IH Cub Cadet Pulling and Hot Rodding

[dkirk]

Thanks Don, I appreciate your comments. You're right on; what makes a good performing engine is everything working in concert to produce good airflow without a bottleneck in the circuit. Engines are air beathing machines - air is their working fluid. It is air that is heated by the fuel; that air expands in the cylinder, doing work on the piston. The more air taken in and trapped per cycle, the more work can be done. The more rapid the cyclic rate, the more power can be produced. It's relatively easy to get more fuel in, but inducting and trapping air efficiently, per every cycle, is the art of good engine tuning. Whether diesel or spark ignition, two or four-stroke, model airplane size to largest marine engine, this basic rule applies and holds true. Knowing the way your engines perform Don, you certainly know the drill!

 

[dfrisk]

DAVE - Excellent comments about engines. Back in the "OLD DAYS" I remember a quote from Smokey Eunick (sp?) about "Engines don't know what NAME is on the fender, They ALL respond to the same Things."
Another interesting comment I heard on a forum a couple years ago is "The only difference between a brand new engine and a totally worn out engine is a few ounces of metal filings."

 

[dvogt]

thanks David , another note the work you spent on your valves also helped with the air flow on your engine. as you note in your engine build up , also putting the large base lifters in can add a bit of duration to the cam , this is a good thing since holding the valve open longer would allow more air in . since it can't flow more with extra lift you would need to do it with duration. I think yo could get by by running the ign. at 22-23 deg. with out damage. it would help with torque . seams like around 26 detonation starts

 

[dvogt]

I'm almost loaded for the trip to Columbus tomorrow , looks like the wheather isn't going to be to bad.

 

[dkirk]

Don - I'm taking your advice and will try bumping ignition timing up to 23 deg BTDC. Going to wait untill weather warms up a bit tho...no heat in my garage.

(Message edited by dkirk on January 23, 2004)

 

[wcompton]

Question on air cleaner housings on tractors that are a little above the "mow" status.

Air cleaners on Kohlers whether they were a "quiet" or not seemed to evolve from sucking ambient air around the engine to sucking from the flywheel shroud. Assuming that the ambient air around the air cleaner is hot since it may have passed through the cooling fins, is there any advantage to switching to the later "flywheel shroud supplier" air cleaner, even if it's slightly lower running temperatures?

 

[shunt]

Wyatt,
"Ram air" effect from the cooling fan?

 

[sblunier]

Any "ram air" of the QL style blower housing air cleaner is probably negated by the more restrictive, partially shrouded QL housing.

Seems to me that the inlet air temps are not going to play here and that the 169 "wanna-be" style air cleaner.....KT-17 cover with 2ea. 1-1/2" holes drilled in it AND the open base is probably the most filter area (i.e. least restrictive) of all of the possible designs that can be easily fabbed with factory parts.

 

[wcompton]

Steve-
I doubt there's any ram air effect, but what I have found is a deep QL-like air cleaner that uses the same air cleaner element as a K582, the 4" element.

 

[dfrisk]

WYATT - Ever thought about the "Leaf Blower Mod." ;-) A Buddy's Son's 2.3L 4-cyl. Ranger pickup responded well to that mod till He ran out of extension cord half way down His driveway. (hahaha just kidding) These Kohlers with the Carter carb. have a little more sophisticated fuel system than Our R/C cars did, but I found it was possible to to get too much air into them which made it hard to set them rich enough on the top end to keep from over-heating while still having them lean enough on the low end to get driveability. Therefore the mod's Don discussed last week are needed. In effect what was happening was it was too easy for the engine to suck more air and run lean & hot. We'd run the larger K&N air filter and head temp went thru the roof, drivability was poor on the low end from being WAY rich, run the restrictive stock filter and it'd run fine. With the K&N We ended up having to run a carb restrictor which made head temps happy again, Plus gave a bunch more low end & drivability. With the Kohler I think I'd want to run an EGT and head temp. gauge. Plus extra Gauges are just plain Cool!

 

[wcompton]

Denny-
It's not even a power question, just wondering if there's any advantages and if one of them is a cooler intake charge that might help keep the engine cooler.

