Hard decision but I'm buying a new engine!

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ChuenouXiao

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I just purchased a 30.5 CC OBR ProStock 5.5Hp and just waiting for it to ship. Can't wait! Just replacing my cheap stock 30cc. Very disappointed about how my 30cc performed. I take good care of my 30cc and have never run WOT for a long period of time. I open the head kit and notice there are some shaving on the piston and the clip around the piston is loose on one side (i believe that band clip that goes around the piston is to help the compression during the combustion?). When you flip the engine's head up side down, you can see a in-perfection like a piece of metal that seems to be a part of the head itself. Here are some pix but will upload more later. The decision I made, to me was the most efficient and gives me the most bang for my buck! Tell me if you agree or disagree :D Base on what I've done to my stock engine (which is not very much) and its already gone bad? Its too cheap for me honestly..... I thought these engines are suppose to be durable? Very disappointed.


1. What are your thoughts on the 30.5 CC OBR ProStock 5.5Hp?


2. What are your thoughts on my finding of my stock 30cc engine?
 
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The piston and the head look pretty beat up, for sure. Something broke loose and got caught between the piston and the head. What does the side of the piston look like? The piston ring is supposed to be loose. When you slide the piston in, the ring compresses and puts tension on the cylinder wall, which helps maintain combustion pressure.

As far as the OBR. Good choice.
 
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Yeah there is a bit of junk on the exhaust side of the head that looks like it has created damage to the top of the piston. If you look at the piston groove where the ring sits you will find that it has a little step in it where the ring joins. So it can be compressed.
 
Deluge said:
The piston and the head look pretty beat up, for sure. Something broke loose and got caught between the piston and the head. What does the side of the piston look like? The piston ring is supposed to be loose. When you slide the piston in, the ring compresses and puts tension on the cylinder wall, which helps maintain combustion pressure.As far as the OBR. Good choice.
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Could this damage to the engine happened when I side swipe my rear right tire to the curb around 5mph while breaking and damaging my out drive and axle cup? Could it be? That shouldn't be enough to damage the engine because people jump their car like crazy and it flips and tumble over and over and the car still runs fine.... why me?
 
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chuefengxiong said:
Could this damage to the engine happened when I side swipe my rear right tire to the curb around 5mph while breaking and damaging my out drive and axle cup? Could it be? That shouldn't be enough to damage the engine because people jump their car like crazy and it flips and tumble over and over and the car still runs fine.... why me?
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Probably not from a collision...do u run without an air filter or not clean your filter?
 
countstevula said:
Probably not from a collision...do u run without an air filter or not clean your filter?
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My XB has never seen dirt before :D And I have clean air filter foam along with outer wear for my air filter. I think it's a defective engine.....
 
More picture of the damage!!!

It may be due to bearing on the piston but not sure. Either way... it cost me..... will confirm when I have time to take engine completely apart to experiment and investigate.
 
I don't know if..... un-flooding my engine (because engine won't start) while the car is in a wheelie position may have contributed to the problem???
 
Yup that engine is toast. If you can take a picture of the end of the sparkplug (end inside the engine) that would be great. We can tell from the color if you were running too lean which would have caused that damage.
 
DemonRC said:
Yup that engine is toast. If you can take a picture of the end of the sparkplug (end inside the engine) that would be great. We can tell from the color if you were running too lean which would have caused that damage.
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Here's a shot when I was troubleshooting my engine due to non start. This was before I cleaned my plug.... tell me was I running too lean? You mean lean on the low speed? Maybe I was running lean on highspeed? I assume it was the HSN because I was tunning the HSN for speed? So I should give my engine breathing space by richen it a little? Is this how you prevent issue like this?

http://www.redcatrampageforum.com/showthread.php?t=7272
 
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look at the pistons ring area closely - there should be a little round pin that the ends of the piston ring touch. this keeps the ring from spinning and snagging the ports. just a thought---
 
Deluge said:
Out of curiosity, you should take apart the crank case and see what's in there.
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Will do when I am taking it apart later and will update you guys here.... thanks!!! (might be in a couple of days guys before I update) Tire of the gasoline smell in my place here :D )
 
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yea split the cases on the motor- that scratch on the pistion-the way it suddenly stops 1/2 way- its on the intake side- looks as though the piston was traveling to the bottom of its stroke- the scar-scratch looks almost like a flat washer was wedged inbetween the bore and piston- yea-split cases and see-keep us posted!
 
I don't think it is your fault, if it has never seen dirt and you don't drive it hard. IMO you just got a motor with some machining waist left in there. I found a ball of metal behind a gear that caused it to wobble. It could have been up by the spark plug thread and just came loose causing your destruction. I'm just speculating. Those motors are mass produced and it is likely that a bad one sliped by quality control. They are normaly durable and run great. The motor you ordered will be a big improvement in performance. You will be happy. Sorry to hear you got a lemon.
 
You might want to get a stock CY 28.5 or 29.5 before you get into the bigger motors. If you lean sieze the big boy engines, it hurts alot more.
 
RCDAD said:
I don't think it is your fault, if it has never seen dirt and you don't drive it hard. IMO you just got a motor with some machining waist left in there. I found a ball of metal behind a gear that caused it to wobble. It could have been up by the spark plug thread and just came loose causing your destruction. I'm just speculating. Those motors are mass produced and it is likely that a bad one sliped by quality control. They are normaly durable and run great. The motor you ordered will be a big improvement in performance. You will be happy. Sorry to hear you got a lemon.
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I think the issue is the nub the holds the ring gap on the piston came off. At least thats what it looks like to me.

I agree with Rob, get a cheap nonported motor to run while ya learn the ins and outs. Your wallet will thank you :)
 
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