Can I swap out Yanmar diesel with another type/brand engine?

[Josh Woods]

The WAM 1600 mower is turbocharged. The refer engines are not.

From John Deere's website:
Yanmar Model Number (4510 & 4610) 4TNE84
Gross Horsepower (4510) 28.6 kW (38.4 hp)
Gross Horsepower (4610) 31.9 kW (42.8 hp)
Rated Engine Speed 2600 rpm
Operating Range 1000 - 2810 rpm

And for the larger engine:
Yanmar Model Number (4710) 4TNE88
Gross Horsepower (4610) 31.9 kW (42.8 hp)
Rated Engine Speed 2600 rpm
Operating Range 1000 - 2810 rpm
(presumably these are non-turbo numbers - but the website doesn't specifically say)

I suspect that the fuel injection pump on the TK486 engine is what's limiting the power numbers to 33 horsepower at 2200 rpm - similar to how putting smaller injectors on an old Detroit diesel will limit the power numbers. It's not unusual to get between 20 to 25 thousand hours on a TK486 engine in a refer-unit between overhauls. I believe that's because the engine is under a relatively light load, turning at a relatively moderate RPM. That being said - I have read that you can modify the the fuel injection on the TK486 (for increased fuel stroke), add a turbo, and make upwards of 60 horsepower. Note: I've only read it - not actually done it. I'm not sure if the stock injection pump is modified/adjusted, or if it's replaced with a larger unit. You'd have to dive further into that topic - if you're interested in increasing power of the TK486. Edit: There's a limit to how much additional fuel you can inject before adding a turbo becomes necessary.

Going back to the Detroit diesel example: a non-turbo 671 with the smallest injectors will make just over 100 horsepower at moderate RPM essentially forever. But if you install very large injectors, add a turbo, and keep the RPM high, you can almost quadruple the horsepower of 671. That comes at a cost however, as your duration between expected overhauls drops from 12 thousand hours to about 2 thousand hours.

Hmm thats very interesting never thought about that i may just have to get one of these engines and out it in the machine and see whay happens

 

[Entropy1]

I made a type-o copying the numbers down from the John Deere website.

Gross Horsepower for the larger engine Model Number (4710) 4TNE88 is 34.5 kW (46.3 hp), not 31.9 kW (42.8 hp)

 

[Entropy1]

Comparing the numbers:

4TNE88 is 133.6 cubic inches and makes 46.3 HP (or 0.34656 HP per cubic inch)
4TNE84 is 121.7 cubic inches and makes 42.8 HP (or 0.35168 HP per cubic inch)
TK486V is 128 cubic inches and makes 33.9 HP (or 0.26484 HP per cubic inch)
4TNE88 turbo is 133.6 cubic inches and makes 60 HP (or 0.44910 HP per cubic inch)

Presumably the fuel injection on the TK486V could be modified/adjusted to make similar power-per-cubic-inch as the 4TNE88 non-turbo engine, which would increase the TK486V numbers to 44.4 horsepower at a comparable 2600 rpm. Turbocharged (0.49910 HP per cubic inch) the TK486V should be able to make 57.5 horsepower. Again, this is extrapolating the John Deere numbers against the Thermoking. I don't know if there's a substantial difference in camshaft profile between the Thermoking and the John Deere engines. Does Yanmar offer a selection of camshaft profiles? I have no idea?

 

[Bobcat Crazy]

Alright I see what you did alright so you just kept the oil pan that came with engine rather than finding a different one

That is correct, but I ended up replacing a Yanmar with a different Yanmar which allowed me to use some of my original parts.

I you end up going with the TK but the oil will not fit in your frame as was the case with mine, there are Yanmar oil pan out there you just have to search for them. Good luck with the swap.

 

[Entropy1]

I was just reading through the service/overhaul manual for the TK486 engine. The only adjustment for the fuel injection pump assembly is a timing adjustment. The volume of injected fuel however remains a fixed value. To get more power, you must procure an injector pump assembly rated for a higher horsepower engine application.

 

[Bobcat Crazy]

Comparing the numbers:

4TNE88 is 133.6 cubic inches and makes 46.3 HP (or 0.34656 HP per cubic inch)
4TNE84 is 121.7 cubic inches and makes 42.8 HP (or 0.35168 HP per cubic inch)
TK486V is 128 cubic inches and makes 33.9 HP (or 0.26484 HP per cubic inch)
4TNE88 turbo is 133.6 cubic inches and makes 60 HP (or 0.44910 HP per cubic inch)

Presumably the fuel injection on the TK486V could be modified/adjusted to make similar power-per-cubic-inch as the 4TNE88 non-turbo engine, which would increase the TK486V numbers to 44.4 horsepower at a comparable 2600 rpm. Turbocharged (0.49910 HP per cubic inch) the TK486V should be able to make 57.5 horsepower. Again, this is extrapolating the John Deere numbers against the Thermoking. I don't know if there's a substantial difference in camshaft profile between the Thermoking and the John Deere engines. Does Yanmar offer a selection of camshaft profiles? I have no idea?

Hey Entropy, This is great info and I really appreciate you taking the time to share all of this with me. I searched and searched and have not found any info even close to this. (Obviously I don't know the correct places to look)!

If I am following you correctly The 4TNE88 with turbo makes 60HP.
My JD 1600 WAM came with the smaller 4TNE84 with turbo.

I replaced it with the TK486 with a turbo.
I have turned up the injector pump 1-1/2 turns (this brought it to very light smoke so I figure that to be the max that I can/should adjust it).
Plus I used the exhaust man including the turbo from my original 4TNE84.

