To summarize what I believe happened that has not been confirmed by any of the three companies involved. Van's attempted to respond to a large customer and many other RV-10 builders that are installing air conditioning in their aircraft, requested Lycoming to switch the ring gear on the YIO-540-D4A5 that Van's resells to a dual pulley gear. Lycoming compiled with the request and supplied a LW-12227 ring gear. Lycoming failed to mention to Van's that the alternative belt grooved moved aft a little. Nobody told Plane Power that even the engine configuration was changed.
With that stated, both Plane Power and Lycoming have responded to my inquiry and have been very actively working on a solution. The list price on a new ring gear is about $1,700. Van's has not responded other than to pass the buck to their suppliers.
The following was the first email that I received today from Plane Power.
Lycoming reports that the alignment difference is .130â€ with the alternator pulley forward of the flywheel pulley. This fits what you have reported as well. If the alternator is adjusted to move aft (toward the firewall) to align with the flywheel pulley the Tension Arm (99-1004) will also be off alignment.
We intend to produce a kit solution for future applications. We understand your need is now so we offer the following suggestion to you.
- 1. Verify that you need your alternator to be moved .130â€ (or whatever your requirement is) and make that your new target point.
2. Leave the 99-1001 spacer attached to the alternator as it presently is. We donâ€™t think you can remove it with satisfactory results. Machine grind the 99-1001 spacer by .130â€. Leave a flat surface. This will move the entire alternator aft. In doing so it will create a void at the 99-1002 front spacer.
3. Add a spacer or washers between the 99-1002 spacer and the mount bracket.
4. Add a spacer or washers between the tension arm (99-1004) and alternator where the tension arm connects to the alternator.
5. The starter strap will be attached on the outside of the mount as usual and no modification should be needed.
The above instructions have not gone through our engineering process. It represents our effort to give you suggestions to assist you in your EXPERIMENTAL effort to fabricate a solution for your application. It is up to you to verify that the above suggestions are appropriate for your application.
To be honest, my immediate reaction was pretty negative with this response. I purchased an engine and a fire wall forward kit from Van's with the expectation that the alternator, alternator belt, and the engine ring gear alignment would be plug and play, just like it has been for years. I don't have the tools to perform these tasks nor the willingness to hire a firm to make them for me. Van's should have stepped up and admitted to the oversight, then work with the vendors to make all the builders that purchased this variation of the engine and the FWF suppled alternator a solution. The more I think about it, Van's should publish a service bulletin on this situation. If folks don't notice the 1/8" offset, they will eventually lose a belt due to coming off or premature wear.
Fortunately, Plane Power understanding that I probably didn't have the tools to be sucessful with their original instructions, sent me the following email a little later today.
We have a new solution for you. We are going to ship you some new spacers which we will cut down the size. So call me ASAP so we can get address, etc. and discus.
We thought removing the existing spacers from the alternator would be very difficult. So we tried and experiment and liked the results. To get your current two spacers out of the alternator do this. Get a container that will allow you to fill to a certain point with lacquer thinner. Arrange your project so you can soak the ear and spacer of the alternator in the lacquer thinner. DO NOT GET THE ALTERNATOR CASING IN THE THINNER - JUST THE EAR AND SPACER.
Leave submerged for one hour. Remove from the thinner and using a vice, pliers, etc twist the spacer out of the alternator ear. Perform the same task on the other ear & spacer. Then you can replace the old spacers with the new ones we will send you.
I suspect it will be a week or so before I can attempt to make this modification. I'll post an update with the results.