Flywheel Ring-gear replacement

[David_Doan]

Flywheel Ring-gear replacement [needed]

Updated: Got the old one off but the new one is too big. I need one for a 948 that has a 9-1/8" INSIDE DIAMETER

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So.... My old ring gear was pretty chewed up. I've been watching ebay for a cheap ring gear or complete flywheel. I found a NOS ring gear for $20 shipped. Now I have to put it on.

Getting the old one off seems pretty straight forward, cut it with a cut-off wheel then pop it with a cold chisel.

I've read what I can find about putting the new one on; seems like the easiest way for a shade-tree mechanic to do it is to put the new gear on the gas grill until it is red hot, then drop it onto the flywheel. Some say to also put the flywheel in the freezer.

Anyone have personal experience to share?

Thanks,

David

 

[nomad]

You don't want it red hot. You don't want it hot enough to even start showing heat colors. I've done a bunch of them over my life but only a couple on spridgets. Getting the flywheel cold is easy so you should do that to help the job along and I wouldn't heat past the point where spit sizzles and flashes away quickly. [technical process!!] Then move quickly!!

Kurt.

 

[nomad]

Make sure the flywheel is good and clean and free of any burr's before you begin the process as well!

Kurt.

 

[Trevor Jessie]

I've done a few using an oxy/acetylene torch, but I had heard of people using an oven. So, for the last one I tried the oven just to see. I set it on the highest broil setting and made sure the ring was extremely close the the heating element. I honestly did not think it would work. However, after about 20 minutes of heating it slipped on with just a few gentle taps of the hammer. But you have to be quick. x2 on removing burrs.

 

[Jim_Gruber]

Yor wife must be really tolerant or was out of town that day.

 

[Trevor Jessie]

Out of town ... and I was just thinking this morning that the engine block I just had machined would fit in out kitchen sink for cleaning. :eagerness:

 

[Jim_Gruber]

Yeah the new SS Dishwasher that was just installed, to replace the one that broke 15+ years ago, and has yet to be used yet. Still solving a plumbing/countertop issues, it would indeed make a perfect parts washer. But I know I would be out of town permanently if I tried that.
Hey honey, look how clean the dishwasher got these spindles and A-Arms...

 

[David_Doan]

Got the old one off, new one is too big. The 948 needs a 9-1/8" inside diameter, I got a 9-1/4".

Anyone have a 9-1/8" ring gear? Anyone need a 9-1/4" ring gear?



In the last pic you can see a spring pin that was driven in - I assume - to tighten the ring gear. There are 4 of these spaced evenly around, was this normal? Or should I scrap this flywheel?

 

[Rut]

David,
that is one rough looking flywheel! I may have a good 948 flywheel in the shop and I'll post pictures in the morning. From what I remember the ring gear was ok, but the flywheel had been drilled to fit a 1275 crank. The 4 original bolt holes looked good iirc. Yours for shipping and it will fit in a medium flat rate box.
Rut

 

[David_Doan]

Thank You!!

 

[Rut]

Re: Flywheel Ring-gear replacement [needed]

David,
pictures aren't the best in the world, but I think you can see them ok.
Rut

 

[David_Doan]

Rut,

That looks a lot better than mine! Is it a lightened version? Yours is dished out out the engine side vs. mine is flush.

 

[BlueMax]

Take note, 1275’s flywheels have two dowel pin holes, 948’s do not!!

 

[David_Doan]

So are you saying that Rut's will not fit on my 948?

 

[BlueMax]

Not only that, the 948’s flywheel only goes on one way too!!!

 

[Rut]

David,
thats the flywheel that came off of my 948 and it fits the smaller diameter ring gear. I have a complete 948 in a box that's bored .060 over that I'm not going to use and this flywheel came with that engine.
Rut

 

[David_Doan]

David,
thats the flywheel that came off of my 948 and it fits the smaller diameter ring gear. I have a complete 948 in a box that's bored .060 over that I'm not going to use and this flywheel came with that engine.
Rut

Rut,

Thanks for the clarification, I sent you a PM with my shipping info.

 

[BlueMax]

1275’s flywheels are index through the dowel pins, can only go on one way for correct balance. 948’s are index with a ¼ mark on the outside edge that is supposed to be at 12 o’clock with engine setting at TDC for the correct balance. There is no way for a correct balance to be achieved unless crank and flywheel are balance together. It’s your call?

 

[David_Doan]

OK, Makes sense. So the re-builder for Rut's engine (assuming rebuilt since he said it was bored .60 over) could have balanced that flywheel to that crankshaft. but there's no way to balance/index that flywheel on my motor.