sylv456

Thanks I'll check those small threads

tmk

@Thunder Trail:

...I think I grok most of the tuner-tips and upgrade parts for the 3.0 now, except possibly the 2.0 spring set retrofit; can the LOSB2904 parts be made to work on the GenII shocks to hold the springs?

Also, I saw the post on someone having center-diff issues - that's what mainly brought me here in the first place. I checked the stuff you noted (I've got the link for the washers saved along with the other things mentioned, so I can put an order in all-at-once), didn't find anything, but the diff still locks up solid with all 4 screws tightened. Is there anything else to check?

Thunder Trail

iTrader: (66)

Yes, LOSB2904 can be made to work. Lower spring cups fit, but front a arms must be shaved down for clearance of larger springs. The plastic upper spring collars need the threads removed and some material to shorten them for proper spring height. They just slide over stock 3.0 spring collar to center the larger springs. A little time with a dremel tool can make these parts fit the larger springs on the 3.0 shocks.
Look at post 738 for an example of what the A Arms need in order for the larger 2.0 tuning springs to fit properly.
TLR SCTE 3.0 Thread

As for the center diff being locked up, take it apart, clean everything and inspect all parts. Make sure you don't use the tiny shims on the cross shafts from the 1.0 or early 2.0 diff gear sets in the newer HD diff case. Also check the case gasket thickness. You can add a new gasket or double them up if you have gear bind inside the diff. Something is causing this and it's best to find the issue right away. You can buy an entire center diff assembly from ebay to eliminate all possible issues the easy way if you have the funds. Send pics of diff parts cleaned up and laid out if you want help with a solution.

tmk

...I think I got it - kind of a brute-force solution, but it seals up and operates without hanging up; just have to see how long it works. There were no shims for the spider gears in the kit, just the square blocks the crosspins ride in.
I reassembled it dry and without one of the seal washers to see how much clearance things actually had - with one washer out, it worked with all the screws tightened. Looking at the backs of the spider gears, I noticed they weren't flat like the backs of the sun gears - they kinda sunk inward a bit around the crosspin hole. There was a ridge just deep enough to catch a fingernail edge on all four. I don't remember if the other sets were like that, because they went together without a hitch...

I ran over to the hardware store and got a pack of emery sandpaper (the black metal-cutting cloth-back type), and surface-lapped the backs of the spider gears down until they were flat across the whole face - I figured that would give me about .002-3" more clearance per gear, and since the seal washer measured .011", it should let the tooth mesh out enough to stop it from locking up; I also gave the backs of the sun gears a run across the paper, and chased the outer edges of the teeth on them with a triangle file to make sure there weren't any burrs left from molding. Also papered the washers just enough to get the stamping burrs off the edges.

Threw everything in the jar, sprayed it all off, fished things out and blew them off dry, then reassembled the diff dry again; this time, it turned without any catching or lockup - it was just a tiny bit stiff, but I attributed that to not having greased things yet, and probably needing to let the surfaces I sanded run in a bit.

Tore it all back down, greased the outdrives, seals, washer, and back of the sun gears, set the spiders in and filled it with 7k, set the top half on and the spur gear, started and tightened 2 screws and checked function - no locking; put in the other two screws and checked again - no locking. Wiped off the overflow, sat here and twisted on it awhile by hand - still a bit tight, but no locking.

The motor and ESC showed up today (rx8gen3/pro4hd4300), and the batteries should be here Friday. Then we shall see how far the pieces fly...

Thunder Trail

iTrader: (66)

You did good. They need to wear in. Most of the time the gears are machined well and the diffs only feel rough for one or two lipos. Bench break in will identify any problems. Hold each wheel and run throttle up 1/4 and hold 5 seconds . To do the center diff, hold both rear and then both front to do the same. That will seat parts and is a good test to see if there are any problems.

That's a monster power combo. Must utilize some throttle control. It will be fast, but parts will only fly if you are crashing

tmk

...Are the aluminum rear hubs suggested?

I only ask because my race day ended before it even started today with a smashed rear hub in practice (cold-cocked by an idiot with an e-truggy going full-blast at the end of the front straight), and nobody had a replacement on hand...

Jgg12002

Thunder Trail

iTrader: (66)

The hubs are fine under normal driving. If you had aluminum hubs a more expensive part might have broken. If you plan to be on the track with rigs bigger than yours, I suggest you pull over and let them by. No good reason to run with them in practice and get run over. Just let them pass and then go burn a fast lap. This is a problem at many tracks.
Carpet setup will not be much different other than tires, sway bar and ride height. If there are other racers at the track find the fast guys and ask for advice. Most don't mind helping, but don't expect him to give up his perfected setup that he worked on for 2-3 years to get an edge on others. There are no real shortcuts for testing and experience, but tire selection and ride height are things some will share to get you started.

Jgg12002

tmk

Ah, for a perfect world where things like that actually =work=... When I said 'idiot', I wasn't being facetious - the only way this twit wouldn't have dropkicked me is if I'd been on the opposite side of the timbers around the perimeter of the track. Nearly all of them have this idea that they need to drive "five feet wide"...

