How to heat flywheel ring

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oldford

Senior Member
How do you guys heat the ring hot enough to install. I have no welding gas. Would putting it in an electric stove. Or maybe burning charcoal fire.
 
I heated the ring in the kitchen oven and put the flywheel in the freezer after cleaning off all oils. The easiest install I witnessed is when dad heated a ring in the big kiln we had in the garage at the time.
 
I heat my ring gears in the broiler of the kitchen stove. I put plywood on the floor in front of the stove with the flywheel already in place and ready. Heat to 450 or so for 20-30 minutes. The gear shrinks quickly once it touches the flywheel so be ready with some large punches and a drilling hammer to make sure it seats. Needless to say, I only get away with this when my wife is not home.
 
nkaminar said:
I heated mine in the gas grill set to 500 F.
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Just did this for my Burtz flywheel. I put the flywheel overnight in the freezer and used the gas grill set to max to heat the ring gear. I put three 2x2x3/8” (dimensions not important, those are what I had) steel flat bar pieces on the gas grill, and set the ring gear on them to keep grill scudge from getting on the ring gear. I heated the ring gear and monitored the temp using a cheap IR thermometer I got from the River Store. Gear needed to be 450F or above, it will be slower to heat where it touches the standoffs. Be prepared with a brass drift and a big hammer (or an air hammer) to seat the ring gear once you get it started. Oven mitts are your friends.

Better to have the gear too hot than not hot enough. If you get it partially on and can’t finish you’re screwed. Either use a torch to heat up the gear or cut it off.

Remember that for a standard Model A starter motor (even with a “modern” Bendix assembly) that the bevels on the ring gear teeth face aft (towards the clutch surface).

Oldford, I think an electric oven would work fine, you might have to use the broiler to get it hot enough. Those IR thermometers are pretty handy, they can be had for well less than $50. I’ve used our electric oven to heat up bearings (e.g, ring gear carrier). Like 400A says, do it when your spousal unit is not around to object, and turn on the range fan. And always act innocent.

Back in the “old days” the guys who made wagon wheels used a ring of fire to heat up the steel bands that went onto wooden wagon wheels. Lots of YouTube videos out there, it’s a fascinating process.
 
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I have a lot of fire bricks under my workbench. They are soft and brittle so they are fairly safe there. They withstand very high temperatures - that's why they are used to line furnaces and they do not absorb much heat themselves. By placing them so that the ring gear is sitting on them (not the concrete floor) and some bricks on their side, then others on top, I have a semi enclosed "oven". I have only a LP gas torch but when I open it up, it gives plenty of heat to get the ring hot enough that it drops straight into position, even with the flywheel at ambient tamperature.
 
Charcoal works, make sure bevel is correct. Preclean the bed in the flywheel. When the ring is seated with a drift punch the flywheel should ring like a bell. The Restorer magazine article I wrote describes the charcoal heating procedure.
 
Electric oven set at 450F for 30 min. Literally causes the ring to "drop on." Use a punch and hammer to "seat" the ring against the ledge as it cools.


Joe K
 
Charcoal grill for the ring, about an hour in the freezer for the flywheel. REMEMBER that the ring is directional. Don't ask how I know. LOL Chap
 
Thanks for all the help. I'm thinking about using oven but I have too wait until wife is gone. She gets anal over using her oven for anything but cooking. I read on you tube where this one fellow used a "weed burner" and said it gets plenty hot. Anyone have any experience using one of these.
 
a hand held digital temperature reader comes in handy. is what i use to check temp.
i just heat them with the big propane torch, they call them weed burners. oven, bbq, anything to get it up to temp. that ring gear will drop rite on, give it a little turn to make sure it is seated, do it fast as it will shrink on quick.

the issue is getting it off if you make a mistake, or if you want to reuse the ring gear on another flywheel. it can be done but i find it challenging.
 
yes you can use your weed burner. just heat it evenly, round and round. like i said the temp gun is good for checking temp. do not get it too hot.
 
Costco has a two Taylor thermometer set, an IR thermometer with laser, and probe thermometer
Item 1759383 | Model 5316480SV for $20 in the warehouse or $25 online right now.
I’m guessing the set of two in a blister pack may be paired just for Costco.
 
oldford said:
Thanks for all the help. I'm thinking about using oven but I have too wait until wife is gone. She gets anal over using her oven for anything but cooking. I read on you tube where this one fellow used a "weed burner" and said it gets plenty hot. Anyone have any experience using one of these.
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You could offer to clean her oven !? That way it would remove any evidence of your activity !
 
I tried all sorts of ways to heat it properly, and none worked well. I finally got frustrated and tossed the ring into my outdoor firepit with a fire going. :rolleyes: Surprise.........it worked! It went right on, super easy.

So for me, if I do another, I'll just put it in my firepit for a while. It was a breeze when it was sufficiently hot enough.
 
So the chamfer on the inside diameter of the ring goes on first. The original ring does not have a chamfer. I'm assuming the chamfer helps to get the ring lined up and started. When I look at the new ring I cannot tell if the teeth are pitch one way or the other. Looks like anyway it's install it will work. But for ease I will have the chamfer pointing down as I install. The wife said I could use her oven. She must be wanting something.
 
oldford said:
So the chamfer on the inside diameter of the ring goes on first. The original ring does not have a chamfer. I'm assuming the chamfer helps to get the ring lined up and started. When I look at the new ring I cannot tell if the teeth are pitch one way or the other. Looks like anyway it's install it will work. But for ease I will have the chamfer pointing down as I install. The wife said I could use her oven. She must be wanting something.
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"Looks like anyway it's install it will work."

No! The teeth are not pitched, but they are pointed on only one face of the gear. The teeth point aft after install. Since you will be installing the ring gear on the forward side (not the clutch side) of the flywheel the teeth go down during installation.

I would suggest that before you get started you take a fine file and go around the flywheel just to be sure there are no burrs on that corner. Same thing with the inside of the ring gear.
 
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