Why do people change the connecting rods and bearings after 1 gal?

[Hypnotiq]

Ive heard this recommended by alot of people but never was told why...

Discuss..

 

[rc ch]

i think it is because the fish say so

 

[frddyj]

good question, I'm guessing it might be related to stress (from pinch) but that would only be a guess. who has facts?

 

[Bankrupter]

1. the pinch of a new motor beats the bushings.
2. same forces stretch the rods.

This changes the total timing of the motor, also creates fail points.

After a gallon you have the motor broken in and the mechanical pinch is gone/near gone. This makes the effect is gone and a new rod is ready to go in and get rid of the one that has taking the run in abuse.

So it puts the motors timing back where it should be and lessens the chance of motor failure. One gallon is not the rule but is fine.

 

[RangerRock]

Not sure on facts but I always thought it was from the tight pinch during break-in and the stress from breaking the engines in?

Always been my looks on it...yet I've never changed them

EDIT: Justin beat me to it

 

[Hypnotiq]

thank you all for clearing that up. Hope this helps others out aswell.

 

[Hypnotiq]

One more question for the bearings.... you change all of them or just the front?

 

[Pope]

The main is the most important but it is best to replace them both.

 

[Tominator06]

Well lots of people associate the front bearing with air leaks and such so hey tend to change the front bearing trying to chase a tuning issue. "I am guilty of this as well". The crank runs on 2 bearings so if one fails then they both should be replaced at the same time. If the front has play then the rear must have some as well. Just my 2 cents.

 

[soulja]

i wonder is this something that i need to start doing???? Robin...what's your take on it?