Case 446 repower

   / Case 446 repower #1  


Nov 18, 2010
I picked up a 446 with a blown up front clutch and the tiller for a good price, but the engine was hurting. I used it for the season, limping it along, but this spring something had to be done.
I had a 15 horse "princess auto" engine sitting in the garage for another project, but the engine wasnt right for the other project, so the repower was born.
My son and I pulled the tins and the old engine in an evening. A little elbow grease cleaned things up enough to make it nicer to work around, then the following saturday I put it back together.


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   / Case 446 repower
  • Thread Starter
With the teardown complete, I had to re-fab the pump bracket. I didnt want to monkey around trying to pull the love joy from the pump, so it got moded to fit.


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   / Case 446 repower
  • Thread Starter
Drilled new mounting holes and expanded 2 existing holes to mount the engine. Fits like it was meant to be there!
I only had to cut the heat shield above the rad cradle (from behind the old muffler) and grind a small corner to clear the muffler completely.
I will remote the key to the dash, and modify the air cleaner and muffler so I can fit the hood back on. Best part is the tractor is useable again, since it runs like brand new! the 15 horse single doesnt even grunt under load of tilling.

Thought I would share with the group.


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   / Case 446 repower #4  
If this works for you and makes you happy, then so be it.

However, I would never, ever suggest that someone else follow in your footsteps. In the beginning, you had an excellent Case 446 from the mid-70's with a slightly tired ONAN and a clutch that needed repair. At that time, the tractor was capable of blowing snow, cutting grass, pulling attachments and powering any of the hydraulic attachments available from Case, providing the PTO clutch got repaired. It's hard to say what was truly wrong with the ONAN because apparently you never took the time to investigate. That's too bad because the ONAN is 5 times better than the engine you now have under the hood.

As it stands currently, you can no longer blow snow or cut grass because you do not have the PTO clutch that is needed. You have not done anything to compensate for the loss of the oil cooler fan and therefore you will cause the hydraulic oil to run much hotter than it should. This will lead to an early breakdown of the oil itself along with a shortened life for the hydraulic pump, drive motor and hoses. You have an unnecessary fuel tank under the hood, the engine is mounted further forward than necessary because you did not shorten the stub shaft on the crank. If you did not use a dial indicator to make sure that the pump is lined up perfectly with the engine's stub shaft, then you can expect early failure of the spider in the Lovejoy coupler.

The Onan had a 15 Amp charging circuit. Something tells me that the Princess engine probably puts out just 3 amps. I see that the ammeter is no longer in the dash and the battery is not where it should be. As you say, you still have to modify the exhaust and the air cleaner so that the hood can go back on. If anything, this thread is a perfect example on why re-powering Case tractors with oddball engines is a bad idea. You ended up with half a tractor that cannot come close to competing with what Case put together originally. Rebuilding the Onan was a much smarter move for the long run, although it would have cost more. Good Luck.
   / Case 446 repower
  • Thread Starter
It actually works perfectly for me. The battery will go back in the original location, since I havent installed the battery yet. The ammeter was trashed, as was the original engine. I have had my fair share of experience with the opposed twin onans - and they are JUNK. Too many issues with broken cranks and terrible fuel systems.
I dont need the 15 amp charging circuit, (this one has a full 9 amps BTW) and there was no front clutch, clutch engagement, fan, or clutch attachments when i got the tractor. moot point, since this machine has been out of production for so long you cant find cheap parts. The exhaust and air cleaner mods will be minor, and are a non issue right now, since I at least have a running tractor which i did not before. FWIW, there is MORE air flow through the rad now than when I was running it with the Onan last year.

I also have set up many lovejoy couplers, and my dial indicator gets used more than you think.

Have you priced out the rebuild for the onan? I have an onan in my Bobcat that has been rebuilt 3 times, and the machine has about 700 (yes, seven HUNDRED) hours on it. Not a good run record in my books.

