New picco .28 monster build!

[TK5310]

Scored a revo 3.3 on ebay fitted with a new, not even broken in picco .28 bump start truggy engine & a bunch of other good bits - got it cheap as it has a busted trans (reverse) & a stripped spur so it's not a runner.
Also came with a spare .28 SH engine, spare BB mount & a bunch of other stuff.

Plan is to strip my old 2.5 chassis revo that has a whole bunch of aftermarket bits, strip the 'new' picco powered revo 3.3 & build 2 cars - 1 from the leftovers to put back on ebay & recoup my costs & the other a monster combining the best bits from both trucks.

Build will be as follows:

3.3 chassis, bulkheads etc.
Picco .28 bump start engine with big block side pipe (dynamite I think, won't know for sure till I get the car later in the week).
3 shoe alloy clutch
Motosaver filter
17/36 gearing
Forward only trans with centre diff & 500k oil
Rear brake
Steel driveshafts
Rebuilt diffs with 100k oil
RPM true track rear
RPM front arms & carriers
TRX alloy pushrods & steering rods
P2 rockers
Purple rear & blue front springs, 65wt shock oil
TRX sway bars
Alloy single servo steering arms
PowerHD digital single steering servo
PowerHD throttle/brake servo
Technics battery box/fuel tank conversion
Revo platinum throttle servo mount
TRX wing & mount
Crowd pleazer body (if I can make it fit the longer chassis)
Big Joes

Probably forgotten some stuff, but that's the basics of it.
Should be one bad ass revo.

 

[TK5310]

Allmost done, but not run yet (maybe tonight), still gotta zip tie the wiring etc & make up a fuel tank pressure chamber to even out the 'mid tank lean':

---------- Post added at 8:57 PM ---------- Previous post was at 8:45 PM ----------

Final specs are:

3.3 chassis

Driveline:
Picco .28 truggy bump start engine
Q Concepts BB engine mount, flywheel & throttle linkage
3 shoe clutch
Regular 1/8 scale 20T bell clutch
40T 1/8 spur adapted to the Revo trans
2047 pipe & ofna header

Forward only trans with STD gear ratios & centre diff with 500k oil
Trans raised up 3mm with alloy spacers to allow proper mesh & for sput to chassis clearance
TRX rear brake
Steel CV driveshafts
Rebuilt diffs with 90k oil
Stock 3.3 axles

Suspension:
RPM true track rear
RPM front arms & carriers
TRX alloy pushrods
TRX alloy steering links
GTR shocks with 65wt oil
Blue front & purple rear springs
TRX sway bars
P2 rockers
Alloy steering servo arm & single servo alloy drag link

Other stuff
PowerHD digital high torque steering servo
PowerHD high torque throttle/brake servo
RPM bumpers
TRX wing & mount
Motorsaver air fliter
Technik RX box & battery box conversion (for big tank - not fitted yet).
Cut down throttle servo mount

23mm hubs
Big joe tyres
Crowd Pleazer body

Can't wait to try this bad boy out!

 

[dan261000]

She looks like a beast! If you are able, take some footage of her in action?

Sent from my SAMSUNG-SGH-I727 using Tapatalk 2

 

[Zdragon71]

Wow! One bad revo you got there.

 

[sv250]

Nice, I have had some thoughts about a revo. I have a LRP.28 with no home.

 

[TK5310]

Got it fired up, goddam it's loud!

Motor only has 1 tank on it, so it's real tight - bump start is a PITA, will get better as it free's up.

Need to find needle settings, it idles & will rev up with very light throttle & the wheels off the ground, but on the ground it dies as soon as you touch the throttle.
I didn't get the manual with the motor unfortunately.

It's a Picco 51233 'factory team turbo' engine.

 

[HPI-Killer]

Awesome rig! What kind of spur is that? I want I want!!

 

[TK5310]

Spur is a HoBao buggy spur, I couldn't find a clutch bell that'd fit the clutch in a traxxas tooth profile, so I used the 'normal' type bell clutch & adapted the spur to the gearbox - just had to drill out the centre in the lathe & drill the 3 screw holes in it, it lined straight up.
It hit the chassis with the trans in the stock position tho & I didn't have enough adjustment to set the mesh, so I raised the trans up 3mm with alloy spacers which fixed both issues.

