Traxxas 3.3 problems

[Got Nitro?]

I'd like to know how the Lodi carb works out.
I mentioned the traxxas engine exchange because lots of ppl don't know about it or have forgotten it. It seems like a realistic option for you and for @Got Nitro?

I looked at the exchange cost, and it's only $15 more to buy at my local lbs, pending on how my bearings sound I will probably just throw a piston and sleeve in this engine so my daughter can learn the how to's of nitro r/c. I'd rather teach her on this engine than a new o.s engine

 

[Certified Mike]

For the $15 I would support the local shop as well. Good call! Prob a good idea to keep the speed and power down some for a brand new driver as well. Nitro can Def be intimidating. I think maybe more so than electric even.

 

[DXtreme1]

Nitro can be definitely more intimidating than electric but some of the tech that goes with LiPo batteries and the new ESCs are intimidating as well. If overgeared and the brushless motors with the combination of the above electrical equipment can cause for your RC to go up in flames. The older electrics like NiMh and brushed motors were definitely more forgiving and safer for newbies.

 

[Got Nitro?]

I bought her a new stampede for Christmas to test the waters,getting back into this hobby is expensive,she fell in love with the stampede and I was shocked when o first drove the new affordable electric setups, but it's still not a nitro. It's a shame that both of my lhs aim themselves towards electric, one of my lhs doesn't even carry nitro and the one that does keeps a 2.5,3.3 and o.s plane engine in stock and that's it. Neither carry nitro models.

 

[DXtreme1]

A lot of people especially newbies to the hobby gravitate towards electric because it's more convenient to run. No tuning or anything and with the newer electrics with LiPos the run times are untouchable by Nitro. it's less messier no fuel spillage or exhaust residue to clean up. But I think the challenge in learning to tune a Nitro engine correctly and once accomplished is much more rewarding. Plus there's nothing like the sound of firing up that motor, running it, the sounds of the exhaust as it climbs through the rpm and when changing gears and the smell of Nitro is just a total different experience. You definitely sense a much deeper connection to it than electric. Almost like driving an automatic car vs a manual.

 

[Got Nitro?]

Update

I finally had a chance to put the engine back in the truck again, I shortened the fuel line by 4 inches, checked to make sure everything fits like it should. Primed the engine and it fired right up extremely rich, I leaned out quite a bit, got the idle set to where it idles. The engine still loads up at idle but that's way better than what it was. None of the fuel lines, tank have cracks or sealing problems that I found. Engine runs all the way through rev range rich. Next step is to figure out why the slipper clutch won't lock up,i tore it apart when the spur gear got shredded from having these crazy tuning problems. But at least the engine runs and seems to run OK.

 

[DXtreme1]

Eventually the ends of the fuel line will expand and may not seal properly. I always put a good length at both ends on all my fuel lines and will trim all the ends every 10 tank fill ups at the maximum to ensure the ends fit tight to prevent pressure leaks. On the pipe end I zip tie it since it's more proned to heat and will expand and shrink because of the temp changes so it's more proned to pressure leaks.

 

[DXtreme1]

If the slipper is for the 3.3 then it could be because the washers were installed incorrectly. The washers are concave and need to be installed like a clamshell. As far as tuning you may need to change plugs. It's summer time and you may need to use a hotter plug if you're using the standard medium plug. Just make sure that the motor is already up to temp before making any adjustments. Just a tip to extract a lil extra ooomph from the motor. If you have the Traxxas TMaxx aluminum pipe bore the stinger out to let the motor breathe better. I drilled mine and used a Dremel grinding tip to clean it up. I would also recommend going smaller on the clutchbell to gain a little on the bottom end. It wakes up the motor quite a bit. If you have the 22t CB maybe gear down to a 20t. You will lose a little on the top end but the engine will be more responsive on the throttle. I was checking out the RB Mods website and there was an option for their TRX 3.7(modified drag 3.5)to use the 11k slide carb found on the Os 18TM/OS 21TM motors instead of the Losi Carb. I have a spare OS 21TM but I have not confirmed if the carb does fit the TRX 3.3 without modification yet. I'll probably do that some time this week when I have the time.

 

[Got Nitro?]

