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? rotary valve differences between 160b2-rv and Champion

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Old 06-09-2006, 09:17 PM
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Darth Shreck
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Default ? rotary valve differences between 160b2-rv and Champion

We had our 160b2-rv rotary valve fall apart last year and bought 2 of the new Champion RV's and understood it was an improvement over the old RV and the old RV was no longer available. The engine ran ok and we didn't think there was a problem at the time.

Just recently we have been doing a lot of testing and found top end performance to be less than expected. After we took apart the rotary vale cover, we found out that the Champions RV had way too much timing. Originally we noticed the increased duration when we installed the new RV and we didn't think twice about it because the old valve needed more duration.

So the question is, does the Champion have a smaller opening on the RV cover (not the carb size, but the intake tract) than the older 160b2-rv?.

When I degree in the RV, I end up with either too much closing or too little closing degrees ATDC and the opening degrees (BTDC or ABDC) are out of the ball park.

What’s up?
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Old 06-12-2006, 10:04 AM
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Default RE: ? rotary valve differences between 160b2-rv and Champion

Dear Sir, Rotary valves simply do no fall apart. They are spring steel with a nylon hex drive. We simply do not have these problems. There is more induction timing with the 160 Champions.
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Old 06-13-2006, 12:39 AM
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Default RE: ? rotary valve differences between 160b2-rv and Champion



What is the open and close timing on a 160 Champion suposed to be, in either mm's from tdc or degrees?

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Old 06-13-2006, 01:58 AM
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Default RE: ? rotary valve differences between 160b2-rv and Champion

"Rotary valves simply do no fall apart" Well they don't

Didn't mean to imply it. Our engine sucked in a loose wire or hose from inside the fuselage and that caused the nylon hex drive to shear, Our fault.

We think ZDZ makes the best airplane engines, Period (No BS). Our 160 is twice the displacement of a Zenoah GT 80 and it weights the same and it's durability and power output has been incredible.

The reason for the first thread was that there is no documentation on your site or ZDZ's site for rotary valve timing and the new valve has 20 degrees more duration than the old one.

Without proper specs for timing (unfortunately our engine is missing the timing mark on the crank), all I can go by is the standard timing for many 2-stroke engines of; Open @ 145 to 147 deg BTDC and Close @ 65 deg ATDC and those specs don't work.

It would be safer to open the new valve sooner than to close it later, but without proper specs, the only other thing that makes sense is a casting change on the rotary valve cover.

Your help with this would be greatly appreciated
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Old 06-14-2006, 10:52 PM
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Default RE: ? rotary valve differences between 160b2-rv and Champion



This doesn't help me at all. If there isn't a new cover, I need the Specs.



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