Archive through December 02, 2004

[jegstad]

Don Vogt, Dave Kamp, etc.....

This is not exactly about a puller engine but I figure the experts on my question hang out here.

I will be running a poor man's dyno to do some carb testing and haven't found a written procedure that says how to do a dyno run. I presume that after warmup with some nominal load you bring the engine to full throttle and then vary the load to vary the rpm. Is this the correct approach?

I also am trying to find reference correction charts and calcs for correcting from ambient to standard conditions. Even though I will be looking at relative performance I will need to correct if the tests are not done under the same conditions. So, can anyone steer me to some good dyno tech documentation?

JimE

 

[sbarlow]

Motor mount question Im trying to mount a 16hp single in a 582 cub.Does anyone make or know where i could get a set? seems the motor needs raised to line up clutch.
Thanks
Scott

 

[dlouis]

yeah it takes a little work to mount a single in those frames. i believe the rear end has a 2 degree slope on it and it takes a custom made bracket to make it all work. i just got one from a guy for my 1641 which is the same frame. i will check and see if he has anymore.

 

[tlowry]

I seen a custom engine adapter for the 82 series from one of the guys at Midwest Super Cub at plowday 8. I first thought that it was oem but he said he build it with the correct angle, nice piece.

 

[tschweizer]

I got a bunch of 682/782 engine plates. Will those work???

 

[dvogt]

can't be to hard to just make a motor mount plate for a 82 series. I've made them for 1000,1200 style frames. just make sure your alignment is correct to the rearend and weld or bolt it in place.

Jim. you'll need some good weather instruments to document all thats needed to do good correction factors

 

[mmasheris]

I used the QL mounts on my 582 with the 16 single in it had to put 1-1/4" under it it think and a 1/8 " hard washer under the front bolts to get the right angle on the clutch disc.Seems to work ok.Had it at Plowday and worked fine.

(Message edited by mmasheris on December 06, 2004)

 

[gerickson]

The guy with the 82 series mount was Chad Gerlach. Nice folks. They pull some nice stuff out of Prophetstown Il. I bought one of the mounts. It's cool.

 

[kmorrow]

What about a mount from a 1282, wouldn't that be a direct bolt-in since it's for a single? Or does single the used in the 1282 mount significantly differently than the 16 you're going to use? Don't know, but it might be worth investigating.

(Message edited by Kmorrow on December 07, 2004)

 

[dkamp]

Hi Jim!

You can do dyno runs in a variety of different ways, but the order in which you mentioned is most common.

Correction calculations predominantly revolve around barometric pressure, altitude, relative humidity, and ambient temperature. As Don noted, there'll be need for some pretty precise instruments to get accurate measurement of some performance changes. You'll also need your poor-man's dyno to be very predictable (or consistent) to get relative comparison data that is actually significant.

Tables of correction factors are often found at drag-racing websites.

 

[dlouis]

yeah chad gerlach is the guy i bought my mount engine mount from. it was laser cut and is worth the money. not sure who made them for him but he didn't have many left last time i talked to him.the reason they put a 2 degree angle on the rear end is because the twins and the singles have different crank shaft heights. so in order to bolt a single up you need between a 1 1/2 and 2inch spacer. not sure if the ones out of a 1282 would work or would be heavy enough but it requires a different set-up then a quietline model

 

[jegstad]

Dave K,

Thanks for the feedback. I will be using a generator with a resistive load bank as a brake because I do not have any high power engines to test and I can measure HP easily that way. I will add torque measurement after I get running. I am just at the parts collecting stage. I'll do some runs over a period of time using one engine with a fixed setup to sort out the instrumentation and corrections.

JimE

 

[sbudd]

I have A cub cadet 100, and I need to know how the clutch went together,it is a standard clutch, I took a 10 hp motor out of it and now I am putting a 18hp in it for pulling,I need to know how the clutch went together, if you could help me that would be great. thanks.

 

[dvogt]

Russ Nichols won the SS , Jim Vogt won the PS. in Columbia MO. over the weekend. lawntec tire has now won all 3 PS class's this year. Mike Fisher took the open super stock class edging out the twin of Midwest Super Cub

 

[dvogt]

Scott you'll want to do a few things before you put it together. true up your drive plates and shim up the spring. put a new disc and throw out bearing in. in order from front to back
front disc
drive disc
rear disc
teaser spring
throw out arm
throw out bearing
clutch spring
washer
pin or coller to hold tension.

 

[sbudd]

thank you Don, that will be good useful information, thank you for your help.

 

[dkamp]

Jim- an electric generator and load-bank is an excellent idea... it's 'clean' as opposed to a hydrostatic stall device or a friction brake.

