Differences in 88 520-H engine vs 90...

[1990Onan520-H 15]

Hey all, long story short I'm starting to think my 88 520 is not worth fixing. That being said I'm debating fixing it anyway but putting the engine onto my 90 instead of back onto my 88 that has really seen better days. However it looks like there are some physical and electrical differences. Does anyone know if I can just swap the tins and harness to do this or are sensors and gauges wired different too?

[cleat 7,259]

The 88 has in my opinion the better harness.

The gauges should wire up the same (possibly in different locations so take note of wire colours) but the indicator panel does not so be sure to use the one from the 88 as well as the plastic dash as the indicator lights are also in different locations so the decal is different and also you need the test switch.

Park brake and neutral switches are also in different locations.

 

That is all I can think of right now.

 

[Ed Kennell 42,014]

I don't have any experience on the wiring differences, but I much prefer the motion control located on the console on the '88 and '89 520s.

I have had shifting problems with every tractor with the  motion lever mounted on the steering shaft. .  

   My preference would be to rebuild the '88 with the good '90 parts.   

[cleat 7,259]

That would be the simplest.

You can swap the front axle and steering quite easily if desired.

An upgrade you can do to either steering system in the early tractors is to drill out the support plate and install a flanged ball bearing (same as the front wheels on a lot of Wheel Horse tractors).

This makes the steering much smoother and easier and also gets rid of a lot of the steering shaft movement (except rotational play, that is another issue).

 

Just pick the best parts and you can build a great machine.

 

If you can build a tractor with all the leftover parts you can sell it to recoup some money or keep it as a spare (just be careful as you may end up like me and end up with a lot of rebuilt 520's and a very patient wife).

 

I personally prefer the early 520's and do not like either motion control but put on Matt's foot control (i have 2 more on order so every tractor I own will be foot control soon).

 

[Ed Kennell 42,014]

I also have foot control(my own design) on all my hydros.    

[1990Onan520-H 15]

I will probably add the foot control also, I can't stand the column shift, the 88 shifter isn't as bad. But when I say the 88 is rough, I mean rough. Every panel has rust pits, steering is so worn I can hardly get it to turn without skipping teeth, wiring is dry and patched etc.

 

The 90, total opposite, great shape, great wiring harness, a solid 7 out of 10 machine, just happened to chuck a rod and destroy everything in the engine in the process.

 

That being said let me rephrase, my plan would be to swap the tins from the 90's engine, as well as use the 90's wiring, however I was hoping to just plug the 90's harness into the sensors. So i would be using all electronics, wiring, gauges from the 90. The only thing I was going to use off the 88 were sensors on the engine such as oil pressure, crank trigger etc. Are those all the same 88 to 90?

[1990Onan520-H 15]

Just for fun, here's the vent my 90 put in her block at 850 hours on the clock. Believe it or not the thing still ran with no noises on the front cylinder. I'm guessing someone didn't change oil. I picked it up blown hoping it was a simple fix based on how it ran... Not so much.

[cleat 7,259]

You can use the older engine. It will come wired with the charge going directly to the starter solenoid through an inline fuse.

That is a better design.

 

I am pretty sure you can plug and play as I have done it.

All other wiring on the engine itself I believe is the same.