REVO 2.5 will many upgrades and just as many questions.

[2revo1maxx]

This has been a long row to hoe, but I am closing in on it.

So far, I took a junked out 2.5 with a Picco 26 Max and installed:

A 3.3 Chassis, Brace and Half Shafts
GTR Ti Shocks
Traxxas CVDs
RPM True Track Rear set
RPM Front A arms and pivot caps
Aluminum Front Toe Links
Aluminum Front and Rear Push Rods
Center Differential
Rear Brake Kit
Water Proof Digital Throttle Servo
Waterproof Digital Steering servo, single
Motor Saver High Flow Air Filter
Hardened Clutch Bell
Hardened Spur Gear
Replaced any missing fasteners
Added a Traxxas Wing

Still waiting on new shock mounts, the truck had Integy mounts on it, they do not allow the roll bar kit to be installed. Also waiting on a THS Pipe.

I have begun to setup the truck for ride height. I am happy with the front end... green springs with pro 2 rockers. I may move down to stock springs, but this is a basher. I have silver springs in back. The rear ride height is where I want it, but it still bottoms out to fast for my liking. I do not want a heavier spring as it would change the ride height. Does anyone know the stock weight oil in GTR Ti Revo rear shocks? Is it 40 weight? If so, I'm am thinking on moving to 50 or 55 weight if I can find it.

I did paint my first body this weekend. It is a Proform Hard Drive. I found putting a mask on the hood with all the vent like stuff to be very difficult, even with a hairdryer to warm up the vinyl. Anyway it is painted, and since it is my fist body, I am not embarrassed in the slightest.


Been fun so far!

Yeah fun is where it's at. I believe the stock oil would be 30 wt. I use 40 wt it works quite well. Look up 'revo setup sheets' on google you can find the setup sheets that Steve Slayden (Traxxas driver) and many others have used on their revos over the years. It's a good tool if you don't have the manual because (for example) you have to set up the bump steer according to your caster and so on.

 

[Traijin]

I got the THS Pipe installed last night. Bending the support wire took some time and the springs that wrap around the crank case were a challenge but all in all it went well. I also removed a pair of integy shock mounts and replaced them with new stock mounts. This will allow me to install the sway bar kit if I choose to.

That completes the build up of the model for all intents and purposes. So, I fired up the motor last night just to see how it liked the pipe. The model is kept at room temperature, so the block was not cold when I tried to start it. I held my finger of the exhaust tip and the fuel primed very well. The glow plug was visually inspected and it become red hot in about two seconds. The problem is that the motor is very cold blooded. Hard to start to say the least. It will start, and a decently heavy run of smoke comes out of the stinger. I do not believe it is anywhere near a lean condition presently. The engine will only respond to about 10% throttle. Anything above that in it cuts out immediately. Not a lean condition hesitation, more like a flooded condition, although I did not notice any fuel dripping from the stinger. Due to the outside air temperature, I cannot tune with any certainty. But I have a suspicion of an air leak in the motor. As vacuum increased, more air was drawn though the leak... maybe. But like I said, the smoke from the stinger always looked healthy. I intend on pulling the motor and sealing it via the methods I saw in a post somewhere on this board. Am I on the right track? The motor was originally tuned by the previous owned for a dual exhaust pipe. For the life of me I cannot understand how a dual exhaust could provide any back pressure or compression. So anyway, the motor was tuned for a worthless exhaust setup. Any idea what the factory screw setting for a .26 Picco Maxx are? is it the same 4 turns out? Is the high idle screw to be flush as well? I ran the motor when I first got the model with the dual exhaust and it idled fine with current settings, now with this THS pipe, it was acting like it was a 10% to 15% throttle. An interesting puzzle.

 

[2revo1maxx]

I got the THS Pipe installed last night. Bending the support wire took some time and the springs that wrap around the crank case were a challenge but all in all it went well. I also removed a pair of integy shock mounts and replaced them with new stock mounts. This will allow me to install the sway bar kit if I choose to.

That completes the build up of the model for all intents and purposes. So, I fired up the motor last night just to see how it liked the pipe. The model is kept at room temperature, so the block was not cold when I tried to start it. I held my finger of the exhaust tip and the fuel primed very well. The glow plug was visually inspected and it become red hot in about two seconds. The problem is that the motor is very cold blooded. Hard to start to say the least. It will start, and a decently heavy run of smoke comes out of the stinger. I do not believe it is anywhere near a lean condition presently. The engine will only respond to about 10% throttle. Anything above that in it cuts out immediately. Not a lean condition hesitation, more like a flooded condition, although I did not notice any fuel dripping from the stinger. Due to the outside air temperature, I cannot tune with any certainty. But I have a suspicion of an air leak in the motor. As vacuum increased, more air was drawn though the leak... maybe. But like I said, the smoke from the stinger always looked healthy. I intend on pulling the motor and sealing it via the methods I saw in a post somewhere on this board. Am I on the right track? The motor was originally tuned by the previous owned for a dual exhaust pipe. For the life of me I cannot understand how a dual exhaust could provide any back pressure or compression. So anyway, the motor was tuned for a worthless exhaust setup. Any idea what the factory screw setting for a .26 Picco Maxx are? is it the same 4 turns out? Is the high idle screw to be flush as well? I ran the motor when I first got the model with the dual exhaust and it idled fine with current settings, now with this THS pipe, it was acting like it was a 10% to 15% throttle. An interesting puzzle.

