1971 Johnson 85 hp woodruff key screwup

[rico suave]

It started harmlessly. I had the flywheel off inspecting points and while I had the flywheel off noticed the woodruff was a little mashed, rounded, slightly flattened, so no big deal I'd order a new one and replace it. I thought I would just pop it out and put a new one in. I thought, it's just a shear key, easy peasy. I started poking, hammering, and it didn't come out. It looks like it's part of the crankshaft and not a separate piece as I thought?...but I was in too deep to quit. Ultimately I found I had to make a new pocket for the woodruff key so I got out the 2" grinding disk and made a new slot. I thought I did a good job, apparently I was wrong. I now know that it should have been carefully machine and slotted in an exact location, perfectly matched. My question is what do I do now? New crankshaft, another slot on the opposite side of crank? I tried JB Weld, didn't hold. Any opinions, help, guidance would be appreciated.

 

[Joe Reeves]

Yeah... oops, ugh! Damn... Wish I hadn't done that! The key way sets the timing as you've probably discovered. The cure = another good used crankshaft.

 

[rico suave]

Crankshaft woodruff disaster...help!

It started harmlessly. I had the flywheel off inspecting points and while I had the flywheel off noticed the woodruff was a little mashed, rounded, slightly flattened, so no big deal I'd order a new one and replace it. I thought I would just pop it out and put a new one in. I thought, it's just a shear key, easy peasy. I started poking, hammering, and it didn't come out. It looks like it's part of the crankshaft and not a separate piece as I thought?...but I was in too deep to quit. Ultimately I found I had to make a new pocket for the woodruff key so I got out the 2" grinding disk and made a new slot. I thought I did a good job, apparently I was wrong. I now know that it should have been carefully machine and slotted in an exact location, perfectly matched. My question is what do I do now? New crankshaft, another slot on the opposite side of crank? I tried JB Weld, didn't hold. Any opinions, help, guidance would be appreciated.

 

[racerone]

What is the model numver of your " belch fire special "----Without that there can not be any good advice !!

 

[derek4325]

Not knowing what motor you have but in pretty Much all cases you cannot cut another key way anywhere else except where it is now. If you did that you would have to cut a notch in the flywheel as well the the EXACT right spot or your timing will be way way way off. Unless you can get a new key back in the original spot I would say it's best to get a new crank shaft. Not knowing what damage has already been done that's the best advice I can give. If it's not too bad maybe a good machinest could "clean" it up and help you get by. Good luck

 

[GA_Boater]

Rico - Both of your threads have been merged. Please don't start multiple threads on the same issue. All of us get confused when advice is splintered.

 

[racerone]

All very funny!!!--------The key for the flywheel does not affect the timing on this motor !!!

 

[rico suave]

If somehow a new slot could be cut on the opposite side of the crank, an accurate one, wouldn't a complete reset of the timing fix it?

 

[Joe Reeves]

All very funny!!!--------The key for the flywheel does not affect the timing on this motor !!!

Yeah I know, and realized that as soon as I sent it... just didn't feel like correcting it as it really didn't matter. He needs another crank regardless.

 

[oldboat1]

There must be some of the initial slot left to center the flywheel. I would clean up the tapers and carefully line up the flywheel slots, and torque it down -- try it. Run it a bit if you can, then torque it again. The key doesn't hold it in place anyway.

 

[rico suave]

I agee, I think I have one more shot at this. There is some initial slot left. I accept the challenge. I need a micrometer to carefully center and the right type of cutting wheel and if I can prove Joe Reeves wrong, then I out rank him?

 

[oldboat1]

Nah. Get to tell your story, though, one way or the other.

 

[Joe Reeves]

I agee, I think I have one more shot at this. There is some initial slot left. I accept the challenge. I need a micrometer to carefully center and the right type of cutting wheel and if I can prove Joe Reeves wrong, then I out rank him?

No, not wrong... I just didn't want to get into a technical conversation with someone who has jumped in every time I make a typo or misspeak about something ever since day one when he finally learned how to turn a computer on. Go ahead, cut another slot somewhere on that crank and install some hardware store woodruff key. There's this thing about balance no one has brought up. Should be interesting if you leave the hood off. Personally I have no use for "Patchwork!". Either do the job right... or don't so it at all!

 

[boobie]

Joe, I'm not trying to be a smart a&* but what's this thing about balance and repositioning the flywheel with a different keyway cut in the crankshaft. ?? Mainly wondering about balance ??

 

[rico suave]

Joe, totally appreciate the input. I have to give it another shot. The cruxt of my problem is really about replacing the engine not just the crankshaft. It's a 1971 so I see it as an all or nothing. I'm still confused about the woodruff and how the crank was made. I see shear keys in many motors, always just pop out. WTF!

 

[rico suave]

Is this something that can be cut in by a dealer? Is there a special tool I should be aware of? I would appreciate any sage advice.

 

[oldboat1]

I would try it without replacing the key or whatever is left in there, as long as the machined slots line up. Line up the flywheel slot, and torque it down to spec. (105 ft lbs or whatever is called for). Taper and torque holds the flywheel in place.

If determined to cut out the old key, take the rig to a machine shop and have them do it.

 

[interalian]

An aside: I've often wondered whether the key is needed aside from initial alignment, if the actual lock is accomplished using the tapers under specific torque.

All the threads where an under-torqued flywheel ends up shearing the key would support this. In practice, if the key were actually holding the flywheel in place, there would be micro-fretting between the tapers and it would eventually wear down and loosen, then shear the key.

Taking my mech engineer's hat off now...

 

[Roberthill]

Taper on crank and flywheel are "self locking tapers" otherwise wouldnt need puller , but to hold have to be precise . Just my 2 cents .

 

[rico suave]

Thanks to all for the input, greatly appreciated. I'll get at it.