425 Engine Swap idea

[woodlandfarms]

What about these guys? I have been reading about the problems with those Kohlers and I have to say I have never seen a diesel engine this size...

http://surpluscenter.com/item.asp?UID=2008110112462442&item=28-1691&catname=

Carl

 

[MossRoad]

I think it is the Robin engines, not the Kohlers that are having problems.

 

[SnowRidge]

A Chinese 10 HP diesel in my machine. I don't thinks so, Al.

Definitely not more power.

 

[woodlandfarms]

I guess I should have clarified myself.

I have not seen a smaller diesel engine that looks similar in design to the Robins / Koehler. Wasn't the Chinese thing as much as it being diesel. Given the reliability of Robins the cninese may actually not be a bad idea.

that said, something now for me to learn. Isn't 10hp Diesel a way stronger engine than a 18hp Gas? I mean you are slinging pumps, not going to the races, so the torque of the diesel outweighs the HP of the gas?

 

[MossRoad]

I think a 10HP diesel would come no where close to an 18HP gas for our purposes. Look at it this way....

10HP is 10HP no matter if it is made by a diesel or gas engine.

 

[J_J]

I think a 10HP diesel would come no where close to an 18HP gas for our purposes. Look at it this way....

10HP is 10HP no matter if it is made by a diesel or gas engine.

I have often wondered about the comparison between the 1445 diesel and my 1445 industrial gas engine PT. Maybe they matched up the hydraulics motors to the rpm and the torque curve. The 45 hp diesel machine has a higher load lifting capacity than my 1445 gas model, but that could be due to larger lifting cylinders. I could intall a larger steering and lift pump. I think the travel speed is the same. So, which is better? I believe my PT is about 20 years old. Now, are we talking about longevity, or fuel economy, or power. The diesel develops it's power at low rpm, whereas the gas engine develops it's peak HP at high rpm. I supposed by using gears, or variable speed transmissions, you could match up one machine to another, just to see if they can get the job done. Which would be more expensive to rebuild? What was the initial cost on the engines?

If you want pure brute power, the diesel wins. They are used in just about everything, except planes.

 

[ponytug]

JJ has a point about the high torque at low rpms. With the diesel 1445, I often set the govenor to mid or low rpms, and go about my work, letting the govenor keep the engine working well.

Only mowing, rototilling or steep slopes cause me to break out the high rpm WOT. Almost everything else gets done at half throttle or less. Just enough to keep the engine from bogging down.

All the best,

Peter

 

[MossRoad]

Yep. Diesels tend to run lower RPMs and are more fuel efficient. For our purposes on the Power Tracs, we need an engine to turn our pumps at a certain RPM to make maximum hydraulic flow. You could gear a diesel or gas engine to get that pump to turn at the proper RPM. So, again, HP is HP no matter what produces it. However, once you put a load on it, the diesel will be able to keep it in the max HP range easier than the gas because of the longer crank arms on a diesel, more torque over a wider range of RPMs, etc.... all that stuff that I am still learning regarding diesel VS gas.

However, I purposely looked for and bought a tractor with a gas engine. Why? Because I have never failed to get a gas engine to start in the winter, when I need it most, to plow snow, so I can get to work. I have on many occassions failed to get a diesel to start in the winter due to fuel problems, no pre heating, etc... plus, once diesel fuel gets on you or your clothes, you smell like a garage mechanic. Lord help you if you sit on the wife's couch with diesel on your pants.

For large machinery, large pickup trucks, professionally used equipment etc... diesel wins for power and longevity. For a 1500 pound yard tractor like my PT425 that only gets 50-60 hours of use a year at most, I could not justifiy the added cost of a diesel engine. I understand gas engines and I can repair gas engines. The Kohler engines had good reputations, are easy to work on, parts are plentiful and repair shops are abundant if I get stumped.

 

[woodlandfarms]

Moss

I just noticed your end icon that now moves (or did it always?)

Very cool

 

[MossRoad]

Moss

I just noticed your end icon that now moves (or did it always?)

Very cool

Yes! It changes implements every few seconds...

Did you click on that icon, by chance???

 

[woodlandfarms]

I have been to your site, but have not seen it in this new fashion. And yeah. Cool idea on linking the icon. Maybe you should apply to PT to help them make a better manual / brochure...

 

[MossRoad]

... Maybe you should apply to PT to help them make a better manual / brochure...

Hardy har, harr!!!

 

[smartguyz]

Good grief, I bought a PT425 MOSTLY because of David's website, which is still one of the best marketing tools that Power-Trac didn't write.

I have have zero problems with my Kohler. Contrary to the marketing materials at the time, mine came with the Kohler Command Pro, which has some of the bells and whistles like the oil pressure monitoring system, bigger air filter, bigger oil filter, etc. I have been VERY happy with it. It doesn't use oil, puts out plenty of HP and Torque and has never failed to get the job done, sometimes working for 14 hours continuously. Yes, I have had to stop and actually do the 8 hour maintenance in the middle of a job!