Chances are it has ALOT more fuel pressure now, you'll have to lean it slowly til you find a happy place.

 

[Traijin]

Thats sounds like a very good point. I sealed the motor last night and in doing so removed the LSN and HSN. The LSN had little slivers of O ring in the threads so I cleaned that all up and re-greased the rings on both needles. I also found the factory setting for the Picco .26 Max on OFNA's website. They show 7.5 turns out. The needle was further out than that, so I can assume a rich condition. This evening the monkey snot should be cured and I'll test fire the motor again. Also replaced the glow plug with a McCoys plug. I intend on warming the block with a heat gun prior to ignition. I expect the motor to fire off quickly... if not, well I'll have to dig deeper. Long live dental picks... They still prove to be indispensable.

 

[Traijin]

Accidental Duplicate

 

[TGL]

Traijin -
Has the radio gear been ungraded or are you still stock Traxxas?
Do you have a failsafe?

 

[Traijin]

Traijin -
Has the radio gear been ungraded or are you still stock Traxxas?
Do you have a failsafe?

When I put in the center differential, I yanked the Optidrive. I have no intention of retaining the Traxxas AM Transmitter or receiver. I am currently looking at the Spektrum DX3S. It looks like that will take care of fail safe issues along with a host of other information it can provide. I only intend on firing the engine today, with the chassis supported and tires off the ground. I am not comfortable with actually operating the vehicle until the snow is melted and I have temperatures above 50 degrees. Otherwise true tuning seems like a waste of my time. I just want to know that the motor I have runs well, so when the weather breaks I can use it. I think the waiting may make me crazy though.

 

[2revo1maxx]

You sound like an experienced rc guy with discipline. I hate running in the cold. It's a rare occasion for me.

 

[Traijin]

Okay, pickuped up the DX3S, wow... that is a sweet radio. I have it installed and went though the binding process. Then it came time to try to fire the engine again. Like I previously stated, the LSN is set at 7.5 turns out and the HSN is set flush to the housing. The engine has been sealed with copper RTV. The model was at room temperature (65 degrees +/-) I fueled it and immediately took it to the garage to fire it. The garage is outside air temp (20 degrees or less) The glow plug was brand new and tested. The motor did fire after a lot of effort. The idle is still very high and the motor will not tolerate any throttle above idle, it cuts immediately. It is running so rich that unburned fuel is spraying from the stinger. I leaned it a bit. But I need to know, is it futile to even mess with this with that air temp? Can the idle be set so high that it loads up the motor immediately? It gets more complicated. I warmed up the block with a heat gun after I had it running for a bit and observed the fuel spitting from the stinger. After it was warm (not burn you hot) The glow plug light on the EZ start would not fully light. I pulled the Glowplug and fired the EZ start. The glow was feeble at best. On a car, hot start problems are indicative of an insufficient ground. The yellow lead from the EZ start harness is screwed onto the front right screw of the motor. Long story short, after the the block got warmed by the heat gun (I did not melt anything) It would not restart. Bad motor?

Thanks

 

[Metalhead Matt]

If it has decent compression, it'll run right. Sounds way rich and the idle's set too high. Use a hair dryer to warm it up. You might want to crack the glow plug loose if it has a lot of compression. Make sure you don't flood it. Replace the glow plug and try again. Use a separate glow ignitor if you have one. It really helps.

 

[TGL]

Yep, sounds rich and too high on idle...
What temp are you running at?

 

[Traijin]

Yeah, so I ended up turning in the LSN by 3+ turns. Runs like a demon now. Still a little cold blooded and does not like to start easy. I ended up buying an igniter and using that in place of the blue wire. I think I might research the EZ start system and see if I can by pass some of the electronics and hardwire the ports for the glow plug to constant hot. That way if I insert the EZ wand it will immediately start heating the plug, then I could wait a few seconds before cranking the motor.

I installed a DX3S, took some effort to get the failsafe to work correctly. In order for it to hold the failsafe brake setting, I had to bind the receiver and hold the full break until the binding loop was removed from the receiver. That is not really well described in the instructions.

Now I just have to wait for the weather to brake.

 

[Traijin]

I could not wait for the weather to brake. I took the truck out last night in a Target Parking lot and spun it up. Sounded good, made goos RPM. Shifted to second gear. So I started seeing what it can do. In the course of two tanks I Broke the rear support for the gas tank and broke the engine mount. I am impressed by the engine mount break. It sheared the outboard horizontal screw in two locations. The impact was directly against the EZ start motor. The EZ will not spin up anymore either. So there is the first damage! Suspension worked great and still looks good.

Too much fun.