Kit to make 422 into 428

bullitt · Feb 16, 2003

Moss Road and duane,

I did not mean that last post as harrassment. If it was not for the Moss Road web site, I would not have this rather amazing machine. Thanks for the info. It will save me about $1800 to buy the engine myself.

I plan to contact Kohler and get the dimensions so I can judge what (if any) modifications are required to the Kohler engine cradle for whatever engine I end up with.

The report from duane on the 425 with the 60" mower is reassuring that with the 25 hp Kohler I will get the performance I expect.

My main frustration now is I can't lift the reliefs with the Robin engine, instead I lug or stall the engine. If I back off the treadle so that does not happen, I have to back off so far that the tractor does not climb. I suspect the variable volume hydraulic pump becomes so inefficient at close to the neutral position that the output pressure drops, and I end up "hung up" on the hill.

If I have an engine that can lift the reliefs, I will be satisfied I am getting all the function I can out of the tractor (I am not yet ready to adjust the relief valves). Right now I am concerned that with the Robin engine I will not be able to drag or push items up a 15 -20% slope, and that I will not be able to cut uphill, even with my 48 inch deck. My land requries that capability.

Thanks for the help and ideas
bullitt

MossRoad · Feb 16, 2003

( I did not mean that last post as harrassment. )

None taken /forums/images/graemlins/laugh.gif

FYI, I've never had the reliefs open on my PT425 except for the time I forgot to hook up the hoses to the main PTO and turned it on. I've lost traction and spun the tires on steep slopes, but the engine and hydraulics never gave up. I have turfs, and have wondered if I had bar tread if I would have kept going up the hill or stalled/releifed it.

Anonymous Poster · Feb 16, 2003

Maybe you could consider making a plate to go across the rear of the 425 in place of the current rear of the frame
make it from heavy steel and removable with four bolts
then you could get easily get to the pump.
- ie if you need more room for the 28 hp model

Anonymous Poster · Feb 16, 2003

Oh just to chime in - I am happy with the power output of the Kohler 25hp - there are many posts talking about the problem I was experiencing - and as Duane mentioned - it was not the engine - I pushed my 60 inch deck up a 21 degree incline
and what I experienced was wheel motor limits - not engine or PTO limits - I think it was wheel motor limit as opposed to the pump because the pump used is fairly powerful. (but it could have been reliefs)

Also - despite it having some difficulty (full throttle required)- it still cut the slope twice a week - i just felt that I was forcing the tractor to do something beyond it's capability - (heat also makes it worse)

bullitt · Feb 16, 2003

Keep the ideas coming. I am still not sure how extreme the modifcation may end up.

bullitt

Anonymous Poster · Feb 17, 2003

( That means the conversion is not practical independant of parts from Tazewell, and so dies the dream of a cheap upgrade to more power.)

What other parts might you need beside the cradle...Are the couplings reusable? What does PT want for that Kohler cradle.

Haven't looked at mine yet real close, so I'm wondering if a local machine shop could take off additional radius of .87" of coupling access and relocate pump mount holes up .87"?

bryce · Feb 17, 2003

Does anyone know where I can get a Duetz diesel for a PT? I am trying to find a better price than PT. charges. Robert /forums/images/graemlins/crazy.gif /forums/images/graemlins/shocked.gif

Anonymous Poster · Feb 17, 2003

If you go to their website - they have a dealer locator - I found a great dealer here in CT - I just wanted to touch base with them since I now have one

-edm

bullitt · Feb 17, 2003

bkmar,

It is all still under evaluation. I need to make some drawings and compare the various dimensional differences. Then I need to evaluate the hassle factor.

The only certainty right now is the engine will be >25 hp.

bullitt

marrt · Feb 17, 2003

I have been casually investigating the possibility of swapping the Kohler 25HP for a Diesel engine. The Briggs and Stratton 26.5HP Diesel (made by Daihatsu) is one possibility. The engine itself is supposed to be one of the most compact Diesels you can buy and measures 19.76”H x 17.43” W x 15.59” L without the fan and radiator. Since this is a water-cooled Diesel, one would have to find a place for the radiator. I don’t know the size of the radiator. This engine has a fairly larger alternator so you could use an electric fan for cooling the radiator (and, therefore, mount the radiator wherever its convenient). The Kubota D1105 is a great little engine. I think it’s the engine that’s used in the BX. I don’t know the dimensions but, judging from the size of the BX, I’d say it would fit. Also, Lombardi makes a number of air cooled diesels. Then of course there is the Deutz 1011F oil cooled series.

At a given HP rating, Diesels tend to have more torque, last longer, and use less fuel. Therefore, there are a number of folks, like myself, who would like to see a Diesel conversion for the PT400 series.