llkoolskillet

Ive had my LRP 30 broken down for about a year now waiting to put the new piston/sleeve kit in. Well i unwrapped it and found traces of corrosion inside the crank case and the rear bearing sounds like theres a tiny bit of sand in it, the front is sealed so its good. One suggestion i was given was to soak the parts in fuel for a few days then thourghly clean them. Would this really work? I really dont want to remove the front and rear bearings if i have to. I can lightly sand the crankshaft with 600 grit so i should be ok. The crank case is different cause of the nooks and crannys.

Does anyone have any suggestions

Argess

It's sometimes difficult to know what's corrosion and what's not. For example, many confuse dried fuel residue with rust. BUt there's not much than can actually rust (except the bearings and crank).

Soaking in fuel will do nothing for corrosion, but it will soften fuel residue.

If the crankcase is corroded, being aluminum, the corrosion should be white. Some wadded up Scotchbrite should remove it, and then maybe use a small buffing wheel, or nylon bristol wheel with a Dremel to get the final bit.

I wouldn't use sandpaper or emery cloth on the crank. Just use scotchbrite and some lube such as WD40 or any type of oil. Wipe at intervals with a paper towel to see how it's progresssing.

If that rear bearing "sounds" like it has sand it in, it may be the balls catching and letting go on sticky fuel residue. BUT if it "feels" like there's sand in it, you really are faced with changing it. I've got by before not doing that, but not with a little engine that winds up 30K+. However you might luck out.

So squirt some WD40 in the rear bearing and spin it a bit. Use a tapered piece of dowel or something so the yucky stuff can get out (with crank in, it's harder to clean the crud away). If it seems to be OK after that, try a little after-run-oil or whatever and it should be OK.

I havn't changed many engine bearings, but the rear one seems to come out quite easily. It always seems to be the front one that causes me grief.

sturb25

The front bearing is only sealed from the outside, leaving a nitro engine for so long requires all the fuel left in the engine to be totally cleaned out before storage otherwise the fuel is prone to atracting moisture from the air and therefore intern rusting your bearings and crankshaft. Personally i would use a 1200 wet and dry sand paper to re-polish the crankshaft.

As for the block i would soak it in mineral turps for about 10mins pull it out and dry it completely then oil the bearings, if it doesnt work repeat a couple of times making sure the engine is completely dry from turps before you oil. Use your afterun oil to oil the bearings.

Its happened to me before and thats what i did just dont leave your block in the turps for to long. Also the turps will clean out any of the left over gummed up fuel that is in your engine.

Gizmo-RCU

My Feedback: (27)

The only sure way to correct this is a replacement of the bearings and a complete cleaning of the block before re-assembly. Scotch brite will not go into the bearing cage and clean each ball or the races. Rough bearings will not heal themselves and in fact will fail sooner than later. Bearings are not expensive if you go to a Bearing house and have them identify what you need ...a typical 46 two stroke will cost me less than $15.00 to do in that manner.
If you run failing bearings it will damage the rest of the engine, no question about that.[:@]

llkoolskillet

Thanx for the suggestions

I think im going to get some mineral spirits and soak like sturb25 suggested. As for the crank i think i might polish it, you no less resistance while rotating. Like Argess said it could just be left over fuel which is what i think it could be to. A good soak should do it i hope. I could take the parts to work and soak in a degreaser we use for aircraft wheels and bearings. Then use some compressed air to blow out the bearings. I really want to avoid removing them. Also would any of you know the thread for the do it yourself modding ie the sleeve and crank? I read it before i just cant find it. I want to try and mod this engine and try it out.

SavagedXXL

I've pulled out engines and I ran them after sitting for several years and I have seen no corrosion. I put my old XTM 24.7 onan old chassis and cranked it recentlyafter about4 years of it being inthe box, and there was no corrosion.Idid see the crusty dried up old fuel, and new fuel makes about as good of a cleaner as anything.

savagecommander

if the motor was in a box the cardboard helped absorb any residual moisture. nitro fuel attracts moisture and will corrode aluminum. i wouldnt use 1200 paper on the crank unless youre staying away from the shaft. thats actually where the seal is, and all you have to do is take that a few thousandths out, and youll have an airleak.

crunchy bearings = bad. change them. pick up a metal shielded one for your front.

llkoolskillet

Ive seen the metal sealed ones but are they that much better than the rubber sealed ones?

SavagedXXL

Yes, I store them in a cardboard inside the house, so maybe that does help.

savagecommander

if you have a gap between your flywheel and the nose of the motor dirt can find its way in there- and if it gets packed in it will erode the rubber on the seal and render it useless. then you have a contaminated bearing. the metal shields will hold up a lot longer in harsh conditions.

llkoolskillet

would ceramic bearings be better for the inside?

llkoolskillet

boca bearings has a kit for $30, is it worth it?

woodwore69

Rebuilding old motors is such a fine line change one thing then another and another and you are at the price of a new one. I did put a new piston sleeve and rod in a axial .32 that had let the rod go in less than a 1/2 gallon I was worried about the bearings with all the metal that want threw them I flushed every thing with fresh fuel and it is still running good .It did sit in a box for 2 years and only had fuel deposits in it .

