Replacing Flathead Flywheel Ring Gear

Can this ring gear be replaced? There is a lip around it that looks like it will prevent it from coming apart. If memory serves me correct, this came from a 59A block ('46-'48?) and had an 11" clutch.

 

It will come off

 

There are a couple of little chips on that lip and the flywheel is sitting behind it. If I knock the ring gear off, it will break that lip.

 

All ring gears are made separate from the flywheel and can be replaced. You need an acetylene torch or arc welder with a carbon rod to get it hot enough.

Here is a video showing how to remove the old ring gear and put on a new one. Note, the ring gear is held on by friction and must be removed and replaced using heat to expand it.

http://www.youtube.com/watch?v=j_sgiTa3gew

 

There is only one way it can come off/go back on. And it is 2 pieces.

 

Great video! I haven't done one in many years and this guy was right on, except for the wood blocks, I always used bricks. One local guy claims to have used a pizza oven to heat his up.

Bob

 

When you are done getting it back on drill four small holes in the joint and pin it.

 

Especially if you flip the old ring around and re-use it.

Bob

 

Should not need to be pinned if it fits right. If not a couple of tack welds will hold it.

 

I have had luck using BBq to heat and eat - heated the ring gear / flywheel and BBQ burgers next to it - used a small crow bar to pick it up ( flywheel not burger ) and tapped off ring. Flipped it and burger and tapped it back on ( ring gear not burger ) this was early man's multi tasking.

 

That ring gear must expand quite a bit when heated....cuz the groove that it's sitting in looks fairly deep. I'll give it a shot if I have any gas left in my torch. :-/

 

If you heat with a torch, use a rosebud tip instead of the cutting attachment. Also if you are going to flip the ring gear, mark it and rotate it 180 degrees as the engine has a tendency to stop near the same point frequently. The wear on the ring gear is from the starter engagement.

 

I won't be flipping the ring gear. It's got some missing teeth. Still having trouble believing this thing is gonna expand enough to fit over that 1/8"(?) lip though. Looks like when heated, it still needs some persuasion to move.

 

You can change it although you need to have it expand enough to get over the ridge. If you stop before you get it in the groove and then tap it into place with a chissle it may be too loose. Flattys are like this same with 8Ns. You can cut the ridge down a bit on a brake lathe.

 

If the ring gear won't expand that much how did they get it on there?

Another way to get the old ring gear off is to split it with a chisel.

 

Magic? I've just never seen a flywheel with a groove for the ring gear to fit in. But then again, I've never had to replace one before.

 

I had seen it done once when I was about 18. Go forward a few years and a guy I worked with brought his flywheel (either a '48 Plymouth of '49 Ford, he had a few cars...) in to be resurfaced and I saw that a bunch of teeth were bad.

So I suggested flipping the ring. We had a b-tank with a rosebud tip handy. Nobody even the old timers had done it before. So it drew a crowd while I was doing it. I had to heat the ring a 2nd time before it dropped on with no effort.

Not so much a groove, it had a shoulder to butt up against. Do parts stores still carry rings? I haven't had the need to do one since my 1st shot.

Bob

 

You can also put the flywheel in the freezer for a while to shrink it and with the expansion of the ring gear due to heating it should slip on a bit easier.

 

This ring gear is sandwiched between 2 shoulders. Yes, ring gears are available. Like already said, it didn't grow there. I'll heat it until it drops off.

 

Buy a new ring gear. They are available and cheap. Make sure that the groove in the flywheel is clean and lay it flat on a table. Heat the ring gear on a flat metal table with even heat from a torch, rosebud is best. Quickly pick up the ring and place it into the flywheel groove. It will fall perfectly into place and it will shrink down onto your flywheel as it cools. Good for another fifty years.

 

All flathead ring gears are installed and removed from the starter side or back of the wheel. Only heat the ring gear up red hot in a couple of spots and drive it off with a large brass drift.Heat the new gear up and it will almost drop on.It's only a press fit nothing else. Not rocket science,kind of like a farmer job.

T

 

Thanks, that guy has some great tips and videos!

 

That is a good video to save for reference.

 

Old thread, new video. No tools, no torch, no problem.

 

This came up in another thread this week, very timely!

 

Sorry, just saw it this afternoon

 

No man. That is an awesome video and timely to post it since somebody else was recently asking! I even learned a couple things! I think I would have staked the flywheel in a couple places for xtra security tho....

 

Replacing these is easy. Knock the thing off with a drift and a heavy hammer. A 4 pounder will do it. Put the new ring gear in the oven (yes, the one in the kitchen) Crank the temp up to 500 degrees, or broil setting and let it cook for 20 minutes or so. Take it out wearing welders gloves and quickly drop it on the flywheel. Be sure the tapered teeth face the starter drive teeth. It should fall right on if there are no old welds or other damage. Lightly tap it down to make sure it's seated. At that point it should have shrunk enough to be tight. Let it cool completely. If the flywheel is good with no tampering, no pins, welds or other farmer fixes is needed. If anything else was needed they would have done it in the factory. Welds, especially, can easily cause an out of balance condition and make you unhappy. Balance is critical.

 

Umm, the video showed all of that?!

 

every one I have done had a lip on it so you cant just drive it off with a punch, it needs to expand or you break off the lip. I set the flywheel on a block, and heat with a accetalene torch, round and round until it falls off. Then, heat the new one until it falls on, again with a torch, round and round until it goes. I did not watch the video cause I know how to do it, many times over.