I am not sure what to think of what you just said thererererere. Stop frequently to check temps and allow to cool if needed? I should be able to run this truck as I please for a whole lipo cycle and once it hits LVC, THEN I allow everything to cool before I put a fresh set of lipos in and keep going. With the outside temperature being what it was at the time and running non stop for 40 minutes, I expected the MMM to have the fan on and the lipos to be close or at 120 degrees. But I would have been happier if the motor showed 170 or 175, not 200. I'll try a larger pinion next time (gotta wait 'till they get here) and see if the motor temp goes down a bit. I hope it does.

Thanks Neil :smile:

I updated my MMM with new settings, it was at 10° timing so I went to 0° and brought down the braking from 40% to 30%. The motor temp went down a bit from 200 to 190. ESC was at 135 and lipos at 118. It's a little better but not quite enough. The weather was pretty much the same as the other day, very hot and humid and I was running the same lipos, bashing in the same spot and doing the same things with the truck which is run it fast and jump it high. I'm thinking a motor heat sink would help.

Anyone know where I can find a good heat sink for a 40 mm motor?

How in the world did a rock get in there, :mdr: and when I yanked it out, I noticed my first breakage of a suspension component.

http://i177.photobucket.com/albums/w...th_pebble2.jpg http://i177.photobucket.com/albums/w...front_arm1.jpg

This should fit:

8E heatsink

Thanks. Nice one, and I love that it's from Losi. I ordered one. I think it should help a lot.

I looked at that one for my build, but I don't have room for those fins with my rear bulkhead brace. So I've been working on a custom heatsink made from flat, square, cpu sinks!

edit: I want to know how the heck that rock got in there too.

I still don't have the answer to that one.

I received my CC BEC today. Nice little thing, I replaced the blue heat shrink with a stronger one that has glue in it and has a shrinking of 3 to 1. So now both ends are sealed around the wires and will keep dirt, dust and water out of it. Now to decide where I will put it on the truck. I thought of just sticking it to the MMM with double sided tape. Since I don't use a switch, I cut off the part of the MMM mount that houses the switch so there is a space on the MMM casing behind the caps that looks big enough to stick the BEC to.

The CC BEC is installed and it's working great. I updated it to 6 volts and I noticed the difference on the steering servo. Quite a bit faster and torquey. I like it and it was easy to install. I chose to stick it to the MMM because when I need to remove the ESC, the BEC just comes with it. So does the cap bank the way I have everything set up. :yes:

http://i177.photobucket.com/albums/w...EC/th_bec1.jpg http://i177.photobucket.com/albums/w...EC/th_bec2.jpg http://i177.photobucket.com/albums/w...EC/th_bec4.jpg http://i177.photobucket.com/albums/w...EC/th_bec3.jpg

Hello,
this kind of temp seems to be normal as the hot weather, the weight of the truck and the no-finned can. Try to open your body, airflows can change everything !

The motor gets plenty of air flow so what it needs is a means to dissipate the heat using that air flow. So I'll take it easy on the motor until my Losi heat sink arrives. I'm hoping it will bring the motor's temp down enough for me not to worry about it anymore. This motor won't last very long if I run it at 200 degrees all summer. If this large heat sink can drop the temp to 180, I'll be happy. Any lower and I'll be very very happy.

There are some that may not agree with this but I did a few things to seal the openings of my NEU motor. I know the holes in this 1521 motor can offer some airflow to help cool it but where I run the truck, I don't get airflow, I get dust flow. There was way to much dust and debris getting inside the motor and bearings. So I sealed the rear with Goop around the wires and a piece of flat Lexan stuck to the motor with servo tape. For the front, I made a disk out of a thin piece of aluminum with just a hole for the shaft and two holes for the screws. Air can still get in and out of the motor but it is restricted. This should make it very difficult for dust and debris to get inside the motor. This is something I am trying here, I need to see if it will change the temp of the motor while running this way.

http://i177.photobucket.com/albums/w...r_sealing1.jpg http://i177.photobucket.com/albums/w...r_sealing2.jpg http://i177.photobucket.com/albums/w...r_sealing3.jpg

Looks good Ray.
The aluminum duct work tape is the easiest way to block off them holes, Shoe-Goo around the wires does work very well but needs to dry a long while.

