Connection Rod

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Did you break connection rod?

For example, This picture is my friend's OS engine.
Why does connection rod is broken?

Over lean high speed needle?
Climate condition？
Failure break in?
Metal stress?

The answer is blowing in the wind by Bob Dylan.
Ha ha.
It occurs at engine braking that throttle cut off suddenly from maximum.
When piston still push down connection rod downward,
Crankshaft from car forwarding power push up connection rod upward.

Power get together one point at oil hole.
This area is weak point of collar metal.

We have to check oil hole carefully.
Is there crack?

Especially OS,Picco press fit collar metal to connection rod.
Then connection rod edge gets stress outward.
So connection rod split from oil hole to upward.
It's not mean OS PICCO connection rod is bad.
It is trade off weight or strength.


This is another brand connection rods.
Upper is FX of HUDY.
Lower Nova.

Nova pay cost collar metal processing.
Nova does't press fit collar metal.
I almost never seen Nova connection rod broken on OFFROAD.

FX connection rod big metal area shapes ellipse.
The shape can recieve stress of power.
Nitro engine structure is so simple.
But engine brands have different way of improvement.
It is the competition.

Can you understand this composition?
It's difficult for me to describe about engines issue.

Comments

underway said…
There are many different reason rods break. Most happen either when an engine is worn(crank pin/rod) has to much wear and the tolerances are out of round. OR when new and piston/cylinder is still tight and over revving or prolonged revving at high rpm put undesirable stress on the conrod. Fuel without enough lubrication can also play a factor. lot of reasons a rod can fail!
23/10/15 19:28
Nimbus said…
Exactly yes.
Almost rods broken came from failure breakin or maintain
23/10/15 19:47

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