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Old 05-30-2010, 08:46 PM   #1
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Default Replacing engine bearings

After you replace engine bearings what do I need to do to break them in? Will either go with ceramic or regular if I find they need replacing. Also, where do u get your bearings. I use avid will that be ok for motor bearings?

Also how do you know when it's time to replace a connecting rod?

This is for a losi454. I was prolly gonna go thru the motor and just check it out. I think everything is fine. Don't wanna spend much on it but i'd throw it some bearings if needed. Been a good motor so far at club races. I'll get a real motor when this one dies.

Does changing either one chane your tune? Or are u going to run it rich anyway when changing these and retune after worn in?

Last edited by bacchus; 05-30-2010 at 08:56 PM.
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Old 05-30-2010, 08:58 PM   #2
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1) There is no use/need to break in a bearing. The break-in period on nitro engines has nothing to do with the bearings.

2) Avid has great bearings.

3) You need to replace a con rod when there is any play between it and the crank pin. BUT, sometimes it's the crank pin itself that is worn (this is why the O.S. Speed "DLC" coated cranks [and others like] it are so valuable). If that's the case, replacing only the con rod won't get you very far.
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Old 05-30-2010, 09:04 PM   #3
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no need to break them in, although some people idle for a tank to seat them. I use tko ceramic bearings. They are very good and don't cost much at all. Not to mention, peter is one heck of a great guy!

where are you from bacchus?
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Old 05-30-2010, 09:06 PM   #4
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Originally Posted by markr04 View Post
1) There is no use/need to break in a bearing. The break-in period on nitro engines has nothing to do with the bearings.

2) Avid has great bearings.

3) You need to replace a con rod when there is any play between it and the crank pin. BUT, sometimes it's the crank pin itself that is worn (this is why the O.S. Speed "DLC" coated cranks [and others like] it are so valuable). If that's the case, replacing only the con rod won't get you very far.
How do I test for play on the connecting rod?
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Old 05-30-2010, 09:09 PM   #5
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no need to break them in, although some people idle for a tank to seat them. I use tko ceramic bearings. They are very good and don't cost much at all. Not to mention, peter is one heck of a great guy!

where are you from bacchus?
La. I was the guy with the losi rtr truggy at Springfield. I think it was you and I talking about glow plugs.
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Old 05-30-2010, 09:10 PM   #6
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you should be able to tell if you take the backplate off and rotate the flywheel and try to check for play by moving it back and forth. Sometimes you will see oil squishing through the bushing. I however take the whole crank and P/S out and just check the play by placing the rod back on the pin and moving it about. This is the best way and how i do it. Make sure the piston skirt (longer part of the piston) is facing away from the crank.
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Old 05-30-2010, 09:14 PM   #7
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La. I was the guy with the losi rtr truggy at Springfield. I think it was you and I talking about glow plugs.
Ha HA. i knew it was you. Hey, just plug your exhaust and carb and clean your engine with some simple green, water and a toothbrush. Try to keep water away from the front bearing. I dry it off real well with a heat gun and then break it all down and check everything.

GOing to a track this weekend in mobile then i will probably be in watson the week after to try the new track

I also figured out why i was having problems in my main last night. I had broken clutch springs and did not realize it till i got home.
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Old 05-30-2010, 09:18 PM   #8
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Make sure the piston is at the TOP of the STROKE when you take the back plate off!!!!
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Old 05-30-2010, 09:24 PM   #9
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Thanks for the info. Can't wait for the Watson track
myself!
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Old 06-01-2010, 07:32 AM   #10
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What are the advantages to ceramic bearings rather than regular ones for the motor?
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Old 06-01-2010, 11:10 AM   #11
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60% less rotating mass. 40% less drag. Cooler running and on average last 3 to 5 times longer than steel.
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Old 06-01-2010, 11:21 AM   #12
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Is it true that ceramic bearings are more "sensitive" in off-road racing due to all the bashing the car goes through due to chassis flex?? Allot of people at my track believe that and say that ceramics last longer and are more suited in on-road use. Im in the process of changing my engine bearings and cant decide which way to go....
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Old 06-01-2010, 11:44 AM   #13
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For any engine they work better. We have them in MX bikes to top fuel dragsters. One easy tank on the track and you are ready to go.
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Old 06-01-2010, 11:46 AM   #14
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Originally Posted by grkboy View Post
Is it true that ceramic bearings are more "sensitive" in off-road racing due to all the bashing the car goes through due to chassis flex?? Allot of people at my track believe that and say that ceramics last longer and are more suited in on-road use. Im in the process of changing my engine bearings and cant decide which way to go....

IF you are changing bearings. GO CERAMICS...specifically TKO or Ready Roller. I've never had a rear ceramic fail in offroad use.
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Old 06-01-2010, 12:04 PM   #15
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Should I change both front and rear to ceramic, or just the rear??? Does the front bearing get abused more due to the clutch bell hitting the bottom of the chassis due to flex???
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