What is “Full Crank”?

[Warlord]

I’ve been seeing some power equipment lately with labels claiming the engines are “full crank”. Well what else would it be? Is there something I’m not understanding here?

 

[Gyro Gearloose]

I believe that refers to the fact that there is a support bearing on each end of the crankshaft and the rod bearing is in the center of the crankshaft. Some of the small economy model two strokes only have one crankshaft bearing which is on the output end of the crankshaft and the rod bearing is at the other end of the crankshaft - unsupported. The crankshaft is very short and the power is low so that will work......for probably as long as anything else on the machine will last.

 

[MrHorspwer]

This is what you'd find a half-crank engine (or non-full crank, if you prefer):

This is what you'd find in a full-crank:

 

[Warlord]

Well there you have it. I had no idea such a thing as a half crankshaft engine existed. Seems like the pinnacle of cost cutting.

 

[2strokeNorthstar]

It means the crank will last longer than the rest. Ryobi usually die an early death because replacement parts are overpriced. In my experience anyway. Recently had a “jet fan” 2 cycle blower for a repair and a the carb alone was $50.The blower was $100 new.

 

[wings&wheels]

This is what you'd find a half-crank engine (or non-full crank, if you prefer):

This is what you'd find in a full-crank:

a half crank, no ring engine! What do folks think the cut away portion of the hollow crank is for? Appears to be in a journal. Is that the port or part of the induction maybe? I find 2 strokes fascinating, irritating, but fascinating.

 

[123GO]

First half crank engine I saw was about 15yrs ago in an old Featherlite weedeater. Big "WTH?" moment for me too..lol
Some compressor pumps use Half crank too so look at those breakdowns before you buy!

 

[FowVay]

Cheapy OPE use these crankshafts that just stick the connecting rod over the lower connecting rod pin. These are half-crank engines and seem to work fine for what they are. I've had these in string trimmers and blowers with small displacements and never had any issue. Once you get some serious rotating mass you want the strength of two crank bearing and another porkchop half to hold things together.

 

[dumkid]

Those cheapy half crank engines die from carb issues before the engine wears out