I did not post to get flamed. I posted to offer a suggestion to make a useable machine out of what would otherwise be a pile of parts junk.
I can still add a front mount blower, hydraulically powered, and I have a perfectly good swisher and cub cadet for mowing grass.
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   / Case 446 repower #6  
The Onan twins were used to power generators that were expected to run non-stop for days on end. When properly cared for, Onans are one of the most reliable and long-lived engines ever produced. Millions of them were sold for use in garden tractors, water pumps, welders, generators, construction equipment etc. The normal expected lifespan of an Onan twin is a minimum of 2000 hours. May of them have been re-ringed and put back into service after deglazing and cross-hatching the bores along with lapping in the valves. I am well aware of the cost of rebuilding an Onan but I am also well aware of their durability and high torque output. More often than not, it is poor maintenance that causes the problems with Onan rods breaking or pistons being damaged. When Case took over Colt, they continued on using the highest quality engines available which is why the Kohler K, Kohler M and the Onan CCKA, BF and BG series were utilized. I am not here to dispute your personal experience with any engine brand.

This is not about "flaming" you either. This is about providing an alternative opinion to the one you gave about re-powering a Case tractor. Those who read this thread are entitled to see the short-comings of your work and then decide for themselves as to which path they believe the better route for them.

Perhaps you saw that tractor as "a pile of parts junk" but I don't. Any missing parts can be found fairly easily on e-Bay and that includes complete, used PTO clutches that would have kept this tractor totally productive that would negate the need for a Swisher, Cub Cadet and the costs of creating a hydraulically driven snow blower. In addition, I have seen excellent, used Onan's for sale on e-Bay but since you had a running engine available, a proper rebuild would probably have lasted as long as this tractor is old. Based on the photos, it appears to be a 1977 or 1978, which makes it 35 years of age. If you still have the engine you took out, it would be simple matter to find out the year of manufacture. A tear-down would disclose whether it had been bored out at any time and by how much. The 9 amp charging circuit is fine for daytime operation but would be sorely inefficient for working in the dark because the stock headlamps do not throw adequate light and most people either add auxiliary lamps or convert to 50 watt halogens and glass lenses.

As I said, if this conversion works for you, then great. However, there was more to the story than you posted and all I did was to fill in the blanks.
   / Case 446 repower #7  
I appreciate both opinions on the engines I'm going to look at a Case 446 tomorrow that needs some work.
Hopefully I'll be able to afford it to replace the aging 12/14 HP B&S Craftsman II LT4000's I've had. I have
a six acre orchard to mow, and the 43" Craftsman mower is too slow. I was looking for a 50-60" mower,
but I've lusted after my neighbor's Ingersoll 444 for ten years, so I'm hoping the Case will be a good upgrade.

Jim in Maine
   / Case 446 repower #8  
I would seriously question the rebuild ability of anyone that has an Onan blow 3 times in less than 700 hours. Either that, or someone doesnt do maintenance.

I am very new to the Case series GTs, but so far, I am stunned at how much abuse these tractors have taken, yet still "git er done", as they say.

Right now, I pulled apart a Case 446 that was making racket, and I thought for sure the rod was gone. Nope. Just a boat load of carbon to the point that the valves arent totally seating. I bet this tractor has 1500 PLUS hrs on it, and has had very little TLC. ( This is possibly what may have been an issue with the re-power that is being discussed here ) IN any event - I will pull the valves and tappets, check the clearances, clean her up, and bolt her back together. I am betting that this tractor will sing like it hasnt for a long time.

Anyhow, I am starting to really appreciate these tractors, to the point that if I find a so called "Bad One", its going to find a new home, get fixed, and put back in circulation. Theres nothing alive under 12K that can match the build of the case 2xx, 4xx, stuff, as far as I can see. I bet today, these tractors would command 8-10k new, without all the goodies.
   / Case 446 repower #10  
This is a good read. It makes me appreciate my 1982, model 448, even more. I wish I had the mechanical ability of you fellas. Other than cleaning the heads of carbon and doing routine maintenance my Case hasn't gotten any special attention. It has mowed my 3 acres and pushed snow for me and my neighbors all this time. It is still in service, but is used less now that I own a Kubota B2620. I'm guessing that the Onan (18 HP) has about 2000 hours or more, and still runs great without blowing smoke. Cheers, Mike