I did a bit of researching, and I think I may have found something that will help: the Tenacity SCT rear hubs (LOS234020) are a direct-fit replacement for the standard rear hubs (LOSB2103), and have more beef around the hinge pin; where mine broke was right at the molding line along the bottom of the hinge pin hole. I'll have to trim one side of each hub flush to get the full-back setting, but that leaves an extra 2mm of material around the pin on the front. (stoopid fkin' forum apparently won't let me post attachments yet - grmblgrmblgrmbl)

...I think I may have also found a no-custom-work-necessary method of fitting the 2.0 springs to the 22 shocks, but the parts I was looking at weren't in stock yet and I needed these before this weekend. I'll play with that in a bit, and if it works I'll post up what I did. I think it'll actually work pretty slick.

Also: how to set front/rear gearbox lash? I got the aluminum bearing blocks for the rear, but I don't know what to set the lash at; 3 shims total takes out all the side-to-side play between the bearings - 3 on the left bottomed the mesh out, so I backed off to 2 left/1 right. Does that sound about right?

tvih

Remember that the Tenacity hubs may well be of weaker material, it is a lower-budget car after all. And frankly in the situation you described I don't think an additional 2mm of plastic here or there would've helped much anyway! The SCTE is a very sturdy car out of the box and I haven't done any durability upgrades on mine and haven't broken anything yet - but naturally it isn't indestructible.

tmk

...it's the same stuff - it cuts and grinds like the stock hubs. Where they cheaped out on the Tenacity is in metal parts - all the shock bodies are plastic, the camber/steering links are all molded, plastic chassis, camber blocks, inner arm mounts, etc. Even so, it's not all that much cheaper build-wise - it's the exact same drivetrain as the 3.0, with center dogbones and CVAs all around, same front hubs/carriers - it's essentially an RTR budget-version of the 3.0.

Thunder Trail

iTrader: (66)

Nothing perfect, but that's the goal

The 3.0 hub material was improved. They seem to hold bearings tighter over time for less slop. Best to buy spares. Most parts on the stock 3.0 are about as good as it gets. The aluminum hubs I have on my old 2.0 rig were hard to work with. Wheel bearings seem to fit too tight on my set. I have had some bad hits over the past few years on every version of the SCTE, never broke a stock hub. I did have some sloppy after a lot of races. Now that I said that I will break them all next time out

Hard to keep this short, but here is the info I think you need to know to set gear mesh properly:

Diff shims with metal inserts on the rear are a big help on maintaining ring and pinion alignment under hard throttle when gear mesh really matters. Every part, bearings, diff case and ring/pinion gear set will be slightly different spec when new or used. First, you need to install the diff without grease until you are satisfied with gear mesh and shims you want to use. The thing most overlooked is how the ring and pinion gear mesh changes when you install the gear box onto the chassis. Don't over tighten the bolts that hold the case half's together. Bolt the box to the chassis before you check gear mesh. Hold the pinion drive cup stationary and slight rock the dog bone cups back and forth. Turn the pinion drive cup a few teeth and test another section of gear teeth. You are looking for a slight feel of gap between the ring and pinion with no binding. This is something you can feel when there is no grease on the gears. To get the most accurate feel, once the gear box halves are together and mounted on the chassis, tap the drive cup on the opposite side of the ring gear. This will seat the bearing in the position it will likely end up in after a few runs push the ring gear out as far as shims and insert allow. That will be the most clearance between the ring and pinion. Too much and you will strip gear teeth or shorten their life. To tight and you will destroy pinion bearings faster than normal and bind up the driveline. You may have to take it apart a couple of times to get it right. When you are satisfied, grease the ring and pinion gears and do the final install. After a couple of lipos the ring and pinion should be smooth and easy to turn with minimum drag. That's about all you can do to make it close to perfect. It helps to have experience and after a couple of times it gets easy. Hope that helps.

tmk

Rojer Wilko. Raced it yesterday at the little track the local hobbyshop plowed in next to their parking lot - worked well, as long as there was some water in the track. Need to find some tires for bone-dry farm-dirt otherwise. Go again today at the track one town over. Same kind of thing, but notably bigger.

tvih

Finally opened the outdoor season here. "Bombed" with both my SC10 and the SCTE 3.0 pretty hard, but no breakages other than the SCTE body starting to fall apart again. Where the repairs held in indoor use, outdoors seems to be making short work of it once more Thinking of maybe ordering a JConcepts Illuzion Hi-Flow body as a spare before the first outdoor race that is in two weeks, won't be fun if the stock body irredeemably breaks just prior to or during the race!

EDIT: It does appear that I actually did lose a screw once more... I seem to keep losing hardware from this more often than I'd like. This time it was a steering post screw. And as usual for imperial screws it's hard to find suitable ones for a reasonable cost. As is I had to snag a non-critical one from the side rails. Should've gotten the Tekno to avoid this particular headache