Hopefully this means that I have increased the HP to 57.5 (or something similar).
So if I am getting close to 57HP and the 4TNE88 turbo (which again is bigger than my original 4TNE84 turbo) has 60HP, then I should be in good shape.

I hope this is actually close to what I have.

Entropy does this sound like I am following your numbers correctly?

I guess the thing that made me feel that the TK486 did not have enough power is when I cranked it (on the test stand) I expected it to roar to life and sound similar to the 4 cylinder Kubota that is in my Bobcat. Although the TK486 runs as smooth as could be it did not sound like the power house my Kubota sounds like. And then with what little info I could find I was looking at the TK486 rating of 33.9 HP @ 2200 rpm to the 60 HP that the John Deere book says the 1600 WAM mower has.

Entropy,
With all of the numbers and info that you have given above it has given me hope that I am in the ballpark (HP wise) and that this engine swap might actually work after all!!!!!!!!!!

Hopefully today I will crank this machine (for the first with the engine installed and not only on the test stand) and actually drive it out of my shop where it has been for 2 years while played with it on and off. THAT WILL BE A GREAT FEELING IF IT HAPPENS!!!!!!

Thanks All,
For the time and info that you have shared over the last couple of years on this thread.

Josh,
Good luck to you on the engine swap. I look forward to seeing how your story turns out.

 

[Entropy1]

I replaced it with the TK486 with a turbo.
I have turned up the injector pump 1-1/2 turns (this brought it to very light smoke so I figure that to be the max that I can/should adjust it).
Plus I used the exhaust man including the turbo from my original 4TNE84.

I was reading up last night about the Yamar fuel injection pump assemblies - specifically how to make them pump more fuel (to make more power). You need to machine/bore the pump-cylinders oversize and fit them with larger pistons. The bores must be precision-honed to a near mirror finish. I suspect this is the low-cost option, where a pump rebuild kit is purchased for a larger pump (kit containing larger pump-pistons), where the pump is modified to accept these larger pistons. The variable is machine work. If you have a knee-mill & reamers, and knowhow, you can do this machine work yourself. If you farm it out, machine work cost becomes a significant variable.

The other option is to buy a pump assembly that's rated for a higher horsepower application - which means it already has the larger pump-pistons. There's an array of aftermarket yanmar pumps to be had. The big question (which I have not researched yet) is whether or not there's a bolt-on ready pump for the TK486V that will kick it up to 44 horsepower naturally asperated, or one that will kick it up to 57 horsepower with a turbo.

Edit: There's a third option. You can take a generic botch fuel injection pump (correctly sized for your target horsepower needs) and modify/adapt the pump to fit a yanmar. Apparently there's a yanmar cult out there where these engines are modified for crazy power - turning them upwards of 5000 rpm under heavy boost.

Unfortunately the timing adjustment will not make the pump inject more fuel - it's just a timing adjustment. You'll know pretty quick whether or not you'll need to install a larger pump.

 

[Bobcat Crazy]

I was reading up last night about the Yamar fuel injection pump assemblies - specifically how to make them pump more fuel (to make more power). You need to machine/bore the pump-cylinders oversize and fit them with larger pistons. The bores must be precision-honed to a near mirror finish. I suspect this is the low-cost option, where a pump rebuild kit is purchased for a larger pump (kit containing larger pump-pistons), where the pump is modified to accept these larger pistons. The variable is machine work. If you have a knee-mill & reamers, and knowhow, you can do this machine work yourself. If you farm it out, machine work cost becomes a significant variable.

The other option is to buy a pump assembly that's rated for a higher horsepower application - which means it already has the larger pump-pistons. There's an array of aftermarket yanmar pumps to be had. The big question (which I have not researched yet) is whether or not there's a bolt-on ready pump for the TK486V that will kick it up to 44 horsepower naturally asperated, or one that will kick it up to 57 horsepower with a turbo.

Edit: There's a third option. You can take a generic botch fuel injection pump (correctly sized for your target horsepower needs) and modify/adapt the pump to fit a yanmar. Apparently there's a yanmar cult out there where these engines are modified for crazy power - turning them upwards of 5000 rpm under heavy boost.

Unfortunately the timing adjustment will not make the pump inject more fuel - it's just a timing adjustment. You'll know pretty quick whether or not you'll need to install a larger pump.

Entropy,
You are the info MAN, and I really appreciate it. Where do you fine so much info? Thanks for all of your help. I finally drove the machine out of my shop today what a milestone! I will post below.

 

[Bobcat Crazy]

Hi All,
I was actually able to drive JD WAM 1600 mower out of the shop today, that had been a long time coming.

I have not reinstalled the 2 side (batwing) mowers on it yet. I bought six hydraulic fittings (3 hoses to each batwing) and capped the side mower hose connections off so I could see how it does before doing all of the extra work of putting them back on.

With just the front center mower there is plenty of power in the TK486 with turbo added. I only ran it about half throttle and it was running good with that setup. Now I know the 2 side mowers will require more HP and at the moment I don't know how much more. But from how it ran today I am encouraged that thus might actually work.

Either on Monday the holiday of next Saturday I will try to get the batwings installed and see what I have.

Thanks to all of you that have had any part in the thread, and those who just stopped by to see what was going with JD WAM fiasco. The project has been real and maybe at times a little fun but to be honest it has certainly not been real fun. Hopefully it will have a good ending. If the TK486 with the turbo added has enough HP to run all 3 mowers I will consider this project a success although it took WAY TOOOOOOO LONG to get to this point.