So what's the current Two stroke oil favorite for

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Her is a duraforce piston that was ran the majority of its life on TCW3 ashless oil. This particular motor died when one of its metal reeds broke and ran through the motor locking the crank. The damage on the upper ring land and crown is from that piece of the reed, but remarkably that is all the damage the piston sustained. The pic of the skirt is in the same location as the other pic posted above. Note the ring grooves are pretty clean for such a high hour engine.20211107_152425.jpg20211107_152441.jpg
 
Yeah , I have seen a lot of damage in lawnboys from improper oil usage , they did not stand up to inferior or non spec'd oils ! Lots of bearing failures in the C & D series for the same reason !
 
Yeah , I have seen a lot of damage in lawnboys from improper oil usage , they did not stand up to inferior or non spec'd oils ! Lots of bearing failures in the C & D series for the same reason !
I don't know much about the older ones other than some had bronze bushings instead of bearings.
The big end bearing setup on the duraforce is weak too. It's a roller bearing over a silver shell type bearing and the rod itself is aluminum. Have to be very careful not to exceed the factory max RPM specs or they break/throw a rod.
 
Her is a duraforce piston that was ran the majority of its life on TCW3 ashless oil. This particular motor died when one of its metal reeds broke and ran through the motor locking the crank. The damage on the upper ring land and crown is from that piece of the reed, but remarkably that is all the damage the piston sustained. The pic of the skirt is in the same location as the other pic posted above. Note the ring grooves are pretty clean for such a high hour engine.View attachment 939940View attachment 939941
Nice , actually pristine for a high hr engine . Amazing that such little damage to the piston crown & skirt after sucking in the reed . Theynreakly thrived on the old OMC oil technology . I use to due a carbon inspection & muffler decarbonizing every 2 yrs of service , just routine maintenance back then likely only 200 hr. frequency max . Never effected performance !
 
I don't know much about the older ones other than some had bronze bushings instead of bearings.
The big end bearing setup on the duraforce is weak two. It's a roller bearing over a silver shell type bearing and the rod itself is aluminum. Have to be very careful not to exceed the factory max RPM specs or they break/throw a rod.
Yep , exactly . The older series used a composite brass / bronze Babbitt material bearing ( bushing) . Low tech but serviceable for the day . That's why oil viscosity was crucial . I still run my old girls yearly on the front lawn portion of my acreage for sentimental reasons !
 
Nice , actually pristine for a high hr engine . Amazing that such little damage to the piston crown & skirt after sucking in the reed . Theynreakly thrived on the old OMC oil technology . I use to due a carbon inspection & muffler decarbonizing every 2 yrs of service , just routine maintenance back then likely only 200 hr. frequency max . Never effected performance !
I never tore into that one until it died on me one day and wouldn't start normaly or stay running for more than a few seconds. Drove me crazy trying to figure out why. I ended up pulling the carb off to try swapping carbs when I noticed my reed valve motor turned itself into a piston port. I had intended to replace the motor with a Toro Rtek, which is a piston port version of the same motor which makes a bit more HP. Never got around too it and ended up hauling the thing to the dump. The duraforce models where no where near the quality of the older ones and I worked on several duraforces for 20 years. Grew sick of it and bought a Honda 4 cycle.
I do still have 2 Rtek snowblower. On nearly new one and the other that's been to hell and back and has a ton of hours on it. No issues either than it requires a new coil every few years. The coils like the duraforce coils are garbage and have a very short life span.
 
Yep , exactly . The older series used a composite brass / bronze Babbitt material bearing ( bushing) . Low tech but serviceable for the day . That's why oil viscosity was crucial . I still run my old girls yearly on the front lawn portion of my acreage for sentimental reasons !
Sentimental reasons are the only reason I got involved with lawnboys in the first place. I first started mowing with a lanwboy.
If I could find a pristine M series with the suzuki engine and oil injection I might jump back in, but parts are a real pain in the ass to find. M-series was the last good lawnboy and it was actually a suzuki engine.
 
I never tore into that one until it ded on me one day and wouldn't start. Drove me crazy trying to figure out why. I ended up pulling the carb off to try swapping carbs when I noticed my reed valve motor turned itself into a piston port. I had intended to replace the motor with a Toro Rtek, which is a piston port version of the same motor which makes a bit more HP. Never got around too it and ended up hauling the thing to the dump. The duraforce models where no where near the quality of the older ones and I worked on several duraforces for 20 years. Grew sick of it and bought a Honda 4 cycle.
Reed valve to piston port , Roflmao ! Had a R-tek in a Toro snowblower early 80' s I think . Performed well , matched the Tecumseh Snowking I had at the time for driveway usage .
 
