Longevity questions LS400
#16
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I'm not sure about the 1997 LS400, but the factory service info for my 1990 '400 shows shim-over-bucket valve actuation with no lifters. The cam rides directly on the shims (the shims are a wear surface) and push directly on the valve stem with no rocker arm. That's the reason this engine needs valve adjustments and engines with lifters like Chevy's don't (not that I'd put a Lexus and Chevy engine in the same league :-)
#17
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I'm not sure about the 1997 LS400, but the factory service info for my 1990 '400 shows shim-over-bucket valve actuation with no lifters. The cam rides directly on the shims (the shims are a wear surface) and push directly on the valve stem with no rocker arm. That's the reason this engine needs valve adjustments and engines with lifters like Chevy's don't (not that I'd put a Lexus and Chevy engine in the same league :-)
The reason *some* Chevys don't need their valves adjusted is because they use hydraulic lifters. If they had a solid lifter, there would be a required valve adjustment.
#18
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The cam rides directly on the shims (the shims are a wear surface) and push directly on the valve stem with no rocker arm. That's the reason this engine needs valve adjustments and engines with lifters like Chevy's don't (not that I'd put a Lexus and Chevy engine in the same league :-)
90% of owners don't realize and appreciate how much smoother and more powerful their engines will run if they adjust the 32 valve clearances on their LS motors precisely. So few owners ever have their clearances adjusted and some complain of ticking noises, low power etc.
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KingLex400
LS - 1st and 2nd Gen (1990-2000)
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08-10-11 04:52 AM