LS - 3rd Gen (2001-2006) Discussion topics related to the flagship Lexus LS430

(Noise) turning crank cc from cams

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Old 06-05-16, 01:59 PM
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d1ma
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Default (Noise) turning crank cc from cams

Weird noise, wanted to see if anyone knew what it is. Working on my tb and wanted to make sure the belt didn't skip when I released the pin on the tensioner. cranked it over by hand a few times clockwise with no issue and realized that it would need a lot more turns for the cam marks/belt marks to align again. While turning the crank counter clock wise I heard an alternating springish tension noise/click between the l and r side cams. My guess is it's vvti related?
Old 06-05-16, 02:53 PM
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911LE
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The belt marks are only for initial installation. They will not line up once the engine is rotated. As long as the crank pulley mark lines up with its pin and the cams line up with the "T" marks on subsequent rotations you are good. They will line up every 2 crank revolutions. Only rotate the engine clockwise. I'm not sure what noises you heard but rotate clockwise a few revolutions and you should be ok.
Old 06-05-16, 04:34 PM
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rkw77080
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The LS430 has what's called the "Interference Engine". This means that the intake or exhaust valves will open into the same space that the piston will travel into. The timing belt is designed to maintain separation between these two moving parts from colliding with each other.

At any time, some of the valves are open (pushed down by the camshaft) and are in the way of the piston. if you rotate the crankshaft independently, at some point some pistons will come into contact with one of these open valves.
Old 06-06-16, 08:20 AM
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d1ma
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Thanks for the input gents, the timing belt was on during the rotation so everything turned in synchrony. There's nothing wrong, just an odd noise and my curiosity, I think it takes 930+ turns on a sti motor to get the marks back in their position

Im thinking there may be a spring loaded device that resets or something like that during a counter clockwise rotation... Waiting for new plugs and finishing putting this bad boy together.

Thanks CL!
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