.

savagecommander

$30 doesnt seem to bad for ceramic.

llkoolskillet

no there just regular steel bearings not ceramic. I can get a complete rebuild minus the piston and sleeve for the Picco 28 for $83 shipped. Add the rear bearing for the LRP and it brings it up to $108. I was looking at the front bearing on the LRP and the bearings look brown. Either its rust or its the plastic turned brown. the Rear bearing actually sounds better than the front. Im going to flush then see where i sit wish it.

purenitro33

I wouldn't use a metal shielded bearing for off-road use, they are used in on-road engines where there is little or no dust/dirt. A rubber sealed bearing will do a much better job keeping the crap out of the bearing and engine in an off-road application.

savagecommander

what happens when you lose a wheel bearing? dirt eats the rubber shield away and crunches your bearing race. what about the rear bearing on a slash 4x4? dirt eats the rubber shield away and crunches your bearing race. what happens when you over heat a bearing? the rubber shield expands, pops out, and dirt crunches your bearing race. better yet- what happens when you put a motor with way too much torque behind a clutch that cant take it? material can build up behind the flywheel, penetrate the rubber seal, and get into your engine. ever look at the snout of some cranks? see the swirls in them? thats dirt getting past the shield and into the motor.

take the pepsi challenge with a metal bearing. try to pop the shield out.

purenitro33

Have you ever "looked through" a metal shielded bearing? if you have then you would know that there is nothing to prevent dirt from entering into the bearing, you can actually see light because they are not sealed... You sure come across as a know it all but the only thing you are correct on is that the bearing doesn't seal the engine, other then that your information is incorrect and will create more issues rather then solve them. But I guess you know more then all the manufacturer's that use rubber sealed in off-road applications and metal shielded in on-road applications. Why do you constantly feel the need to challenge people who have forgotten more then you will likely ever learn about nitro engines? Sure the metal shield may be more robust, go figure... The fact that dirt can freely enter the metal shielded bearing is exactly the reason that all the off-road engines come with a rubber seal, but again, you know better then everyone... I gave my opinion and you gave yours, one of us is right and is done in this thread because arguing with you is a waste of my time, give it a rest kid as your antics are getting moldy.

savagecommander

defensive? testy are we? i must be talking to an engineer.

no, ive never looked through a metal shielded bearing- and i dont know where you get yours, but they must be cheap. and off road engines come with rubber seals for exaclty that reason. they're cheap. i used to burn up wheel bearings all the time because the "seal" would pop out.. got tired of it and switched to meatal shield and i dont fix wheel bearings anymore. same thing with the front motor bearing - one hard run through tall grass and the heat can pop the seal right off. how many times have you taken the flywheel off and the bearing was exposed? happened to me a lot. switched to metal- doesnt happen any more.

if you want to discuss who knows what instead of standing on your soap box and calling me a "kid" maybe you should give some facts to support your claims other than "i'll forget more than you know"..... yeah, because i havent heard that before.

purenitro33

I may have been a little crass with my reply, but you repeatedly badger supertib and accused me of making up fictitious stories, now your reply to me in this thread which was very ignorant and misinformed. ST and myself make a living from knowing every aspect of every part for every application, we live for this stuff. I will not give advise unless "I know exactly" what I'm talking about! I never referenced you in my reply, I just gave good solid information, unfortunately it was the opposite of yours. I may have interpreted your reply the wrong way, but your reply's always seem to belittle or contradict the information given by the pro's, you seem very bitter for such a young chap, lighten up buddy, they're just toys remember

llkoolskillet

Well arguing aside im going to get the Boca bearing kit for my Picco (5gals thru now) Currently soaking the LRP 30 in fuel. Since i put in the fuel the Rear bearing seems fine now turns great and doesnt have anything in it. But the front bearing is a different story after sitting in the fuel for a few hours it seems like the front bearing might have rusted. Has anyone used the Boca Bearing kit? Does the front bearing come with the rubber on one side or both sides? Cause the LRP factory one only has the rubber on the out side so if i get the bearing from Boca and it has rubber on both sides, would it be ok to remove the rubber seal on one side then install?

purenitro33

It is fine to remove one seal, remove the one where the balls are exposed. It will be packed with grease so I suggest cleaning it all out before installation, WD-40 seems to break it down fairly well.

llkoolskillet

thanx

purenitro33

Any time buddy.

jbooker82

My Feedback: (4)

They are called metal sheiled for that very reason. They are only shielded and not sealed. You can see day light through them.