Archive through May 06, 2004

[dvogt]

KENtucky, not a bad idea with the fancy balencers. but you're about 2 years late. been running one on our pullers for a while now

 

[dkamp]

Hi Ken, Hey Don!

Ken- the balance gears and balancer-dampeners don't work on the same concept, so one doesn't really 'replace' another... but there's plenty of reasons one way vs. another.

The balance gears are located above and below the crank so that their imbalance counteracts the swinging throws and reciprocating mass on essentially the same planes, and from what the K-series manual describes, Kohler went through some 'learing experiences' and changed some of the counter-balancing concepts, probably as a result of gear-spitting.

If the stuff I've been reading, the balancer-damper came into being as a method to cut down on the amount of torsional vibration along a crankshaft. Consider a large inline 8-cylinder engine... 8 throws, 9 main bearings. When the front cylinder fires, it's pushing against the crank, which at certain speeds, will twist slightly... winding up like a spring, until the flywheel catches up. In this case, fatigue could eventually yield to the crank's demise. Of course, this action would be much worse at certain speeds. If you look at a mantle-clock (or an old railroad signalling timer) you'll find that many don't have conventional pendulums- they have a flywheel on a torsion-spring. The flywheel spins one direction, twists the spring, and snaps back the other way... where it's spinning time constant is determined by the characteristics of the spring AND the flywheel's polar moment of inertia. (phew... that engineering class was how many years ago?)

Testing different materials and shapes one would find a crank that would withstand substantial service life... typically the result was forged steel or nodular iron, and pretty stout, but there HAD to be another way... less expensive and lighter... to keep a crank from rattling itself to pieces.

It's been a while since I read the balancing section of this book, but I believe the harmonic balancer really came into being (along with quite a few other automotive technologies) late in WW2, probably in the V engines of aircraft.

Anyway, the basic idea of the harmonic damper, is to make it's mass and elastic properties such that, when installed on a crankshaft with a given axial Frequency of Oscillation, the damper's reactance cuts the crankshaft's ringing propensity, and reduces the amount of crank-fatique.

I'm not lookin' over Don's shoulder (and I'm sure he wouldn't want me to be reverse-engineering his stuff), but my assumption is that the stock Kohler crank is short enough so that under 'STOCK' conditions, no funny twisting is going on... but with Don's 'refinements', there's probably quite a battle going on in there. If he's running a forged crank (which is stronger, but springier than cast), a little axial dampning would help keep the crank from 'jump-roping' more than twisting...

Thing to note- when doing the toothed-belt design analysis, one of the things the belt drive engineers want to know is Service Factor. Service Factor, in the case of the belt drive, is all about how SMOOTH the application is against the drive belt. In a generator application, the load is very predictable- lots of mass in the generator's armature, and the load won't change very quickly. If the generator's turned by a turbine, the belt will be subjected to very little shock, so the Service Factor will be pretty low... but if your load is a drop-hammer, and you're operating it with a big single-cylinder engine, the belt will get pounded-to-death, so the Service Factor you use in determining appropriate belt-sheave combinations is pretty high. The service-factor of multi-cylinder engines are quite a bit lower than singles, because you get more distributed torque through a rotation. I'd be willing to bet that Don's gettin' more'n enough fire-in-the-hole to make crank deflection... he might even have a few 'second-place trophies' (busted cranks) to show for it!

(Message edited by dkamp on May 07, 2004)

 

[dkamp]

Oh; the references:
The Internal-Combustion Engine in Theory and Practice; 2nd. Ed., C1985 Charles Fayette Taylor pub. MIT press (9th printing). ISBN 0-262-20051-1 (hard bound) or -70026-3 (soft bound)

--This is a great read, but warning- if you thing MY posts are deep, you ain't seen NOTHIN!!!

On Service Factor and belt drives:
Industrial Power Transmission Products catalog, document #102160 (rev 2003), C. Carlisle Power Transmission Products Inc., and

DriveEngineer; software for DIY application development for Carlisle/Dayco belt drives, available free through your Carlsile dealer. Cool stuff, especially if you're interested in checking my work on the Loader-Mutt pump-drive!

 

[jluckey]

Oh Ryan,

I got this finished this morning. I have blurred out my lack of welding ability. It has been about 5 years since I have done any SMAW welding. Mig has really spoiled me. Now that I have arc in the garage, I really need to practice more. I got a couple of good welding lab books at the library last week.

 

[sblunier]

Roy,

With that center button that galled up you will have problems with that PTO no matter what spring you have in it. Dress it up until it's mirror smooth and leave the PTO "ON" when not attachments requiring it are installed on the tractor.

 

[jluckey]

I have decided before I jump into building my cupola furnace (which is a very fast melter of cast iron) I am building a crucible furnace. This will be a much much slower melting process, but one much easier to handle my my self. I also don't need to have 40 sets of flasks setting around.

Here is a pic of my fuel jet assembly for the crucible furnace. Although the crucible that I am using will hold 46 lbs of the hot white stuff, I am only going for the 26-28 lbs for the wheel weights at this time, the rest of each pour I will put in ingots.

 

[rmull]

Hey Jon! Looks nice! Will work quite well on the 1872...should be able to move my trailer around without the truck now.

