ring gear

Is it really necessary to freeze the flywheel? Has anyone ever measured the reduction in diameter doing it this way? Seems to me to be a waste of time, the ring gear will expand far more than the wheel shrinks.......IMO......, eih? phil k.

As stated previously it is the temperature differential that matters, and to get adequate differential by heating alone the heated part may be over-heated. By srinking the second part you gain significant differential advantage without the danger of damaging the outer part from overheat. If they are made of the same material each will change size by virtually the same amount per degree of temperature change, in opposite directions.

Yah, but, the flywheel is cast iron and the ring is steel. Cast won't move as much as steel. We need some actual measurements!!

Per The Engineering Toolbox

Grey cast iron 6.0 (10-6 in/in oF)

Steel 7.3 (10-6 in/in oF)

Dan

Per The Engineering Toolbox

Grey cast iron 6.0 (10-6 in/in oF)

Steel 7.3 (10-6 in/in oF)

Dan

We need to actually 'measure a flywheel' ! phil

WHY? I have installed probably 50 ring gears and other assorted items this way over the years. Used this same set of temps for years.

This is also the factory method for the particular engine.

It falls into the category of "Don't fix what ain't broke"

Expansion rates per degree F i n microinches for various irons and steels are as follows:

Grey Cast Iron 5.8

3% carbon cast steel 7.0 Ductile Iron 5.9 to 6.2 Maleable Iron 7.5 Nodular Iron 6.5 Pure Iron 6.8 Wrought Carbon Steel 7.8

Has the flywheel material been definitely identified? Some are cast steel, some are nodular iron, and very very few are grey cast iron (and then some are aluminum).

Assuming it is cast steel or nodular iron and thering gear is carbon steel, there is a 10 to 20 percent difference in the rate of expansion, so you get 10-10% more movement per degree out of the ring gear than the flywheel. In this case, that is hardly significant.

Awl riiight..... Let's crank some numbers here: Both the ring gear and flywheel are at 70 F., 12 inch wheel. Cool the flywheel to -20 F., 90 deg change.

0.000006 x 12 x 90 = 0.00648 reduction in dia. Heat the ring gear to 400 F., 330 deg change. 0.0000073 x (12 x pi) x 330 = 0.09082 expansion. (12 x pi) + 0.09082 = 37.78993 heated "length". 37.78993 ÷ pi = 12.0289 So we get the ring to expand 0.0289" in diameter and the wheel shrinks 0.00648 inches. So I ask you, do you still think you need the 0.00648? I don't think so, it's a waste of time to freeze the wheel. That's my answer and I'm sticking to it. I don't care one whit how many you've done. phil k.

I have no argument with your conclusion, but you made the math for the =

ring gear overly complex. Some people might be a little intimidated by t= he =

method you used, even though it is correct.

A simpler way is to treat the ring gear the same as the flywheel.

Heat the ring gear to 400 F., 330 deg change.

0.0000073 x 12 x 330 =3D 0.028908 increase in diameter.

The changes from diameter to circumference and back to diameter are =

unnecessary and only add the opertunity for an error to creep in.

WayneJ

=

I have no argument with your conclusion, but you made the math for the ring gear overly complex. Some people might be a little intimidated by the method you used, even though it is correct.

A simpler way is to treat the ring gear the same as the flywheel.

Heat the ring gear to 400 F., 330 deg change.

0.0000073 x 12 x 330 = 0.028908 increase in diameter.

The changes from diameter to circumference and back to diameter are unnecessary and only add the opertunity for an error to creep in.

WayneJ

Sometimes I'm too methodical for my own good, but that's the way my brain works ..... ;>)) phil k.

I'm only a tech, but FWIW, I concur here.

Cheers! Rich

...

At least yours still works.

Of all the things I've lost, i miss my mind the most.

Karl

I was just wondering, do you guys find that people become less productive after 40? I will have my 40th anniversary in march

40th birthday I assume you mean..

Physical things (especially vision) go downhill, but the mind can keep working just fine. I think you have to work a lot harder at staying physically fit in order to keep the mind going well.. when you're young it just happens. I have the good fortune to do work with a gentleman in his eighties who is sharper than many 25-year-olds (Professor Emeritus at the University of Toronto, Order of Canada, one of the folks who helped save Apollo 13), so it _is_ possible.

