John Deere 420 Garden tractor question

[barretreasures]

Hi been getting a lot of good info from the site Now I Need Help !!!

My Onan P220 in my 1989 420 garden tractor broke a rod this week I think the block is ruined. the cyl. walls look good and are very smooth with very little ridge at the top. My concern is at the bottom of the cyl. wall where it looks like the rod broke off about 3/8" of the wall I know that it is well below the rings and not in the compression area. I also know that I need a crankshaft. Question 1. In the opinion of the experts am I right to assume the block is trash? Was looking at used crank and pistons with new rings. This leads me to Question 2. Will the P224 fit a 420 using the 220 oil base and some exhaust mods? looking at one on ebay. Locally there is a Onan 20.5 horsepower ohv performer. It's out of a Miller trailblazer welder. Trying to do some research on these 2 engines (Crankshaft dia,length, exhaust placement etc ) to determine if either are usable. Any and all help will be GREATLY appreciated. THANKS

 

[RandyT]

Welder engines normally have a tapered crankshaft. May want to look into a bore and sleeve job to see if that is possible.

 

[barretreasures]

thanks

 

[Amvcane]

I believe the onan used in a welding application will have a different amount of fly balls in the governor, you probably won't get the rpm range you need to use in a tractor.
I would go over to Weekend Freedom Machines forum and contact a member named Boomer. He will definitely answer all your questions and supply you with the new or used parts required to solve your problem.

 

[barretreasures]

Thanks

 

[Richard001]

Hi been getting a lot of good info from the site Now I Need Help !!!

My Onan P220 in my 1989 420 garden tractor broke a rod this week I think the block is ruined. the cyl. walls look good and are very smooth with very little ridge at the top. My concern is at the bottom of the cyl. wall where it looks like the rod broke off about 3/8" of the wall

The block does not look ruined to me. That little punched out part is not a real problem.

I know that it is well below the rings and not in the compression area.

I also know that I need a crankshaft.

OK I give up, how do you know that you need a NEW crank?

The photo is a little blurry when zooming in on the journal. You didn't use a cell phone to take this picture did you?

Question 1. In the opinion of the experts am I right to assume the block is trash? Was looking at used crank and pistons with new rings. This leads me to Question 2. Will the P224 fit a 420 using the 220 oil base and some exhaust mods? looking at one on ebay. Locally there is a Onan 20.5 horsepower ohv performer. It's out of a Miller trailblazer welder. Trying to do some research on these 2 engines (Crankshaft dia,length, exhaust placement etc ) to determine if either are usable. Any and all help will be GREATLY appreciated. THANKS

Richard

 

[barretreasures]

Thanks for your input Richard. I did use a cell phone for the pictures. Its probably more the light than the cell phone as I did not turn on the flash. The crank looks pretty scored to me but I'm no expert. I will take some more photos in a few minutes with my camera and try to get some better ones. as for the block I was hoping that was the case. (You know hope for the best expect the worse). I had about decided to just replace the pistons and rods with some used ones with new rings to try and get another year or 2 out of it, then put a repower in it that I can't really afford at this point. Again Thanks

 

[barretreasures]

Some pictures I took at the same time that I didn't post. Let me know if you need more or different

 

[ovrszd]

My Son converted his to a Honda engine for around $2K. I can get specific amount if you need it. Improved the performance of the tractor dramatically. Mows much faster.

 

[Spanner]

I agree with Richard001. The block should be ok.
The crankshaft will probably 'polish' up ok on the journals. Take it (crankshaft) to an engine reconditioning shop and ask them to try to polish it. The scoring is mostly soft metal from the Big End bearings onto the steel of the crank.
If you can get used pistons and rods etc. and it gets you running within your budget, go for it.
Good luck.

 

[barretreasures]

Spanner Thanks for your input

 

[Spanner]

:drink:

 

[pmsmechanic]

Here's what I would do.

FARM SHOW - Garden Tractor Repower Kits

Onan engines are frightfully expensive to overhaul with no guarantees. This way might cost a bit more money but you will be up and running with a new engine.

Home - Small Engine Warehouse

 

[Amvcane]

Have you tried this link yet?
Boomer's Used Onan Engine Parts

An email or phone call will surely steer you in the right direction.

 

[barretreasures]

Thanks to everyone for all your help and advice it is GREATLY appreciated. My budget has changed overnight and I just ordered the Vanguard 23 HP from Small Engine Warehouse. I will at some point rebuild the Onan and put it back in the 420. However for now I need to get the tractor up and running ASAP as my 6 acres of grass doesn't know my tractor is down. Again THANKS to everyone for all your help and advice.

 

[pmsmechanic]

I'm thinking that the Vanguard will use so much less fuel that you will never put the Onan back in. I dropped a rod on a John Deere 400. It had a Kohler, same design as the Onan. I swapped in a 20 hp water cooled Kawasaki V twin. I modified everything myself and made it all fit without changing the outward appearance of the tractor. It used about half the fuel doing the same job.

Have fun!

 

[Richard001]

So you have decided to invest $1,299.00 for a new engine for a 25 year old lawn tractor. Ops let me correct that, it's $1,750.00 for the kit.

I wish you the best of luck with this.

Richard

 

[Amvcane]

That garden tractor will last another 25 years now. Great choice.

 

[ovrszd]

So you have decided to invest $1,299.00 for a new engine for a 25 year old lawn tractor. Ops let me correct that, it's $1,750.00 for the kit.

I wish you the best of luck with this.

Richard

I think you need experience with a 420 to appreciate this. And an LX178 isn't that experience.

 

[crazyal]

That 420 probably cost $7500 back in the late 80s when it was new. Once running again will mow circles around anything that you can buy today for $1750. It'll probably last longer too.