I use aluminum tape to do the same thing on mine. Not sure where it can be bought (I get it from work) - but that stuff works great in certain applications like this.

Aluminum tape!!! I have a roll of that somewhere! I should be slapped :slap: I never thought of using that, it's a great idea and would've looked better. I think I will remove the Lexan in the back and replace it with a piece of aluminum tape. Thanks for the idea.

I received the Losi motor heat sink today. It is very well made and has very large fins. It fits perfectly in my converted LST XXL and doesn't interfere with anything. What a difference this thing makes in motor temp. On the first test run on 4S, the motor ran at only 125 degrees. Tomorrow I will charge a couple sets of 3S and test running on 6S. Right now I am very pleased with this heat sink.

http://i177.photobucket.com/albums/w...heat_sink2.jpg http://i177.photobucket.com/albums/w...heat_sink1.jpg

I received my pinions from Mike last week. Thanks Mike. So I tried going up one tooth on the pinion. 54 spur and 24 pinion with Crime Fighters MT tires on MT wheels. I had my new heat sink on the motor and went out on 6S. Outside temp was 91 F with the sun shinning, with the humidex, it felt more like 105 F. It was really hot in my garage and the temp of the motor before starting was already at close to 100 degrees. I ran hard for 20 minutes, non stop. Climbing, jumping, speed runs on asphalt, grass and gravel, donuts. Had a few tumbles, broke a front suspension arm again and the doohicky in a rear CVD that you put the grub screw in to hold the pin.

Temps were:

Motor: 170
ESC: 140
Lipos: 145 :eyes:
front and rear diffs: 140
Center diff: 170 at the tranny casing. So the CD inside might have been close to 200.

The heat sink really helps but I think I need to go back to the 23 T pinion to bring the lipo temp down. The front tires were balloning like crazy so I will take out the CD as I suspect that when it gets too hot, too much power is wasted on the front wheels making the motor rev needlessly. This truck is so tough. My old E-Revo would have been in pieces if I subjected it to what I do to this XXL.

Hello, this kind of temp is the CD is normal, I hit the same in my truggy with a 1520/1Y. Are your wheels really balanced ? I had temp issue with non balanced wheels, which is always the case when you use monster truck wheels... Try maybe to do some air flow in the body, that helps a lot...
The hot batteries means that you are pumping of lot of amps, can you reming us your mph gearing setup, the weight of the truck and the type of batteries ? Maybe something is wrong in the transmission, and that would explain this temps.

This is what I had.

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1.8333333333333333
Other Ratio: 1
Spur Tooth Count: 54
Pinion Tooth Count: 24
Total Voltage: 22.2
Motor KV: 1577
Tire Diameter (inches): 5.65
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0.008
Spur/Pinion Ratio: 2.25 : 1
Total Ratio: 13.64423 : 1
Tire Circumference (inches): 17.75 inches (450.85 mm)
Rollout: 1.30:1
Total Motor Speed: 35009.4 RPM
Vehicle Speed: 43.13 mph (69.28 km/h)
Effective KV Value: 1577
KT constant: 0.86 oz-in/A

Now I opened the tranny and took the CD out and put back the stock Traxxas spool. I checked the gears and all bearings and everything is in top shape in there. My wheels are well balanced. I always balance my wheels the best I can. There's no binding anywhere on the drive train, everything spins very freely. The body had holes in the front grill and a big round hole in the windshield. Plenty of air flow there. I was running a pair of Zippy-H 3S 5000 mah 20C. The truck weighs very close to 14 pounds with 3S lipos in it.

While I was working on the truck, I reinstalled the stock XXL Losi wheels and tires so I changed my gearing. Now when I use Brian's top speed estimator, I never factor in tire ballooning. Maybe I should so I recalculated with .25'' tire ballooning this time and this is what I'll be trying.