Guess that will have to get a 902 paint job since it is an attachment.

 

[wweckwerth]

Thanks to all for for the reply on my 149 vibe issue ,and thanks to Ken for emailing me the section on the new and old style balencer gears from the service manual . Wayne

 

[jluckey]

Ryan

I am going to weld the other one tonight. Hopefully the welding will be a little better. Gets a little better with every bead run.

 

[kweaver]

Johnathan -- but there is a "break over point" on the "gets better with every bead run" theory. I loaded up my Bobcat Miller to power my Century 225 MIG to weld a friends big double door safe yesterday. As I've been saying , I'm going blind! . I welded 3 inches past the plate I was putting on the front of the door because I couldn't see where I was at !! Of course that extra long stringer bead was helpful in giving me a stopping point when I came down the other side

On your setup there , man you wasted a lot of parts / time / fittings / money. Didn't you see my burner close enough ? A nipple welded on the side of a pipe with a 1/16" or so hole drilled through the burner pipe then a shut off and hose fitting on the nipple. 7psi of propane and a blower melts iron. I was suppose to get you a pic of the nipple wasn't I ... oh did I mention that if you burn enough rods you also get short term memory lose ???

Wayne -- I was wondering if the screen captures @ 100% resolution was big enough for you.

Don -- but he didn't ask about B-gears a couple years ago ...

 

[dkirk]

Dave Kamp - My hat's off to you man! Great explanation in fastidious detail. The book you reference is also an engine "classic".

As an aside, the pendulum dampener was actually invented by Taylor, author of the book. Both Wright and Pratt & Whitney used this device on their large radial engines. In addition to keeping crankshafts together, it eliminated many unexplained gear failures that were caused by torsional vibration.

 

[dgelabert]

What can I do to make my Original shift easier? Thanks for any help.

Dave, mowin in South Bristol, NY

 

[dvogt]

Torsionals were killing our forged cranks. we had one fail after 5 dyno runs. since the dampners were put on there has not been a failure. seams to affect engines that have the ability to run in a certain RPM range.

 

[jluckey]

Here is the rest of the burner assembly for my wheel weight furnace burner.

 

[kweaver]

So , is there enough of a demand to be able to do Titanium "mail order" TIG welding ???? Our local supplier doesn't have any customers doing it , not even the airport shop.

 

[till]

Ken,
I have titanium frames (eye glasses) that need to be fixed.... Does that count??

 

[kweaver]

come to think of it my $225 frames are Ti too ! It's a shame the $11 glasses I bought at walmart to see the monitor with are a more ridgid frame !!!

Well I got fishin gas money yesterday (even though I can't straighten up today) so I was gonna go fishin tonight ... then I seen the boat registration renewal card sitting on the counter ... guess I'll stay home tonight since it ran out 4/30 at midnight .... if it's not one thing it's a 'nuther ! But at least I can siphon the gas out of the welder and mow the yard this weekend !!!

HEY PPL - WAKE UP AND PEE , THE WORLDS ON FIRE !!!



(Message edited by kweaver on May 07, 2004)

 

[wdeturck]

David G.: Make sure your clutch turns free when depressed. If the clutch is all gummed up it will turn the main shaft in neutral and they are hard to get in gear. Make sure your clutch is adjusted properly when you get it working free and also the teaser spring may be broke.

 

[dkamp]

Hey Everybody!

Cap'n Kirk- I'm honored. Honey- go get the tape measure, I'm gonna need to measure my skull for a new hat!

But as much as Taylor's book is great reading for the finite-detail introspective engineer, many a garage hot-rodder whom I've recommended it to called it 'tedious' or 'hopelessly out there'. In reality, I think those individuals were simply looking for a Popular Hot-Rodding article on the latest mix of what's-hot parts, rather than the actual WHY it works answers. But I found it to be a fascinating, and a relatively easy read... but then again, one of my degrees is English, and can read quite a bit of paper in a short time. But in a strange way, I'm just as attracted to reading about odd stuff like Sleeve-Valve Knights and Desmodromic Ducatis... ideas that in theory and practice, had potential to do great things, but from a manufacturing-cost or precision perspective, were overtaken by cruder methods. 28,000 years of evolution, and the basic design of the hammer hasn't changed, right?

Ken- d'ya have design plans for that propane-fired iron-melter? You and Johnathan have me seriously considering building a small foundry back in the back corner of the lot... if'n I could pour myself a half-dozen wheel weights and mebbie cast a few replacement parts (oh... and a block for my 109's original now-confirmed-dead K241... I DID find a point-of-impact within the block where that half-rod did whack a chunk out'a the bottom of the cylinder.

Anybody bored out a K241 and inserted a SLEEVE? Just a bit of this one's lower edge (where the piston skirt travels) is chunked out, but the rest of the casting looks really good...

 

[sblunier]

Dave K.

10hp blocks are a-dime-a-dozen, why fight it, get a servicable/rebuildable block outta somebody's junk 100,102,104,105,etc. and go for it. If it was a 14hp or a 16hp I'd try and save it, but a 10 is just too common to mess with.

Better yet, get a 12hp and nobody will ever be the wiser, STEALTH power!!!!!