New picco .28 monster build!

[joshman1204]

New era makes one but it ties to the front shock mount instead of the chassis like yours. Also the new era bar does not allow the use of the motorsaver filter you are limited to the stock filter with their bar.

Seriously if you are intersted in making me one PM me the price. I fully understand if it isnt worth your time to make a one off piece like this and that is totally fine as well.

 

[TK5310]

Yeah, that's pretty much it, I'd have to get around $250 for it to cover shop time & materials - I'd feel like a pure bastard charging that much for a little roll bar!

Not to mention I have no idea if it'd fit with other bodies, I made it to fit with the crowd pleazer body but haven't tried it with anything else.

That was also the last bit of 1/2" cromo tube I had left & I gotta buy it in 5m lengths.

Just use stainless or mild steel tube, bend it up yourself (oxy torch makes it easy, but you can bend mild steel without one if need be) & take it somewhere to be welded.

 

[joshman1204]

Totally understand!

Now we just need some video of that thing tearing some stuff up.

 

[TK5310]

Been meaning to get some vid, but every time I take a camera with me I bust something before I remember to use it!

Should be pretty much sorted now tho, the RR slipper conversion just showed up as well, so that's the last piece of the puzzle for a bulletproof driveline.

Was getting pretty fed up with feeding it trans gears, diff's, slipper pads etc every time I took it out.
It would seem if you plan to stick a BB in a revo & use it on high traction surfaces then you'd better plan to replace everything in the driveline with metal stuff!

 

[joshman1204]

Been meaning to get some vid, but every time I take a camera with me I bust something before I remember to use it!

Should be pretty much sorted now tho, the RR slipper conversion just showed up as well, so that's the last piece of the puzzle for a bulletproof driveline.

Was getting pretty fed up with feeding it trans gears, diff's, slipper pads etc every time I took it out.
It would seem if you plan to stick a BB in a revo & use it on high traction surfaces then you'd better plan to replace everything in the driveline with metal stuff!

Do you think upgrading the slipper sooner could have save some of the driveline?

 

[TK5310]

Nope, woulda just killed it quicker!

Slipper was ok untill the motor loosened up & started making real power, now I have to lock it up hard or it just shreds the pads, last time out I killed 2x sets of pads in 30 minutes.

 

[TK5310]

Got the new clutch sorted, fitted up the RR slipper etc.

Gone from 17/40 gearing with a close ratio gear set to 17/38 gearing with a wide ratio gear set.
Final drive has gone from 16.75:1 to 13.43:1, that'll give a 25% increase in top speed (I have no doubt the picco will pull the gearing to peak power rpm), I doubt acceleration will be affected at all - as it was I couldn't give it full throttle in 1st gear anyway, now I'll be able to give it a little more throttle.
With any luck the taller final drive will stop it wheelstanding on the 1-2 gearchange & when it hits bumps in top gear.
Gets interesting when you're going flat out in top & a bump causes it to wheelstand at 40+mph.

 

[TK5310]

Shakedown run this morning to check all is functioning as it should after the last round on mods.
Clutch is great, motor running sweet, heaps of grunt & just stupid fast with the new gearing in it.

But sheared the main shaft in the trans - probably my fault, running on concrete with big joe tyres, heaps of traction from the big soft tyres & maybe a little tight on the slipper:

Don't have a spare with me, I'll have to fix it tonight & loosen off that slipper a little so there is some give in the driveline.

Never heard of this happening tho, with a RR full metal gear set the trannys are supposed to be indestructable!

 

[Snook Man]

Nothing is indestructable...
I've broken every shaft there is to break in a transmission many times.
(I make my own shafts now).

 

[TK5310]

Yeah, turned out I didn't have a spare, so I made one, wasn't thinking & made it out of mild steel - the 1st gear 1 way bearing chewed it up, killed the shaft, the 1 way, the dog clutch & the bearing in the back of #2 gear.
Bugger!
The RR gears are pretty tough tho, the destroyed bearing scattered rollers through the trans, the RR gears just chewed up the rollers with almost no damage, got a right mess to clean up inside there!

The only things in the entire driveline I havent broken yet are the 1/2 shafts - but they were getting real loose on the joints (metal CV's now), the gearbox input & output shafts & 2nd gear.
I even sheared a wheel hub drive pin.

Locals want $56 for a bloody shaft, I can get a whole gearbox on ebay for that money, but it'd take up to 3 weeks to get here.

What did you make yours out of?
I could always make another from mild steel & case harden the area for the 1 way - but I'm not sure I could get it hard enough just doing the normal heat to cherry red & quench in oil hardening.
Using tool steel etc becomes a problem for drilling the holes, I can turn it no probs with carbide tooling, but drillng the holes is a real issue.

I'm going to take the big joes off the rims & replace them with some GRP's I have - less traction = less breakages & less traction rollovers.

 

[Snook Man]

I make them out of mild cold rolled steel and then send them off to be hardened/tempered and treated with black oxide coating.

 

[TK5310]

Well, I ain't paying almost $60 for a bloody shaft, I'll make another & case harden it, with any luck it'll last until a new one off ebay gets here.

