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Old 05-17-2013, 10:39 AM   #43 (permalink)
mechman600
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Quote:
Originally Posted by Christ View Post
Yes, every time I have to change bearings in an engine and the valves are closed for that piston. It's a large volume you're pulling on, takes patience sometimes to bring the piston down to mate it back up to the crank after you change the whole bottom end.

...aaaaand that's why I don't like Triton V8's.
Don't forget that while it is difficult to pull the piston down on the intake stroke with high manifold vacuum, the volume of air on the piston that you are "stretching" acts like a giant spring and pulls the piston back up on the compression stroke, helping turn the engine and effectively cancelling out any effort it took to pull the piston down.

Throttling losses have to do with the friction of air rushing around a throttle plate and not necessarily with a specific amount of vacuum in a cylinder on the intake stroke.
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