View Single Post
Old 01-23-2021, 07:57 AM
Scott Hersha Scott Hersha is offline
Join Date: Jan 2005
Location: Cincinnati, OH
Posts: 1,826

I changed my SIM timing from Advanced, 30*, to fixed, 25* with the dip switch selections. After getting it all internally timed, then timed to the engine at TDC, and torqued in place (150-160 in/lbs!) you are supposed to check the LED flash pattern to make sure you have it set correctly. Well, my flash pattern indicated that I had set 25*, but it was still Advanced. I must have checked my dip switch setting 4 or 5 times. I didn’t want to pull the mag for access to the dip switch plug so I spent an hour getting that little bugger out while still mounted on the engine. With a mirror I was able to determine, for the 6th time, that I had my dip switches in the correct positions for Fixed, 25* timing. So - off came the mag. On my work bench, I checked a few different engine timing settings, and they all worked as far as the timing number goes (20*, 25*, 30*, etc), but all of them indicated Advanced. The #1 dip switch controls the Fixed/advanced functionality, and it is apparently stuck in the open (OFF) position. The SureFly tech rep talked me through this. Whenever you changed one of those dip switch settings, you have to flash power on the timing terminal in order for it to take effect, which I had done. The tech rep told me that without a manifold pressure line attached, it would just default to fixed timing. That didn’t make sense to me, especially since they want you to leave the MAP port uncapped when in Fixed timing. The mag advances the timing based on RPM & MP that it sees on that port, like the others do, and it just seems like I would now be sensing ambient under the cowl pressure. As I climb and the ambient pressure dropped below 25”, there should be some advance. The mag is still indicating, via the LED flash pattern, that it is electronically operating in the Advanced mode. If I changed the #1 dip switch to OFF, I still got the same flash pattern.
Anyway - sorry for the long description, I’m just trying to get this straight in my feeble mind. The mag is on it’s way to Granbury, TX for repair. If you make changes on yours, make sure you flash that timing terminal with the mag grounded. You can use your main power lead for this, or an external battery. Taking the threaded cap plug out to access the dip switches while mounted on the engine wasn’t worth it for me. It is made out of nickel plated brass with a too wide slot that is easily damaged, especially if you are removing it after use. The thread locker they recommend using makes it difficult.
RV6/2001 built/sold 2005
RV8 Fastback/2008 built/sold 2015
RV4/bought 2016/sold/2017
RV8/2018 built/Sold(sadly)
RV4/bought 2019 Flying
Cincinnati, OH/KHAO

Last edited by Scott Hersha : 01-23-2021 at 08:00 AM.
Reply With Quote