520H/ Eaton hydro needs extra 1-2mph

[Greentored 3,217]

 My 91 520H is working as it should- the linkage is clean, adjusted, rod ends lubricated, fresh fluid and filter, engine at 3600rpm, and I get full travel out of the shift plate. Not trying to make it a race tractor, but sure would be nice to have it move 7-8mph when going from one area to another or quick buzzing the lawn. Seems if someone changed the shift linkage for more travel or welded up and re-slotted the shift plate this could be possible. Anyone tried it?

Again, not looking to go 40mph, heck, not looking for 10. Old man's worn out 317 deere hydro would flat out blow the doors off my 520 in a drag race. Ok, suppose thats fine, because ill hook a chain between them and drag that 317 all over the yard with some wheel horse grunt hahaha.

[pfrederi 17,876]

Trade it for a Charger or Electro  with a Sunstrand they go 7mph.  Seriously I think Consumer Product Safety comm (or damn lawyers) had something to do with lower top end in later WHs

[cafoose 3,355]

I believe the 520HC is faster. I wonder what they did to make it faster than the 520H?

[ol550 830]

Get some rear gears from a 520-HC or a 1848. Will get you 7.0 instead of 5.6 MPH.

[WVHillbilly520H 10,374]

1 hour ago, cafoose said:

I believe the 520HC is faster. I wonder what they did to make it faster than the 520H?

C standing for "commercial" less frills and more speed for commercial mowing operations by way of final ratio in the gearing.

[Greentored 3,217]

My thoughts were to modify the 'cam' plate to move the hydro lever further, but that lever is at the end of its travel exactly where the cam takes it, so looks like its either a gear or pulley change.

 

OL550, help me out here, never had one apart. Im assuming there is a pinion gear on the hydro pump and a ring gear of sorts on the diff that could be changed?

 

[Goofey 89]

I think @Skipper has done something like that. He also vent thru all the options. Try a search. 

[Greentored 3,217]

1 hour ago, Goofey said:

I think @Skipper has done something like that. He also vent thru all the options. Try a search. 

I did find some random 'skipper' threads, but nothing that spells out exactly what needs to be done. Ill shoot him a message.

I know they say to not do a pulley swap on hydros as theyre rated for the same 3600rpm as the engine, but am wondering if it may be safe to do it in this case, as it would not be run at that speed on a regular basis. 

Based on 5" pulleys, a 1" change in the drive pulley would overdrive the pump approx 20%, taking it to approx 4200rpms IF im running it flat out, which would not be often. It would also allow me to work the tractor at a deent speed without having to spin the bejeesus out of the engine. Win win?

[Goofey 89]

I'm sure eaton has a safety margin on the rpms but I think it's the wrong approach to go that high.

[ol550 830]

Don't know if this link will open. Gears 23, 24, 27. and 28 are different.

Toro 31-20OE01 (520-H) - Toro Garden Tractor (1988) TRANSAXLE Parts Lookup with Diagrams PartsTree.url

[wallfish 17,079]

How about going with larger 26" rear tires and you'll get another MPH out of it.

[Rob R 966]

If you want take a look at my recent post where I did a transmission pulley swap going from a 6" pulley to a 4.5" and it did the trick for me as your aware this is a gear transmission not hydro but I don't see why if won't work. I did mine to increase the mowing speed since prior to the swap 2nd was too low and 3rd was too high for mowing..... p.s. one of the side advantages was now reverse is also improved. 

[Skipper 1,788]

Greentored has asked me for my 2 cents on pm. I post it here, so others can get info too if needed

 

You have several options to increase speed. You might want to go for a combination of some of them, to reach your goal, in a way that suits you best.

