flyrotary@lancaironline.net Mailing List Archive

OK Kelly that should work fine.

One more thing to check when doing RX-8 trigger wheel transplants:

Yesterday I found yet ANOTHER source of high speed (~ 4000 - 5000 rpm) misses on my 20B. The pilot on the 20B, and possibly 13B too, is slightly smaller than on the Renesis engine. This allows the trigger wheel to sit slightly off-center. This causes the CAS waveform to have a modulation on it which causes an error in the EC2 because it sees this modulation as a pulse at higher rpms.

Depending on how the wheel happens to sit on the crank, it might run perfectly or might commense to miss and backfire at higher rpm. When mounting the RX-8 trigger wheel on the engine, measure the sensor gap at 4 - 6 places around the wheel to be sure it remains the same at all positions. If not, adjust the wheel until it is. A change of only .005 - .010" is enough to cause problems.

Tracy

On Feb 4, 2008 10:46 AM, Kelly Troyer <keltro@att.net> wrote:

Tracy,

    I am using only one of the 3rd gen. sensors with the Renesis

timing wheel and my EC2 was modified (By you) to be used

on my 13B.......

Thanks,

--
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold

-------------- Original message from "Tracy Crook" <tracy@rotaryaviation.com>: --------------

Good question Kelly.

You are one of the few using the 3rd gen sensor. I have not evaluated them but they do look very similar to the Renesis sensor so may have similar characteristics. In any case, putting the 1000 ohm resistor across it will not hurt anything (this includes the 2nd gen sensor as well) so I would say it's a good idea to install them on any installation. You will need to do this on both sensors since the 2nd & 3rd gen engines use 2 sensors. I will be installing them internally on all EC2s from now on.

Tracy

On Feb 3, 2008 10:53 PM, Kelly Troyer <keltro@att.net> wrote:

Tracy,

   I am using the 93-95 RX7 CAS and Renesis timing wheel

on my unfired installation.........Any problems with this setup

or am I the only one using it ??

--
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold

-------------- Original message from "Tracy Crook" <tracy@rotaryaviation.com>: --------------

I did the 9.7 CR rotors in mine but have never done a front to back comparison with the stock 9.0s. It does run strong with the 9.7s though!

BTW, all builders using the Renesis Crank sensors take note:

I had a lot of trouble starting my 20B with Renesis CAS installed. Just yesterday I found out why. The Renesis CAS is a much higher impedance sensor than the RX-7 CAS and this makes it much more sensitive to noise pickup, especially when the starter is running.  It needs a load resistor across it to avoid this problem. Install a 1000 ohm (1/4  or 1/2 watt is fine) across the leads of the sensor either at the sensor or near the EC2.

After installing one on mine it went from very difficult to instant starting.

I'm not sure why I have not seen this problem on my RV-4 with Renesis engine but one other Renesis user has seen the problem and the resistor fixed it immediately.

Mark S., you should definitely do this on your 20B / Renesis setup as well. I am starting to suspect that this is why your earlier steel mount (for CAS) did not work. A very small difference in how the CAS is mounted affects the noise characteristics a lot. Either mount would probably have worked fine with the resistor installed.

Future EC2s for Renesis engines will have this installed internally.

Tracy