Sentimental reasons are the only reason I got involved with lawnboys in the first place. I first started mowing with a lanwboy.
If I could find a pristine M series with the suzuki engine and oil injection I might jump back in, but parts are a real pain in the ass to find. M-series was the last good lawnboy and it was actually a suzuki engine.
Best engine lawnboy ever put in a mower , the injector system was troublesome & sketchy at best . As I said previously converted to Premix & still run my "M" series to this day , I have had to modify or adapt blades which is frustrating . Hard to find own up North here ! P.S. sentimental yes , my lawnboys & my Harleys !
 
Best engine lawnboy ever put in a mower , the injector system was troublesome & sketchy at best . As I said previously converted to Premix & still run my "M" series to this day , I have had to modify or adapt blades which is frustrating . Hard to find own up North here ! P.S. sentimental yes , my lawnboys & my Harleys !
The last lawnboy I bought, the one pictured above that had the read failure was purchased out of Winnepeg when I lived in NW Ontario. It was one of the last ones in Canada.
 
Reed valve to piston port , Roflmao ! Had a R-tek in a Toro snowblower early 80' s I think . Performed well , matched the Tecumseh Snowking I had at the time for driveway usage .
This wpuld be a different Rtek. They were only sold for around 10 years before being discontinued due to emmissions regs. Basicly they where a lanwboy motor minus the reeds with more radical porting so they made 8hp.
 
This wpuld be a different Rtek. They were only sold for around 10 years before being discontinued due to emmissions regs. Basicly they where a lanwboy motor minus the reeds with more radical porting so they made 8hp.
8hp Performance Class , special order option for the Toro snowblower . Yes believe it also had a high peak operating rpm also , likely due to the more radical porting / tuning . I just remember the advertisement banners at the Toro Dealer " New Retek high performance Engines" I think the actually Tech Specs mentioned Briggs 5.5 hp , so perhaps a different 2 stroke ?
 
I don't know much about the older ones other than some had bronze bushings instead of bearings.
The big end bearing setup on the duraforce is weak too. It's a roller bearing over a silver shell type bearing and the rod itself is aluminum. Have to be very careful not to exceed the factory max RPM specs or they break/throw a rod.
I saved a lot of the early engines by making a replacement bronze bushing on a lathe and boring the case on the mill and pinning the bushing in place. Never lost one due to bushing failure/spinning
 
8hp Performance Class , special order option for the Toro snowblower . Yes believe it also had a high peak operating rpm also , likely due to the more radical porting / tuning . I just remember the advertisement banners at the Toro Dealer " New Retek high performance Engines" I think the actually Tech Specs mentioned Briggs 5.5 hp , so perhaps a different 2 stroke ?
Yes, two different motors.
The 8hp Rtek and the Duraforce had the same max RPM. 4200rpm IIRC.
Edit: I actually just looked at the service manual the Duraforce and R-Tek share. Duraforce has a max RPM of 3200rpm. R-tek is 4300rpm. R-tek is actually 7hp and the Duraforce 6.5hp. I always set the governor of my Duraforce over max spec as they would get out of there own way when set to the factory max spec. And the crank, bearings etc are Identical to the 7hp R-Tek.
 
It's a shame one could just adapt them to ball bearings. Much better setup.
There wasn't really enough meat in the case to bore it for a ball bearing assembly. I considered a needle bearing setup but didn't know if the crankshaft steel was of sufficient temper to allow direct contact with the needle bearings. A bronze bushing is long lived if it has a sufficient and correctly placed groove in it to carry lube to the bottom of the bushing.
 
It's a shame one could just adapt them to ball bearings. Much better setup.
Probably could reverse engineer mechanically , although oil delivery
path was rather rudimentary on the old C& D series . Once a seal became iffy a bearing went south very quickly ! If I remember correctly Joisey is spot on with the casing liabilities !
 
Probably could reverse engineer mechanically , although oil delivery
path was rather rudimentary on the old C& D series . Once a seal became iffy a bearing went south very quickly ! If I remember correctly Joisey is spot on with the casing liabilities !
After fitting the bushing I used a double lip seal. IIRC, I had to bore the seal recess slightly deeper and larger in diameter to fit the double lip seal. The garter spring prevented oil leaks from the bottom of the crankshaft and relocated the outer seal lip to an unworn area of the crankshaft. OE used one groove in the bushing, IIRC, I used three narrow grooves. It's been a few years since I've done any.
 

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