Coming from a new losi 3.4 engine. It leaks from the bearing. I'm new to nitro, will this cause any sort of internal damage? Engine only has about 5 tanks through it.

That's very dirty looking. Did you run it without an air filter, or possibly get dirt in the engine somehow? What color is your fuel?

that is pretty normal for a engine to leak from the front...especially if it was running rich and stored with excess fuel int he engine......

try not to run your low speed so rich , that is THE reason front bearings fail prematurely

So you actually think extra fuel leaking out the bearing actually harms it ? I dont buy that for a second dude ! LOL what harms the bearings is when the engine breathes thru the front sucking up dirt into the bearing...thats actually what kills the bearings....dirt kills bearings !!!!! . I would rather have a engine leak a little fuel then suck a little dirt ! a little extra fuel only lubricates the bearings, it doesn't harm them...dirt is what kills the bearings...not fuel ! this why we block the little oil bypass port....we get extra fuel leaking out the front, but have zero issue with dirt getting sucked into the engine......... After blocking that port all the engines show slight leaking out the front, yet the amount of front bearings failures was reduced to nil....and this is tested and proven over hundreds of engines now...............As I say, its better to leak a tiny bit of fuel then it is for the engine to breath thru the front...Breathing in dirt thru the front bearing is what kills the bearings....fuel seeping out does no harm at all.......fuel is a lubricant, and having extra lubricant only seals and protects the bearing better.... Personally I would rather see a slightly damp front bearing then a bone dry bearing...if the bearing is bone dry then I always suspect the engine is breathing in thru the nose....which means it is breathing in unfiltered , dirty air..........

Now of course a little extra fuel leaking will cause a collection of dirt on the nose of the engine, that may eventually wear out the dust shields....But this is far less of an issue then the engine breathing in unfiltered air thru the bearing....... As under some conditions these engines will actively breath thru the nose and will suck up large amounts of dirt, which absolutely destroys the front bearing in a very short amount of time...........this is far more of a concern then a slight bit of fuel seeping out the front bearing.,....

here is a before and after of a Bonito......

this Bonito was bone dry on the nose....having tuning issues, but showed no signs of any bearing leaking or anything like that...Until we opened it up there was no evidence of any bearing issues whatsoever....However once we opened up the bearing we found it was packed with dirt...not only was the bearing packed with dirt, but also the dirt had passed right thru the bearing and was actually being sucked right into the engine itself..

now here is a engine after blocking the bypass port...The engine did now leak a tiny bit out the nose and had a collection of dirt behind the flywheel....However once we opened it up the bearing and engine were completely 100% free of dirt......Yes it was leaking some fuel, but dirt was no longer being sucked up into the engine.......... the first set of pictures shows a engine that ran with a bone dry nose...no fuel leaking and the bearing was stuffed full of dirt...... the second set of pictures is of a engine with the bypass port blocked (which increases the lubrication), run in the same conditions, except the front was seeping fuel because the bypass return was blocked....Yet when we open the bearing there is zero signs of dirt....... 100% sterile clean......you tell me what is harming these bearings...a little extra oil and fuel, or being stuffed right full of dirt ?








edit.... I have multiple sets of pictures and had actually thought these were of the same engine...but the first is a Bonito, the second is a P5.... I will have to dig up the original dirty P5 pictures...

Oil goes out as positive crankcase pressure pushes and sucks dirt in as negative pressure sucks
Leaving a super rich lsn will cause this by filling the crankcase with extra oil and then flowing out the path of least resistance (front bearing) ,i know this for fact

I have seen no major benefit in plugging the so called " vacuum port" or wtvr u call it now , yes i have plugged many of them , there are a number of manufacturers who use this style of oil ring film seal forming vacuum oilers . A crappy front bearing can last longer than a killer front bearing that was ran with ultra rich lsn .

Quite frankly i have seen and dealt with MANY more engines in "race" application than you have so please spare me

I wasnt going to say anything but........ well , ya know

So your saying a rich setting causes the engine to breath thru the front bearing ?


I actually believe a little differently... IMO running the engine lean causes them to breath thru the front bearing.... A lean setting results in a loss of the engines hydraulic seal along the crankshaft.....These engines rely on a fluid film to seal the crankcase...disrupt that film and these things will start hoovering thru the nose......

At the end of the day tho we do agree that dirt kills bearings..... doesn't matter how it gets there, lean, rich , osmosis or teleportation ..dirt kills bearings.........

And for plugging that bypass port...You may not have found much reason to block it, but I most certainly have ...On my engines I have no choice in the matter......plain and simple the more HP a engine makes, the stronger the vacuum signal the engine makes ,and the harder its going to suck..... and because of that,any areas of vacuum loss will magnified... On a stock or mild powered engine that bypass may supply just enough vacuum to remove excess oil and fuel from the nose to prevent it from leaking... However On my high powered modifieds that little port becomes more like a nozzle on a mini vacuum cleaner, With strong enough vacuum to actually start drawing atmosphere in right thru the front bearing..which if your running in a dusty environment results in the front bearing plugging solid with a dirt in only a matter of minutes....A no a 17011 will not help any, it will fill up with dirt just as quick as any other.... The only way to stop this from happening is to block the bypass port..............Now a low powered or mild engine will not benefit from from blocking the bypass port nearly as much as would a high powered modified, but it will still benefit to some degree... Even a mild engine run in dirty conditions will ingest less dirt thru the bearing then it would if the bypass was not blocked....Basically the more powerful a engine is, the more it is going to benefit from having the bypass plugged...On most of my engines blocking the bypass is necessary ...

Quite frankly i have seen and dealt with MANY more engines in "race" application than you have so please spare me

you really have absolutely no idea how many engines I work on ..for you to even say this just shows me how arrogant of a person you really are...All I can say is keep on talking buddy, I am going to enjoy the day when our paths cross and I can make you eat those words..

I have no argument against when you push an engine past its designed limits you will create many problems that will not show when the engine is kept within its designed limits .

I will also enjoy the day

Just curious , what makes you think i dont work on and deal with a massive amount of micromotors in the engine room and on the track ?

thats me , mr. Arrogant , please Neal , all who know me know its quite the opposite , so please stop trying to discredit

Its pretty apparent you are a hardcore sell your product kinda guy with a heart on

Many can see it but u

Settle down guys, you're acting like a bunch of Norwegians arguing over the last drop of Aquavit

your the one making stupid arrogant comments about engine numbers, not me......

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Someone dim the lights and go get popcorn... we are in for a great show

Extra butter please

Hey ,we both have a great passion to bring you guys the best of the best , that is a bonus for you guys

Some are just more ruthlessly competitive than others but in the end the goal is the same , bringing you guys great products from great manufacturers

I think I pretty much agree with you here !!!!