Frankly, I haven't heard of many problems with these. I am rather glad to have picked one up with the Kohler as opposed to other brands. Parts and maintenance items are very easy to find - virtually any small engine shop has 'em.

I would NOT swap with a diesel, unless things got dicey (e.g. gas went up to $10/gallon) in which case I might switch to a diesel just to use alternative fuels like biodiesel or vegetable oil to run my tractor. However, if things get that bad, I suppose I'll have other things to worry about... Don't get me wrong. I drive a diesel SUV, and I love it. Wouldn't change it for anything I can think of right now. It has TONS of torque, is reasonably fast, gets pretty decent fuel economy, and just runs and runs and runs. I love diesels! I agree with David though. I have NEVER failed to get a gas engine to start in the winter or when the chips are down.

Rob

 

[MossRoad]

So let's petition Power Trac to go back to Kohler engines. I love mine. Started right up this morning. The exhaust is the stock Kohler muffler and it points straight out the back. Never a problem. I did have to take the muffler off to change the battery last year. But that was after 6 years of use.

 

[J_J]

Someone must have convinced PT that the Robin engines were just as good and lower in price, That almighty buck talks loud. You see, PT figures it is not their problems if the engine is not that good. I am sure they got a good price for all those engines they had to order.

 

[smartguyz]

I was grossly disappointed when PT switched to the Robins. Not that I have anything specific against them, but let's face it. With the PT, we are ON OUR OWN (physically) in terms of service. That is, Terry and the boys are NOT going to come out and help us fix anything. At least with the Kohler, I know I can find parts, I KNOW I can find service if I can't fix it myself. There is something to be said for a product with a very broad service and distribution network. To my knowledge, Robin, which may well be a quality product, does not have anything close to what Kohler has for a service and parts network. The fact that so many lawn tractors and riding mowers use the Kohler helps to make the Kohler parts and service easy to find.

It is difficult when one manufacturer has a built-in advantage in this way.

If I had to buy another new PT, I would hesitate if it didn't have a Kohler (or Tecumseh, or something where parts are easy to find) in it.

-Rob

 

[SnowRidge]

I think Kohler sales are going down. A lot of the pro equipment is being built with Kawasaki engines these days. That has to be eating into Kohler's sales figures.

Kohler parts aren't as easy to get as they used to be. Napa lists the entire Kohler parts catalog, and yet my local Napa store could not get me a single part, even when they did what they called a "factory" order. The "factory" called the next day and "zeroed out, " Napa's term, every part I ordered.

I finally got everything I needed by going to a combination of Internet orders and a local small engine shop. The owner of the small engine shop told me there are three Napa distributors and two out of three have stocking issues. He had a direct computer connection to the one he uses, and it indicated they had over 5,000 lifters in stock, which he had in hand in a couple of days.

None of the other sources I tried could get me the lifters unless I was willing to wait an unspecified amount of time.

 

[Gravy]

I've got some comments:

When I researched several years ago, at the consumer level (like Northern Tool), there was a big cost difference between the Robin 25HP and the Kohler 25HP. I recall seeing the Robin for something like $1200, while the Kohlers were more like $1800. That differential seems to have narrowed now, but at the time it was a difference a small manufacturer like PT can't afford to ignore.

Based on research on the infallible interwebs, most Robin small engines have a really outstanding rep for reliability - as in "better than Honda". It's looking like the v-twins as installed in the PTs may not be doing as well as their single cylinder brethren. My impression is that the v-twins were really designed for stationary use in generators.

Since the reports of Robin v-twin engine problems started up a couple of years ago, I've also run across an increasing number of Kohler v-twin reliability problems. If I understand correctly, this may coincide with some new EPA requirements. Maybe they are all running leaner and having heat related problems? Those great old engines of yesteryear can't be sold today, but reputations may outlast realities.

I've worked on a lot (thousands) of engines in my career, and I think I've learned to recognize junk engineering and superior engineering. I'm definitely not totally thrilled with my Robin 25hp (it's underpowered for the application, it sucks at cold weather starting, and I don't like the air filtration), but I believe it's a very good engine for it's price point. I even suspect that it's better bang-for-the-buck than the Kohler. The Kohler is likely better in an absolute sense, but it costs significantly more and it's reputation as a paradigm of reliability is beginning to suffer as well.

I think we need to take a fresh look at all of the engines currently available, rather than ASSuming too much based on past performance.

My dream engine is a ~1000cc diesel that will fit in the same space as the ~750cc Kohler or Robin. 25-50% more torque, and 50% less fuel consumption. All for under $1500.


Yeah. Right. Sure.

Later,

Gravy

 

[SnowRidge]

Well said, Gravy.

And when that little diesel you mentioned becomes available at my corner Northern Tools, I'll take two. And no, I'm not being a smart a__.

 

[cqaigy2]

Well said, Gravy.

And when that little diesel you mentioned becomes available at my corner Northern Tools, I'll take two. And no, I'm not being a smart a__.

Assumer?