Yeah...kinda screwy, huh?!
The TT .40 and .46 and the O.S. .40, .46, and .55 and Evo .40, .46, .52, Magnums, etc. all use those same two bearings...

If you've successfully changed bearings in your car / truck engines, then it should be easy for ya...
I use heat and cold (toaster oven or propane torch...and the freezer ) the bearings will literally fall into place.

Hi!
All .40-.46 two stroke engines on the market ,except Rossi and MVVS, has those ball bearing sizes! One metric one inch! MVVS has the same at the rear but a smaller metric up front , Rossi.40-.45 has a larger metric at the rear and a larger metric up front.

Here is a picture of how one of the best bearings look like!
From Swiss (WIB) with C4 play, for best reduction of friction and with phenolic retainers.
These bearings are used in racing engines like Nelson and JETT (and some MVVS engines) and could of course be used in a sport engines too.

I wouldn't say "all" .40-.46 engines except the rossi and mvvs use those sizes, even though a lot do. My experience with supertigre and Nelson/Jett engines indicate that they don't use these sizes, either.

Not to be picky, but if we can save someone from buying the wrong sized bearings, it might be worth it.

Yes, use the oven. I never advocate using a torch because you have no control over the temperatures you are getting on the metals and you can distort or otherwise damage the crankcase and shaft.

I found a cheap used toaster oven on craigslist or something like that, keep it in the shop for doing engine bearing changes.

That way I don't have to use the "food oven" - helps keep the peace!

My wife hasn't seen me using the oven for engines, but I told her about it. I would get an oven thermometer if I used a toaster oven.

Barry, for a "small fee", I wont remind her about all this. LOL

I actualy ordered me 3 sets of bearings from Paul at RC Bearings today for my Club 40 racing Pro 40 engines , they currently have the stock bearings in them, so I just want a little peace of mind I guess for the upcoming 2011 Club 40 season.

John

I had a junk car engine that I practiced on popping bearings out of - it was beated down badly and took some elbow grease and a few burned gloves to get the bearings out. This is what I called the "worst case scenario" bearing swap. Anything will be easier than this. (it took a couple soakings in 2 gnarly solvents and a 450°F oven for a half hour to get those bearings out)

This engine will be much easier to do, I'm sure of it.

Those bearings are now on order. I ordered the stainless bearing set for $12 and found a 10% discount coupon online.. Do the metal shielded front bearings leak much oil?

Most of the front bearings nowadays will have either one dust shield or two shields, you can pop one shield out (side that goes to the inside of the engine) or either leave it there, your choice. If yours have no dust shield, you should be fine. If by chance it leaks it some after you install new bearings , it could possiblly mean you have some play in the crank (?).
Install the bearings and go fly
John

Oil goes right through a metal shielded bearing

Quote:

ORIGINAL: 1QwkSport2.5r

...Do the metal shielded front bearings leak much oil?

1QwkSport2.5r,


It is not the front bearing's job, to seal the oil inside the engine.
A model glow engine is a rather greasy creature...
It feeds on fuel that contains 15-20% oil, that in general, does not (or should not) burn in the combustion process.

So, it spews out most of its oil through the exhaust (and also through its carburettor) - it is a total loss lubrication system.

Only for engines that do have an independent lubrication system; should any oil leakage be a cause for concern.

Our two and four-stroke obviously do not need (although some may disagree) an independent lubrication system.


So, if I see an oil leak from my glow engine's front bearing; frankly, I could not care less...
..."Frankly, my dear; I don't give a damn"...

...You shouldn't care either; even if it means your your cloths get oiled. They will take some oil anyway.

Such an oil leak is not a reason to change the front bearing.
If an air-leak results in the inability to shut-down your engine, it is a different case; and changing to a sealed bearing may help.

G'day

In support of what Dar and others have said about oil coming through front bearings - here is a quote from the instructions for the Jett sport series engines. I have just bought one and after some "fast, lightly loaded rich two stroke running", it is now happily turning 16,500 rpm on an APC 10 x 6 on 10% nitro fuel. It is not noticeably throwing oil out the front but if it does, I won't be worried. It is a very beautiful and powerful engine. I think I am going to have some fun frightening people (including me) with it. If the weather is right this weekend it will get its first flight.

"Wet front bearings" It is perfectly normal for the engine to blow quite a bit of fuel out the front bearing when running, especially during full throttle. This keeps the front bearing lubricated. Jett Engineering.

