Briggs and Stratton engines.....aluminum bores?
Briggs and Stratton engines.....aluminum bores?
(OP)
From disassembleing these engines for repair, I discovered that the cylinder bore is made from aluminum with no hardening treatment at all, unlike chainsaw engine which are aluminum but have a hard chrome treatment. Now how is it possible for the engine to not wear out?. Is it because enough lubricating oil is supplyed to the parts, or are the engines made from a speacial alloy?
Regards,
Dj
Regards,
Dj
RE: Briggs and Stratton engines.....aluminum bores?
I believe that aluminum cylinder bores without liners were pioneered in the 70's in the Chevy Vega. By making the interior of the bore have a higher silicon content (by casting cooling rates?), the dissimilarities between the piston and cylinder prevent galling and seizing. That being said, it must have been a tricky process because junkyards were soon full of seized up aluminum block Vegas.
The other thing to remember is that these are CHEAP and DISPOSABLE engines. Probably loose sloppy tolerances play as big a role in preventing seizure as anything else.
RE: Briggs and Stratton engines.....aluminum bores?
As far as the plating I don't think you can hard crome plate aluminum. The Chain Saw motors also have a metal liner and them and are crome plated to help prevent wear. However you can't bore out a hard cromed cylinder, you just replace it. Briggs however have a cast iron liner just no crome so you could bore it out and rebuild it. However since you basically have to dismantle the entire engine to be able to bore out the cylinder (one piece construction) I would guess that Briggs have made the liners to thin to bore out, and rebuild. After all to get it stripped down and rebuilt by a shop would cost more money than a new motor. The lesson i've learned is just to get old stuff and keep them running, as the new ones are disposable.
I can't speak for what they are building now, but when I was at MTD (Yard Man, White, Cub Cadet) 4 years ago this was the case.
Will
RE: Briggs and Stratton engines.....aluminum bores?
DJ
RE: Briggs and Stratton engines.....aluminum bores?
All engine models named Vanguard, I/C, Industrial Plus, Diamond Plus, Intek Edge, Intek Pro, ELS (Extended Life Series), 3LC (Three Cylinder Liquid Cooled), Animal or Europa, have a cast iron sleeve in the cylinder bore. All other engines are dependant on the model, type, and code numbers to determine whether or not the engine has a cast iron sleeve installed.
I had always assumed it was a marketing ploy. I know for a fact that horsepower's are often under reported. They do this to show slightly different models and prices. I will say that if you match the two engines up side by side and they look the same and the smaller engines vary by some fraction or the larger ones vary by one or two horsepower they are the same engine.
However I guess I was wrong, it didn't used to be this way. I would guess they just started matching up life expectancies of the motors with the equipment. Some of the low end roto-tillers only have a design life of 120 hours. I would imagine an aluminum would only last that long.
Will
RE: Briggs and Stratton engines.....aluminum bores?
Below are links to Tecumseh engines where they actually specify that the cylinder is aluminum.
Also if you go into the products section and then select utility engines then Formula®, they compare all their models, where you can actually see that some engines have aluminum cylinders and other are specifyed as "aluminum w/cast iron sleeve"
http://www.tecumsehpower.com/Tecumseh.nsf/Second%20Level?OpenFrameSet&Frame=FrameB&Src=_l5ta6aorldlpmaq1edppmcbqge9nm8lq28la5eh1v9to6ari6dtp6q9i1elq6uhjic5mmap00_
Regards,
DJ