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Old 06-16-2004, 08:18 AM
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A question about dual lift profile engines.

I have two 55 sedans in my shop and one mr2 spyder. The mr2 recently got a motor/transmission swap done to it. I put what is known as a 2zz engine in it along with the 6 speed that is normally found bolted up to that motor. The 2zz has what Honda refers to as vtec and Toyota calls 'lift'. Basically, in addition to the continuously variable valve timing there are two different cam profiles on each cam shaft - high lift cam lobes and normal (low rpm) lift cam lobes. Its a very simple setup and works well. I recall seeing at some point in the past some kind of variable lift setup for small block chevrolet motors. Unfortunately I don't remember what it was called or any details about how it worked. I'm not having much luck finding information on the net about it.

Anybody else heard of something like this?

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Old 06-16-2004, 08:36 AM
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Are you referring to solenoid driven lifters?

I was talking to our engine builder about it one time and he had nothing but raves about it. High cost and durability were the biggest issues.
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Old 06-16-2004, 03:22 PM
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I don't think thats it. I think I may have found it. Something called Rhoads lifters. They increase lift duration by as much as 25% as the rpm's increase. I was hoping for something more abrupt...say around 75% to 100% increase like the toyota enjoys.
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Old 06-16-2004, 05:39 PM
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The rhoads lifters just make a big cam street drivable.. it gives you the low end of a stock cam, and hi end of a bigger and badder cam... they will not give an increase in lift... actually a decrease at lower RPM's
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Old 06-16-2004, 06:08 PM
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wait so how does that work??
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Old 06-16-2004, 07:32 PM
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It is basically a loose hydraulic lifter, kinda... At idle, the lifter plunger absorbes some of the lift of the cam... and then as the rpms rise and so does the oil pressure, they get hard like hydraulic lifters and give you your total lift and duration!
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Old 06-16-2004, 07:36 PM
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o cool so you could run a somewhat aggressive cam on the street...right?
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Old 06-16-2004, 08:03 PM
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Something along these lines? Dan

http://www.hotrocker.com/index.html
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Old 06-16-2004, 10:31 PM
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Yes!

That is what I was remembering. Thank you Dan!
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