I plan on pulling the slipper clutch apart tomorrow and fixing it. I noticed when I rotated the spur gear over it looks like its not on the shaft straight, and then I remembered that when I put it together I hadn't locked the tranny in place. So I'm assuming that it's just loose. I did check and I am running a standard plug, and living in so-cal the weather tends to be really hot. And I don't think my lhs carry's any plugs for different temp ranges. I am running the stock aluminum pipe that comes with the 3.3 Max's, about what percentage and or size did you still out your tip too? I'm pretty positive my clutch bell is stock. Once I get the truck more dialed in I'll have a better knowledge of what needs changed, I am however running pro line 40 series tires and they seem like more rotational mass than it really needs,not my first choice for tire, more adjusting tomorrow.

 

[DXtreme1]

Definitely fix the slipper before your next run since the slipper is a critical part of the drivetrain. It's your lifeline in preventing the primary gears from grenadine on your tranny and over revving the motor. As far as how much to drill out the stinger there are pretty good tutorials on YouTube about it. Here's a link to one

The one step that was not included on the video that I did to ensure smoother flow is to use my Dremel grinding tip to clean out the bore on the stinger and the pipe entry. You can also use the grinding tip to bore out the exhaust manifold which I did as well. Gearing down your CB will help getting you off the line and powering out of turns at this time I would also recommend getting new Clutch shoes or better yet upgrading to a 3 shoe aluminum clutch or a bi-directional clutch. Hot Racing makes both kinds and is an excellent upgrade or you can go all out and get a Buku Clutch(which I did) I would also recommend swapping out your steering servo with something that's faster and higher torque . I'm using a Spektrum S6230 servo with 311/oz-in/ .14 sec transit speed at 6v. If you feel like your steering is lazy and slow the servo swap would solve that issue. You can then use the old servo for your throttle/brake duty.

I plan on pulling the slipper clutch apart tomorrow and fixing it. I noticed when I rotated the spur gear over it looks like its not on the shaft straight, and then I remembered that when I put it together I hadn't locked the tranny in place. So I'm assuming that it's just loose. I did check and I am running a standard plug, and living in so-cal the weather tends to be really hot. And I don't think my lhs carry's any plugs for different temp ranges. I am running the stock aluminum pipe that comes with the 3.3 Max's, about what percentage and or size did you still out your tip too? I'm pretty positive my clutch bell is stock. Once I get the truck more dialed in I'll have a better knowledge of what needs changed, I am however running pro line 40 series tires and they seem like more rotational mass than it really needs,not my first choice for tire, more adjusting tomorrow.

 

[DXtreme1]

I can confirm that the the 11k Slide Carb for the OS21TM/18 OSTM motor does fit on the TRX 3.3 motor. This should be a good fix to the OEM carb that came with the TRX 3.3 motor.

 

[Got Nitro?]

View attachment 90982 View attachment 90981 I can confirm that the the 11k Slide Carb for the OS21TM/18 OSTM motor does fit on the TRX 3.3 motor. This should be a good fix to the OEM carb that came with the TRX 3.3 motor.

Update I tightened up the clutch and it keeps coming loose so I tightened it up a little more leaving what I thought was a pretty good adjustment.

However today I fire the truck up and it runs like crap, it doesn't hold idle, it jumps to a high idle, my pinch test is right at three seconds, if I adjust the idle screw it either runs to 1/3 or shuts itself off, I can't get the temps above 200,the truck is running rich but I can't lean it out without it either dieing or idling up, I've screwed with it, reset it but today it just won't run right, it wants to stick wide open and I'm not really sure why. It revs Al the way through the rev range, but it either dies when I come to a stop,or it idles up and takes off. It will not idle without the tires moving.

I ended my crap show with another stripped spur gear, Wich backed the center nut out enough the spur caught the throttle and held it wide open.

This truck absolutely hates me and I'm done messing with it.,I can't find an air leak anywhere,it has a brand new plug, new fuel and temp outside hasn't changed.

 

[DXtreme1]

It looks like you're not getting a good mesh between your spur and the clutchbell. Because of the tight space to mount the motor it's quite tricky to get a proper mesh. It pretty much has to be the right tension and has to be straight as possible. I really take my time getting the mesh perfectly. Until I get it silky smooth where the spur and CB spin without any tension and smoothly that's the only time I bolt all the screws down tightly then I check the mesh again. I've messed around with Nitro for a long time so I think that's why I got it down but to be honest the TMaxx is the hardest RC I know to get the proper mesh that I've worked with. The TRX 3.3 seems like a hit or miss. Maybe because it's considered a medium or a little above entry price range motor and it's manufactured in larger quantities compared t OS, Picco, Novarossi and the rest of the premium brands that manufacture in smaller quantities so it's understandable that there will be more motors with issues.