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1.8333333333333333
Other Ratio: 1
Spur Tooth Count: 58
Pinion Tooth Count: 19
Total Voltage: 22.2
Motor KV: 1577
Tire Diameter (inches): 6.75
Tire Ballooning (inches): .25
Motor Current Draw: 0
Motor Coil Resistance: 0.008
Spur/Pinion Ratio: 3.05 : 1
Total Ratio: 18.51147 : 1
Tire Circumference (inches): 22.78 inches (578.52 mm)
Rollout: 1.23:1
Total Motor Speed: 35009.4 RPM
Vehicle Speed: 40.79 mph (65.52 km/h)
Effective KV Value: 1577
KT constant: 0.86 oz-in/A

Sounds Fairly good then except the lipos temp. Maybe 5000mah 20C don´t quite cut it?

"My old E-Revo would have been in pieces if I subjected it to what I do to this XXL."

So you are saying that the Lst is tougher then huh HUH!? :whip: :party:

I really like this build now Mc, you are truley a real enthusiast ( or how it´s spelled :oops: )

Ok
The batteries are too weak :(
Here in France we experienced very bad things with 100A discharge (5000, 20C) zippy lipo, even on light buggy, so in heavy Monster truck like yours ... Zippy batteries are often overestimated in their discharge capability, that's why you have this kind of temp in yours. The batteries will start to take volume in the time :( A good temp for batteries is 120 MAX !
Keep us posted if the setup without CD heat less !

Today is another extremely hot day in this heat wave we're having up here in the Great Toronto Area. So I took out the LST again in the same spot and let it rip on 6S. I over did it again as I blew the front diff after 5 minutes but I kept on going despite the loud clicking sound and at the 22 minute mark, I broke a front shock shaft. Good news is, the temps were great even though it is 40 degrees outside with the humidex.

Motor: 162
ESC: 134
Lipos: 109
Tranny case: 106
Front diff: 162
Rear diff: 141

So lesson learned here, when using the Top Speed Estimator, it is important to factor in the tire ballooning because since I didn't do it before, :whip: I was geared to low every time.

My truck is resting right now until I get the new TiNi shock shafts and a couple more parts in the mail to fix it. On the shock with the snapped shock shaft, I also noticed that the shock cartridge had started to come out of the shock body. So I searched on the LST forums for a fix and I came up with the idea of straps to limit suspension droop. I used zip ties that are secured to the upper arms and sandwiched between the shock towers and the CF plates I made to reinforce them. I'll be trying those out when the truck is fixed.

Compressed
http://i177.photobucket.com/albums/w...usp_strap2.jpg

Resting
http://i177.photobucket.com/albums/w...usp_strap1.jpg

When the suspension is extended, the straps let the arms drop almost fully, just shy of full extension to releave the stress on the shocks.

So I have a snapped shock shaft and a bent one. While I'm waiting for the new shafts to arrive and start playing with my truck again, I searched the web to find stronger shock shafts. I couldn't find any. I'm thinking that 5 mm shock shafts would be stronger then the original 4 mm shock shafts. Problems would be, where to find them and how to make them work in the shock cartridges.

Is there any manufacturer that makes 5 mm shock shafts and cartridges? If you know of any, please tell me.

In the meantime, I started looking at the stuff I have in the garage to try to make my own. My E-Revo's pushrods are 5 mm in diameter and are about the right length. Just a little too long. They have M4 threads on each end.

http://i177.photobucket.com/albums/w...ock_shaft1.jpg

So I grinded one end to make it short enough to match the LST shock shaft. The center hole of the shock piston would have to be drilled to 4 mm and a 4 mm washer with a 4 mm lock nut would be used to secure the piston to the shaft. Then to shorten the opposite end to match the length and put some M5 X 8 threads on the shaft.

http://i177.photobucket.com/albums/w...ock_shaft2.jpg

With the shock piston drilled to 4 mm and the shock ball end drilled to 4.2 mm, this is what it looks like assembled, with the stock assembly next to it for comparison.

