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Old 09-20-2017, 12:30 PM   #1231
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What tires are you running? With stock tires in my experience the transmission is flawless. If you start messing with tire sizes and weights, you invariably run into issues with the shifting… Especially if you are running a high powered engine. Basically all nitro monster trucks that I've ever heard of had shift/tranny issues if you go to big power engines.

And LST's are especially sensitive to tire changes in my experience....
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Old 09-20-2017, 05:15 PM   #1232
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At one point I also ran a modded Picco P3. Had the 4 shoe clutch set up as well. I can honestly say that I don't even remember noticing the shift. It must have been pretty fast though..like almost as soon as I punched the throttle. There were never any issues with performance falling off, so I never paid it much mind. Was definitely a torque monster, although I could never get the xxl to wheely on demand with the stock wheels and tires. I made a grainy vid with a laptop of the set up about 5 or 6 years ago. If I can find it I'll try to link it up. Just some food for thought...
I'm running bone stock drivetrain and tires on the shorter LST2 platform and both the Picco and Novarossi will wheelie with ease. The shift is pretty fast when it happens, but it's happening very soon after takeoff - I want it shifting about 3/4 up the rev band so the engine isn't lugged so hard when it hits second. I have the Picco timed close to what an on-road engine would be (a bit hotter than the FTT version - and as such I don't want it lugged down. I want it rippin the revs. It will wheelie for 50-100 feet or more from a dead stop; the Nova isn't as aggressively timed, so it has a bit better bottom end. It will wheelie for probably 100-150 feet or more. It's an incredibly strong engine, but the Picco is no slouch either.

I may swap out the slipper pads, steels, and hardware and see if that cures the trouble. I'll try to get a video of what's going on if I get the time.
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Old 09-20-2017, 05:20 PM   #1233
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Originally Posted by Herrsavage View Post
What tires are you running? With stock tires in my experience the transmission is flawless. If you start messing with tire sizes and weights, you invariably run into issues with the shifting… Especially if you are running a high powered engine. Basically all nitro monster trucks that I've ever heard of had shift/tranny issues if you go to big power engines.

And LST's are especially sensitive to tire changes in my experience....
Stock ATX tires on XXL 40-series wheels. Everything is stock in the drivetrain; except the transmissions are Forward only converted. As I said in my last post, I'm going to change the slipper parts and test it. If it doesn't behave, then I'll do some other work to it - perhaps stronger springs in the clutch shoes may be the answer. If the screws are too tight, it's probably not engaging the 2spd bell.

The trucks drove fine with the LST header and whatever pipe I put on it, but the engines ran way too hot on the long header. Maybe stock engines would tolerate the long header better and not cause problems. I didn't want stock anymore. My Picco truck has run 44.5mph on stock gears and bald ATX tires (40-series). I haven't tested the Novarossi truck yet. For comparison, my SH .28 P6 (same as early big red) only managed 38.1mph.
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Old 09-20-2017, 06:17 PM   #1234
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I think I posted these vida before, but I'll post them again anyway.

A rich running Picco P3 .28 - https://youtu.be/TUjuG9zsgYA
Novarossi Legend 28-8RT - https://youtu.be/XbeJWFzDcVA

The Nova 2spd shifts way quick - if you listen carefully, you can hear how quick it shifts. The Picco truck behaves a little better, but they both shift too soon despite the clutch shoes being set *just* loose enough to actually shift.
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Old 09-22-2017, 02:29 PM   #1235
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I think I posted these vida before, but I'll post them again anyway.

A rich running Picco P3 .28 - https://youtu.be/TUjuG9zsgYA
Novarossi Legend 28-8RT - https://youtu.be/XbeJWFzDcVA

The Nova 2spd shifts way quick - if you listen carefully, you can hear how quick it shifts. The Picco truck behaves a little better, but they both shift too soon despite the clutch shoes being set *just* loose enough to actually shift.
Looks like both trucks are ripping it up pretty good to me. You're definitely not having problems with the 2 speed slipping IMO pulling those wheelies. Think you might be on the right track finding a heavier spring and/ or somehow modding the clutch on the 2 speed if you want to better tune the shift point. Nice work on those mills.
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Old 09-22-2017, 04:44 PM   #1236
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Looks like both trucks are ripping it up pretty good to me. You're definitely not having problems with the 2 speed slipping IMO pulling those wheelies. Think you might be on the right track finding a heavier spring and/ or somehow modding the clutch on the 2 speed if you want to better tune the shift point. Nice work on those mills.
Thanks for the kudos. I had a lot of help from a friend (Thanks D!) pointing me in the right direction for the modifications. Overall, they turned out pretty good and run damn hard. I think I'm gonna get my hands on another Nova 9886 pipe for the Picco though - I like the sound a little better. Probably won't do much for power production, but it certainly wont hurt.

