repowering a 520-H

[fishingstar 17]

I'm looking in to putting a predator motor in my 520. My rear cylinder has only 35 lbs of compression. I spent around 700.00 on intake seat repair and it lasted less then 50hrs.

I'm having a hard time finding someone to even look at it with a Onan motor in it. 

I tried searching for a entry for someone that has put a predator motor in a 520 but couldn't find any. I'm looking for what to expect and what kind of fabricating that is needed.

 

Thanks for the help

 

Dan

 

 

 

[lynnmor 7,307]

1 hour ago, fishingstar said:

My rear cylinder has only 35 lbs of compression. I spent around 700.00 on intake seat repair and it lasted less then 50hrs.

 

While I can't much help on your engine swap idea, I will say this, your seat repair was not done right and you paid way too much.  I would pull the head and see what is going on in there, post photos so we can help if possible.

 

 

 

 

[kpinnc 12,083]

I know many have used a Predator engine, but I haven't seen one yet that didn't cut the hood to clear the muffler. Personally I would modify the muffler if possible before cutting the hood. Just something to think about.

 

Unless you have a 60 inch deck, 20hp is overkill. Your tractor uses an adapter plate to fit an Onan P series engine, and the frame is drilled to fit a K series or Magnum Kohler.

 

If you're using a 48 inch deck, you can get away as "little" as a 12hp Kohler. Point being, you don't have to repower with another large engine unless you need that much power. The old cast iron Kohlers have oodles or torque, so don't let the lower HP fool you. So long as you keep oil in them, they last forever and are simple and reliable. 

Edited August 6, 2021 by kpinnc

[richmondred01 2,237]

That eaton 1100 is going to eat 2 hp making that 12 hp engine a 10 hp which is not enough to turn that 48” deck with any performance.

You will need at least a 14 or better a 16 hp to effectively utilize that 520.

[Lee1977 6,664]

I have two Predators neither is on a Wheel Horse. If.the 520 is your main mower I would suggest finding a better engine. They are good for back up equipment, or for temporary use to get

you by for 3 or 4 years until you get something better. I don't ex[ect them to last a long time for regular mowing. I have the 212 and a 420 I don't have the large one but I don't think it's any better. 

Other may have had better luck with there Predators, but that my opinion. 

 

 

Edited August 6, 2021 by Lee1977

[richmondred01 2,237]

Every Predator I get in I scrap. 
They weigh about 70 pounds scrap price is .011 per pound. 
Each engine brings in about $8.00. 
some people love them but for me, running or not, that’s what they are worth. 

[littleredrider 409]

I told myself if and when something happens to my motor in the 520, Id swap in the Predator. But my other 520 has a 10 horse single cylinder diesel, it will embarrass an Onan with the torque. Not gonna look now since don't have the money, but I'm gonna swap in a 2 cylinder Kubota from one of their smaller tractors. They list em as lower horsepower, but who knows on the torque. I have a Yanmar 3 cylinder I want to swap into the D-250. someday lol. 

[fishingstar 17]

I use this tractor for blowing snow and spraying. 

[Snoopy11 5,714]

On 8/5/2021 at 11:11 PM, kpinnc said:

I know many have used a Predator engine, but I haven't seen one yet that didn't cut the hood to clear the muffler. Personally I would modify the muffler if possible before cutting the hood. Just something to think about.

 

Unless you have a 60 inch deck, 20hp is overkill. Your tractor uses an adapter plate to fit an Onan P series engine, and the frame is drilled to fit a K series or Magnum Kohler.

 

If you're using a 48 inch deck, you can get away as "little" as a 12hp Kohler. Point being, you don't have to repower with another large engine unless you need that much power. The old cast iron Kohlers have oodles or torque, so don't let the lower HP fool you. So long as you keep oil in them, they last forever and are simple and reliable. 

20 hp is overkill...

 

Hmm...

 

What would you call 51...? 