http://i177.photobucket.com/albums/w...ock_shaft3.jpg

The shock cartridge has to be disassembled to enlarge the center holes of the cartridge and the snap cap to 4 mm. The spacer between the two O rings inside the cartridge either has to be drilled or a new spacer has to be found or fabricated. I had a spacer with a 4 mm hole in the middle but it didn't have the right length so I cut it to match the length of the stock one as close as possible.

http://i177.photobucket.com/albums/w...ock_shaft4.jpg

I was able to squeeze the new 5 mm shaft in the cartridge using the stock O rings but it is too tight so a new set of O rings with a 5 mm ID and 2 mm cross section (9 mm OD) would be needed. I could get durable Viton O rings for cheap from this guy on ebay.

http://cgi.ebay.com/10-x-Viton-o-rin...item4145e04d6e

So what do you think? I made one shaft to see if it could be done without to much trouble. Would this be something that would benefit the LST?

I just happened to come across these:

http://cgi.ebay.com/Losi-LST-Shock-s...item2eae749e8d

4.93mm diameter

quote: "These are replacement shock shafts for the Hot Racing Reservoir Shock Shocks that fit the Team Losi LST ( lst255r06 lst255r08 )."

Brian I saw those and even though they look really nice, they are to short for the LST2 shocks I'm using. IMO, the only way to make them work properly with the LST shock cartridges is to do exactly what I plan to do which is to open the cartridge, enlarge the holes for the shaft and replace the O rings with ones with a thinner cross or thickness. Unless the Hot racing reservoir shocks use a cartridge that fit the LST2 shock body. I'm not sure. Maybe they could work but I wouldn't get the full extension that I have with the stock length of the shock shafts, it is something like 87 mm long if I remember correctly. Thanks for searching I appreciate it.

On an another note, I gave up on my E-Revo to go with the LST because I find it is tougher and easier to work on. But there are things on the E-Revo that I really liked. The tranny for one which I installed on the LST but also the Traxxas VDPs (Variable Damping Pistons) in the shocks. So I am going to try it on the LST with these little valves I made out of a piece of thin polycarbonate from some packaging that was lying around in the recycling bin. I know Hot racing makes pistons with tapered holes which are supposed to have the same effect, I'm just trying to do it on the cheap.
The valves block 10 of the 24 holes of the piston on compression which should give better, stronger damping, and the valves bend slightly to let the oil pass through all 24 holes of the piston on the rebound.

http://i177.photobucket.com/albums/w.../th_valve1.jpg http://i177.photobucket.com/albums/w.../th_valve2.jpg

I made a second 5 mm shock shaft and ordered the Viton O rings I linked before. When all the parts get here, I can finally try out those shafts on the front end with the VDPs front and rear.

Yeah - I couldn't remember the length of the LST shock shafts - I guess those are closer to the muggy shock length.

Anyways - I'm interested to see how you like your VDP setup - I'm pretty happy with the rc-raven springs on my big truck - but I could definitely see this helping - I have some .030 lexan I might try out.

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 !

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.

.030 will be too thick and too stiff. The valves won't bend up to let the oil flow through. The ones I made are .006. The thinner the better actually but it still has to be just stiff enough to hold it's flat shape when resting and flexible enough to bend slightly to let the oil flow.

I had these Proline 40 series Mashers mounted on Axial 8 spoke over sized chrome wheels. The chrome was flaking off and it just looked ugly. I dipped the wheels and tires in Acetone for 36 hours and ended up with very clean wheels and tires but it ruined the foam insert. I took the chrome off the wheels with Easy-Off oven cleaner and then dyed them with black Ryt dye. I purchased Racers Edge two stage 40 series foam inserts and put an extra layer of foam around the middle part. This over stuffs the Proline Mashers, making them firmer and gives a nice crown that I like. I like the 40 series Mashers on the LST because I think they are the perfect size for the truck. The same width as the Losi 420 series ATX but a tad smaller on the diameter.

http://i177.photobucket.com/albums/w...her_rulux3.jpg http://i177.photobucket.com/albums/w...her_rulux2.jpg http://i177.photobucket.com/albums/w...her_rulux1.jpg

You're probably right - i have some thinner lexan I can try.