If it works out with no issues once I've run it for a bit I may get a metal spur.

---------- Post added at 10:24 PM ---------- Previous post was at 10:23 PM ----------

All sources say the needle settings are 10.5-11.5 turns out on the low speed 3-3.5 on the high speed.
But the low speed would be sitting in my hand if I screwed it 11 turns out, anyone know if they've changed the carbs on these things?

 

[Extreme RC Mods]

If it will run, just fine tune the LSN so it will idle and the HSN so it will drive off idle. Those needle settings haven't been changed in years and refer to a tapered needle that hasn't been used since the first .26 models.

 

[TK5310]

Ah, ok, I got it set 3 turns out on the LSN & 3.5 on the HSN now, gotta get some actual work done now tho so I won't get a chance to see how that goes for a bit.

You wouldn't happen to know what the settings should be would you? - motor is fresh still, gotta do break in so I don't realy want to risk the motor trying to break it in with unknown settings.

---------- Post added at 11:09 PM ---------- Previous post was at 10:58 PM ----------

While (if LOL) I have your attention - the centre diff may be an issue, with the 2.5 chassis & 3.3 motor I was ballooning front tyres pretty bad on high traction surfaces even with 500k oil in the centre diff.
The 3.3 chassis & larger big joe tyres should help that, but methinks it'll still be a major problem.

Can I use something like thick wheel bearing grease or something in it? - I love the handling with the centre diff & don't want to go back to a solid shaft, but I really have to limit it's action or I reckon I'm gona blow the front tyres off the rims on a regular basis.

 

[Extreme RC Mods]

The settings are where the engine runs as I described in my last post. Any factory setting is just a reference point, as long as the engine will run with a slightly rich setting, that's where the needles should be. I don't know much about the center diff of your truck, someone else will have to chime in with that info.

 

[TK5310]

Took this out last night to break in the picco, got 5 tanks through it & got it up to 200 deg with the aid of a sock on the motor (cooler night).
Got the tune roughly right - was miles out, lean on the low speed, pig (+ an extra pig) rich on the high speed & too low on the idle, no wonder she was a bitch to start!
Got the idle bumped up a little while it's still tight, got the LSN just on the rich side & the HSN rich - I'll leave it like that for a couple more litres of fuel.

Got a few WOT runs - holy sh|t it's got some poke!! Even rich & tight it was wheelspinning all 4 big joes in 2nd gear on bitumen with a centre diff, it's gonna be plain crazy when it loosens up & I get a proper tune in it.

Showed up a few minor issues tho - first hard run the front brake disk got pushed backwards by acceleration & slipped off the lugs on the driveshaft = only back brakes & moving quite fast.
The spur alignment is a little out after everything settled into place.
I have to shift the trans forward about 2mm & that'll sort both those problems.

While I've got the trans out I'm gonna take the centre diff out & put the solid shaft back in - front tyres are ballooning real bad, even after I gaffa taped the inside of them, if I leave the centre diff in I'm gonna destroy those big joes pretty quick.
I've ordered some diff lock grease, but it won't be here for almost 2 weeks, when I get it I'll put the diff back in, till then I guess it'll just be a wheelstanding pig.

Not real happy with the throttle linkage either, I'm gonna go back to a normal setup with a return spring.

All in all went pretty well for a fresh build, some minor issues but I got to see the potential of the thing.
With the tall 20/40 gearing it fires through 1st gear in an instant & then hunkers down & f*cks off in top. It's gonna be crazy fast! The gearing in it should take it to 50-60mph, which is plenty fast, looks like it'd pull more gearing no problem, I've got a wide ratio gear set sitting there but I'll get some time on an RC race track before I decide if I'm going to use it.
A mate had his 3.3 out as well - when I had my 3.3 short chassis setup his was a tad quicker, now it looks like a slow ass toy.

No vid yet - it was night time & I was busy with break in.

 

[Extreme RC Mods]

I wouldn't let the rpm get too high for the first gallon, it's extremely hard on the components when they're so tight and will wear the moving parts faster. I know it's hard not to do but picco uses high grade aluminum and chrome compared to many other engines. That's the main reason it takes so long for them to break-in fully, and it's the reason they will last so long as well.