I'll pull the springs out of a spare set of 2spd shoes and see if I can find some new springs with a little more tension and see how that works. Beyond that, these trucks rip pretty good.. I just want the shift point closer to peak power so it pulls a little harder after the shift.
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Old 10-12-2017, 05:17 AM   #1237
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I'm finally going to experiment with some different 2spd clutch springs. I found these 5/32" OD springs at a local hardware store. They are about .015" larger in OD than the stock springs, but the wire thickness is about 30% thicker and a fair bit firmer and will fit the existing holes in the shoes. Any larger of OD and they wouldn't fit without drilling the holes larger.

So I'm going to cut the long springs down into 2 sets of springs - a longer set and a shorter set and basically setup 2 clutches that I can mess with in the truck. I think the stronger spring will require less tension/preload, so hopefully it will give a firmer shift in a more controlled manner.

One thing I think Losi goofed up - making the stock springs a coil or two too long and not firm enough. If you setup your clutch the way they outline in the manual, you're sure to bind the spring and distort it like the spring on the right. I've setup a half dozen new 2spd clutches and all but one got distorted despite my absolutely best efforts not to. The last one I did I didn't setup the same way but rather set the screws to the same depth (shifting early) and adjust deeper (later) rather than bottoming the screw/spring first and then backing it off.
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Last edited by SlowLST2; 10-12-2017 at 05:54 AM. Reason: Clarified wording
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Old 10-12-2017, 09:25 AM   #1238
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I don’t totally follow you, as I never experimented much. In my experience though, the LST 2-Speed is absolutely rock solid reliable - as long as you don’t change tire size etc too much.

Vastly better than Savage trannies for ex. My trannies lasted years - til I put in the LRP ZR.30X anyway. They don’t seem to like excessive power either I guess. But with stock size tires and say an LRP 28, in my experience the trannies last forever... And the shift point doesn’t wander (like on Savages..) They are sensitive to experimentation in tire size and to bigger engine power I think..
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Old 10-12-2017, 02:53 PM   #1239
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I don’t totally follow you, as I never experimented much. In my experience though, the LST 2-Speed is absolutely rock solid reliable - as long as you don’t change tire size etc too much.

Vastly better than Savage trannies for ex. My trannies lasted years - til I put in the LRP ZR.30X anyway. They don’t seem to like excessive power either I guess. But with stock size tires and say an LRP 28, in my experience the trannies last forever... And the shift point doesn’t wander (like on Savages..) They are sensitive to experimentation in tire size and to bigger engine power I think..
Follow this - the shift point happens too soon regardless of the clutch setting in the 2spd except if I get too tight, it won't shift at all. Keep in mind I'm not running stock engines. With stock RTR engines, it works and shifts fine. With these stronger engines, it seems that perhaps the torque or some other factor is causing the 2spd to shift way early - as in it shifts at around 8-10mph where it should be shifting closer to 25mph or so. So my idea is to stiffen the springs a little bit so that the clutch holds first gear longer before it shifts. I'm basically adding a little more stall to the 2spd clutch. If you go back and read my last several posts where I discuss this issue, it should make more sense to you.
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Old 10-12-2017, 11:39 PM   #1240
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Got it.. I guess stronger springs would make sense, at least theoretically. Over many years in various MT forums though, I saw an awful lot of guys simply go to a single speed conversion with big power engines… I personally would rather have a medium power engine, but keep the two speed…

Good luck with the springs though. Actually, as things stand now, my current engine blowing up transmissions too… I think on my case it's more the tranny..
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Old 10-13-2017, 01:38 AM   #1241
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Got it.. I guess stronger springs would make sense, at least theoretically. Over many years in various MT forums though, I saw an awful lot of guys simply go to a single speed conversion with big power engines… I personally would rather have a medium power engine, but keep the two speed…

Good luck with the springs though. Actually, as things stand now, my current engine blowing up transmissions too… I think on my case it's more the tranny..
I just want to make the trucks behave now like they did with RTR engines - shift where the engine is at peak torque. On the new engines, this is several thousand rpm higher (or more). Shifting too soon just lugs the engine and with high timing, it's hard on them. I basically have one timed right in step with an on-road engine and the other one is a little bit milder. They need rpm.

