Project “Old School”. A Littlemotor Jammin’ CRT.5 1/12 nitro truggy build for 2025!!! 😎🍻

[Lukedavis]

This ain’t your typical “paint by number” kit build here..

Worked on it about nonstop the past two days straight. Started going through, and editing photos at 10:30pm, posting an hour after that, first post hit right around midnight, and I had hours to go.. I make every post with my cell-this thread doesn’t update itself…

You've been documenting this on your CELL PHONE?!?! That's nuts! Holy crap dude! This is insane!

 

[CertifiedMike]

Thanks man! It’s worth it, I just find myself covered up with posting lately, as I’ve had to wait on parts, and take on other portions during the “down time”, but don’t wanna post it up out of order.. I’ve spent between 4 and 6hrs just doing the progress/documenting/updating more than a couple times with this particular build thread.. You’re not a slacker holmes-I just need my head examined with this thing…

No need for an exam my friend!

 

[Littlemotor]

No need for an exam my friend!

Oh-I’m very aware sir..

 

[Littlemotor]

Let’s get to some real meat and potatoes..

This was a very thought out decision for me, and anyone that knows me as far as RC goes, would note that this was not an easy choice to make.. OS has been around literally FOREVER, and they’ve always been very reliable engines, but 20yrs ago they just could not touch my Italian based nitro engines, and the price was flat out ridiculous.. The quality as far as longevity, and durability wasn’t there either-considering I was getting 3-4 TIMES the life out of my Picco, Ninja/GRP, OPS, Collari, etc. nitro engines.. I felt like My Italian engines made NOTABLY more power in every situation as well..

I still run Picco to this very day, and absolutely love them. I own several, including a recently acquired motor that literally NOBODY could get their hands on if they tried.. It’s also brand new in the box, AND freshly modified by arguably the best engine guy in the country..

That being said-Picco has slimmed down their offerings across the board HEAVILY over the past 5yrs, and now they only offer .21 engines, in either onroad, or off-road. That’s it.. No more stuff for the bashing crowd, no monster truck engines, no boat motors-NOTHING… And OBVIOUSLY; no more Picco Monza .12 for the ultra competitive 1/10 sedan guys-which is what this build of mine would require.. Picco was one of the biggest engine manufacturers in the world for YEARS, and supplied some of the best engines any RTR vehicle had ever seen, while still maintaining an absolutely EXCEPTIONAL race engine program.. There is only ONE distributor in the entire country of Picco engines, and it’s literally impossible to get them on the phone, or via email if you should ever happen to have a problem. Good luck talking to Picco on the phone, if you’re not fluent in Spaghetti.. I see the writing on the wall, and do believe they are planning to close the doors in the next few years..

I had PLANNED to pick up the same engine (Picco JL “Red Dot” .12 7-port) that I ran in my last Jammin’ CRT.5, as I had a longtime friend that has about half a dozen of them in brand new condition from way back when.. Considering how hard it is to find parts (like say oh-I dunno; a replacement CONNECTING ROD ), I decided that no matter how much I loved that engine (20yrs ago), it just didn’t make sense for this build, and at present day.. I wanted to do this thing “If Jammin’ built a nasty little CRT.5 in 2025”… Well-time to put my money where my mouth is..

Who makes the nastiest out of the box .12 nitro onroad engine today? Enter OS Speed to the party, with their current T1204 offering.. It is flat out NASTY… Also “factory modified”.. All the bells & whistles.. DLC, modified, drilled & filled, Tungsten weighted, crank. Billet, lightened, dome piston. Billet con-rod. Modified piston sleeve. Ceramic rear bearing. Blah, blah, blah, blah… I’ve decided to run it bone stock, out of the box (aside from shimming it for 30% nitro, as they are setup for 16%), in order to truly give OS Engines a “fair shake” once more.. After I get some mileage on it, I’ll likely grab another, and have it modified by my guy as well.. Until then-this is what we’re working with.. You guys know I always tear down, inspect, clean, shim, oil w/Bones ARO, and reassemble every nitro engine I get my hands on right off the rip..

Grabbed a pack of shims, as well as a replacement rod for it.

Standard OS Speed packaging/protection..

Various caps, as well as the rear exhaust silicone gasket..

OS medium RP6 turbo plug..

I gotta say-it looks good AF.. I’ll flip the fuel/air mixxerator for my setup..

That’s more like it..

OS has always made a super nice carb..

Very nice..

 

[Littlemotor]

I do like the color scheme.. Literally every Tee-shirt hangin’ in my closet is black..

In all her glory..

“factory modified” 3-port ABC sleeve..

 

[WickedFog]

Why did I stop getting notified about updates here? Now I have a weeks worth of reading to catch up on. I thought you were taking a break.

 

[Littlemotor]

Billet, domed, CNC’d, lightened piston & Billet OS Speed con-rod..

Very nice work..

DLC coated, drilled & filled, Tungsten weighted, “Factory Modified” crank..

Turbo head button with tapered deck, and very nice burn room. Complete with O-ring seal to minimize dirt, and debris getting in your engine during routine maintenance..

Trying to get a shot of the tapered firedeck..

 

[Littlemotor]

Why did I stop getting notified about updates here? Now I have a weeks worth of reading to catch up on. I thought you were taking a break.

Don’t even get me started.. I STILL don’t get but 1 out of 20, DIRECT tags to my user name homie.. I figure it’s just the forum’s way of FORCING me to actually get out and mingle between my 5hr build thread update sesh’s..

 

[Littlemotor]

Billet hard anodized backplate.. Nothing fancy.. Would’ve much preferred to see an air-boost deal, but that doesn’t seem to be quite as beneficial, nor as common in onroad stuff as us hillbilly off-road see from it..

