Archive through May 24, 2010

[dfrisk]

DAVE - That pillow block is to prevent accelerated wear on the needle bearing on the back side of the reduction housing pinion. With the different color die springs used on the engine clutches all that force is pushed back into that small needle bearing. The pillow block bearing is used to absorb that force.

I looked in my older MWSC catalog at the NQSP rules and saw a clutch/flywheel cover of 1/8" steel or 3/16" alum. was a general requirement, along with a cover on the right side of the engine block with the same thickness of mat'l. Rules were for 5-2008 to 4-2009.

Didn't see any kind of RPM limit for any of the classes listed. I know I don't want to be around a stock 40 yr old cast iron flywheel at anything over 4000 RPM. If it broke it could cut a Cubbie in two!

 

[dross]

Dennis, a guy showed me once how much the drive shaft deflects at speed under power. Made me think the bearing was supporting the drive shaft.

 

[dfrisk]

DAVE - Depending on over-all tube diameter & wall thickness, and material, a solid drive shaft won't come CLOSE to transmitting the torque a tube will. I can definetly see a 5/8" dia solid shaft turning into a pretzel at some of the HP levels pullers are getting now.

I didn't get NEAR enough meaty engineering courses in college to figure out the math, BUT, when I was buying automobile shredder rotor shafts, the BIGGEST shredder rotor we made had the smallest shaft, 16" in dia and had a 3" dia hole trepanned thru it. Every other rotor depending on style and brand of mill it went into had a solid 16" or 20" dia ahaft. My Engineer said that little 3" dia hole in the big mill's shaft increased it's torque capability a LOT. Something about "not concentrating forces at a single point in the center of the shaft".

To describe what these rotors looked like, Imagine a hammermill feed grinder or #59M shredder with the rotor six to eight FEET in diameter, nine FEET wide. Depending on size & model just the bare rotor & shaft weighed 63,000 to 82,000 pounds without ANY wear parts installed. Wear parts like spider caps, hammers, hammer pins, and pin protectors could easily add another 15,000 to 30,000+ pounds. Tie one onto a 4000 to 7000 HP elec. motor and a full size automobile is reduced to softball sized pieces in 20-30 seconds. One rotor we built was sent to Detroit to shred a MOUNTAIN of old Detroit city diesel bus engines. Company is still located in Moline, just east of the LeClair Hotel downtown about a block, you can see the place from I-74.

 

[rlsmith]

Does any one know what I could do with my tractor for $220 to gain hp immensily.

 

[nbextermueller]

Dennis,

So your telling me at some power level I should replace my solid steel driveshaft with a 5/8" tube?

That does make sense to me. In my alter-ego racecar builder life, we put literally hundreds of HP through thin wall aluminum driveshafts. And even thinner carbon fiber wrapped ones. (Think carbon wrapped soda can!)

but those all have welded forged ends to secure the u-joint to. how do I avoid ripping or wobbling out a tube? I would think welding a solid piece at the ends would only move the twist/shear point to the soild piece.

And... Is anyone currently selling a tube style driveshaft for our little pullers or are they all custom built?

 

[nbextermueller]

richard,

assuming you have a stock engine. I'd say bore it to your clubs maximum allowance, buy a new piston to fit it and have the machine shop shave the head to get you in the 10-12 compression ratio. But doing all that will need more timing to really see a difference. And doing that with points is hard.

Oh, and running race gas will let you pull more timing with out detonationg that new piston. But again... $$$

But you did say "gain hp immensily."

Then again, you could always go the simple route and just buy a bigger engine.

 

[dfrisk]

NIC - The 5/8" dia solid driveshaft has about 3/10ths square inches of steel surface area. SPREAD that out into a tube 1/10th inch thick and 1 in. diameter and THAT will have much more torque transmitting capability than the 5/8" solid shaft.

Since the clutch & reduction housing both need 5/8" dia on each end, maybe something like a 1-1/2" OD by 1/2" ID seamless tube could be made into a heavy-duty driveshaft, counterbore and press in the 5/8" shafts & cross drill, then plug weld the stub shafts into each end.

Problem I've ALWAYS had with GD CC's is the back end of the driveshaft wallowing out the hole where the spirol pin attaches the solid shaft to the back coupler. Anything over 10 HP wallows the hole out in 500-700 hours, 7 & 8 HP will run for thousands of hours. I've got about 150 hours on my MWSC 4140 driveshaft now, but they've all be easy hours.

Neatest driveshaft I've ever seen was in an early 90's C1500 4.3L V-6 5-speed Chevy pickup. For some reason it came from the factory with a carbon fiber DS. Bonded to forged alum. yokes. Bet the whole thing didn't weigh five pounds.

NIC - I suppose if Richard loaded his NQSP-required fire extinguisher with NOS the safety techs would find it wouldn't they!?!?!? I seem to remember my +.010" O/S Kohler piston for my K321 costing over $100 five-six yrs ago. Gasket & seal kit would probably eat up the last of his budget.

