Front sealed bearings

[Joe Reese]

What causes the seals to go out so fast, and what could I do to prevent them from wareing to he point of air leaks? / Whow often should the front bearing be replaced.

 

[izitbrokeyet?]

Hey joe,

what motor? There are some motors that shouldnt have sealed bearings in the front. If you put a sealed bearing in some motors it will kill the bearing quickly due to lack of lube.

 

[Joe Reese]

The Rossi engine, both of the rossi engines I have use the sealed bearings with one seal pulled out for lube, now the two pto bearings have seals on both sides of the bearings. :blink:

 

[Mike Broad]

You can remove the seals quite easially, they are usually held in place by a small circlip. Otherwise carefully place a jewelers screwdriver between the inner race and the seal and gently prise the seal away. Don't forget the circlip!

Mike Broad

 

[Joe]

Hey Joe

I don't know how you clean your ( outboard ) engines but here is what I've seen others do to rossi, novarossi, and cmb that ( thought ) they were cleaning . I've seen people take their WD 40 and corrosion x and spray through the carb while turning the engine over with the starter. Now they have a clean engine with plenty of lube on the bearings. ( WRONG )!!!! By cleaning that way you don't get enough lube to the top bearing to put a bad taste in your mouth. If you don't want to pull the engine off the boat after running each time, you need to stand the boat on it's nose ( outboard boat ) so your cleaner can get to the top bearing good ,and flush it out with WD 40. Then I go back with my corrision x to lube the engine. I've only had to change two bearings in two years. The first one was because I hadn't learnd the right way to clean an outboard yet and the second one was in a novarossi that was bad from the factory and sucked air the first time I tried to run it right out of the box.

Joe Grace

 

[Don Ferrette]

"I've seen people take their WD 40 and corrosion x and spray through the carb while turning the engine over with the starter. Now they have a clean engine with plenty of lube on the bearings. ( WRONG )!!!!"

Well then how does that bearing get lubricated when it's running? :huh: The groove that's cut in the crank will get the WD40 up there. I sure hope you guys are using WD40 ONLY for cleaning THEN following it up with a good after run oil. WD40 alone is not the way to go & Corrosion X is not a good after run oil either as it will leave a film on the bearing running surfaces, tightening up the clearances & actually accelerate wear (this applys to all motors, inboard or outboard). Also on the outboards that small bearing takes alot of abuse, mostly from the way they get started. Those bearings are not designed for the excessive thrust load from that starter motor getting slammed down on them. They are there to support the crank so when you start these motors use the lightest possible pressure that will turn motor over. When I used to run o/b's I would always start them (3.5 & 7.5 class) with the glow plug loose so I could use even less pressure on the starter. I can't tell you all how many o/b bearings I've seen with the wear on what would be the bottom (back) side of race, as the motor sits on the boat. Less pressure with those starters gang. The small bearing is also relatively unprotected with the design of the o/b flywheels & how it runs exposed to constant air (airborne grit) & water (washes away lubricants) flow. As far as bearings (both crank bearings), replace after EACH GALLON of fuel run thru them, especially the NovaRossi which has weak bearings to start with. Trust me one this one, been there, done that! :blink:

 

[Joe]

Don

I have seen engines that have been given a drink of water and cleaned the way I've seen others do it and when you break it down have still found traces of water in the top bearing. I've also done it the way I do mine now and find no water in the top bearing. This is why I feel it don't get enough cleaner in the top when boat is flat when you clean your outboard. That is just my findings and my not be others. As for corrision x you can take down any of my engines and they will be as clean and shinny as the day they were made.

Joe Grace

 

[Don Ferrette]

Hey Joe-

Like I said in previous post I have found that the coating left behind by Corrosion X (how do you think it protects electronics) will tighten up clearances on bearings which can make them too tight. Plus it has absolutely no dry start up (first firing up of the day) protection whatsoever & it's actually worse in my opinion. I've helped prolong a number of boater's bearing lives by getting them to stop using Corrosion X as an after run oil. My tried & true after run is 50% Marvel Air Tool oil (NOT Marvel Mystery oil) & 50% Dexron ATF (auto trans fluid). I will say that when I did have an o/b go "belly up" I would hose down the top bearing area with WD to displace the water. B)

 

[Bart Drieghe]

Its like Don says , WAY to many people think that WD 40 is good enough , i can tell u , its not !!

I once did a test what wd 40 does with a brand new bearing , placed them just in a bag , sprayed once with wd 40 and i can tell u , it did everything except running smoothly so i would advise u to follow newbie hmm nah its beginner lol ooooooooh no its clubracer Don's advise ( how the heck do u get a clubracer so fast Don lol )

Regards ,

Bart

 

[Preston_Hall]

WD = Water Displacement

It really doesn't even flush the motor and that is why you can see water in places still. However the WD has displaced the water from making contact with the metal surface. If a motor takes a dip then I would run it and not count on cleaning to do the job. Ever heard of after run fuel? It's fuel minus the nitro. Now your engine has been flushed.

Extra lube of types is best, but I'll have to say that my engines sit all winter with only the usual WD flushing.

