Building your own PT?

[J_J]

What is the difference between industrial engines and automotive engines? More power/torque at lower rpm? And what are the optimal engine rpm and torque requirements for the PT's hydraulic system?

I still haven't totally given up on the build a PT idea, but from the responses, it sounds like maybe I should.

Bagtic,

What is BMEP?

I looked at your profile, and could not ascertain what your occupation is/was. If you are serious about building a machine similar to the PT, you need to be a mechanical engineer, an expert welding, and have a good knowledge of hydraulics, plus an electrical background. Now, you will have to buy most parts at retail, unless you have a good source for the material that you will need. You also need to be able to cut, shape and weld up things like a built in hydraulic tank, etc. It will not be an easy project, but it can be done, with a lot of money, and friends to help, and your dedication to the project. I believe that if you pay yourself and add up all the cost of the parts, and labor, you will just buy a PT, or something similar and save your self a lot of time and misery if it doesn't work out . Pt, has done a lot of R&D in their effort to build a good machine for the masses. They are not perfect, but they are making good money at what they sell.

 

[KentT]

Ok, so what rpm engine speed do I want for running the PT hydraulics? If you remove fuel consumption from the equation, should I be looking for an automotive, industrial, or diesel to power my custom PT? I personally like the diesel I have in my tractor, but if I were to do this (which judging from the responses, I'd be crazy to do) would any of these do the trick (fuel efficiency aside)?

PT uses air-cooled engines (both gas and diesel) that operate at 3000 RPM. That's what their pumps are "speced out" for -- consequently, the pumps direct connect to the crankshafts without needing any type of "gear reduction" to match engine speed to optimal pump RPM.

Many water-cooled diesels are designed to operate down closer to 2000RPM, with a "red-line" of around 2500 RPM.

 

[ddonnell]

I have to say that for a bunch of tractor jockeys who would weld a lightning rod on top of their ROPS, you guys are definitely throwing some serious negative vibes (and I understand why). Seriously, I am thinking of this as a year long project involving a fair amount of input from you. If money and time were the issues, I'd be heading for Tazewell. But that is not why I'd try this. It just seems like a project that is possible and fun at the same time. It is very probable that it wouldn't look exactly a PT, but at the same time it might end up with some features that are better (and worse).

J.J. As to my occupation, I am a dentist. My dad was a farmer, and I grew up builiding stuff. I'm not sure if I will or can do this, but I tend to try things when people tell me I'm nuts. For the most part, it has worked out pretty well over the last 28 years.

Nuts and bolts: I'm thinking gasoline inline six. Fab the entire engine/hydraulic mess on a 5/8" plate of steel with hooks so the entire unit can be lifted out of the tub for service, etc.. I'd build this from the inside out.

 

[BobRip]

I don't think you are nuts. We would like to help and sometimes that sounds a little too critical. Sorry about that. We are probably a little jelous and would like to do this ourselves.

I think starting from the inside out is a good idea. Try to put the weight in the back and don't get discouraged. I think a 4 cylinder is more than adequate, but what do I know. Go with big tires and lot's of wheel motor torque and it will be better than a PT. Use two speed wheel motors for good low speed torque and high speed.

Good luck.

 

[ddonnell]

BobRip,

I agree that an inline 4 would be more than adequate. Inline, I think, is the key to this, as MR said earlier. Thank you for the positive. I understand where everyone is coming from, but I am looking at this as a project to test my fabrication skills as well as giving me something to do. I already have a nice subcut so it's not like I am in dire straits here. Any advice (other than "don't do it") is welcome. Certainly specs. on pumps, motors, etc., or places where I should be hunting would help.

One other good thing: A project like this gives me the excuse to buy more tools! Might need a bigger shop though. Isn't it funny how things seem to expand. I had a friend who's wife only wanted a bathroom faucet changed. By the end of the day, he had the water turned off out at the street! Been there, done that.

 

[MossRoad]

If you are really serious about building your own machine, you should price everything out first. Just the price of sheet steel alone may sour your stomach. List all of the components that you will need on a spreadsheet and start adding it up.

Also, consider the cost of a welder and consumables.

I would also suggest you join Machine Builders Network and start asking fabrication questions over there, as well. Really see what you are getting yourself into.

As for an articulating machine, make sure you know how it articulates AND oscillates or you will build a machine that will get wheels off the ground real quick.

 

[ddonnell]

Power Trac guys and gals,

This building a PT is a probably stupid idea. But it is an idea. You talk all the time about fabbing this or that and all sorts of hydraulic upgrades to make your PTs better. I don't even own one and I already have ideas (mostly from you people) to improve it. I know that Power Trac can make them for less than what I can. But can they build one in between the 425 and the 1430? Better question is: would they want to and what would it be?

I think that there is an "in between" PT that gives more lift, more power to attachments and wheels without having to be 1430 size. Might be a little bigger in front (steel wise) but with the appropriate sized rear (I'm talking tractor weights - lose the trailer hitch) and the heavier engine, I think this is possible.

Hydraulics, well I'm a novice. But I'm guessing that those issues can be figured out.

Bottom line: I think you could make a PT. Power Trac did. Question is, can you make it better without breaking the bank. As someone a lot smarter than me once said "if it's been done, it's probably possible".

 

[Gravy]

It's going to be really hard to build something smaller than a 1430 using any of the engines mentioned. The air cooled v-twins in the smaller machines are around 15 inches front to back and maybe 18" wide. At a guess, an Iron Duke with fan and radiator is probably over 3 feet long and likely at least as wide as the v-twins. You might consider using one of the Briggs Vanguard big block v-twins that go over 30hp. Someday the Generac 32/38 hp engine may actually be available. According to Terry at PT, that one fit the 425 with no changes to the tub.

Gravy

 

[IrTxRx]

ddonnell,

I'll just start making requests to desing improvements... and I don't have one yet either, LOL

1.) a true emergency break on one wheel. Hydraulic, mechanical, magical... I don't care, but something to keep me from running my new PT (and me) over my cliffs when the hydraulics fail OR something that will force the PT into a sharp turn, so it turns uphill if a catastrophic failure occurs

Thanks

 

[RegL]

ddonnell,

I'll just start making requests to desing improvements... and I don't have one yet either, LOL

1.) a true emergency break on one wheel. Hydraulic, mechanical, magical... I don't care, but something to keep me from running my new PT (and me) over my cliffs when the hydraulics fail OR something that will force the PT into a sharp turn, so it turns uphill if a catastrophic failure occurs

Thanks

Cliffs? I would add a parachute maybe!!