 

[Got Nitro?]

Agreed, yesterday it ran fat and fine, today it's erratic and runs wide open without the carb moving. I'm gonna pull the engine back out and run through the re sealing process again. It's has a flaw somewhere I just have to find it. I'm also going to pull the slipper apart and make sure I didn't get something outta place, getting the engine to mesh up is a pain. I've checked everything I can think of. I looked at the video you posted and I wonder if it's getting too much back pressure,wich is forcing fuel into the engine, it's extremely easy to over prime this engine, the tank lid seals so well that if you open and close it forces fuel into the carb quickly.

Just checked my slipper against Traxxas schematic and I have my washers in the wrong place but other than that it's correct.

Not to looks over the schematic to see if I missed anything during the carb rebuild.

 

[DXtreme1]

Installing the bored out stinger actually should tend to force you to lean out your carb settings more. My CVEC pipe requires me to lean out my carb settings by a lot compared to the original pipe and I had mines bored out. Are you still using the original CB? What spur are you using and what pitch. It's easy to overlook the mod pitch on both the spur and CB. The Revo runs a 1 mod pitch while the TMaxx runs .8 mod pitch and mismatching the mod pitch will definitely strip the spurs eventually even if you happen to somehat get what it seems to be a decent mesh. As far as your carb I would make sure you did not overtigthen the pinch bolt that adjust the angle on the inlet for the fuel line going into the HSN. I've done this before and it gave me an eratic tune since I was not getting proper fuel flow. Also check make sure there's no hairline cracks on the inlet.

Agreed, yesterday it ran fat and fine, today it's erratic and runs wide open without the carb moving. I'm gonna pull the engine back out and run through the re sealing process again. It's has a flaw somewhere I just have to find it. I'm also going to pull the slipper apart and make sure I didn't get something outta place, getting the engine to mesh up is a pain. I've checked everything I can think of. I looked at the video you posted and I wonder if it's getting too much back pressure,wich is forcing fuel into the engine, it's extremely easy to over prime this engine, the tank lid seals so well that if you open and close it forces fuel into the carb quickly.

Just checked my slipper against Traxxas schematic and I have my washers in the wrong place but other than that it's correct.

Not to looks over the schematic to see if I missed anything during the carb rebuild.

 

[Got Nitro?]

What's causing the spur gear to slip is it snapping wide open throttle while I'm In a turn. My 3.3 is junk, it's needs piston/sleeve and front bearings. I leaked tested it at temp and theirs a air leak at the front bearings so I'm junking it. I'll dig the truck out this winter hopefully and try it again budget willing.

 

[DXtreme1]

If budget permits I would recommend the OS 21TM. The Picco (realy hard to find now) I heard is really good but takes some mods to make it properly fit. I recommend the 21TM assuming you don't want to modify your 3.3 to accommodate a true big block(chassis, throttle/brake linkage and servo relocation, 1/8 scale diffs, steel tranny internal upgrade, steel CVDs all around). The OS upgrade is drop in and mild enough not to require a major upgrade on the parts I listed.

 

[Got Nitro?]

I've been thinking of going to a. 28, most of those parts you listed are worn. My front diffs already destroyed. And I want to go through my clutch and tranny making it better. I've been looking towards the novarossi engines. I personally like o. S but j want more power than the TM puts out

 

[DXtreme1]

I'm a big fan of Novarossi engines. I used their .12 motors on my NTC3 back in the days for racing and parking lot bashing. I'll be using their .21 off-road motors once I start putting together my TLR Losi 8ight 4.0 buggy build.

I've been thinking of going to a. 28, most of those parts you listed are worn. My front diffs already destroyed. And I want to go through my clutch and tranny making it better. I've been looking towards the novarossi engines. I personally like o. S but j want more power than the TM puts out

as far as the diff mod I would do the FLM Hybrid diff housing. You will just need to purchase and install 1/8 scale Spider Gears from a Hyper 7 or Kyosho 7.5 diffs.