clarkie_ni

hi guys, wondering if anyone can help. got myself a 4 gallon old FX engine but with new front & rear bearings replaced by the seller before selling.
when i attach the brass collet, flywheel and then screw down tight the clutch nut the rotation of the crankshaft becomes 'gritty' and non free moving.
iv tried everything from shiming behing the collet, changing the standard collet to the short losi collet, using a differnt flywheel, removing the bearings
and then reseating them again (bearings seem perfectly free spinning both inside the engine and when outside the engine during reseating proceedure).
the crank spins perfectly free when the cluch nut is semi loose and has a loose grip on the crank, but goes 'gritty' when you start to tighten the nut in anyway.
the collet has definately grabbed a hold of the crankshaft as there is no sign of slippage.
completely at a lose and never had this issue before. can anyone help??

HomicidalBunny

iTrader: (4)

Sounds like the bearing acts fine when it's not under load, but as soon as you add the load of the collet being pressed against the front bearings inner race, it gets notchy. Its very hard to tell if a bearing is bad when it's not under load. In other words, the axial (back and forth) load being put on the bearing by the collet is revealing a wear or damage issue. Try replicating the issue by pressing the bearing inward with your index finger and turning, to see if you get the same gritty, notchy feel. If so, that's your issue, and you probably need new bearings.

22Racer

iTrader: (67)

One of the bearings are probably not seated all the way in.

Rex

sickpuppy1

iTrader: (32)

I was thinking the same thing about seating. You may try heating the case and trying to re-seat the bearings. But that being said. putting a load on each bearing as stated is a good thing to do also. It may have been damaged during install, or maybe he only replaced one bearing......

houston

iTrader: (96)

+1

Usually the front ,i bet there is metal behind bearing if you removed it

BigInJapan

iTrader: (18)

the conrod/crankpin might be making contact with the backplate, try pulling the crank forward as you tighten the clutch nut, before you go changing bearings etc

UrabusDenis

Had the exact same problem with my engine after I put brand new bearings, both front and rear. Turned out the front bearing had some debris inside it (from the factory). I simply cleaned it, reassembled the engine and the problem was gone. Runs perfect to this day. Learned to check the bearings even when they are new I am 99% sure you have the same problem