Engine bearings

[blckrevo33]

hello everyone, well i stripped the 2.5 revo that i bought last week.everything was really dirty but in good condition,so the last thing i had to do this morning was give the mill a good going over,first thing i noticed was the needles were extremely rich,so figured an air leak right?then i look and see a lot of oil seeping out behind fly wheel!!! front bearing leaking, so i pull the front bearing now my question is how do i get that inner bearing out?it spins good and doesn't feel gritty or anything should i pull it or leave it? just for a little more info,the piston and sleeve are a little worn but i still have a pinch at the top about 1/16 down from the top of the sleeve so i am gonna reuse the piston and sleeve. Any suggestions? thanks.

 

[olds97_lss]

Well, if your going to replace one, you might as well replace both.

With the engine completely disassembled, heat the crank case up in an oven to 300F. While still hot, wack the back of the crank case on a block of wood. The bearing should pop right out. I did that to 3 crankcases not to long ago and worked perfectly every time.

To put the bearings back in, put the bearings in the freezer for a few minutes, heat the crank case up again, then drop/push the bearings in. Once the bearings warm up and the crank case cools, they should make a good seal around the outer race.

I watched this guy:
At the 2 minute mark, he shows the rear bearing popping out. Around the 3 minute mark, he puts them back in. He just heats the case I think, doesn't cool the bearings.

 

[blckrevo33]

Thanks olds,i just got back from lhs and got both bearings. commons sense prevailed and said dont do just one.lol i will let you know how it goes.

 

[blckrevo33]

success!!! mill is back together,sealed,and ready for installation,the oven trick worked real good bearings popped right out. thanks again olds.

 

[Scrogg]

If the needles are set rich , fuel is going to seep out until it is tuned properly. New bearings are always a great idea though. Every two gallons at a minimum they need to be replaced unless you are running Abec 7 or higher Ceramics.

 

[olds97_lss]

So... 7-8 gallons is too much then... hmm... lol

I've only ever replaced bearings a couple times in engines and on average, I run 9-10 gallons through my engines. Like right now I probably have 3 through an XTM24.7, 4.5-5 through a LRP28S3 in my aftershock, 2.5-3 through the LRP28S3 in my savage and probably around 2 through a TRX2.5R in my slayer... all of which are on original bearings.

Whenever I pull an engine out for clutch/slipper maintenance, I always check my crank for any slop. Only had that a couple times... which is why I changed only a couple.

Got a link to a site with good engine bearings? I'm kind of iffy now on the LRP bearings. Would rather play it safe and just swap them out before they go through my engine. I know LRP's aren't known for stellar bearings... so, would probably be a good idea to pick some up. I"ve been to boca, but they have 20 kinds of engine bearings and I'm never that sure what to buy.

 

[2revo1maxx]

I guess it depends on what you're doing. I do what Olds does, but if you race, every 2 gallons is a good idear. :smart:

 

[blckrevo33]

The only other bearing i have done was a front bearing on my other revo and that was also due to leaking.that one had 7-8 gallons through it.

 

[2revo1maxx]

Yeah I just did one too, they were new, about 1/2 a gallon, but it was leaking badly. I do have to keep up with my 3.3's though, I'm lucky to get 3-4 gallons on the bearings and rod. 7-8 gallons on the piston/sleeve, no problem.

 

[Evofreak]

My current engine has 1 1/2 gallon throught it. I did the leak test and front bearing is leaking. When i run it though i get no oil resedue or any kind behind the flywheel. But my temp reach about 290f sometimes. Do i need bearing replacement?

Blckrevo how did the newly replace bearing mill running?

 

[hamz9561]

Evofeak: 290* is probably just a touch too hot. You might want to make the mixture a bit richer.

 

[blckrevo33]

finally got a chance to run the 2.5 today no problems it ran great after some tuning,but notice there is not much pinch when warmed up. still starts ok but i can tell it is getting weak. looks like a trip to the lhs for a piston and sleeve.ARRRGH!!!!! I should have just done it when i did the bearings,oh well it will give me something to do when it rains this weekend. On a side note i am gonna strip the other revo down tonight for a real good cleaning and inspection. this is the last one of the three rigs i picked up.

 

[2revo1maxx]

finally got a chance to run the 2.5 today no problems it ran great after some tuning,but notice there is not much pinch when warmed up. still starts ok but i can tell it is getting weak. looks like a trip to the lhs for a piston and sleeve.ARRRGH!!!!! I should have just done it when i did the bearings,oh well it will give me something to do when it rains this weekend. On a side note i am gonna strip the other revo down tonight for a real good cleaning and inspection. this is the last one of the three rigs i picked up.

If it has any pinch at all when it's cold, it's good.....unless it's all scratched up.

 

[blckrevo33]

Its not scratched up at all but not much pinch, i am gonna sell it so i will put a new piston and sleeve in while play with it before i sell it

 

[olds97_lss]

Maybe just send it in to get it pinched if it's in good shape:
https://www.rcnitrotalk.com/forum/showthread.php?t=56420&highlight=pinch

 

[blckrevo33]

Thanks olds i am definately gonna look into that.