 

[bpalsgrove]

To clarify one thing: No "sucking" involved in an engine, air flows from areas of high pressure to areas of low pressure. So the engine just creates a low pressure area and the air flows from the high pressure area to the low pressure area . . . no "sucking" involved

Close off one or two of the air bleeds on the carb nozzle and u will "fatten" up the high end. Might even have to move their location on the nozzle. They are what controls the high end mixture, with the right tweaking you can have a kohler carb run efficient at all rpm's. If u run to rich on the high end do the opposite and open the holes up. It will bleed more air in and lean out the high end. One thing I'm not sure of is it the bleeding of air in or is it the lose of fuel signal which makes this happen? Still trying to figure that out on the flowbench . . . might be a chicken/egg thing?

 

[wcompton]

au contraire, "suck" is a verb defined as: To draw in by establishing a partial vacuum . . . a partial vacumn, a differnce in pressure.

 

[dfrisk]

BRUCE - Then "VACUUM" is really just very low pressure? Not trying to be smart-alec. In theory I agree with You that Nature loves equilibrium. The engine tuning situation I was describing was on a .129 Cubic Inch 2-stroke rotary valve engine that made about 1.5 HP at 32,000 RPM. Carb style was a rotary barrel that moved the tapered needle into/out of the main needle jet fuel adjustment.
Since the ventury of the Carter carb references the pressure differential of the air going thru the carb I think those holes are causing "Loss of signal" in the Carter carb. Not sure how consistent of a air/fuel ratio that would make at variable loads & RPM's. Those carbs have only have two, maybe three sources of A/F ratio adjustment, where carbs like the Mikuni used on motorcycles had as many as five. Tell Us more about Your flowbench!
WYATT - I didn't have any heating problems Sat. cleaning the driveway. I had My engine oil analysed one spring right after I put the K-241 in the 72. When it's REALLY cold they run so cold the analysis company said I had a carb. problem, and that was after only 5-10 hours of running blowing snow then mowing in the spring a couple times. Oil never got warm enough to vaporize the raw gas out of the oil.

 

[bpalsgrove]

I'll give in on the "sucking", just doesn't sound professional to me

Follow the link in my profile and u can findout all you wanna know about flowbenchs and how to build one for yourself. I sponsor a forum specifically for this purpose. Trying to remove the "dark art" from it. There is more to flowbenchin' than just measuring CFM's. We can all learn more from sharing ideas, the world of the internet opens up so many sources . . .

 

[dkirk]

Guys,

A gentle reminder least we forget the contributions of the infamous German, Dr. Otto, credited with inventing the four stroke-cycle engine. And these four strokes are;

1) Suck
2) Squish
3) Pop
4) Pthooey

The two-stroke is a bit more difficult, gas dynamically, as it has a "flush" mode, but we won't get into that.

 

[fmorski]

Wyatt

Cooler air charge will actually cause higher engine temps. This is due to the fact that the mixture will lean out somewhat as cooler air is more dense and thus more oxygen rich, usually. That is why race cars tend to run better at sea level than at altitude such as Denver.

 

[sblunier]

Denny,

You won't get "too much" air to a Kohler by just changing to a larger air filter or different housing. As Don pointed out, you will have to make SERIOUS flow improvements to the internal flow parameters of the engine to increase it's air flow rate. BUT, you will only run lean if you loose your vacuum signal at the carb venturi (assuming you jet the carb right for the conditions at hand). The biggest thing is to have the correct amount of pressure differential across the carb at all operating rpm's to insure the correct fuel mixture is being maintained.


Why do I run K-341 AC's on my tractors.......increased dirt holding capability and flow area when partially blocked with those $%^&* dandelion seeds!!!!!

 

[wcompton]

Mr Kirk-
While the Otto Cycle is good, I'm a bigger fan of the Miller Cycle . . . . but the camshafts tailored to Miller Cycle are few & far between, but that's my 2.3L engine and not the Kohler.

As for my question earlier about the air filter, I just made up my mind and do my own thing. It'll just get done my way.

 

[dkirk]

Mr. Compton,

Indeed! The true Miller cycle relies on a supercharger combined with asymmetrical valve events. Without the supercharger it defaults to an Atkinson cycle (power stroke longer than compression stroke) made possible by late inlet valve closing, effectively shortening the compresson stroke. Doesn't work well on single cylinder engines - no adjacent cylinders to swallow blowback.

Inline 4-cylinders set up with Atkinson cam timings and a small carburetor can be very economical on fuel, but not good at specific power outputs. Miller realized this, added a supercharger, and got the best of both worlds - excellent part load economy with stellar full power performance.