Best regards, Spehro Pefhany

...

You screwed, get out the black flags, life is over

I'll just speak for myself. From 40 to 50 I lost maybe 10% physically and mentally no significant change. For the mental part, I started "working at it" in the late 40s. That is try to learn new complex stuff as part of my life. I learned object oriented computer programming as a new task for example.

From 50 to nearly 60, I've lost considerably more physical strength and endurance. As a check I'm now maybe half the strength and endurance of my 28 year old son. I could have done better here if I'd worked at it harder.

My ability to learn new real complex stuff has slowed considerably from 50 to almost 60. I doubt I'd ever take up something totally new. Here, if you don't use it, you'll lose it. I read stuff like Scientific American and take on serious hobby projects like refitting complex CNC machines to stay sharp. As to mental productivity, I'd still take on a 20 or 30 year old. An older person can use experience to compensate for speed.

Just one data point for you. I'm sure how well people age is as variable as their original talents.

Karl

That's odd. My mind is the thing I miss the _least_ of the things I've lost. For example, a digital camera is a lot more useful. ;-D

Or a job. )-;

Cheers! Rich

You left it behind your lathe. ;-)

It sure didn't do Bret Favre any good!

Our capabilities change with time. Some people become more productive in later years. Physical strength and stamina diminish and it gets harder to assimilate facts and details by rote short-term memory, but experience starts to become wisdom, judgement and "intuition" that can produce good decisions no amount of algorithmic analysis, deduction or induction could produce. Athletes and soldiers are best before 40. Generals, judges and professors require more seasoning.

An older person may have a much richer skill set than his junior associates if he's bothered to grow them along the way. He may not be able to perform a given menial task as quickly as a younger person, but he may be able to work a lot smarter with fewer errors, and hence be more productive. I include software coding as a menial task in this context. Not software design, crunching code. He may be able to mentor and lead a group of less-skilled people, thus greatly magnifying group productivity.

I won quite a few more patents after age 40 than I did before age 40, but I had one hell of a time learning to use PIC microcontrollers at about age 65. That task would have been trivial 30 years earlier. My problem was short term memory for arcane details in assimilating a

187-page data sheet. The "data sheet" for the then-new Motorola 6800 in 1975 was the size of an urban phone book and I had no problem absorbing that in a couple of days ... when I was in my 30s. I learned FORTRAN self-taught in two days when I was in my 20s. I mastered PASCAL in a week when I was in my 40s. I still haven't mastered C and probably never will. I'd like to, but I'd need a coach and I don't know anyone who would have the patience to coach me and I don't blame them a bit. Maybe when it's my turn to be in a home I'll have a laptop on Wi-fi or whatever it is. I'll definitely have an unregistered ancient pepperbox .22 pistol secreted in me kit.

Mar is en pointe in our current episode, I'm on her six. The rehab facility looks like Valhalla on their website but it ain't. It's not quite a hellhole but it's way far from Mayo. We lucked out with a very good nurse, Demitu, an African, beautiful young woman. She's stunning, a headturner. She shortened it to Demi for us. She's the RN that gave me an A on ace bandage wrapping.

Some people change priorities a bit after a couple of decades of adulthood. They've learned how to be productive enough to sustain a comfortable standard of living without busting their hump so they segue from growth-as-job1 to a more level maintenance mode -- just enough growth to avoid career stasis -- and increase focus on other things like family, friends, leisure, avocations, community service, stuff like that. They're very productive if you expand the notion of productivity well beyond income production and treasure accumulation.

Note: Days spent fishing are not deducted from lifespan. Hours spent taking a child fishing are added to lifespan.

What's gray and comes in gallons? Elephants, not old men. But 40 is not old. My sex life began at 40 after my first wife threw me out at

2. I do recall a bonk at age 40: my son and I had made a birdhouse on a kid's weekend with me in 1982 when I was 40 and he was 10. He designed it, made it, painted it and wanted it up in an oak tree in my (rented) back yard. Hey, no prob, I'll toss a rope over yonder high limb and squirrel up the rope hand-over-hand like I did back in Army days, right?

WRONG! I did make it up there with the birdhouse doing a sort of reverse rappel but that was definitely a wakeup call. UNGH!

Don't blame yourself. It was the 70 pounds of paint that did it! ;-)