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Old 10-21-2019, 04:21 PM
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What causes a needle bearing to fail

Ive got a dle 55 23x8 xoar wood prop 32:1 redline and the needle bearing that is on the top of the rod failed, motor is not set lean and has never quit till this failure. Anyone got an explanation as to why it failed?
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Old 10-21-2019, 04:33 PM
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If the engine has never been mistreated, bearing quality is probably the main reason. While some of the Chinese engines have upgraded to higher quality, name brand bearings, some have not. Early production DLE engines were noted for early bearing failures where later ones have improved considerably though they don't advertise using name brand bearings like EME and some others do. I have a small fleet of DLE engines and have only had one bearing failure .... the same one that failed in your case. Less than $10 and a few minutes had that engine back in service as the failure was caught early. I find them very serviceable engines for the $$.

With that said, I've had or seen bearing failures in high quality engines like DA and have had (2) bearing failures in DA engines. Some time back, some engines recommended replacing rod bearings at certain service intervals. Sometimes things just fail with no single reason.
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Old 10-21-2019, 04:37 PM
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Originally Posted by Truckracer View Post
If the engine has never been mistreated, bearing quality is probably the main reason. While some of the Chinese engines have upgraded to higher quality, name brand bearings, some have not. Early production DLE engines were noted for early bearing failures where later ones have improved considerably though they don't advertise using name brand bearings like EME and some others do.

With that said, I've had or seen bearing failures in high quality engines like DA and have had (2) bearing failures in DA engines. Sometimes things just fail with no single reason.
Yep its an early production year and it beat the piston up real good, couple of marks in the cylinder wall and the top of the cylinder was also beat up good so I went the safe route and replaced the cylinder too.
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Old 10-21-2019, 06:46 PM
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China made bearings,thats all that needs to be said.Some get lucky and get the ones that were correctly heat treated others don't.Your lucky it was the wristpin bearing and not the crankpin.Then you would be replacing the crankshaft assembly,but that will be next.One odd thing you don't hear to much trouble with their twins and rod bearings.
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Old 10-29-2019, 09:42 AM
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I've had good success with DLE engines, and their bearings, but a friend of my has not been so lucky. The rod needle bearing failed, and pretty much destroyed the engine. The parts to rebuild would cost more than a new engine!
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Old 10-29-2019, 12:51 PM
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That's the problem with DLE,there's not the same quality control,from one batch of bearings to the next.The hard surfacing gives way on the bearings and from there everything else is down hill.It's to bad because when everything is rite (castings,bearings,) they run great.
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Old 10-29-2019, 02:06 PM
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Originally Posted by closetguy View Post
That's the problem with DLE,there's not the same quality control,from one batch of bearings to the next.The hard surfacing gives way on the bearings and from there everything else is down hill.It's to bad because when everything is rite (castings,bearings,) they run great.

I have 2 dle 55 one new and one used the used one crapped the wrist pin bearing it is a older production run and they do run great, after this happened i found out about the bearing issues. I dont have anything new coming up so i think ill run these and see how it goes. Thanks for everyones replies
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Old 11-01-2019, 03:34 PM
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Ha! Needle bearings! The Achilles heel for most of our gas engines.
DLE 30 with a ton of running has given no problems. Lucky so far.
EME 60's spit their big end needles with nauseating regularity..several rebuilds, some under warranty and some on my nickel. Couldn't keep one running a full IMAC season.
Tried DA60..the best, right? Blew it up big time in 2 years and probably 60 hours...not sure why, because they don't usually give you detailed reasons for failure. But the 3 year warranty got me a new engine.
DA85 threw a front main bearing seal and warranty rebuilt that one too...new crank, main bearings, etc. Both DA's running strong...for now.

Don't know what to think anymore...using the Red Line 40:1 like the DA good book says...ran the EME on 32:1 and the DA 30 on the same. So everything will go after extended running, it seems. Others here have similar needle issues, DLE, whatever brand. Some go a long time (but hours unknown...) Seems to me that hours flown between 30 and 50 is about average life for these chinese bearings. Can't say how long yet for the DA's I'm running...but not trouble free.

Anyone got REAL run time numbers on DA engine life?
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