Also on the outboards that small bearing takes alot of abuse, mostly from the way they get started. Those bearings are not designed for the excessive thrust load from that starter motor getting slammed down on them.

I wouldn't think they see any greater load than when being launched or running. How much thrust is required to run 100mph?

 

[Don Ferrette]

"I wouldn't think they see any greater load than when being launched or running. How much thrust is required to run 100mph?"

Alot less than what these guys are creating starting the motors I would say. While the thrust of a prop pushes on the motor, the boat can move forward as a result, not the case with that starter motor being smashed down on that little outboard. How many times have you seen them having trouble getting them fired up & they're just repeatedly jamming that starter motor down on it, and more violently as pit time starts running out. Plus the thrust on the bearings while running in a boat is pretty well controlled, that cable is spinning in a fairly concentric circle being controlled by the stuffing tube (i/B), pto & lower unit (o/B), etc. How many times do you think that o/b starter motor hits the flywheel the same. Well, probably never. Akward, unbalanced & often somewhat violent loading from the starter motor. Only reason I say this is I've rebuilt a number of those outboard motors for people & those bearings always seem to look alot worse than thier inboard counterparts. Plus there always seems to be that same wear patttern on the o/b's that I never see on the i/b motors. Not a sermon, just my opinion based on things I have seen from the outboard days.........

 

[Preston_Hall]

30mph to 70mph in 1.5 seconds.

8 pound boat

neglect any friction

17 pounds of force

I think :huh:

 

[Don Ferrette]

30mph to 70mph in 1.5 seconds.8 pound boat

neglect any friction

17 pounds of force

I think :huh:

Sounds about right. I think some of those guys we've seen starting those outboards could exert a little more force than 17lbs, especially when panicked by the start clock!

 

[Chris Wood]

don

are you saying that the nova rossi bearing's need to be replaced after every gallon, does that include a inboard motor?? if so that get really expensive at 40 bucks a pop!!

chris

 

[Joe Reese]

The worst iswhen he engine takes a drink I only "flush" the engine with STP and Mystery oil mix, and away I go. On the other hand hanging the boat is a good idea! to alow the oil to drain into the front bearing. I think I mite have to bring some coat hangers to the Races to hang between heats. on top of he hard sarting ya I admit to slaming the starter on the flywhell .

What about tefflon seals on the bearings? I know that the rubber seals are softened by petrolum oils, would it be wise to change to tefflon if made and all the secemstances are met?

 

[Don Ferrette]

Yup, especially the NovaRossi's! The bearings in those are not very strong. A number of years ago Kentley Porter (who has some of the best running N/R's I've ever seen) told me the set of bearings per gallon thing on the NovaRossi's. Wish I listened to him back then as my N/R motor had a little under 2 gallons thru it & grenaded the big bearing on last lap of last heat in 20 hydro & cost me a motor & 1st place overall for that race. <_<

 

[Ben Stein]

Haven't ben here in a while (no pun intended)

some objective info to keep everyone on the Up-and-Up

F=MxA

F=8lb x A

If A=(40m/h) / 1.5s

Then A=(26.666 m/h) / 1s

Rewritten A =39.116 ft/s^2

0r A=(39.116 ft/s^2) / (32ft/s^2)=1.22

back to the original equation F=8lb x 1.22 = 9.76lb (without friction)

 

[Scott Schneider]

:unsure: Thought I would chime in here and make a point.

Because our "Nitro" engines are designed to NOT HAVE a mechanical seal on its crank shaft sealing entire engine, the case is build with a very close fitting web of materal that is between the big crank bearing and the pto bearing. This web acts as a seal to make sure crankcase is fairly well sealed. As engine is running the pto bearing will starve for lubrication unless a slight amount of blowby is allowed to get past the web seal area and into and out of the pto bearing.

You will see a few engines with sealed pto bearings and in most cases the MFG. has given a small bleed hole or a spiral passage to aid lubrication getting to the pro bearing.

And last point is real important !! If you run a sealed pto bearing you CANNOT flush out water or contaminates from the front bearing and you will have much shorter service life from that bearing. Scott

 

[GTR]

Hi Guy's

This is most interesting and Don's point about people smashing down the starter is a fair one. Many could learn to improve their starting techniques taking it a bit easier on the engine. If you really want to do away with it use a one way bearing and a starter probe like helis use. The NR front nearing thing is interesting as in car use they never have the sort of problem you're talking about so it must be the load placed on the shaft/bearings by the flex that Scott was alluding too. I don't know what is right or wrong but NR use the best materials available in their engines so it is surprising. I use ATF as an afterrun engine oil and take the powerhead off the OB and spin it over with a starter (plug out) as ATF is designed to operate reliably in pretty harsh circumstances and is abused by it's users constantly.

GT :blink:

 

[Don Ferrette]

" I don't know what is right or wrong but NR use the best materials available in their engines so it is surprising."

Agreed...... except for the bearings. NovaRossi spec'd in their own special size bearing on those motors & they are rather weak. Ron Byrd of RaceCraft Bearings had a good post about them back on another bearing thread. As for the car guys, they don't use remotely the level of nitro that we do plus the RPM range is lower & rather varied were as we spend our time running WFO screaming these engines to the limits of their mrchanical lives.