Engine Swap A comin!

Hawsie

New member
I know this isnt a popular subject with all members but I just got a few steps closer to my engine swap project. This last Sat. I finally got lucky. I bought two f2560 Kubota lawn mowers and low and behold they happen to have d1105 engines in them. The d1105 is a a bored and/or stroked version of the RTV's d905 engine. The physical dimensions between the two are identical and the obvious comparison would be like comparing a 305 SBC and a 350 SBC or a 289 and a 302 Ford.
In this mower model, Kubota actually offers a couple versions and one has the d905 and one has the d1105 and one has a larger 4 cylinder. While the overall weight listed in the specifications is heavier with the 4 cylinder model, the 1105 and 905 engine models are listed to weigh exactly the same so in these applications it seems kubota didnt need to change anything but the engine(no drivetrain parts).
Its not a drastic hp increase and it isnt the more powerful turboed d1105-T I originally had in mind for the swap,but this will be a lot easier then plumbing in a turbo engine in there and will be less taxing on the drive train. I will try and take some pictures if anyone is interested. I think this will be a good answer for recovering the power lossed after installing a larger tire size. We will see.
 

BovsRTV

New member
From what I can recall and I will take a peek and repost later after checking I thought someone said the RTV900 has the D902 engine??? I don't know if there's any big difference between the 902 and 905 and I hope not! Again I will check later and relist! I sure hope that later down the road as these thing start aging there will be other options for us if this does work! I for one am interested in this subject! Keep up the efforts!</P>
 

mikeyd

New member
Before you swap out your engine you may wish to verify the HP on the d1105. I have done extensive research on this motor and it comes in a variety of configurations from kubota with HP ratings as low as 18hp up to 28hp . Depends on how old the motor is, rpm settings etc.Assuming you have the 25hp d1105 you are only talking about a three hp increase in power over the stock engine in the rtv900. That 3 hp gain could be easily achieved by advancing the timing on the fuel pump along with an increase in the max fuel screw. Seems alot easier to adjust the fuel pump on the existing motor than swamping in an engine with a dubious history.Either way you are voiding the warranty, so why not take the simplist avenue first? Just a thought.
 

mikeyd

New member
More food for thought...I did some quick research on the F2560 and yes it did come with a d1105 engine rated at 25hp but at only 2700rpm. The motor in your rtv is rated at approx. 22 hp but at 3200 rpm. So, with that particular d1105 motor you will reduce your rpm speed by 500 rpm which will in turn mean you are turning your hydro pump that much slower etc.</P>


Like I said you need to know exactly the hp and rpm rating of the d1105 engine you are considering before you make the swap or you will end up reducing your performance over stock. For example, you might be better off with the d1105 engine that comes with the zd28 as that is rated at 28hp at 3000rpm. The new rtv1100 also comes with a d1105 but that is rated 25hp at 3000rpm.Same engine as the zd28, same rpm, yet 3 less hp. My guess is they turn up the pump on the zd.</P>
 
G

Guest

Guest
So are you really going to try this? I gotta say, its sparked my interest. </P>


</P>
 

RTV900

New member
[quote user="mikeyd"]That 3 hp gain could be easily achieved by advancing the timing on the fuel pump along with an increase in the max fuel screw.[/quote]</P>


Could you please elaborate on how to do this and what the down side of this is. I'm very interested.</P>
 

mikeyd

New member
At a minimum you will need to refer to a kubota engine manual. I suggest you take the machine to an good diesel mechanic along with the manual.The timing of the fuel pump is advanced/retarded by the use of shims under the fuel pump. The manual gives you infomation regarding the differences in the shims and how much they effect the degrees of timing. The factory retards timing in the neighborhood 5 degrees for emissions. The max fuel screw increases/decreases the amount of fuel delivered per injection stroke, a general rule of thumb is to turn it up until the engine smokes and then turn it back a bit. You can also use larger injector nozzles in conjuction with turning up the max fuel screw.A smoking diesel engine rapidly leads to excessive exhaust gas temperature(EGT) which can melt your engine. It is best to tune a diesel using a pyrometer which measures EGT so you don'tmelt it. Again let me stress going to a good diesel mechanic.</P>


The point of my post was that it is a whole lot easier and cheaper to squeeeze 3 hp out of a 22hp diesel engine by consulting a diesel mechanic and making a couple relatively simply adjustments than it is to swap out an entire engine. Either way you void the warranty.</P>


Downside is you void the warranty, if you don't know what you are doing you can melt the engine, turn the wrong screw and you have excessive rpm and ruin the motor. Anytime you increase the hp on a motor you shorten it's life.Depending on what adjustmentsyou make or where you live might be violating emissions laws etc.</P>
 

bczoom

Senior Member
Staff member
Gold Site Supporter
[quote user="mikeyd"]if you don't know what you are doing you can melt the engine, turn the wrong screw and you have excessive rpm and ruin the motor. Anytime you increase the hp on a motor you shorten it's life.[/quote]
OK, I've been avoiding posting in this thread. You're entire post had great info, but the qualifier above makes me wonder why people would want to take such a risk. Messing with the suspension and maybe messing up a U-joint is one thing, but messing with a perfectly good engine makes me scratch my head. Personally, I trust the engineers at Kubota. I'm sure they've reviewed everything and adjusted accordingly. Unless you like throwing things away, why would you want to intentionally want to change something that may dramatically shorten your engine life?
 