 

[nbextermueller]

Ok, so the solid bar vs. tube question was getting to me. So I walked down the hall to the stress dept. here at my work. (we design freight railcars…)

The question I asked was this:
Given a solid bar and a tube both with an O.D. of 5/8” and the tube having an I.D. of ½”, which one will handle more torque and why. The answer is the solid bar will always handle more torque.

So I showed them the example of the 16” dia shaft with and without the 3” hole down the middle. They said the hole was drilled to increase rigidity. A solid shaft of any significant length will start to bow in the middle due to its weight and begin to “throw” that weight as it begin to rotate becoming worse with increasing RPM. But a tube is much lighter (and mathematically stiffer) and won’t bow in the middle. But has a lower torsion rating. So they didn’t bore a hole down the middle to increase its torsion capability (they actually lowered it) they did it to increase the fatigue life of the shaft and the bearings holding it.

So if you want to retain the torsion rating (torque tolerance) of the solid shaft when replacing it with a tube, you have to increase the diameter of the tube. But just replacing a 5/8” solid bar with a 5/8” tube, the tube is actually MORE likely to twist off under high torsion loads but much LESS likely to deflect in the middle.

So if you want to keep that torsion rating of your OEM 5/8” shaft but lower your deflection by using a tube, you’ll need to use a tube with a 1.25” OD and .125 wall. (that will also retains most of the shear force of the solid bar.)

Oh, and using a tube of equivalent torsion rating WILL in fact transmit more power to the rear end because less energy is lost vs. the “wobbling” that occurs with a solid shaft. But giving we are talking about an 18” shaft what weights relatively very little. The difference in the fractions of percentages!

Most guys have just avoided the tube by using the bearing in the middle of the driveshaft to minimize the “wobble” and increase the fatigue life while retaining the torsion rating.

But tubes now need to consider the buckling forces, and that would take them all day…

See, isn’t science FUN!!

I can get all the equations we used it what me to back up those claims….

 

[nbextermueller]

I just picked up a stens .020 over piston and rings for my K301 for CC classics for less than $100.

but thats cast. nothing worth throwing power at.

 

[nbextermueller]

BTW, a 5/8" solid bar does have .307 sq in of surface area.

but t 1" tube with .10 wall thickness only has .282 sq in of surface area. So I think your math is off.

 

[ldunlap]

I think I'll just keep my MWSC 5-puck clutch with the 5/8" solid shaft and pillow block bearing. If it could handle the twin engine half-pint it ought to handle anything my single twin will do to it.

 

[rlsmith]

Does anyone know where I could go to get my engine bored out at. I live in baltimore ohio and I am trying to find somewhere in central ohio that I can get my engine bored out and a new piston and a new rod.

 

[mkreek]

What modifications are needed to repower a Wide Frame (Quietline Cub 1200) with a Kohler Command engine for a pulling application? Do the rubber motor mounts need to be changed? Does the engine need to be raised or lowered to keep the clutch from binding?
Any information would be great…

Thanks in advance.

 

[kweaver]

Nic - Interesting Bar / Tube comparison.
To make it real short and quick ... Automotive torsion bars are solid , enough said , enough proof

 

[ldunlap]

Matthew - The original engine cradle and bushings will have to be removed. The bottom of the frame notched out and a new cradle made for the engine to set on. I can't remember for sure, but I think approx 1 3/8" below the bottom of the frame. We made a couple of "U" shaped cradles out of 1/4 X 3" flat strap for the engine to set on.
LD

 

[rvoelz]

Good morning everone. I have another newbie query I need help with. I have the kill switch mounted on my 100 but need to hook the wire to the coil. I have gotten different answers on what side, - or +, of the coil to hook to. Can anyone tell me which side is better ? Any help would be greatly appriciated.

 

[jdiederichs]

Robert,

You can install it on the (-) side which goes to points. That'll work fine, no problem if it is a grounding type kill switch like MWSC sells.

 

[rvoelz]

Jim, Thank you very much for the info.

 

[bperegrine]

There will be a benefit pull on June
26th in King City Missouri. A time has not
been set but it will be in the evening.
Also there will be a silent auction. All
proceeds will be going to a life long
puller ,Jo Gawatz "Lil Sprout", who has
been diagnosed with cancer. Everyone
is invited to come and pull with
Northwest. For more information go to the Northwest Missouri Garden Tractor Pullers website. Or you can call me at 660-582-1521 Hope to see alot of new garden tractors. Brian http://www.nwmgtpa.net/

 

[nbextermueller]

Good morning guys.

Just a quick mention that our clubs first pull is this friday night in New Melle, MO.

Check out our brand new website at :
http://www.pantherpulling.com

No event pictures yet. (we haven't had any yet.) But check back often for up dates.

Thanks guys