1994 520-H Revival

[jsoluna 242]

It appears the Wheel Horse bug has hit for real.  Stumbled upon this 520-H not even 5 minutes from our shop.  Really don't need another project to add to the list, but couldn't pass it up for the price.  It's pretty rough.  Almost 2k hours, single owner machine though. 

 

What I know so far:

 

Owner said "it needs a starter solenoid"....

 

Does not run.  Will crank (solenoid is fine) and has compression.  Looks like they hooked up the replacement ignition coil wrong and sent battery 12v+ to the ground side of the ignition module.  It's toast, as is the coil.  Pretty pricey way to start the revival, but it is what it is.  Followed proper procedure for testing both components and they are indeed bad.

 

Steering is extremely sloppy.  Most of it is in the tie rod ends, but a good portion of it appears to be in the steering gear backlash.

 

Has hydraulic leak near the rear somewhere.

 

Has previous owner wiring "fixes".

 

Loaded rear old school Goodyear treads.  

 

Deck shell looks newer than the rest of the tractor.  Maybe a replacement?

 

Has axle bracket installed.

 

Dash lights all come on at startup, but I will plan on going through the whole system.  Don't like having hidden gremlins and I enjoy the electrical challenge.

 

All in all, pretty excited.

Edited 23 hours ago by jsoluna

[ri702bill 10,222]

Nice start...

Not too many of us ever feel we "enjoy" the electrical challenge though....

Edited 23 hours ago by ri702bill

[lynnmor 8,139]

Looks like she was rode hard and put away wet.  That steering gear backlash might come out when you adjust the nut in front of the gear, that requires a cotter pin removal and a 3/4" wrench.  If it is severely worn a washer behind the nut will give more adjustment and still have cotter pin engagement.

You might find a complete kit of ignition parts on eBay for way less than OEM, they are aftermarket but some have had good success.

[Ed Kennell 43,298]

47 minutes ago, jsoluna said:

Deck shell looks newer than the rest of the tractor.

Looks like a $400 48" er.

[jsoluna 242]

1 hour ago, lynnmor said:

Looks like she was rode hard and put away wet.  That steering gear backlash might come out when you adjust the nut in front of the gear, that requires a cotter pin removal and a 3/4" wrench.  If it is severely worn a washer behind the nut will give more adjustment and still have cotter pin engagement.

You might find a complete kit of ignition parts on eBay for way less than OEM, they are aftermarket but some have had good success.

Thanks, I'll look into that steering gear and see what I can find.

 

Found a few kits on eBay that are clearly aftermarket copies, any experience with a particular seller?  Or is it like most of these things, where it's luck of the draw?

Edited 22 hours ago by jsoluna

[jsoluna 242]

Definitely rode hard and put away wet.

[8ntruck 8,238]

I wonder if Pertronics makes an electronic ignition kit for the 20hp Onanz.

[jsoluna 242]

1 hour ago, 8ntruck said:

I wonder if Pertronics makes an electronic ignition kit for the 20hp Onanz.

It is already "electronic ignition" technically - it's transistorized breakerless.

 

Its a simple design, reluctor wheel on the crank and a module that serves as the hall effect sensor and ignition coil control source.  

 

I think what makes it expensive is that it's all proprietary Cummins/Onan stuff.  I'm sure you could make your own system using a separate hall effect sensor and control module like GM's HEI or Ford's TFI.  The time/money fallacy comes into play there though.  By the time you get the hall effect setup dialed in right at the crank, you could probably just have bought the proper setup.  Still might be a fun project to pursue at some point.  Might help keep these old Onans alive longer.

Edited 18 hours ago by jsoluna

[Handy Don 14,841]

3 hours ago, jsoluna said:

It is already "electronic ignition" technically - it's transistorized breakerless.

 

Its a simple design, reluctor wheel on the crank and a module that serves as the hall effect sensor and ignition coil control source.  