mikeyd

New member
There are entire industries devoted to "messing" with perfectly running engines. The SEMA show in Vegas draws thousands of vendors. I have a 67 Camaro that came from the factory with a perfectly running motor. It currently has a 350 V8 with a 6-71 blower, dual carbs etc. good for 700hp. Everytime I take it out people give me the "Thumbs up", no one asks "WHY".</P>


However the minute someone entertains the idea of souping up a RTV or a Tractor for that matter, people start asking "WHY?". Because a gearhead is a gearhead is a gearhead.</P>


I trust the engineers at kubota too, I own a kubota tractor, excavator, ZD mower and a Bobcat with a Kubota engine. I also have a RTV1100 on order. Kubota designs thier engines for thousands and thousands of hours of use. They are de-tuned and consequently do not run at thier actual capacity. For example the engine in my ZD28 is a D1105 rated at 28hp at 3000rpm. The engine coming in the RTV1100 is the exact same D1105 but rated at 24.8 hp at 3000 rpm. Clearly there are 3 hp to be had with a minor adjustment that will have little or no effect on the life of the engine. Furthermore, kubota makes a 31.5 hp turbo version of this engine. I do not believe that a modest increase in the hp on a stock diesel motor will have a significant effect on engine life.</P>


The reason for my "disclaimer" is because I would never advise anybody to start turning screws, adjusting timing, altering intake, exhaust etc. unless you know what you are doing. If you don't know what you are doing, go to someone who does. When you go about altering factory vehicles you void the warranty. Even when an engine is modified by someone who knows what they are doing things may not go as planned . Simply said, my Camaro may implode tomorrow, in the meantime it makes me smile.</P>
 

doggman

Member
I guess the question is one of risk/rewards. Seems to me that a 15% hp gain isn't going to do much for me. If I get a 3 mph gain that's really not too exciting. Maybe ifI could get a 10 mph gainby advancing the pump 3 degrees I'd be interested in the risk. But real performancegains arestill going to be limited by the pump(s) and motor capacities. </P>


Actually, one of the things that I like about the RTV is how much you do get for so little fuel consumption. I've got a stable of diesel equipment (and gas) and the RTV still tickles me because it's so miserly on fuel. I usually get about 5 hours per gallon on dirt and gravel. </P>
 

mikeyd

New member
A hp increase will not increase the top speed of the RTV as that is determined by the transmission, gearing and hydro pump. A hp increase should increase the rate of acceleration and the pulling power of the machine. More powerful, just not faster. Increasing the top speed would require changes to the transmission, gearing , hydro pump or some combination thereof.</P>


A 15% increase in power is significant, especially if it can be had easily and cheaply. For those of you satisfied with your stock machines, I say thats great for you.If you need an explanation as to why someone would want to alter a stock machine then you surely will never understand.</P>
 

mikeyd

New member
As I stated I have an RTV1100 on order. I understand it should be here soon. Believe me I am dying to get my hands on it. I do intend to do some modifications to the engine...to an extent that I am sure some will think is radical and stupid. I will reveal more at a later date. I have modified many engines for performance in cars and motorcycles. Obviously, this will be my first RTV. I have done extensive research on the D1105 engine, diesel motors in general and the Bosch md mini fuel pump that comes on the engine. I have also consulted a reputable diesel shop and they will aid in any modifications. Why even consider modifing a machine that is not on the market yet? Again, if I need to explain.....</P>


As I have tried to make very clear, only a fool would try and modify an engine for performance without proper knowledge or the aid of someone who has that knowledge. That in no way means only a fool would modify a perfectly running engine. Millions of people add turbo's, power chips, performance intakes and exhausts to engines everyday. Why there is such resistance in the "tractor world" is beyond me.</P>


I realize and accept that if I modify the engine while in the warranty period I lose the right to make a warranty claim. Accordingly, I will run the machine for probably 100 hours before I implement the intended modifications. That way I get the benefit of a good portion of the warranty period, allow the engine a reasonable break in period and give myself time for fabrication of the intended modifications.</P>


I would like to go back to my original statement...it is a whole lot easier and cheaper to get 3 hp out of the existing engine than an entire engine swap. In either case you are voiding the warranty so why not take the easier route.</P>


Once you modify for performance the powerplant of any machine you run a degree of risk that you will shorten engine life or possibly harm the engine. If you are clueless as to what you are doing you raise that risk substantially. Personally, I have yet to toast an engine, but there is a first time for everything.</P>


I do find it interesting that some of the aftermarket companies are now offering performance chips for electronically controlled diesel fuel injected John Deere tractors. I guess for some members this marks the end of the world as we know it.</P>
 

doggman

Member
When Cat was developing the 3600 series, their largest, the chief engineer of the engine division made a statement that I'll never forget- "An engine is just a box of horsepower - you can take it out a little at a time or all at once." </P>


Keep us posted on the hot rod Kubota. </P>
 
Top