• Gear set from an HC will upgear 16%, and roughly give you the speed you aim at. It is a simple swap of gears, but you will need a HC tranny for parts, as the gears are NLA. (or just do a swap if the HC unit is strong) Do check bearings etc. and refresh seals while you are in there.
• Pulley swap, and over revving the hydro unit. Eaton for sure has a safety margin, but I would not go to +20%. I run my 195 at 3800, and that gives a good boost. It ain't all linear. This is not me saying that it is OK to over rev it. I do it and it works for me. Yours might explode or in other ways fail.
• RPM's of engine. There is a larger than linear speed drop, if you do not reach the 3600, so check the rpm's with a meter to confirm.
• Make sure your hydro is strong, and not worn out, as they can loose speed that way too.
• Tires has also been mentioned as a valid option to increase speed. Simple calculations can determine your new speed with a given tire size compared to the old ones.
• Cam plate modification. Yes this is also a way to go. The hydro unit is not set up to max flow, and it is WH/Toro that has set the flow via the camplate. Eatons manual (non WH specific) states that OEM's should never exeed 14 deg of travel on the motion controle arm in either direction. WH has it set a lot lower than 14 deg. I would not go all the way to 14 deg, but aim for some middle ground. Remember it is a variable volume oil pump and an oil motor built into one unit. If you increase volume (more degrees), you also lower the torque the unit is capable of at that setting. You might find that the last bit of travel on the control arm is mostly for travel, and less for work/hauling. The unit is capable of transferring roughly 10 hp. That's a lot at low flow volume and gives abundant torque at lower speeds, and is also enough to go very fast, but not both at once. Botton line, yes you can go faster by tweaking the cam plate, but make very sure you do not go over 14 deg, and don't expect a locomotive at 14 deg.
• Over revving the engine is an option for some, but not something I would even consider.

Hope that helps. Shoot if there is other questions

Edited January 13, 2020 by Skipper

[JAinVA 4,621]

The only practical pulley swap is a larger engine pulley.The pump snout on an Eaton 1100 will not allow a smaller pulley.The trans pulley is bell shaped to clear the pump.

[Greentored 3,217]

Awesome- this is the kind of info I was hoping for!  I like technical discussions, and like to know WHY an idea will or wont work. The ol girl JUST got a brand new set of tires, or a pair of 26s out back and some 18s up front would have been a great option. Think ill keep the stock pulleys, and sure as hell wont be twisting than Onan over 3600 and have the rods make babies in the crankcase

  Think the HC final drive gear swap is my best option, if they can be found. 

Skipper- I worked on the linkage and cam plate yesterday evening. Seems the big struggle with these 520Hs is getting good forward speed without losing reverse, or vice versa. To accomplish this I adjusted for a safe neutral and maximum forward speed using the unmodified plate. As expected this made reverse about 0.2mph, so I welded and reground the reverse slot only, to a bit steeper angle. After some final tweaking I have a safe neutral, a safe forward AND reverse speed. 

The length of the slots in the cam plate were not altered, so I should be safe as far as the 14 degrees of travel are concerned? 

You all have been a HUGE help im making my first horse exactly the way I want it. THANK YOU!!!

[Greentored 3,217]

Ok, so it appears the circled items are the ones id need to find to do a HC swap, correct?

Item 27 is offered in a 44T vs 46T

Item 28 is offered in a 22T vs 20T

Believe id need the 22/44.

Item 23 is the shaft itself- this should be the same?

Item 24 only shows a 46T, no option. What should I be looking for?

[WildmanC120 613]

I have a 418-c for trade/sale and it has the Eaton/gearset you are looking for. 

[Greentored 3,217]

2 hours ago, WildmanC120 said:

I have a 418-c for trade/sale and it has the Eaton/gearset you are looking for. 

I need another toy like a hole in the head

[WildmanC120 613]

8 minutes ago, Greentored said:

I need another toy like a hole in the head

It's well used. I would pull the motor and rear end from it. Great donor rear end for you. It's one of the few units where you will get the gears you want.

[Goofey 89]

was 418 made in a HC version or is it a swap from a 520HC?

[WildmanC120 613]

14 minutes ago, Goofey said:

was 418 made in a HC version or is it a swap from a 520HC?

418-c is a commercial model. It is missing all the electrical crap that breaks and has heavier duty front spindles and the faster trans. 

[Goofey 89]

So same trans and hydro unit as a 520HC then? Newer heard about that model before. interesting.

[WildmanC120 613]

12 minutes ago, Goofey said:

So same trans and hydro unit as a 520HC then? Newer heard about that model before. interesting.

It's a 1 year model. 1987 I believe. 

[N875ED 98]

Greentored:

Can you please send a photo(s) of your work...I'd like to do the same to my 520H

Thanks!

[N875ED 98]

I mean the modifications you made to the reverse slot, that is...