IO-540 Starter Ring Gear

Auburntsts · #1 11-07-2012, 05:23 AM

I need to mount my starter ring gear (and its support assembly) to my IO-540 but I’m not sure of how to get it properly aligned. I was told that there would be an “O” stamped/engraved on both the gear support assembly (near one of the bushing holes) and a corresponding “O” on the prop flange and that all I needed to was align the “O’s” together. Problem is neither the gear support assembly nor the prop flange on the engine have any “O’s” stamped anywhere that I can find. So I then figured I could then just use the #1 cyl TDC mark, put the #1 Cylinder to TDC and align the TDC mark to the engine case vertical split line. Problem #2 is there are timing marks (#1 TDC, 20 deg and 25 deg) on both sides of the gear support assembly and they aren’t located at the same point on the gear’s perimeter. So if I go this route, should I use the timing marks on the forward side or the aft side? Am I making this too difficult?

fehdxl · #2 11-07-2012, 05:32 AM

It will only fit one way... Just six possibilities. Do not use a hammer though, it'll go on by hand. There should be two shorter stubs on the flange, and the wider one is the '0'. But that does no good if your ring gear isn't marked though. Best, Jim

Walt · #3 11-07-2012, 05:43 AM

The marks on the forward face of the flywheel align with a small "timing" hole on most starters, the aft facing marks align with the top case center line.

timandmeli · #4 11-07-2012, 05:45 AM

Hi,
The marks on the rear of the ring gear are for alignment using the case split. The marks on the front of the ring are to align the TDC mark etc with a little pin hole that is part of the starter (Which I find is the easier way to do it) It will make more sense when u finally get it in place. The O is for the oversized lung on the prop flange. Take ur calipers and measure each lug on the flange. One is bigger than the others. Good Luck Tim and Roll Tide

Auburntsts · #5 11-07-2012, 06:02 AM

Ah ha! Thanks for the info gents! I wonder where the stamped 1/8" ish "O" came from--other models or an oversight on my particular parts?

And Tim all I got is SEC! SEC! SEC! (it's the only silver lining I've got for this miserable season unless there's a miracle on 24 Nov).

barryrv10 · #6 11-07-2012, 06:07 AM

Just to be clear, the flywheel has the timing marks on it; the ring gear does not have any timing marks on it. The ring gear is a interference fit to the flywheel.