In the case of your trans - are yours fwd/rev and high/low still or are they FOC? I haven't blown my trannies up - just broke an output gear pin once or twice. Otherwise I'm running the original hardware inside and outside from the beginning. I have replaced the bearings a few times though.
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Old 10-13-2017, 02:18 PM   #1242
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Here are the springs I made up to test out in my LST2 trucks. One set of springs is the same length as the stock springs and the other is a coil longer roughly. The preload is a fair bit higher than the stock springs, so they likely will require the screws to be set further out. I believe the OD is 5/32" and wire diameter is .032" compared to the stock springs which I believe is .023".
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Old 10-14-2017, 04:38 AM   #1243
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Besides the springs the other way to adjust the engagement of the 2nd gear clutch is the weight of the clutch shoes themselves. Lighter clutch shoes = later engagement with the same springs. Of course the only way to make the clutch shoes lighter is to remove material. This would require drilling holes in them or cutting grooves in the sides. And there's no easy way to add weight back.

I think experimenting with springs is the logical first choice since you're not potentially ruining any parts. Modifying clutch shoes definitely has the potential to ruin them. Unfortunately without a custom made testing device there isn't any way to compare springs without running them on the truck. You can measure wire thickness and count coils but you don't get force numbers. Clutch shoes you can weigh for a concrete number and quantify by running on the truck. And once you have 3 different clutch shoe weights you should be able to spot a trend. Although if you only vary one aspect of the spring (vary wire thickness but have the same material and coil count on all springs) you should be able to spot a trend here too.

I only bring this up because on most centrifugal tuning, changing the weight is required in addition to the springs. Plus this just got my brain thinking way too much so early in the morning.
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Old 10-14-2017, 05:15 AM   #1244
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Besides the springs the other way to adjust the engagement of the 2nd gear clutch is the weight of the clutch shoes themselves. Lighter clutch shoes = later engagement with the same springs. Of course the only way to make the clutch shoes lighter is to remove material. This would require drilling holes in them or cutting grooves in the sides. And there's no easy way to add weight back.

I think experimenting with springs is the logical first choice since you're not potentially ruining any parts. Modifying clutch shoes definitely has the potential to ruin them. Unfortunately without a custom made testing device there isn't any way to compare springs without running them on the truck. You can measure wire thickness and count coils but you don't get force numbers. Clutch shoes you can weigh for a concrete number and quantify by running on the truck. And once you have 3 different clutch shoe weights you should be able to spot a trend. Although if you only vary one aspect of the spring (vary wire thickness but have the same material and coil count on all springs) you should be able to spot a trend here too.

I only bring this up because on most centrifugal tuning, changing the weight is required in addition to the springs. Plus this just got my brain thinking way too much so early in the morning.
Yeah, it's too early to blow my mind. I haven't had a drop of coffee yet.

After I test the spring mod, I'll mess with weight of the shoes. I don't think it will be necessary though, but who knows. I just want the damn thing to shift at just short of peak rpm a bit so I get full rpm from both gears. I am doing a personal all-out top speed challenge, and as such I'm gearing up to see how fast an LST truck can go with drop-in parts. The consequence to a super powerful engine is I think it overpowers the 2spd and causes the hub to engage right away. The Novarossi is horrible about doing it, where the Picco truck behaves a bit better. BUT the Picco is basically setup with on-road timing profiles, so she doesn't have the brute force down low like the Nova that is more in-between on and off road type engine profiles. At least that's how I view it.
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Old 10-18-2017, 04:32 AM   #1245
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I tried out my modified 2spd clutch with the larger springs. I used the set of springs cut to the same length as the stock springs to start with - wouldn't shift at all. Backed the screws out to the edge of the clutch shoes, no shift. Removed springs and cut one coil off, and readjusted screws to find it worked exactly as I wanted it to. I may fine tune it a tiny bit, but this video shows how it shifts now which is how it behaved with the base engines that were in the trucks. (Mach 427 and SH .28P6).

This truck has 5 quarts of fuel through it, still on the original glow plug. It's a nice running engine. https://youtu.be/4t7fUpwSWQA
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