 

Don

[Snoopy11 5,714]

 

Duromax engines are reliable... in my experience. If you compare a Duromax to a Predator... there is little difference internally, except for the Duromax 457 being stroked beyond that of a predator. Generac 420 is identical to a Duromax 420, AND a predator 420. 

 

Where things get interesting is physical sizes of engines, with Duromax going with slighly bigger wristpins and rods. Cylinder bores are identical. 

 

In my opinion, Ironton is just about the cheapest made engine that you can buy. 

 

Truth is, none of the above engines are as durable as a v twin with positive oil pressure. BUT, not being as durable has nothing to do with it being a scrap or crappy engine. 

 

If I was going to buy an engine, I would by a Duromax any day, particularly after taking apart these engines and comparing parts. BUT, I will say, there is nothing wrong with buying a predator, if that is what you desire. 

 

You put a billet rod in a Duromax or predator... you will be running it from now until doomsday.

 

https://www.amazon.com/DuroMax-XP18HPE-Electric-Certified-Refurbished/dp/B071XVM71F

 

Don

Edited August 11, 2021 by Snoopy11

[richmondred01 2,237]

I’m sorry, in an effort to be “woke” and not offend anyone. 
I made an attempt to be funny and I gather it wasn’t well received by several snowflakes. 

I won’t offer my opinion in predator engines anymore.

I will consider myself canceled regarding any issues surrounding any and all my experience dealing with predator engines. 
Please accept my upmost humble apology.
 

Edited August 11, 2021 by richmondred01

[Snoopy11 5,714]

By the way, 

 

Duromax engines will physically fit on your tractor, and very well may reuse your stock engine mounting points. Issues with mounting MIGHT include things such as the following which can be dealt with ...with purchase of a few parts... air intake, fuel tank, and exhaust muffler. 

 

With muffler, you can buy/make something like this:

 

 

Air filter...

 

 

Fuel tank, I leave at your discretion.

 

[Snoopy11 5,714]

18 minutes ago, richmondred01 said:

I’m sorry, in an effort to be “woke” and not offend anyone. 
I made an attempt to be funny and I gather it wasn’t well received by several snowflakes. 

I won’t offer my opinion in predator engines anymore.

I will consider myself canceled regarding any issues surrounding any and all my experience dealing with predator engines. 
Please accept my upmost humble apology.
 

 

 

Look man, I'm the first one to stand up for free speech, including yours. Nobody wants/or is going to try to cancel you. But I just don't want to discourage someone from working on a project and buying an engine that is fine for the application. I have had success with these engines, and quite a few others. Some people may find your perspective helpful... maybe funny. I just hope... people find my perspective more helpful from an engine builder standpoint. Been buildin' 'em for years... 

 

 

 

Don

Edited August 11, 2021 by Snoopy11

[richmondred01 2,237]

I understand and bow down to your vast experience on the aforementioned subject. 
Once again, I’m sorry if your feelings are hurt.

If you want, please forward me your address and I will be glad to send you a trophy. 
 

[Snoopy11 5,714]

Just now, richmondred01 said:

I understand and bow down to your vast experience on the aforementioned subject. 
Once again, I’m sorry if your feelings are hurt.

If you want, please forward me your address and I will be glad to send you a trophy. 
 

“When you can’t make them see the light, make them feel the heat.” -Reagan

 

stevasaurus-(Moderator) I'll let you take it from here... I've breathed a little heat into this discussion... but I haven't even breathed heavy yet... and don't intend to. 

 

Just getting sick of seeing perfectly good questions and threads trashed... 

 

Don

[richmondred01 2,237]

I agree Don.

I couldn’t have come up with a better quote.

Thank you. 

[slim67 2,735]

1 hour ago, Snoopy11 said:

By the way, 

 

Duromax engines will physically fit on your tractor, and very well may reuse your stock engine mounting points. Issues with mounting MIGHT include things such as the following which can be dealt with ...with purchase of a few parts... air intake, fuel tank, and exhaust muffler. 