 

[TK5310]

Yeah, I didn't run it anywhere near top speed, just short bursts & I've got the shift set pretty low.
I won't wind it out untill I've got at least a gallon through it, will be a few weeks before I tune it for power & wind it out in top.

Good to know the motor will last, one of the reasons for the switch to the picco (along with scoring it & a whole 3.3 revo dirt cheap on ebay) was I got sick of the cheap ass grenade 3.3's. Between me & a mate we've killed 4 in 4 months. My first I broke the top of the block clean off (cheap metal) & the second died last week with a split rod - fortunately I heard it change note & stopped it before it did any other damage, so a fresh rod in that one & it'll be fine to sell with the parts car.
His 1st broke a rod & took out the piston & sleeve, his second broke a rod again but he caught it in time & got away with a new rod. He has a .26 red dot on it's way.......

I had a look inside the picco when I had the back plate off to seal it - it's in another league to the 3.3's, huge rod made of nice metal, big rod bearing, nicely machined crank with real nice porting, back plate is billet, piston doesn't have that 'cheap pot metal' look, looks more like a quality aftermarket piston (for a 1:1 engine).

Very happy with it, especially for what I paid - once I sell the parts car I should be about $150 down from where I started & I've got the picco, pipe, 3 shoe clutch, 3.3 chassis, GTR shocks, 23mm hubs & a set of big joes + a spare SH .28 engine, spare BB mount & spare RPM arms - bargain!

 

[hamz9561]

The replacing the center gear won't necessarily help the ballooning problem. One of the best ways to help with that is to strap the inside of the tires before you glue them or mount them with strapping tape.

I had the same problem with several of my rigs including my Revo with a Picco .26 Maxx and this helped out a lot.

 

[TK5310]

I did tape them - with 100mph race tape!

It's only the fronts that are ballooning bad, just way too much wheelspin.

Had a look last night, can't fit the solid shaft & retain the rear brake, so I'll have to figure out an interim measure to moderate the front wheelspin untill the diff lock grease arrives, got some adhesive grease I may use for now.

 

[TK5310]

Filled the centre diff with blutack, real stiff but can still be turned - should work ok.

Moved the trans forward & spaced the rear brake pad forward with washers, spur gear mesh is heaps better & disk has proper engagement on the lugs so it can't come off again.

Sorted the throttle linkage, working well now.

Unless more teething issues show up it should be pretty much sorted for now.

I'm gonna grab a much bigger fuel tank, that picco is thirsty! Got all the stuff required to fit up to a 250cc tank, but I probably won't go that big as I'd have to shift the steering servo to the other side & I'd prefer the weight of it where it is to counter the weight of the motor.
I'll grab a header tank the same time as I get the big fuel tank, that should make the fuel system as good as it can be.

 

[roachbug]

good info

 

[TK5310]

Been real busy with work & weather has been lousy, so I've just barely finished break in on the Picco.

I've fitted a header tank - tune stays nice & consistant now.

I sheared a pin in the rear metal drive shaft, made a new one out of tool steel - that won't shear!

With less than 1/2 a gallon on the Picco the car is a monster, 20/40 gearing & blutack in the centre diff - it still balloons the front tyres & will pick them up at speed on throttle application a bit too easy! Nailing the throttle off the line just results in a backflip & the car skidding along on its roof - need to learn better throttle control, may fork out for a digital throttle servo for more precise throttle resolution.
Thing is mental fast, had it skipping over the tops of bumps last night, only touching the ground about 1/2 the time on a rough surface & lifting the front wheels at something like 40mph when it hits bumps.

On looser stuff it just wheelspins & balloons all 4 tyres throwing roost everywhere.

I'm thinking softer suspension may help with traction & reduce wheelstanding to controllable levels whilst also keeping the wheels in better contact with the ground over rough stuff, reckon I'll put some softer springs in (currently has purple rear & blue front).

Bump start died tho, has been a PITA, not enough grunt to spin the tight motor over properly (even warmed up) so starting has been a royal bitch, then it just up & died last night.
Debating whether to just grab another hand held bump start or a starter box & modding it to suit the revo.

 

[rc 66]

any idea where the tires came from i would like to get them for my revo thanks