Has anyone ever thought of getting rid of the E clips on the LST's suspension? I did some web searching and it looks like the 4 mm hinge pins with E clips could be replaced with M4 X 0.7 X 55 mm 12.9 grade socket head cap screws. These screws don't have threads all the way. only at the end, leaving a long shoulder before the screw head (not sure but it looks like around 40 mm long) that could act as the hinge pin. Put an M4 washer on the screw, slide the screw in, put a second washer and a lock nut and cut the excess threads with a dremel. No more E clips. I also thought about using the shock shafts but the screws would be easier. I know there's other Losi RCs that use threaded outer hinge pins but I'm not sure of their dimensions and I won't pay 5 bucks plus shipping just for two.

Here's a link to the screw I'm thinking about.
http://www.fastenal.com/web/products...5PF0000&ucst=t

The image in the link is not representative of the real screw which does not have threads all the way up to the head. I found a CAD drawing of the 60 mm and 50 mm screws but I couldn't find a drawing of the 55 mm screw. The 60 mm screw has a shoulder of 46 mm, the 50 mm screw has a shoulder of 36 mm. A little more than 38 mm is needed so the 55 mm screw with an estimated shoulder of 40/41 mm would be perfect.

JAILBIRD found these http://www.teamstrc.com/ebproductdet...mainid=3&id=68
You might get away with sckt hd cap screws if you are still running all plastic parts there, but the finish on them is not meant to be used as a bearing surface. Thread length on them should be around 14mm - so your guess of 40mm was close. Probably function ok though. Use a nylock nut.

Someone on the LST forums gave me the link to the ST Racing threaded hinge pins also. Like I said to him, $20 plus shipping for 8 bugs me a bit. They look good though but for $0.65 for a screw and the Nylock nut, I can have the same thing, maybe better for so much less. All it needs is a little effort on my part to make the surface of the shoulder smooth. I'll just chuck the screw in the drill press on high speed and use fine sand paper to smooth out the shoulder. It'll work very well I'm sure of it.

Tightwad!!! :intello:

Tightwad? What does that mean. Language barrier I'm French remember...:intello: If it means that I'm a cheap bastard then you would be right :lol:

Yeah, we'll just settle on cheap bastard!!!

I couldn't wait for the 5 ID X 2 mm cross O rings to come in so I found O rings at the hardware store that had imperial measurements that were close enough and reassembled the front shocks with the 5 mm shafts I made and the valves for the shock pistons. I also got some M4 screws to replace the hinge pins. I went with the 60 mm long ones and the shoulder was just right. I just had to cut the excess threads since the shoulders were so smooth I didn't feel the need to polish them. only the front suspension is done for now. I bashed it on 6S and it all worked very well. The 5 mm shafts held up but more testing needs to be done. The wrong sized O rings didn't leak but I suspect they might because they didn't fit as tight as they should around the shafts. The shock straps worked great, more testing needed on those two. The hinge screws worked awesome and let the suspension move very freely. The piston valves really seem to give more damping on hard landings. I noticed a lot less bottoming out. The over stuffed Proline Mashers are excellent for bashing, they give good grip on many surfaces and the over stuffing firms them up quite nicely giving a lot of support for this heavy truck. I'm very pleased.

A little while ago, the pinion and internal gears stripped in my rear diff. I repaired it thinking it was just what happens when you bash too hard. A couple days later, I blow the internal gears of my front diff and a pinion in the rear diff. I thought I was just unlucky. Yesterday, the internal gears of the front and rear diffs blew. This is a problem. I can explain pinions stripping if I didn't shim correctly but internal gears, there's not much I can do in there. I use the Losi HD diff cases so I'm baffled. What can cause the innerds of my diffs to strip so often?

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 !

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