Mag timing - alignment

[Gary 40274]

How old are the mags. It sounds like the internal timing points are so worn that it won't let you rotate enough. I think a mag overhaul might be in order

Gary Specketer

[N520TX]

For the 540, the mag "gear" is not physically attached to the mag, it's in the accessory housing. The mag interfaces with it via a pair of rubber cushion clamps and the magneto drive "coupling". I had the same problem with my right mag. I needed to pull the gear out of the accessory housing, and rotate it one tooth, then re-install it.

[Robert Anglin]

Just be glade they are not helical gears mashing up. Those take some time getting used to offsetting. Hope this helps. Yours, R.E.A. III #80888

[aerhed]

Ron has it. You probably need to pull the gear out and rei-ndex one tooth. If you have this problem on the 4 cylinders where the gear is attached to the mag, you pull the gear and give it a 180. That swaps you half a tooth.

[mcgaughy]

I'm thinking the mag should initially be set on the engine... with the timing pin locked in the mag....when #1 is at Top Dead Center (TDC). Give your magneto manufacturer a call for 100% assurance & accuracy on this. Then, when you time the mags, you use the timing light and the 25 (or whatever)degrees Before TDC.

[jabarr]

Regular Mags are not installed with the #1 cylinder at TDC. They are installed with the engine at the point BTDC that is listed on the data plate. Pmags are a different story but we're not discussing those here. Several posts have been made that are giving the wrong information. The OP is actually using the proper engine position.

[Auburntsts]

If anyone is interested, Tom Olson complied Sacramento Sky Ranch's Slick Mag Timing tutorial which you might find useful.

http://www.myrv10.com/tips/maintenan...ming_info.html

[DennisRhodes]

do Bendix mag installations have the option of an impulse coupling like slick? If so be sure you're setting the timing with the impulse coupling already 'kicked " and out of the way . If no impulse arrangement Ignore this post.

[8 ball]

Be sure when you are rotating the engine for timing to click the impulse then set your timing.

[WA85]

Possibly check the E-Gap (aka internal timing or points to mag drive shaft timing), sometimes if its set to one end or the other of the permissible range, it is not possible get the mag to time to the engine within the adjustment range of the hold down slots. Not sure what the 1200 series E-Gap is, but the S-20 series was something like 8 to 14 deg. Setting the E-Gap to the mid range is optimum, but sometimes you have to set it towards one end or the other to account for tolerance stack up. The Bendix mags use special tools (dwell pointer and degree plate) and a timing light for doing this.