Bad news for my new red arrow 34cc engine

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Rep732

Rep732

The alchemist ☠️
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so Ive been wanting to check the squish clearance on my 34cc revolver engine and now since the losi is down until I get parts for my killswitch I figured why not its a good time to do it.

Well let's just say im not liking what I see on the cylinder walls,the dome of the head and in the crankcase. ?‍♂️

The piston looks to be sandblasted on the skirt. Its matte finish and rough in texture...great! Were off to a good start. The cylinder wall has 3 deep grooves running up on each side of the cylinder. the "4th" side is smooth .

There was grey colored oil on the skirt so Im assuming something is letting loose in the bottom end.
At the top of the head around the dome I seen some small chunks so I took a magnet and sure as sh*t they stuck to it. Excellent!

Rotated the crank around for a peek and there's more grey oil on the crank. Perfect!


Im going to say going to that construction site was a bad idea especially with the type of dirt out there and im eating this engine and im pretty much out 600 bucks and now I get to do it all over again.

Any input as where to go next20201122_011816.jpg20201122_011922.jpg20201122_012603.jpg20201122_012430.jpg20201122_011934.jpg
 
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Was brand new lol...carb wasn't the issue this time...if i had to take a guess it was lack of good air filtration. I ran the 3" uni the redneck prefilter with an outerwears and the uni and redneck were oiled. The type of dirt was almost like clay and the dust was as fine as cement dust. I stripped the whole engine down and its not looking good. I'd like to reuse the crank but im a littler nervous about the sand messing with bearing tolerances. Case bearings Is no issue and I'll just throw an esp top end on this if I can salvage the crank
 
3 runs on this engine. About 30 minutes each run....looking on the inside of the fan cover and behind the flywheel it looked like it was just hosed with sand. All of the black paint is gone on the inside. I ran this against my better judgment in this and I paid heavily
 
Yea and I knew better too. Im having a hard time locating a conrod bearing on the crank side in the us ?‍♂️ ..ddm only sells wrist pin bearings and everywhere else is over seas. I really hate to waste a modified crank....
 
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My options are new 2mm crank at 49 dollars or 20 dollars for a stock crank that i can seperate and steal the bearing out of that.. im just worried that the sand messed with the bearing tolerance.

I have a 50 ton press I can use at work so im not worried about that lol
 
Damn that sucks. Hate to see this happened to you.

I've rebuilt demo saws that ingested concrete dust and ones that were dropped underwater while running. Granted, the distance between carb and cylinder is farther than those on RC engines, I've never seen one as filthy as yours.

I have a large bearing vendor nearby. If you have the bearing number or the ID and OD, I can give them a call on Monday to see if they have one in stock.
 
Thanks i would appreciate that @Top Dead Center .zenoah part# 576449501 not completely sure how accurate it is. And i won't be able to have diameters until Monday when I can get to the press and honestly ive never seen this much contamination in an engine like this. Something in there really wore down to get that grey and I have a feeling its the piston that suffered the most as its looking pretty dull...and yea @dougstar They are but its 50 for it and 159 for the esp top end kit. Or 239 for a full kit with cases,bearings ,etc. But ddm says if it was to be built it requires more parts....if i save the case im saving 10 bucks ?‍♂️ :ROFLMAO:....the red arrow was a splurge and a fail now im penny pinching because i can't afford to be wasting engines on a monthly basis here
 
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Since the rod journal is hardened steel and the connecting rod bearing is a roller bearing, you should be good to go with a bearing replacement. I doubt you have much wear on the journal.

Unfortunately, the Zenoah number is Zenoah specific. I need either the dimensions, including width, or an actual number from the bearing.
 
@Top Dead Center ill take a good look at it in the morning. I maybe able to press it out at my neighbors he has a 12ton press. And @Troopermaniac I use pj1 foam filter oil. This run was pretty bad. Ill post a pic of the redneck prefilter in the morning. It looks pretty embarrassing honestly. It was hard to see what it looked like when the outerwears was over it. The uni filter didn't look as bad but you can see a portion where the dust bled through to it
 
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