T 3-15 engine swap

   / T 3-15 engine swap #1  

Alexhasson

Bronze Member
Joined
Jun 4, 2013
Messages
76
Location
Conowingo, Maryland
Tractor
Terramite t3-15
well Maryland had a bad winter plus i didn't give the loader proper attention during the winter. the tarp blew off and the loader was covered with snow multiple times. some how water got in the hydraulic tank and not just the normal amount from building up over time, something like 2-3 quarts of water was drained out. heres a pic. there's some oil on top, also a small amount of oil water mixed (grey)


so on a warmer day i pulled that out of the tank. I got to the engine a couple days later and it was low temps again. I couldn't get teh carb to play nice so i pulled it apart to clean it and it was a frozen block of ice.


I was already unhappy with this old worn out engine (k321) last year that i didn't hesitate to start shopping for a new engine. honestly if i had the cash i would have bought a better engine. but if the harbor freight 420cc last a few years it wil have done it's job.

any way i'll be pulling every hose the main pump and the drive motor apart in the coming weeks to clear them of any water and then put it all back together with the new motor.
gonna be fun.
 
   / T 3-15 engine swap #2  
Looks like the old girl has been thru a flood. Was the cap missing from the hydraulic tank? I can't imagine that much water getting into the tank with the cap on. You will always have some condensation, but 2 or 3 quarts is a lot of water. I hope you can get her back up and operating again without to much trouble. Let us know how the engine swap go's.
 
   / T 3-15 engine swap
  • Thread Starter
#3  
Well i only have some working theories on has that much water got in. now it did snow a lot in Maryland and it was uncovered so that might be some. but the upright arms that the loader attaches to the tractor doubles as a reservoir and the tubing is open at the top to receive the arms. so i thought maybe a cracked weld may allow water to enter. just a theory , i'll pressure test it in the future but for now on with the motor swap.

Alrighty so here's the main event, pull out the K321 from 1975 and install the Harbor freight predator 420cc (chonda motor).

Primary hurdles.
- motor mount to the frame is different.
- existing bell housing for the hydraulic motor doesn't match anything on the new engine.
- overall size and shape of the new engine is different.
- does the new engine have to torque to start against the hydraulic load from the trans pump

so on with the pictures.

Here is the bell housing adapter. It takes the trapezoid bolt patter and marries the square bolt patter on the new motor.




here's the motor frame mount adapter.




had to cut out part of the frame due to the shape change, carb and air intake stuck out a bit. i'll weld some metal back in once the engine is done.


all bolted up. but it was 10pm and i couldn't test it out. until the next day.


TESTED. It all worked except my love joy walked. upon removal i noticed the set screw wasn't hard to back ut on the pump side so i'm thinking this was my fault. I'll be buying 2 shaft clamp collars to assist.


HILL BILLY BONUS
I made this adapter to run on a corded drill so i could run the loader and backhoe. the drill didn't have enough power to handle the drive needs though.


I'll update after i get to tinker again.
 
   / T 3-15 engine swap #4  
The shaft clamps should do the trick to help keep the coupler together. I would use Loctite on all of the set screws for the clamps and coupler to keep them from backing out.
 
   / T 3-15 engine swap
  • Thread Starter
#5  
well i found the right pump adapter after a couple weeks of hunting. it will be here before next weekend so i'll have time to rework the body of the tractor to better accommodate the new engine also i need to build a wire harness to extend the ignition switch to the operator dash. My plate worked but I'm happier with the right part.
 
   / T 3-15 engine swap #6  
My question is how well this chonda is going to power this unit. All the old kohlers had some pretty heavy flywheels that made torque. On my T5c with the newer Kohler engine style, it seems to me that it would have been much better to have had a diesel engine both from the viewpoint of fuel use and from the standpoint of having enough power to really run the machine.
 
   / T 3-15 engine swap
  • Thread Starter
#7  
My question is how well this chonda is going to power this unit. All the old kohlers had some pretty heavy flywheels that made torque. On my T5c with the newer Kohler engine style, it seems to me that it would have been much better to have had a diesel engine both from the viewpoint of fuel use and from the standpoint of having enough power to really run the machine.

Fair question, based on the existing limitations of the t3-15 I doubt it will be noticeable. I think it's too small of a tractor to really worry about. I also would prefer a diesel for this application.
 
   / T 3-15 engine swap
  • Thread Starter
#8  
The new adater delivered yesterday afternoon. it was test fitted and everything was perfect.


engine is all tightened down and ready to go. New adapter had access on both top and bottom and that was a welcome upgrade.


my breif use of it the other day using the first bracket proved that the engine worked fine at half idle just driving around so i think it will do well.
FYI to the other t3-15 owners, the pump installed in these units can handle up to a 40 horse power (1975) engine. So if you're in the works for an upgrade that could be a factor.


New adapter courtesy of P&J commercial products
Log Splitter | Hydraulic Cylinders | Hydraulic Wood Splitters
Hydraulic pump mounting bracket to small engines for log splitters
for reference my adapter is #9.

new engine uses the 6.5" bolt circle and the pump uses the SAE "B" 2 bolt 5.75" bolt circle.

I'll update with a review later, i'll likely be doing yard work this weekend so i'll have some real data.
 
   / T 3-15 engine swap #10  
I think you deserve some applause for figuring out how to adapt this engine to work.
 
 
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