Aluminum bushed rods

[Joe Warren]

West coast Jim Wilson is the Alum Rod guru, Maybe he will answer a few problem areas?

 

[Joe Wiebelhaus]

Here are some examples of different rod breaks, what I was originally trying to determine is what caused each type of failure, bushing, heat, crank thrust, top/bottom snapped off ect...

First pic, that shear crack upward ?? Ive done this twice this year ????

 

[Joe Warren]

Joe dont forget the times we have dunked the boat while running. (water) Hyd lock can start a failure too

 

[Joe Warren]

Hyd lock can start a failure too depending on the water getting On top of the piston or under the piston would determine the type damage

are these 21-45-60 engine failures

 

[Terry Keeley]

Thanks Terry, Do you drill all the way thru the rod for the music wire? Can you post a picture? What size do you make the oil holes? I've seen some that are very small and always wondered if I should open them up.

Thanks,

Chris

From my RS21:

Blind hole (ie: not through).

Most I've seen these days have a vertical oil hole, I leave it alone.

 

[Joe Wiebelhaus]

Hyd lock can start a failure too depending on the water getting On top of the piston or under the piston would determine the type damage

are these 21-45-60 engine failures

Mostly 45-67, not all mine, but failures I have seen through the years, thanks for your input.

 

[David Bryant]

I also reamed the bushing .003" over the crank pin size. Never broke an aluminum rod again

exactly the solution a significant source explained to me back in the 80's- ie. provide a few thousandth's clearance for the rod lower-end such that it would be less proned to "grab" onto the crank-pin under hi-temp/hi-stress conditions
This is why I posed this question in the "45 VAC into the Future" thread (post #50):

http://www.intlwater...=45#entry498232

 

[ids987]

One of my personal favourites.

No prizes for guessing where one of the oil holes was.......

 

[David Bryant]

One of my personal favourites. No prizes for guessing where one of the oil holes was.......

a Picco?

 

[ids987]

One of my personal favourites. No prizes for guessing where one of the oil holes was.......

a Picco?

OPS .21. I can't blame the engine though. It was on a gearbox; the flexi coupler came loose, caused the gearbox shaft to bend, which in turn wound a corkscrew in the flexi. Still a fairly characteristic mode of failure - for a rod with an oil hole in the top of the big end. Especially where the beam of the rod is also relieved in the middle - along its length.