question about rear bearing

[jmcnittsavage1]

i recently tore down one of my rc engines for cleaning and maintance and noticed that the rear crank bearing was loose and upon further inspection the crank was spinning inside the race and also rubbing on the case. i guess my question is what might have caused the rear bearing to do this. the engine has about 5 gallon through it and I've always run it on the safe side little rich. could it be defect or somthing else?

 

[Revo Rancher]

Have you checked the conrod for slop?

 

[FastEddy]

5 Gallons of fuel through your mill is great. Your a gallon or two more past what most people get. Its only natural that the bearings are worn out with this amount of usage. Defect, no. Lucky it lasted this long, Yes.....

At this point you will need to decide if you want to get a new mill or or do a total rebuild of the one you have.

 

[Plaidfish]

what mill is it?

 

[jmcnittsavage1]

xtm 24.7 pro

 

[J_Bone]

5 gallons isn't much. I have yet to blow or wear out an engine under 5 gallons.
If you have good compression when it's up to temp, you’re doing good.
Check into how much a new bearing and rod cost. With how the rear bearing is, I would also replace the rod. Cheap insurance.

 

[jon2]

i recently tore down one of my rc engines for cleaning and maintance and noticed that the rear crank bearing was loose and upon further inspection the crank was spinning inside the race and also rubbing on the case. i guess my question is what might have caused the rear bearing to do this. the engine has about 5 gallon through it and I've always run it on the safe side little rich. could it be defect or somthing else?

Did you ever take the engine apart before? Depending on how well you maintain your engines is the root cause of your problem. Leaving fuel in the crank case can cause the internals to corrode if it sits for long periods of time. That being said, how does your crank, Conrod look?

 

[olds97_lss]

I had the same thing on an old OS 21 RG I tore down before putting it away for the winter. But I had 15 gallons through the engine (pinched at 12). My front bearing was leaky and my rear was shot. Con-rod has a tic of play in it... I had two blown 21 RG's a friend gave me, so I poached some bearings off of it and lubed it up until spring. I hope it runs as good as it did the last time I took it out... that engine just runs so well, it will be a sad day when it's dead.

 

[jmcnittsavage1]

The crank looks good only small marks on it from the case. the conrod looks good only minor amount of play in it. i did tear it down one other time. i have been using it pretty regularly every weekend or so. i have been oilling it after every use.