 

I think what makes it expensive is that it's all proprietary Cummins/Onan stuff.  I'm sure you could make your own system using a separate hall effect sensor and control module like GM's HEI or Ford's TFI.  The time/money fallacy comes into play there though.  By the time you get the hall effect setup dialed in right at the crank, you could probably just have bought the proper setup.  Still might be a fun project to pursue at some point.  Might help keep these old Onans alive longer.

I picked up a 400 hour P220 that had one cylinder seize while running (lots of scrap metal inside!) for very short money to strip for parts. Already paid for itself since I needed a muffler; the rest of it is insurance and convenience: carb, coil, stator, voltage regulator, ignition system, governor parts, engine wiring, solenoids (starter and kill), starter, and PTO bits. I even got a couple of the flywheel magnets off intact. 

Edited 15 hours ago by Handy Don

[Bill D 2,393]

11 hours ago, 8ntruck said:

I wonder if Pertronics makes an electronic ignition kit for the 20hp Onanz.

The ignition module was out of stock on the Cummins website awhile back.   I called Pertronix and asked if they made one for Onans.   They did for a short time until Cummins threatened them with a lawsuit.  All documentation was destroyed.   No one could even tell me the correct module to use if I wanted to fab up my own setup.  The part was back in stock last time I checked.

[JoeM 9,029]

Those Onan 20's really have a lot power.

Often wondered why they use a lot fuel.

Onan 20 has 47cid

Kohler CH20 has 38cid.

 

Those extra cubes put it in the same class as a 25-27HP engine. just saying. 

 

Like the car guys say "there is no replacement for displacement!" 

 

Sure would have been nice if WH left all whose "idiot lights" off the machine. Imagine how clean the wiring system would be! 

 

[jsoluna 242]

54 minutes ago, JoeM said:

Those Onan 20's really have a lot power.

Often wondered why they use a lot fuel.

Onan 20 has 47cid

Kohler CH20 has 38cid.

 

Those extra cubes put it in the same class as a 25-27HP engine. just saying. 

 

Like the car guys say "there is no replacement for displacement!" 

 

Sure would have been nice if WH left all whose "idiot lights" off the machine. Imagine how clean the wiring system would be! 

 

The flatheads are much less efficient due to the nature of the combustion chamber and valve arrangement, and have lower compression than a typical OHV engine.  This, they use for fuel to make the same power.  They tend to be very torquey engines though. My personal favorite is the Magnum twin.  

 

I enjoy the engineering behind the wiring systems on the 520-H.  Definitely overcomplicated for a garden tractor, but really cool all the same.  

[ebinmaine 74,895]

20 hours ago, jsoluna said:

I enjoy the electrical challenge.

 

All in all, pretty excited.

 

20 hours ago, ri702bill said:

Nice start...

Not too many of us ever feel we "enjoy" the electrical challenge though....

 

I do... to a point...

 

Building a wiring harness from scratch for a 6 or 10 wire system is relaxing to me. 

I dont have much desire to tackle a 520 set up. But it is certainly interesting to see and understand.  

 

@jsoluna

I've personally had better luck installing used OE electrical parts than new aftermarket. 

Possibly @76c12091520h Brian Badman or Lincoln at A to Z Tractor in PA could be a source.  

 

 

[lynnmor 8,139]

5 hours ago, JoeM said:

Sure would have been nice if WH left all whose "idiot lights" off the machine. Imagine how clean the wiring system would be! 

 

The "idiot lights" can be covered with duct tape if you hate them so much.  Personally I never had problems with them.

[Handy Don 14,841]

2 hours ago, ebinmaine said:

a 520 set up. But it is certainly interesting to see and understand.  

The shift to using solid state components to “interpret” the sensors and activate LED indicators was inevitable. Most buyers were impressed with the lights but discrete bulbs, sockets, and wiring would have been a maintenance PITA. 

Like @lynnmor, I’m good with having the extra instrumentation