LOSI LST XXL Conversion ideas - Page 19 - RC-Monster Forums

Bondonutz · 07.15.2010, 12:40 PM

The Hot Racing Jet Vent pistons are great, I found they make a big difference on the big jumps.

STAY AWAY from HR Titanium shafts, Total JUNK !

mistercrash · 07.15.2010, 01:39 PM

Thanks Bondo, nice to know that the HR pistons work like they are supposed to. If the valves I made don't work like I want then I'll definitely get the HR pistons.

Bondonutz · 11:48 AM

I do my best NOT to drive on the street or concrete. The high traction surfaces are death to diffs under 6s power.
Sorry to state the obvious Ray, loosen the slipper a touch !

nuz69 · 07.21.2010, 11:40 AM

Punch control !! (Especially if you drive on High grip surface)

mistercrash · 03:51 PM

Your comments and suggestions are welcomed, no need to be sorry. My slipper is set correctly, I'm pretty anal in checking it often. I can hear it work constantly when I get on the throttle. That short ''whizzzz'' it makes when it slips. I will check my punch control settings and I will probably make sure my slipper is set correctly again (anal I told you).
I will definitely not avoid running on any surface I wish to though. But maybe I'll try to remember to take it easy on high bite stuff. I feel that a construction site where I bash most often is the worst for the drive train. Sand, rocks, dirt, wood, piece of concrete, bumps, ruts, hills etc. All these give different traction to each wheels. Slip, grip, slip, grip a lot, grip a little, slip a lot, slip a little, grip a lot, at a different rate for each wheel all the time, I think that is way more difficult on the diffs then the linear traction you get from asphalt or concrete. I may be wrong but I noticed that I never seem to break drive train parts on concrete, asphalt or grass, always when I go have fun in those construction sites. Anyway.
After I opened the diffs and cleaned every part, it was obvious that it was the spider gears again that stripped a few teeth which caused a little damage to the output gears. Here's what I'm going to try, I had a couple sets of rebuild kits for the Thunder Tiger S3 buggy and I'm going to try those spider gears. After comparing them with the Losi ones, they seem better made with more meat on the teeth.

The Thunder Tiger spider gears are on the left

Here's a different view that makes the differences easier to see. Both gears have the same number of teeth and the same pitch. But the Thunder tiger spider gear has a slightly bigger diameter and is thicker. This results in the teeth being longer and having more surface to mesh with the output gears. I hope that it makes them stronger.

The Thunder Tiger diffs also use thin shims behind the spider gears and the output gears. So I installed the shims and the spider gears from Thunder Tiger and all the rest is Losi diff parts. It all seems to work together and the diffs are very smooth. Now to go out and try them.

mistercrash · 07.22.2010, 06:48 PM

After 4 cycles on 6S the Thunder Tiger spider gears are still holding.

mistercrash · 07.23.2010, 11:10 AM

We went out to play with the trucks this morning and after bringing the LST back after the first set of lipos, I noticed that the rear diff felt notchy when turning the wheels by hand. And all of a sudden, it locked.

I took the diff out again opened it, cleaned every part and the problem was a single tooth broken from one of the Losi output gears. The severed tooth was floating around in the oil and locked the diff. The Thunder Tiger spider gears are fine so I replaced the Losi output gear and put everything back together I'm out of diff parts and diff lube.

mistercrash · 07.23.2010, 10:07 PM

After spending some time this morning rebuilding the rear diff, I blew it again this afternoon and I was running on 4S. Same problem as last time, the Losi output gears broke a tooth or two. It seems that the Thunder Tiger spider gears are too hard for the Losi output gears. I'm thinking Hot Bodies Lightning buggy diffs

http://cgi.ebay.com/HOT-BODIES-C8178...item3effd0febe

With a 13 tooth pinion also from Hot bodies

http://cgi.ebay.com/HOT-BODIES-C8030...item5ad96933ff

I heard they are really tough, I just don't know if they fit the Losi LST XXL diff cases. I searched these forums for an answer and I got a conversation between ''its me'' and ''angry alien'' about it but never found a definitive answer. So I'm still wondering if it would work. Anyone know for sure?

On another note, we all know that it's not good for our sensitive equipment but a perfect mud puddle is totally irresistible. Pics of my LST and my son's Brushless E-Revo from this afternoon.

mistercrash · 08.02.2010, 07:38 PM

I completely took apart the LST. cleaned and inspected every single part. I replaced whatever was worn and started reassembling it. Even though not much was worn and nothing broken on the drive train, I put new shafts all around and in the middle, new bearings at every corner. I have brand new diff parts to build two new diffs but I'm just missing the sun and planetary gears which haven't come in yet. Once they arrive, I can finish the overall and start using the LST again and see if I still have a rear diff problem.

JThiessen · 08.02.2010, 09:25 PM

I dont recall your early steps, but did you shim your arms to make sure they dont slide back and forth?

mistercrash · 08.06.2010, 12:46 PM

I received the diff internal gears yesterday, this morning I finished reassembling the truck and it's ready to go again for this weekend.

I made a new front skid that houses the Muggy steering bellcrank. I shortened the bellcrank an extra 2.5 mm in order to use a single front skid instead of a doubler one like I had before.

mistercrash · 08.08.2010, 08:33 PM

I have been beating the snot out of my LST for the last two days and other than a snapped steering upright (knuckle), everything is running great on 6S. After going over everything, I think the most important change I made is to the ESC's punch control. It was still at the default setting of 0%. It is now at 80%. Thanks for all your input.

mistercrash · 09:42 PM

It seems that my diff problems are gone. I am down to 70% on the ESC's punch control. But now I have a new problem and it's bumming me out. We were out playing for about 18 minutes when I had to go turn over my son's ERBE that was on its lid. When I got back to my LST, I hit the throttle and this loud sound came from it, like some terrible cogging. The truck didn't move much, I let off the throttle right away and noticed a small puff of smoke coming from the truck. I ran over to it, ripped off the body, disconnected the batteries.

The ESC looked fine and so did the lipos. I got close to snif around and the burnt smell came from the motor. Looks like I may have fried my Neu 1521 1Y.

It's the first time I fry anything, I'm not sure of what I should do. It looks like there's little grub screws around the edge of the can but I don't have anything that fits it. Not that I could do anything if I could open the motor but I would've liked to see inside if I can detect what burned. I took a pic of the end bell and some burnt wires can be seen in one of the holes, but I don't know if that is the damage or just from the soldering when manufactured. This was bought at Offshore Electrics and I can't find my proof of purchase..

lincpimp · 07.24.2010, 10:34 PM

Hmm, I have never had an issue with breaking the diff output gears, I run nova rc al cups, with the tin coated gears. Stock lst diff internals. Are you using the al cases for the diffs? I run the dull looking aftershock cases. I also run 30k diff fluid in the diffs...

mistercrash · 11:16 PM

Yes I run the aluminum diff cases, 10K in the rear and 30K in front. Here's the problems I had with XXL diffs. Snapped off drive cups twice, broke teeth on the little spider gears in the front diff once and two times in the rear if I remember correctly. Changed to Thunder Tiger S3 Buggy spider gears that I had lying around in the rear diff. Now it's not the TT spider gears that break, it's the output gears which are the original Losi ones. Looks like the TT spiders are too hard for the Losi output gears. My slipper slips like crazy, I can't even wheely. The LST XXL diffs were very tough in my E-Revo, but the LST weighs about 3 pounds more. The diffs don't seem to like that. I got a set of hardened internal diff gears from Hot Bodies coming in. I bought them even though I don't even know if they will fit. I think they will, at least I hope they do.