muffman

IN less than a year I have had two Savage X crank pins shear off I am talking about the crank itself,where the connecting rod attaches.Im running 20% good temps and plenty of smoke ,No unusual abuse,
Am I alone in this situation ????
These were the stock X 4.1 engines
Too strange these were first batch Savage X
I still like the engine but aint worth a darn ,broken
Talk to me guys

46u

My Feedback: (3)

What does HPI say? If I am not mistake they have a 2-year warranty on their engines. Of coarse it says limited warranty. I read a lot of different forums and yours the first case like this I have seen. I do not have the 4.1 but my K4.6 has been great and still ripping.

SAVAGEJIM

I never had the F4.1 engine, but my neigghbor has a S25 and we tore that engine down at least 3 times since he had his Savage. Everytime we took it apart to clean it and check it for whatever reason, there seems to be nothing wrong with the conrod pin on the crank (no indications of fatigue or over stressing).

The only thing I can think might be the cause of your crank pin problems is using a piston locking pin you screw into the glow plug hole. We never use those since there are too many stories out about how bad the piston locking tools are.
What I can imagine happens when a piston locking tool locks town the piston is that the stress of the tool puts excessive shearing forces on the conrod pin on the crank and the pin eventually fails from the increased fatigue.

An alternative to the piston locking tool when you have to pull of the flywheel nut is to use a flywheel holdeing tool and a cross wrench. That wasy, no stress from any tool is ever put on the piston, contod, and crank.

Other causes that might cause this breakage (but I think are improbable) are metallugical flaws, poor design in the F4.1 (I seriously doubt this since the F4.1 is designed very closly to the S25, or at least I think it is), or detonation (the engine having its timing advanced to much).

46u

My Feedback: (3)

Not trying to start and argument but just discussing. I understand what people say about the piston-locking tool but compression to it just think how much force and stress is put on all piston, rod and crank just from the normal running of the engine when the fuel is ignited. There is a big explosion in a combustion chamber when fuel is ignited. I do understand where it would be hard on the piston as it is only putting pressure on one small spot. I try to stay away from using them but on occasions have resort to it.

SAVAGEJIM

Yeah, I can see where resorting to a piston locking tool might be necessary. I have one, not because I use, but for the time I might have to. I have never had to resort to use it (and I hope I never will). I guess have it in my mind that the tool is a bad thing from the many bad experiences I have heard and read about them.

The reason I think the piston locking tool could be the cause of fatigue to the crank pin is the stories I hear and read. I'll admit, I'm not sure if those stories are old wive's tales or actually true.

DaveG55

It's not impossable that it's a flaw in the manufacture of the engine. The Mach.26 had similar problems for a while.

Personally I don't think a locking tool causes any problems. I did read a good suggestion for those that don't like them.
Take the owb off and reverse it and grab it with a wrench to hold the crank.

DaveG55

As a point of intrest, one of the reccomended ways to remove/reinstall the flywheel on a SeaDoo is to thread rope into the cylinder to lock the piston. Those take over 200 ft lbs to tighten/break free.

burkes_22

yeah i have used every thing to lock the piston from screw drivers to rags in the cylinder, i have actually had this problem only once wuth my s25 so i just scrapped the engine and bought a sh .28 p6 pro, very powerful engine

tmodlin

Good point. When I took off my flywheel nut on the old NS25 I just wadded up some paper and put it in the cylinder. Install the head and button without a glo plug and wrench away.


The big thing with using a stop like mentioned above in a larger engine is creating a surface imperfection that would cause future pre-detonation. I am sure it still could be a problem with these little engines but I know it is a problem with larger engines.

DaveG55

Now that I think about it, if the crank is broken, the OWB trick won't work very well.
First time I've quoted myself.