LST2 clutch problem

[Greywolf74]

I have an LST2 and I seem to burning up clutch bell bearings and aluminum clutch shoes at a high rate. I'm on my third set of each in about 1.5 gallons of fuel. I'm assuming this isnt normal but I am fairly new to the hobby so maybe I'm wrong? Also something else that seems weird compared to my friends MGT is it seems my RPMs have to spin up a decent amount before the truck starts moving. The MGT starts rolling as soon as the gas is applied. I'm wondering if maybe this spin up is causing additional heat that is causing the shoes and bearings to wear out faster?

Anyone have any ideas why this is?

 

[mjneid]

I have an LST2 and I seem to burning up clutch bell bearings and aluminum clutch shoes at a high rate. I'm on my third set of each in about 1.5 gallons of fuel. I'm assuming this isnt normal but I am fairly new to the hobby so maybe I'm wrong? Also something else that seems weird compared to my friends MGT is it seems my RPMs have to spin up a decent amount before the truck starts moving. The MGT starts rolling as soon as the gas is applied. I'm wondering if maybe this spin up is causing additional heat that is causing the shoes and bearings to wear out faster?

Anyone have any ideas why this is?

Have you looked at and/or adjusted the slipper clutch?!?

i have an MGT, and i had a similar problem when i installed the 8.0 transmission. tightened the Slipper and it worked like a champ.

 

[Greywolf74]

yeah I forgot to mention that someone had metioned that to me. I have the slipper set to the default 1 turn out but my friend suggested maybe 1/2 turn out might work better since the clutch needs to be tightened some as the parts wear. I planned on trying that after my visit to the LHS this afternoon.

 

[olds97_lss]

A loose slipper wouldn't eat up clutch shoes and bearings. It would make the truck not move, but it would actually reduce the load/heat put on the CB clutch/bearings.

IMHO, the big tires on the LST2 are too big for running in grass. At least with stock gearing. I mean it does ok, but they labor the clutch and engine quite a bit if your not on dirt or concrete.

It definitely sounds like you have some slippage going on with the shoes. Do you sand the face of the shoes a bit and inside the bell when you change them out? Do you clean all the parts really well with DA to remove any oils? Only takes a drop of oil to ruin a clutch. How's your shimming and gear mesh? Running too tight of either will also shell bearings in short order.

Have you tried the long life shoes yet?
http://www.horizonhobby.com/Products/Default.aspx?ProdID=DYNP5180

Might help.

You can also do a 3 bearing mod to better support the bell. If your running the LST2 bell, you can get the OFNA shim kit with shaft extender and a 5x13x4 bearing to go in the outside of the smaller pinion gear.

Snagged a photo from somewhere else to show you:

Just make sure to put a small thin shim between the normal bearing in the bell and the big bearing you see on the end so they aren't touching each other.

If you have the older LST1 threaded bell, you can still do it using similar parts but you just use a 3rd stock sized bearing.

 

[Greywolf74]

I can try cleaning all the parts with DA but I dont know what DA is.

The extra bearing looks like a good idea but I fail to understand what the ofna clutch shim kit is for. I've only been at this for 6-8 weeks so forgive my noobness.

I have the clutch shimmed the way it came from the factory and as far as I know my mesh is fine. I used a piece of paper in between the gears to set the mesh like most people say to do.

I just bought the dynamite max life shoes although the LHS tells me the losi aluminum shoes that I have been using are also max life shoes.

I do actually have a smaller set of tires (17mm hex) that I could put on the truck. I bought them cuz they looked cool but ended up taking them off because I was flipping over too much in the grass and on pavement or really hard ground. They work great in the sand, dirt, and gravel though. Should I try running these for awhile and see if it makes a difference? Again though going back to my friends MGT he has after market tires on his that are just as big as mine or very close to it and again he doesn't have this problem. Maybe I am comparing apples and oranges though?

 

[mjneid]

I can try cleaning all the parts with DA but I dont know what DA is.

The extra bearing looks like a good idea but I fail to understand what the ofna clutch shim kit is for. I've only been at this for 6-8 weeks so forgive my noobness.