Spare a thought for the pilots who in World War I flew behind rotary engines in planes such as the Sopwith Camel. Not only did the engine not have a throttle but it used several litres of castor oil in a total loss system every hour. The oil was ejected from the exhaust valve on the top of the cylinders and much of it ended up on the faces of the pilots. Now you know why they all wore large scarves. It was not just to look impressive and stop chafing from their leather coats but also to wipe the castor off their goggles.

Mike in Oz

My car engines leak some, but they are rubber shielded. I hadn't seen metal shielded bearings in an engine so I was curious. I expect some to seep. I should say I want some to seep. I nicknamed my k&b sportster "slimer"

I would think that rubber seals in car engines are designed to keep dirt and grit out, more than they would be to keep oil in.

Personally I like to see some leakage from the front bearing in an airplane engine, means the bearing is truly getting lubricated!

A lot of it has to do with the engine design. Car engines have very short crankcases and it is difficult for them to have enough case at the front bearing to do an adequate sealing job. The sealed bearings are just extra insurance. Saitos use a sealed front bearing for the same, and another reason. They want to make sure that the blow by oil gets to the other parts of the engine rather than leaking out the front. Their cam arrangement makes for a very short front case area. All YS engines I have seen use a sealed front bearing for another reason. The four strokes have an O-ring on the crank behind the bearing to prevent crankcase pressure from leaking. In this case you need a fully sealed and lubricated front bearing. I have seen a lot of bearing sets being sold on eBay lately for these engines with shielded bearings. Too bad there are dealers out there that have no knowledge of the engines they are selling bearings for!

It is awhole lot easier to use a heat gun to replace bearings. I have used a torch before, but would not recommend it to any one.

I think the oven is better for two reasons. One, its easier to stick it in there for 15 minutes and have the bearings just fall out. Two, it heats the block evenly much like it would be when running. I would think using a torch or a heat gun would just be inefficient and time consuming and possibly create other problems down the road.

Thats just my opinion. When I change bearings, I'll use the oven. if it does stink the house up, I'll use some Febreeze.. lol.

I've used both a torch and a heat gun in the past and haven't had any problems with it. You just have to keep the flame or heat gun moving to avoid hot spots. I do wonder though if it makes the casting more brittle however?

I agree, the oven would be the better method.

Hi!
Agree! A torch is best! Oven takes too long and heat gun is not putting heat as precisely as a torch!

since we've seemingly moved off the topic of TTpro .46 issues and onto bearings and changes, I have a question.

I have a couple of Taipan gold head .15's from days gone by. I ordered new bearings (from rc-bearings) and have yet to put the engines back together, as the rear bearings just WON'T come out.

I've tried oven and torch, neither is doing the trick. If I remember correctly, the inside diameter of the bearings is 10mm for the rear bearing. Does anyone know of a good, not too expensive bearing puller that might help (coupled with heat) to remove these VERY tight fitting bearings?

I don't want to spend a fortune, as I doubt I ever run the engines much, so I won't ever need to do this again. But, I would like to put new bearings in them in the event that I ever DO want to run them.

I've replaced many a set of bearings, and NEVER had any that were this reluctant to be removed.

Thanks!

I have used a punch to remove a stubborn rear bearing in the past. Don't use a lot of force and keep moving the punch to different sides.

But if heated enough, the rear bearing should come right out when you slam it on a wood surface.

Heating these isn't going to budge them, I've tried.

When the front bearing and crank are out, there really isn't enough of an edge to catch on that inner race to tap it out, either. There isn't much difference in the bearing race ID and the hole in the crankcase, so there isn't much to attempt to snag.

I know OFNA makes pullers for RC car engine bearings - anyone ever used one? I see the kit for the .12 and .15 engines has a 10 and an 11 mm puller.

I use a special tool that I made out of a flat blade screwdriver. (they used to call them "Carburetor screwdrivers"...long shank, and the blade is only about 1/4" wide )

I took a cheap narrow bladed screwdriver and bent over just the tip (about 1/8" ) 90 degrees and sharpened it w/ my Dremel. I can go in from the front bearing opening, and catch on the inner edge of the inner race, and tap the bearing out w/ light hammer blows. Moving the tool around each blow so as not to get the bearing cockeyed in the bore as it is driven out.

Set the case on a block of wood with the backplate opening down...front bearing opening pointing up. Heat the case on the block of wood...then use the tool and a small hammer...works every time for me...never had a bearing that didn't come out...never damaged a case either.

It always makes me nervous to think of slamming down a hot Alum. engine case...I think my method is MUCH gentler on the case.

jaka, is motor mount broke from crash or touch?