If I just case harden the 1 way bearing area then it won't be as brittle through the areas where the holes are, so with any luck it won't snap & the case hardening will last.

Gotta find a new 1 way tho, may have a spare, will have to have a scratch in the junk box.

 

[TK5310]

So, new shaft, new 1 way etc.

Out last night giving it hell - sheared the screws that hold the crownwheel to the alloy diff cups on both diffs
Borrowed an Erevo diff & a spooled diff to keep playing, sheared a drive pin in a steel axle, replaced that.

Thing is balistic, got a wheelie bar on it now - it'll get up on the bar & stay there until I chicken out & back off, had it doing about 40mph in top on the wheelie bar.
Putting the wheelie bar on the lowest setting to keep the front down works great on flat surfaces, but I suspect it'd get busted off pretty quick doing jumps with it right down like that.

Spooled diffs suck, very difficult to simply keep it in a straight line without looping out under throttle, at full throttle it kept on looping out on the 1-2 gearchange.

Gotta see if I can dig the sheared screws out of the diff cups & tap the threads to the next size up, see if that'll hold.

On the plus side the trans held like a champ, I was giving it hell & nothing in the driveline (other than the diffs) broke, so it looks like once I get the diffs up to scratch she'll be reliable.

It would seem the picco .28 turbo head engine has more hump than an LRP .28 (mate had his LRP powered revo out last night as well), maybe a tad too much for the revo, that little extra is punishing everything in the driveline & I'm still only running it fairly rich (200 deg temps).
Oh well, too much is just enough - provided I can sort the diffs.

 

[SchrodeMode]

I hate linking to another forum, especially the Traxxas one, but here's a thread about LST diffs in a Revo. They're putting them in an E-Revo, but you should be able to do it to a Nitro.

 

[olds97_lss]

I run an lrp28 in mine and haven't had near the trouble your having. I run pretty short gearing as well. Trans is all RRP steel inside, 38 or 40T spur/15 or 16T bell (can't remember). 1/8 clutch/flywheel/bell, stock axles all around, stock diffs, standard gearing in the trans.

I change out center axles about once a year... have easily put 8 gallons through it over the past 2 years. 4 with the LRP, 4 with other various bb's and the 3.3. Only ran the 3.3 for about 1/2 gallon... after having a bb revo, a 3.3 is just a joke. lol

Personally, I'd put some milder tires on it. Those joe's are some heavy sob's that may be adding to some of your excess stress busting stuff.

I really dig your throttle setup though. I had to cobble a mess together for mine, but it's reliable now. I run the new era 3 point roll bar as well, but have about 3/4" spacers on the rear legs to raise it up to protect the engine.

Just recently picked up a savage X and am remembering some of the reasons why a savage is a chore... but I have most of those issues sorted out and my revo has been wasting away on the shelf. Until next year...

 

[TK5310]

Took the big joes off, I was running badlands last night plus a bit of time on some road rage's.
The picco is just stupid powerful methinks!

Roll bar is one I made, looks a bit like the new era, but it bolts to the chassis instead of the shock mounts & it's made of thinwall chrommoly tubing so it's pretty light but very strong.

Fixed 1x diff now, drilled & tapped the thread in the alloy cup to 3x.5mm, opened up the bolt holes in the crownwheel to take the bigger bolts, turned some 3x.5mm bolt heads down to fit & screwed it together with loctite.
Bolts are 1mm fatter & 3x longer - it should hold now.
That diff is going in the back & I'll leave the Erevo diff in the front until I've got time to fix the other diff.

The spooled diff I took out was looking pretty sad - where the axles go on I've twisted the shafts coming out of the diff centre a good 1/3 of a rotation - they were about to snap.

 

[TK5310]

PS - I've had the rear diff out so many times now I can replace a rear diff in 20 minutes start to finish LOL.

With any luck I won't have to for a while now.

 

[sv250]

I had a Picco .26 turn the same spool into a pretzel in a Maxx.

I just finished my LRP Revo conversion. I have Picco .28's in my Savages and LST. They shread drivetrains on every r/c. Plenty power to appease the animal inside.

 

[SchrodeMode]

The spools are known for twisting, they'll do it pretty quick with a 3.3.

 

[TK5310]

Sorted other diff, both all good now.
Had it out last night at a skate park, running sweet, stupid fast & handling real well finally.
I had a trx FOC in with the plastic gear rather than the RR output shaft gear - theory was to soften the blow to the diffs.
Shreded the plastic gear, didn't have the RR steel gear with me but found another FOC in my tool box, so I put that in & then proved 10 minutes later that shredding the 1st one was no fluke (even after I loosened up the slipper to try to preserve it).
I guess I really do need all the RR gears in the trans!

Other than that it ran like clockwork, diffs held, trans main shaft held.
Looks like the last thing to do other than regular maitenece is stick the RR output gear back in & it should be fairly reliable.

I got enough run time to finally get the tune nailed down, running around 220-230 deg & ripping so hard it was just ridiculous.

I'll get some vid of this thing next time out!