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Is the 721 QZE a Loncin engine?

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#1 ·
Are the new 721's 212cc Loncin engines? I can't find any info about them. Are they decent engines? Cast iron sleeve? Ball bearing cam? Or are they garbage?
 
#2 ·
I have what I believe is a Loncin engine from a Toro 721r with a broken connecting rod caused by the owner not adding oil when first purchased. The motor has a steel liner and ball bearings on the crankshaft but just bushings on the cam shaft. I replaced it with a Harbor Freight 212 Hemi Predator since buying the necessary repair parts aren't available and didn't seem cost effective, at the time. I may in the future buy a predator rod and gasket set to repair it, just to see if the parts will work on it. Both engines LOOK to be identical in construction.
 
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#5 ·
I'm re-opening this thread because I decided to gamble on purchasing a 212cc non-hemi Predator (dished) piston and rod for the blown up Loncin 212cc Toro power clear 721 motor.


The rod\piston assembly and gasket set were $30 and I know a new predator is only $70 more, but I had to know if the Loncin and Predator were designed the same.


I was surprised to find the Locin has a nylon geared cam shaft compared to a metal geared Predator cam.


I lapped the valves, cleaned the carb (had a blocked low speed jet), removed and polished the crank where aluminum was built up from the old rod seizing and honed the cylinder which is a cast iron insert that had no bad scratching.


I couldn't find any torque specs for the Predator, so I used the information from a Honda GX200 motor .


After putting the motor back together, it started on the first pull and I then adjusted the top rpm's to 3700 since it is a fixed speed throttle.


After some research, I THINK a Honda GX200 ring geared flywheel and starter will fit if I ever decide on converting to electric start.


I'm HAPPY with the results.
 
#3 ·
Yes, all Toro walk behind equipment engines are Loncins. All Toro snowblowers have them, and have had them for 7 years. They are pretty good in my opinion. I have one on a Toro 721RC, and I love it. Easy to start (even first start of the season), and plenty of power. I do driveways, and this thing has plenty of power. We got 13" last November, and it was able to get through everything, even the plow pile. My one gripe is that mine is a bit loud, but I suppose that is typical for an engine.
 
#8 ·
It wouldn't be my choice in material, but the GX100 engine in my EU2000i generator has a plastic cam (OHC engine, not OHV). And those engines can run for thousands of hours. So a plastic cam may certainly seem like an odd choice, but at least some of them can go for a long time.
 
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