You COULD use the bank and appropriate measuring shunts to do some mathematical power output, however, it won't actually give you a finite torque level, and It likely won't be too accurate unless your generator is DC, and capable of generating 2-3x the engine's output power... below that capacity, the generator's windings will get hot, and the corresponding output will be errant. AC generators won't be accurate at all except when they're at synchronous speed (either 1800rpm for 4-pole or 3600rpm for 2-pole)... inductive reactance makes the generator most efficient at 60hz, so off that frequency will cause the generator to yield an inconsistent torque load. It will, however, be predictably repeatable...

Railroads and locomotive rebuilders do their load-testing by connecting the engine to a common railroad generator, set it on a test-bed, hook the generator output to a load cell (about 200' of 2" steel pipe mounted to the building roof) and fire it up... they can accurately test (measuring voltage and current), but since the prime-mover is intended to drive that generator, anyway, and the resultant power output is electric current and voltage, the calculated output is much more relevant there.

But that's an excellent idea for general loading, as well as ballpark tuning out-of-chassis. I've got an old truck alternator that'll be right at home serving as the load for a break-in stand. Actually, I've got most of it built already- made a floor-stand which i can bolt K-motors, with ignition, power, and fuel source already mounted, just drop on the engine and go... with a new motor, it'd be preferable to hook up a load to ensure proper ring-seating... fire it up, and let it howl for a while... it'd save me the trouble of mounting it in a tractor...

 

[dkamp]

Speaking of dynos...

The hotel here has a recumbent exercise cycle here, that has a built-in dynomometer function. It's an electric load, just like Jim noted, and uses an array of stepping-resistors to establish the load. It uses a tachometer to measure speed.

Back when I worked at a popular-american-brand bicycle dealership, I assembled the popular-brand 's exercise cycle that used aerodynamic loading and a tacheometric gauge to indicate the 'victim's power output. As part of the assembly test procedure, I (and the other 'technicians' would run them casually for a minute or two to check for basic alignment and fastener issues, then up to 'our' limits to make sure there were not high-speed balance problems, loose blades, or non-functioning tach. Most couldn't do it, but I could pin the needle for about 10 seconds...

Anyway, this machine upstairs... I just HAD to check it's capacity. I haven't raced bicycles in geeze... 15 years, and haven't ridden much in 5 years, but was still able to find the machine's upper-limits for measuring, and realized there was a caveat which might be important to this thread...

I noted below, Jim, about the resistive load working against a generator designed for 60hz operation won't be linear in loading, as a result of the Xl (and in some part, Xc) of the generator. A DC generator (like the machine upstairs) will also suffer a non-linearity, as a result of the DC winding's armature inductive reactance. In short, if you run a DC motor really fast, you'll find that the armature's generating capacity falls off rapidly above a certain RPM simply because the windings' inductance limits outflow of current.

On the machine upstairs, I found that the load-cell became quite overwhelmed when I put the machine in 'Olympic Sprint' mode. At full-blast, the dyno gave a decent load up to about 190 pedaling RPM, and as I crossed 200, it dropped off quickly. When I held that load, the resistors started getting way too hot, and the shutdown alarm sounded. Apparently, they don't expect many folks to exceed 2kw of input and be able to sustain 225 pedalling RPM. In rough terms, I pushed in about a 3.5hp sprint for 100 yards... and it couldn't soak that kind of power.

So... the lesson- use a big generator, and don't run it above it's peak speed efficiency. BTW... just so happens that I've got a friend with a 200A 250v DC generator, 2800rpm input shaft lying on a pallet... that'd be good for oh... 35-40hp as a dyno load... it'd take what... about 15' of 1/2" copper pipe as a shunt-resistor... Hmmmm....

 

[jegstad]

Dave K,

For carb the testing I was going to do, I was going to run pretty much steady-state at around 3600 rpm because I do have an AC gen head for that rpm. I basically am interested in two things: 1) a reading of the stock hp because I am testing an engine that has a military hp rating and I wanted to see what it actually would put out when corrected to standard conditions and 2) to investigate the effect of several mods to increase the hp at normal operating rpm.

The miliary rating is much lower than what you would expect for the cu in and no one on the sites I have been visiting has been able to publish a definite figure. The rumor is that the mil rating is at 5000 ft. More likely, knowing mil contracts, it is a minimum guarantee or some minimum acceptance spec number. So, I am curious since I will be using this engine on a cub project someday. I already have the AC gen head which one guy has run for hours at about 300% of rating without adverse effects, or so he says.

JimE

 

[jshuper]

Hello, I have a quick question on engine RPM's. My neighbor gave me a Cub Cadet 108 tractor without an engine. I have a B&S engine that I was thinking about dropping in it. Could somebody tell me how many RPM's the original Kohler engine was rated for? The B&S engine that I have is rated at 3600 RPM. By running this engine with 3600 RPM's will it do damage to my creeper gear or tansmission? I do not plan on doing any tractor pulling with it but just to tinker with.
Thanks for any help.