I have the clutch shimmed the way it came from the factory and as far as I know my mesh is fine. I used a piece of paper in between the gears to set the mesh like most people say to do.

I just bought the dynamite max life shoes although the LHS tells me the losi aluminum shoes that I have been using are also max life shoes.

I do actually have a smaller set of tires (17mm hex) that I could put on the truck. I bought them cuz they looked cool but ended up taking them off because I was flipping over too much in the grass and on pavement or really hard ground. They work great in the sand, dirt, and gravel though. Should I try running these for awhile and see if it makes a difference? Again though going back to my friends MGT he has after market tires on his that are just as big as mine or very close to it and again he doesn't have this problem. Maybe I am comparing apples and oranges though?

DA = denatured alcohol / Also called, ethanol (ethyl alcohol)


Comparing the MGT to the Losi is a apples to oranges.

IMHO the Losi variant is more a track truck. They preform really well on dirt, lose gravel and such. Where the MGT is made more for bashing it up. I don't know that i would EVER put mine on a track with other trucks. I know i'd have to work pretty hard to keep up with the Revo's and Losi's. But if you wanted to go head to head on BMX track, or an construction site it'd be on like Donkey Kong.

Don't get me wrong the Losi is a NICE truck. In fact i think i'm going to start piecing one together. and build it over the fall/winter. but it's just not the brute the MGT is.

 

[olds97_lss]

Factory shimmed may be ok, but running a 3 bearing setup spreads the load more and you need the OFNA shim kit to get it put together right. To get a third bearing in there, you need to extend the shaft, which the shim kit includes. Then you use the shims to separate the new 3rd bearing from the original outer bearing and then you use the shims to get the proper fitment when you tighten down the bolt that holds the bell on.

If it's too loose, it will wander on the bearings and shaft and will also wear on the spurs, shaft and bearings. If it's too tight, the bell won't spin free and you get a lot of load on the side of the bearing, which ruins them very fast. What you want to end up with is a "tick" of play when you push/pull on the bell when the bolt is tight. Just enough that you can feel it move in and out.

As for the gear mesh, the paper trick does usually get you close, but with the dual spur setup, sometimes you will end up with a loose and tight spot as you rotate the spurs. So you may have to adjust that by feel as well to get it not too tight in the tight spots and too loose in the loose spots.

I still think the stupid thing is geared too high for the stock ATX tires they run. It seems losi is more concerned with speed in some cases. If you had a stronger engine, good tune and a good pipe, then it would do better. But, with a stock engine, "beginner" tune (no offense), it's an uphill battle for you. With mine running an LRP28 (fairly decent engine), I tried running a set of the stock tires and it really labored the truck. I had the gearing at +1 over stock on the bell, but it was obviously putting way more strain on things than I like. So now the tires are sitting on a shelf and I'm running 17mm revo wheels/tires.

I run the second from the left on it now:

Left to right: t-maxx 3.3, revo 3.3 talons, HPI savage 21 stock tires, t-maxx 2.5 stock chevrons

I used to run the ones on the far right, but the revo ones are a good balance between speed, ground clearance and rotational mass for the bashing I do. I still run the chevrons on my revo though, just on 17mm wheels. They work well for running in skate parks. Not a ton of side bite and they wear out really slowly. I run the ones on the far left on my savage, but it has a 3-speed trans and another LRP28 engine in it, so it's got the torque to deal with the larger tires the best.

Here's a link with a bit of clutch bell bearing troubleshooting. May help you out a bit as well:
http://www.twf8.ws/new/tech/clutch/clutch-bearing-trouble-shooting.html

 

[Greywolf74]

Well i think I figured out what the problem is...I tore my transmission completely apart the other day and discovered I have 4 bearings in there that are not free spinning...2 dont spin at all. got the parts on order so we will see but I'm sure this is the cause.

 

[olds97_lss]

Yeah... that would cause some drag.

How did the shafts and case look? If they weren't spinning, something was slipping, which means either the shaft may be tore up where the bearings rode or the case where the bearings seat may be tore up.

 

[Lukedavis]

We miss you greywolf! Please come back…