Wheel Horse 520H Onan engine rebuild

[Joey baga donouts 0]

Hi I have an original Wheel Horse 520H with Onan engine. I think it’s an 85’ with about 1500 hrs on it. 
I have had several Wheel Horses, all models and engines and do all the maintenance on them. 
I’m looking to have the Onan P220 engine rebuilt. Valve is tapping a bit. 
does anyone know a good engine shop in or near PA? I can get to Ohio, NJ, NY MD DE but I live in West Chester ,PA. 
mainly need the valve seat job and would do new pistons. 
tractor is currently working and cuts grass. 

 

[ri702bill 11,653]

Joe - Welcome!

I hate to be the bearer of less than good news, but here goes.....

Onans are notorious for having the valve seats get loose after 1100-1200 hours. The loose seat(s) get hammered into their recess and ruin it. Ruin as in not worth trying to fix it. That could account for the valve noise...I hope you did not already start to acquire parts - it is strongly advised to pull the heads to inspect the condition of the valves & seats. My , 

Others will chime in on this, for sure...Pictures would be helpful.

Edited 8 hours ago by ri702bill

[sqrlgtr 2,438]

I just pulled both heads on mu 520h just so I could inspect and adjust valves. In my case everything thing looked great. I decarbed heads and combustion chambers and put back together. Btw all my valves were on the tight side. Had to replace manifold and cleaned carb also not to bad of a job but I recommend taking all the motor mount bolts out except one so you can turn motor enough to take heat sheilds off easier or pull motor.

[Achto 31,443]

[Handy Don 16,162]

41 minutes ago, sqrlgtr said:

recommend taking all the motor mount bolts out except one so you can turn motor enough to take heat sheilds off easier

This is a nice idea, since things are pretty cramped on the 520’s! Thank you.

[WHX?? 55,872]

 

2 hours ago, ri702bill said:

less than good news,

I'll have to second that. 

While a Onan is a fine engine when it runs when it needs refreshing the general consensus here is they are not worth rebuilding. Especially if you have to pay a shop to do it.

By the time you are said and done with machine work, parts & what what not you can easily do a repower.  

Then there is the dreaded valve seat issue and if the tractor was poorly taken care of meaning fins plugged lack of oil changes etc. belt guard not ventilated ...  is it worth it? Only if you have a sentimental attachment to it. 

I would just do a compression check, decarbon & valve adjust and run it.