a friend's 1986 22RE powered 4 runner.
We're trying to verify valve timing, and there may have been lower end movement while the top sprocket was not connected.
Now, in every motor I've ever worked on, No.1 piston has to be at TDC for the camshaft marks to line up.
But every guide I read says I have to take the crank pulley off, and the oil pump, and the timing chain cover off just to see the mark?
Is it possible to just see the mark and the timing chain with the oil pump off alone? Do I have to remove the timing chain cover, too?
Working on a friend's 1986 22RE powered 4 runner.
We're trying to verify valve timing, and there may have been lower end movement while the top sprocket was not connected.
Now, in every motor I've ever worked on, No.1 piston has to be at TDC for the camshaft marks to line up.
But every guide I read says I have to take the crank pulley off, and the oil pump, and the timing chain cover off just to see the mark?
Is it possible to just see the mark and the timing chain with the oil pump off alone? Do I have to remove the timing chain cover, too?
04-24-2015, 06:38 AM
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How on earth could you set ignition timing if you can't see the timing mark? What kind of guide would suggest removing the crank pulley (which is what has the mark)?
http://personal.utulsa.edu/~nathan-b...nce/2maint.pdf (page 11)
While I don't have a lot of experience with the 22re, valve timing is determined by aligning the "bright links" of the timing chain with the marks on the sprockets. You can do that at TDC or anywhere else. But once you spin the crank once or twice, the bright links will no longer line up, so in that case you will be looking for the mark on the cam sprocket to be pointing straight up or straight down at TDC. And TDC is set with the crank pulley on.
http://personal.utulsa.edu/~nathan-b...nce/2maint.pdf (page 11)
While I don't have a lot of experience with the 22re, valve timing is determined by aligning the "bright links" of the timing chain with the marks on the sprockets. You can do that at TDC or anywhere else. But once you spin the crank once or twice, the bright links will no longer line up, so in that case you will be looking for the mark on the cam sprocket to be pointing straight up or straight down at TDC. And TDC is set with the crank pulley on.
04-24-2015, 06:43 AM
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How on earth could you set ignition timing if you can't see the timing mark? What kind of guide would suggest removing the crank pulley (which is what has the mark)?
http://personal.utulsa.edu/~nathan-b...nce/2maint.pdf (page 11)
While I don't have a lot of experience with the 22re, valve timing is determined by aligning the "bright links" of the timing chain with the marks on the sprockets. You can do that at TDC or anywhere else. But once you spin the crank once or twice, the bright links will no longer line up, so in that case you will be looking for the mark on the cam sprocket to be pointing straight up or straight down at TDC. And TDC is set with the crank pulley on.
http://personal.utulsa.edu/~nathan-b...nce/2maint.pdf (page 11)
While I don't have a lot of experience with the 22re, valve timing is determined by aligning the "bright links" of the timing chain with the marks on the sprockets. You can do that at TDC or anywhere else. But once you spin the crank once or twice, the bright links will no longer line up, so in that case you will be looking for the mark on the cam sprocket to be pointing straight up or straight down at TDC. And TDC is set with the crank pulley on.
I don't have a clue!
I think we might be 180 out.
So the top sprocket's (Camshaft sprocket) dimple should be facing 11:55 when the bottom crank pulley is at 0 degrees TDC for proper valve timing?
04-24-2015, 06:59 AM
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First, you CAN'T be 180° out. Just spin the crank one more time and the cam sprocket will move 180° (put another way, the crank is at TDC twice per 4-cycles; the cam determines which of those two TDCs is on the compression stroke).
But for the cam sprocket alignment, I'll have to defer to someone else. Here's the manual section: http://personal.utulsa.edu/~nathan-b.../8timingch.pdf While you can probably eye-ball the cams to determine if they are in the right place at TDC, ultimately you might have turn the crank (which could be 20 times or more) until the bright links come around and line up again.
But for the cam sprocket alignment, I'll have to defer to someone else. Here's the manual section: http://personal.utulsa.edu/~nathan-b.../8timingch.pdf While you can probably eye-ball the cams to determine if they are in the right place at TDC, ultimately you might have turn the crank (which could be 20 times or more) until the bright links come around and line up again.
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