 

With muffler, you can buy/make something like this:

 

 

Air filter...

 

 

Fuel tank, I leave at your discretion.

 

I got the flange that you can weld a nipple to coming. I can run any muffler which saves me from cutting the hood. Also pal on that same air filters ( but red).

[pacer 3,173]

This topic - engine swap - has come up in quite a few postings and the comments sorta remind me of - which oil is best, which filter, paint, etc, etc,  And, as on those varied topics there is a quite large range of  .... opinions? on them. 

 

My suggestion to the poster is to read thru them, picking up what kernels of info that strike you. This post is - I think - a good one, there are several good bits of info in it. For instance, I am pretty well up on .... comments? re the Predator and I am .... maybe 50/50 on it and in @fishingstar proposed use of it, Id say go for it. 

 

@Snoopy11 info on the Duromax was new to me and was glad to see that....

 

 

[Snoopy11 5,714]

2 hours ago, pacer said:

This topic - engine swap - has come up in quite a few postings and the comments sorta remind me of - which oil is best, which filter, paint, etc, etc,  And, as on those varied topics there is a quite large range of  .... opinions? on them. 

 

My suggestion to the poster is to read thru them, picking up what kernels of info that strike you. This post is - I think - a good one, there are several good bits of info in it. For instance, I am pretty well up on .... comments? re the Predator and I am .... maybe 50/50 on it and in @fishingstar proposed use of it, Id say go for it. 

 

@Snoopy11 info on the Duromax was new to me and was glad to see that....

 

 

Yes sir, that is what I am running at the moment... 

 

Duromax with racing internals... 51 horsepower on the dyno...

 

With this build, I know one thing for sure, ...the block is strong... 

 

Don

[Snoopy11 5,714]

3 hours ago, richmondred01 said:

If you want, please forward me your address and I will be glad to send you a trophy. 
 

Chicken Dinner Road, Idaho, USA

Kidding...

 

 

Don

[stevasaurus 22,764]

I hate to lock this thread, because I see some good information here.  Let's see if we can stay on topic, please.  Attacking members is not staying on topic.  

[Snoopy11 5,714]

19 hours ago, slim67 said:

I got the flange that you can weld a nipple to coming. I can run any muffler which saves me from cutting the hood. Also pal on that same air filters ( but red).

 

Don

[Snoopy11 5,714]

19 hours ago, pacer said:

which oil is best

 

 

Klotz oil... Mobil-1 high mileage if you can't get Klotz!

 

I had to say it... 

 

Don

Edited August 12, 2021 by Snoopy11

[DoctorHfuhruhurr 137]

I'd cram in the biggest smokiest diesel I could find but I'm a rebel. 

[kpinnc 12,083]

Me personally- I would look closely at that Onan before replacing it. That being said:

 

There are plenty of engines out there that are good candidates for a repower. Pros/ cons discussions can go on forever if you ask for them.

 

If you're mechanically inclined with any imagination whatsoever, you can repower with most anything of similar HP rating. If you can spare some time, you will likely find a Onan P220 on local classifieds or Craigslist. Maybe even Ebay. Again, your ability to repair engines can affect how successful such an endeavor can be. 

 

"New" engines are almost as much of a gamble these days as a used one. At least older engines were rebuildable. Only a few new ones have parts and access to them. Some do have a large aftermarket of parts, and if you look around- likely there are forums than can be helpful if you need them.

 

Regardless which path you decide on, there will be some expense and work involved. Even a direct swap with another Onan can be a full day of work. 4 bolts, a couple simple electrical connections, the PTO linkage and finally the belt and sheetmetal is still a bit of work. Plus an Onan is one heavy chunk of metal. Buy a buddy some beer and have him help moving the engine around. Your back will thank you later. 

 

Good luck with whatever you decide. A 520-H is definitely worth saving. You can't replace a machine like that anymore. 

Edited August 12, 2021 by kpinnc