Note that it IS an “interference” backplate.. I always make sure I’m not at BDC when I remove ‘em anyhow-just good practice IMO, as ya just never know on a new engine..

Ceramic rear bearing, single sealed Japanese front.. This crank case is super nice, and the machining looks much nicer than my current Picco’s I must say..

Carb throat area..

Reinstalling.. Start with the crank and then the rod/piston assy.. Upside down is the move.. Get off your head-I mean the daamned engine ya silly bastid..

Then the sleeve-also upside down for me anyhow. This was obviously after..

 

[DavidB1126]

Why did I stop getting notified about updates here? Now I have a weeks worth of reading to catch up on. I thought you were taking a break.

The Elf's magically clicked unwatch for ya

 

[Littlemotor]

Fully seated in the bore..

Next is the backplate. Btw-everything is getting a reasonable coating of Bones Motorsports ARO as I go.. I don’t has three hands-as I’m not from West Virginia, so no photards of that for you’s guys..

Don’t go apeshit with your fasteners, they’re TINY..

Factory shim stack at .25mm.. As I said-configured at the factory for 16% nitro content onroad fuel..

I’m running 30% content-VP Fuel “Lutz Blend”, so I need to get my head clearance to .026-030”.. Grabbed a pack of shims from Amain to get me there.. Should be close..

Be CAREFUL.. These dudes will bend, or dent in a freakin heartbeat-hence the uber-cautious packaging from OS..

Never trust ANYONE when it comes to engine building, maintenance, etc. Do yourself a favor and get in the habit of measuring for yourSELF.

Alright, almost ready, let’s just do some soldering on this nitro motor..

 

[Littlemotor]

Looky here.. A “hook” of my usual .8mm Kester solder. Right up to the edge of the fire-deck of the head button, and low side of the piston dome. This is where the “quench” is tightest inside the chamber. Ultra important..

Set to the side, momentarily..

Some Tony’s M3 flat washers to protect my head button. It’s a machined surface that’s designed to sit flat against the machined surface of the cooling head. I’d prefer not to tear it up during this simple procedure. Ya always wanna use your daamned melon when working with nitro engines, and not just caveman this shiit-they’re not cheap, and will last you MANY gallons if you take proper care of them.

“Smooth” side DOWN, and stamped edge UP. That mess will ABSOLUTELY leave an impression in your head button if you don’t do this my way. Just sayin..

Tighten them down exactly as if you were going to run it. Criss-cross pattern obviously, and I go in (3) passes from snug, to more snug, to the snuggester… Again-don’t be an animal-they’re tiny..

Sacrificial crank “bolt” so I can rotate the crankshaft 360deg. -and be able to remove the fastener when the procedure is complete..

Solder “hook” in place (through the glow plug bore), and slowly rotate the engine 360 degrees, and stop. Carefully remove the “hook”..

Biggerize this photo if you need to, and you’ll see the “flat” from being smashed between the piston face, and the fire deck of the head button.

This is what unmolested .8mm Kester solder measures.

And here is mine. This verifies a piston to head button clearance @ .0285”. I needed to be between .026-.030 to run 30% nitro content. Perfect.

Just to show you guys an exaggerated example-this was me smashing a short piece of the exact same Kester .8mm solder to .5mm with the flats of my Mitu’s.. Any questions?

Using a folded cheap-o ziptie in the exhaust port for a “piston stop” so that I can remove my crank “bolt” without any damage to the engine.

Like so…

ZERO witness mark to the machined, billet aluminum head button’s fire-deck..

 

[Littlemotor]

“But, but, but-what about the piston, Lilmotah?!?”… Same deal, fellas.. Yes-you CAN stick “metal” in your fancy, high dollar engine to verify piston to head clearance..

Reassembly..

VERY nice piece-that nobody ever gets to appreciate..

There ya go.. Ready to rip.

This was “THE” pipe to run 20yrs back.. Fits the truck perfectly, is hard coated by Jammin’ (which is a big deal as it hangs out OUTSIDE of the body, and is beat to death by the left front tire everytime ya wheel this little animal), and ran good on every engine out there.. Let’s hope this rowdy little onroad OS monster likes it.. I’ll be grabbing a few specific onroad sedan pipes to play with as well.. They may work killer-they may be complete turds.. Hell this JP-5 may be a turd on this OS..

Now we wait another 24hrs for my engine mount to fully cure.. it’s absolutely KILLING ME over here..

 

[Doom!]

This stuff all looks so cool, even if I am clueless about nitro engines. But I love your new avatar!

 

[Warby]

Why did I stop getting notified about updates here? Now I have a weeks worth of reading to catch up on. I thought you were taking a break.

I don't get any noti's for this awesome thread. It's like I've ignored him or something and no I haven't.

 

[CertifiedMike]

I don't get any noti's for this awesome thread. It's like I've ignored him or something and no I haven't.

I don't get them sometimes too. Not just this thread.
Any chance you clicked 'unwatch'?

 

[Warby]

I don't get them sometimes too. Not just this thread.
Any chance you clicked 'unwatch'?

Nope. I've double checked.

Doesn't matter. Who wants to see this dumpster fire of a build anyway? No plan or quality control, crap parts and complete kaos. What a mess.

jk

Damn cool build

 

[WickedFog]

This is turning into a piece of art. And you guys have to take into consideration - @Littlemotor is going to run the dog out of this! It's gonna be like the equivalent of taking the Mona Lisa outside and playing frisbee with it

 

[TeknoJ]

I guess it’s looking good
Your attention to the details is ridiculous, carry on!

 

[Littlemotor]

You guys are all nuts…