Fly wheel ring gear

[David R.]

Any one replace one? How much of a job is it? Engine is already removed. Surface on flywheel is good but ring gear worn.

[1crosscut]

Easy to do. Use a torch to heat it so it expands and push it off.
Heat the new one and drop it on. Work fast and have a hammer and drift handy to push it in place.
Be sure that you orientate the new one the same as the old one.

[David R.]

Thanks Dave. Orientation? Not sure what you mean. Is there a front or back? You have AA? That is what I’m working on.

[aermotor]

Don't do like I did. Beveled teeth on the REAR side of the flywheel as the Bendix comes from the back. Get it wrong and out comes the engine. Not fun for a simple screw up.

John

[Jim/GA]

Originally Posted by 1crosscut

Easy to do. Use a torch to heat it so it expands and push it off.
Heat the new one and drop it on. Work fast and have a hammer and drift handy to push it in place.
Be sure that you orientate the new one the same as the old one.

You can also fire up the charcoal grill with a load of charcoal and place the ring gear on the hot coals. When the ring is good and hot, expanded, it will slip right on the flywheel. Tap it down on the flywheel until seated on the ridge and it will then cool off and lock on. No need to rush.

[David R.]

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I was thinking of firing up the coal forge. Same process as setting wagon tires!

[David R.]

Right! Bendix pulls in from back. One side of teeth beveled. Got it.

[john charlton]

If your wife doesnt mind put the flywheel in the freezer overnight it makes an easier drop on and as the good folks say bevelled teeth to the back .

John in a lovely sunny afternoon Suffolk County England .

[redmodelt]

I use a cold chisel and split the ring gear to remove, clean up any burrs around where it sits, heat the ring and drop on.

[Brentwood Bob]

A wire brush is your new friend, and avoid overheating (no color). The cold flywheel and hot ring are the correct combination. A brass drift to seat the ring. Work around the flywheel to gradually seat the ring if tight fitting. I used dry ice and the barbecue.

[Jim/GA]

Originally Posted by Brentwood Bob

A wire brush is your new friend, and avoid overheating (no color). The cold flywheel and hot ring are the correct combination. A brass drift to seat the ring. Work around the flywheel to gradually seat the ring if tight fitting. I used dry ice and the barbecue.

Oh, yes! I forgot the dry ice packed inside the flywheel. Thanks, Bob!

That plus heat the ring in the charcoal grill will do it.

[Big hammer]

Heat the old ring gear in one spot to cherry red, then with a big hammer and punch knock it off. Install with a cold flywheel and a hot rind gear it shoul almost fall on.

[Brentwood Bob]

The hard part now will be locating the dry ice.

[Tom Endy]

Several of us have had the experience with repo starter ring gears pulling forward away from the stop on the flywheel and jamming the starter. The solution was to take it to a machine shop and have it pinned in place with set screws. It would have been better if Henry had put the stop on the front side.

Tom Endy

[David R.]

I have a chest freezer I use for freezing parasites out of honey bee equipment.

[Jim Brierley]

Freezing is not required, and too much trouble. If you're cheap like me, you could remove the gear, rotate it 90* and re-install it. The gear always shows wear in only 2 places, 180* across from each other. redmodelt does it by the book, I just knock the gear off cold, heat the replacement gear with a acetylene torch and slip it on. Seating with hammer and punch should always be done.

[chap52]

I used the charcoal grill approach as Jim suggested. I also left the flywheel in the freezer for a couple of hours prior to dropping the ring gear on. This was on a Ford V8 flathead which has a directional ring gear. In other words you can put it on backwards...don't ask!... Chap

[The Master Cylinder]

Originally Posted by Brentwood Bob

The hard part now will be locating the dry ice.

They sell it a Von's near me. You may try at a grocery store near you.

Originally Posted by chap52

This was on a Ford V8 flathead which has a directional ring gear. In other words you can put it on backwards...don't ask!... Chap

As is the Model A ring gear.

[Joe K]

I have removed a ring gear at room temperature using a 1/4" punch. You start at one point and give it a slug. Then move 1/4 the way around the diameter and do it again. Rinse and repeat until the gear falls away.

Going back on I put the flywheel in the freezer overnight. Next day I put the wife's oven at 550 - one notch below self clean. Ring gear inside for 1 hour.

Then the two come together - you "drop" the ring gear on.

Nice even heat - nice even cold.

After it is in place and room temperature - I run blue Loctite into the groove. Don't use Loctite red as it requires plus 300 to break the bond.

I've even "relocated" a ring gear 1/4 turn by this method to get past the starter bendix "jamming." (Engine tends to stop at two places 180 degrees apart - the ring gear wears especially at these places - turning it 1/4 turn puts "new teeth" at the point of greatest load/jamming.)

Clean off any rust on the "outboard" side of the machined portion of the flywheel before you begin. And clean it up again before reinstall.

Joe K

[David R.]

Thanks everyone. I have new ring gear on order. (Plus a bunch of transmission parts)