Originally Posted by Foodie (Post 14881606)

Oh well, first engine dead... Looks like they forgot to grind down the bottom of the piston in one of my 2 engines. Bought 2 of the exact same engine and you can see the difference.

It died while driving but the shop i bought them at is saying i did not move the piston up when removing backplate (Rookie mistake, and never done that with the other +20 engines i have had).

Originally Posted by kawasaki161 (Post 15769981)

First up, sorry for the huge pics, no idea how to resize them inside the post while keeping them clickable so I put them into spoiler tags.

"If something sounds too good to be true, it probably is."
^This is the statement I should've kept in mind when searching for a cheapo engine. With affordable .12 engines being basically not available here with Novarossi being unavailable and me definitely not buying a T1204 to power a boredom project I went through Italian shops looking for something that might fit the bill. Then I read it, .12 engine with ceramic bearings and pipe included, for 99€. The SCHEPIS MODEL SM.12 PRO (another Sirio made brand like Bliss and Boss) bundle from modellismo e ricambi where I also picked up a MTX6 for 299€ (not advertising, just being transparent). Gimar actually had a better deal (MTX6+Novarossi Flash+pipe for 399€) with cheaper shipping but when I contacted them they said they were out of stock.
After it took them about a week to ship my order it arrived on thursday evening (after the tracking assured me an hour earlier that it'll arrive on friday, thanks UPS). I opened up the engine so I know what I'll be dealing with and well, I'm glad that I did.
Now let's begin with the carb having particles from the packing material inside:


Brilliant, not that hard to clean and hopefully the only setback. Well, not quite, there was a weird residue inside the pipe, probably just flux so no biggie but still weird.
Then I popped out the sleeve, piston looked fine:


But the sleeve itself... ohhhh boy:


Those ports needed some cleanup before this went back together, wasn't really thrilled about how this looked but hey, once it's broken in it'll probably be fine right? Right?
Well I went ahead and did some break in today, I think I've got 7 tanks through it now and went ahead and took it apart to check how it looks.... Doesn't look good, piston's got a ton of microscratches on it:


I wondered where those came from, then I took a look at the rod and the backplate:


Fuuuuuuuk me. At this point I checked the crank for axial play and well, the front bearing has some axial play, not a ton, maybe 0.2mm, still the first more or less brand new motor I had that had axial play.
And the cherry on the shitcake, this is how the sleeve looks:



Well, looking at the positives, it only took 7 tanks for it to get so loose that the piston doesn't get stuck in the pinch when hot anymore (still does when cold) and it still runs fine for now.
Let's see if I can make it last the whole can of fuel or if it dies before it gets to see a race tune.
Here's the whole album.

Originally Posted by nitrodude (Post 15770325)

The piston and sleeve after break in doesn't look that bad, that's pretty normal

Originally Posted by kawasaki161 (Post 15776402)

Okay, the Schepis SM12 Pro is a definite not recommend from me by now.
It's incredibly temperature sensitive and as such a bitch to tune. Tuning on the box is impossible as by the time you made an adjustment, the engine temp dropped enough to make it impossible to judge.
Spares are expensive in comparison to engine cost.
​​​​​​It seems to eat through bearings like nothing else, though I could've found that one out earlier if I searched through the Sirio thread on the off road forum more carefully. I'm at about 2 liters through the engine and there's both radial and axial play now. The rear bearing being proprietary (12x22x5) doesn't help.
The rod wears out quickly too, though I'm used to rods that were used in break in not lasting as long, I expected it to last at least a can of fuel before developing play.
I can't seem to find header springs. The stock ones are the "one per side" type in a length that's not in stock anywhere, one of them broke so I needed something new. .12 "all the way around" springs are too short and break after a tank, .21 "one per side" are too long and most .21 "all the way around" are too thick to fit past the carb. I ended up finding an old spring somewhere that fit but damn that was a pain.

When you've hit the tune just right, it runs very well and has tons more power than I as a onroad noob can handle. It just has a temper.

Originally Posted by 1/8 IC Fan (Post 15777537)

Did you break it in with a break in bench?

Originally Posted by 1/8 IC Fan (Post 15777537)

What Nitro % are you running?

Originally Posted by 1/8 IC Fan (Post 15777537)

Also have you tried Manifold to Pipe Springs?

Originally Posted by kawasaki161 (Post 15777541)

Regular in-car break-in with clutch set as loose as possible, full pre-heat to 90-100C before every start, full cool down to ambient temp at BDC after every tank. Two tanks rich idle, then two slowly rising and decreasing RPM with the car sat on a box, but still staying in a low-mid RPM range, all four while checking the engine temp regularly and using a heat gun to heat it up if it dropped too low. Then I leaned it out just enough that the clutch would engage (out of box settings were basically rich enough for the full throttle break-in method) and slowly ran it up and down the road while monitoring temps until it started richening up and dropping in temp, then I started slowly leaning it out until I arrived on something close to a good tune .



16%, didn't ask about the exact oil% but considering the mess I made more than enough.



Yes, but no dice. The plate on the manifold the springs hook into is further back compared to for example Nova and OS manifolds where it's flush with the end, so they're way too short.