Super Stubborn Flywheel Nut

[gregwils]

I need to replace the main leads for the stator on a 160. I have the correct clutch basket tool and the correct flywheel removal tool. I have actually done this on my 250, so thought it should be pretty straight forward. I had the clutch basket locked with the tool. However, the flywheel nut would not budge, so I applied a little heat on the nut. I then got an extension on my breaker bar and had to be applying over 100 lbs of torque, then finally the clutch basket broke under the pressure. Bummer.

I could not find anything that suggested the flywheel nut was counter-clockwise. In fact, I can see the last few threads on the crankshaft and they appear the conventional direction. I still need to get the nut off and get a new basket.

The only think I had think to do is an impact gun and hope the small repeated blows might break it free. I am totally open to suggestions. Thanks.

[Dave450]

Hi there - an impact gun should undo it, and it should be a conventional right-hand thread. I have only worked on the larger singles, but I would be surprised if the 160 was different in this respect.

You don't say where you are but you should be able to buy a Clarke Impact Wrench quite reasonably. I can say it does the job on very tough nuts. Or, if you're close to a tool hire company, check them out.

I suggest you replace the nut.

Only use the impact wrench to undo engine nuts, not to tighten them.

Let us know how you get on.

Dave

[gregwils]

Thanks Dave, I hope you are correct. I have a gun and compressor, but won't get a chance to work on until a little later in the week. I'm in Pittsburgh, PA.

[pear0]

Looks like a good one to try the lighter and candle on. Beware of the red Loctite though. That needs more heat. TomA

http://dsportmag.com/the-tech/education ... and-bolts/

[gregwils]

Thanks. I am an expert at applying heat and did use a little, but was not expecting a dog fight. I certainly was not expecting to actually break the basket gear. However, after thinking about it, these motors only make 15-20 hp and probably no more than 10-15 lbs of torque, so there would be no need to have the engineering and metallurgy of that specific gear withstand 100 lbs of torque.

I feel a little stupid in retrospect, but I just didn't stop to think about it, so use to working on my car. I will approach challenges going forward with a little more reasoning and a little less muscle. I think some amount of heat and an impact wrench at 50-60 lbs with repeated small blows should loosen it. At least I hope that's the case.

[Jordan]

If the impact gun does not work, just as an idea:
Prevent the crankshaft from turning by removing the cylinder and piston, put the gudgeon pin back in the conrod small end, and a steel bar through it.
Turn the shaft until the big end is about 90 degrees ATDC, use packing under the steel rod on both sides so it cannot turn any more, then proceed.
It's not ideal as the big end bearing could be stressed, but if all else fails...

[gregwils]

Clever thought and follow your point. I hope you as you say that the impact gun works.

[gregwils]

Just to close out this thread, my air impact wrench loosened the nut in question so quickly that I thought something else went wrong. Too bad I wasted an otherwise good clutch basket in the process.

[ducwiz]

My method to operate the nut:

- dismantle the clutch basket to protect it from damage (cast iron!)
- block crankshaft with a hardwood (hammer shank) or aluminum bar placed between the flywheels, against the conrad's big end
- use airgun, after heating the nut (in order to break possible application of Loctite thread blocker)

- after reassembling, tighten the nut with a torque wrench after having placed the blocking bar on the bigend's opposite side.

If you don't have a mounting fixture to immobilize your engine, ask a friend to help

Hans

[gregwils]

Thanks Hans. Sounds like a good plan which I follow to reinstall and for future reference. One question, how much torque on the flywheel nut?