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Old 04-14-2007, 03:33 PM   #1
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Default o.s. tz help needed

I have a eb mods .12 o.s.tz. Motor runs great and was broken in propertly, until today. I started the engine and it was running great as usual, it was still on the starter box warming up idiling. My buddy turned to ask me to look at something on is car so I was over with him for a mintue or so. By the time I got back to my car it had flamed out, no big real, so I went to fire it back up and I noticed the flywheel wasnt turning over on the starter box. I figured the piston had gotten stuck since the engine is only about a gallon old and the engine is still tight. I was wrong, some how the piston is stuck in the sleeve!!! So I take the engine apart to inspect and the piston is stuck half way up in the sleeve below were the sleeve is at tdc. So managed to get it un stuck and noticed that now the piston wont go past the part were it was stuck at? Any ideas or suggestions I can try?
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Old 04-14-2007, 03:57 PM   #2
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a new piston and sleeve sounds like the most straight foward fix . I know thats probably not what you want to hear or not the cheapest option, but it probably will be the most reliable.
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Old 04-14-2007, 04:15 PM   #3
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Quote:
Originally Posted by tony montana
I have a eb mods .12 o.s.tz. Motor runs great and was broken in propertly, until today. I started the engine and it was running great as usual, it was still on the starter box warming up idiling. My buddy turned to ask me to look at something on is car so I was over with him for a mintue or so. By the time I got back to my car it had flamed out, no big real, so I went to fire it back up and I noticed the flywheel wasnt turning over on the starter box. I figured the piston had gotten stuck since the engine is only about a gallon old and the engine is still tight. I was wrong, some how the piston is stuck in the sleeve!!! So I take the engine apart to inspect and the piston is stuck half way up in the sleeve below were the sleeve is at tdc. So managed to get it un stuck and noticed that now the piston wont go past the part were it was stuck at? Any ideas or suggestions I can try?
how did you brake the motor in?
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Old 04-14-2007, 04:17 PM   #4
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Quote:
Originally Posted by tony montana
I have a eb mods .12 o.s.tz. Motor runs great and was broken in propertly, until today. I started the engine and it was running great as usual, it was still on the starter box warming up idiling. My buddy turned to ask me to look at something on is car so I was over with him for a mintue or so. By the time I got back to my car it had flamed out, no big real, so I went to fire it back up and I noticed the flywheel wasnt turning over on the starter box. I figured the piston had gotten stuck since the engine is only about a gallon old and the engine is still tight. I was wrong, some how the piston is stuck in the sleeve!!! So I take the engine apart to inspect and the piston is stuck half way up in the sleeve below were the sleeve is at tdc. So managed to get it un stuck and noticed that now the piston wont go past the part were it was stuck at? Any ideas or suggestions I can try?
Dude, now that is really wierd man. Is there any obvious scratches/gouges on the piston sides or inside the sleeve? Any noticable damage at all? If there is no visible damage, I would clean it and put it back together. Then heat the head up with a heat gun and try and start it. After VERY THOROUGH inspection only though. This area where the piston got stuck at is the tightest spot of the sleeve. Well TDC is, but it's really close.

What might have happened is that the engine was warming up and the sleeve expands with the heat. Then the engine stopped and the sleeve started to shrink making the piston get stuck. This is why when we break in our engines, we let it cool down with the piston at BDC. So the piston won't be in the sleeve when it cools off.

So you might be ok. Just oil it a little bit after you clean it and inspect it and put it back together. I put oil on both the inside and outside of the sleeve, just a thin layer. Also oil the rod bushings. Put it all back together and try and start it. I would still use a heat gun just to be on the safe side if you can. Good luck and let us know what's up. Hope it's ok!
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Old 04-14-2007, 04:35 PM   #5
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I always with every engine but the piston to bdc before it cools down. The engine hadnt shut off for no more than 5 minutes before I tried ro restart it. Im really confused and the engine had lots of compression before I wanted to run it today. I broke it in according to eb mods breakin instructions. I just dont want to buy a new piston and sleeve the engine is only a month old
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Old 04-14-2007, 07:13 PM   #6
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I think I fixed the problem. Believe it or not when I took the engine totally apart the piston and sleeve were gummed up!!! Not real bad but I felt it with my finger nail and I could feel like a gel around the top of the piston and right before tdc in the sleeve. I soaked the piston and sleeve in after run for about a half hour and rubbed it with a rag and it came off. put the engine back togehter and it spins like butter now
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Old 04-14-2007, 08:16 PM   #7
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I would stronly recommend you preheat this engine with a heat gun before you attempt to turn it over for the first litre or so...

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Old 04-15-2007, 02:29 PM   #8
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Quote:
Originally Posted by tony montana
I think I fixed the problem. Believe it or not when I took the engine totally apart the piston and sleeve were gummed up!!! Not real bad but I felt it with my finger nail and I could feel like a gel around the top of the piston and right before tdc in the sleeve. I soaked the piston and sleeve in after run for about a half hour and rubbed it with a rag and it came off. put the engine back togehter and it spins like butter now
thats great news!
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Old 04-15-2007, 06:26 PM   #9
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Castor oil will leave a buildup if the engine isnt hot enough for a long time.
Ive seen blue thunder fuel do it real bad if the engine isnt run at high enough temps. Keep the engine above 200 degrees.
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Old 04-15-2007, 06:58 PM   #10
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well I got the engine started today and it ran like a dream like it did before, thank god, i didnt want to buy a new piston and sleeve
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Old 04-15-2007, 07:00 PM   #11
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Ok this is what happend. Your new piston and sleeve seized. It happens , you then took the piston out (not needed , just free it next time). You can do this a number of ways , removing the heatsink and tapping a wooden dowell on it or anything that wont damage the piston top.

After that , put back together and refire.

What happened was your piston was stuck , you took apart and then tried to shove it into the sleeve dry after a seize , which is due to tight parts. Anyhow after it cools its not going to go as far into the sleeve anyhow.

Everything you saw was normal. Cleaning it is fine and gel can make for stickier parts. But its fine , I can sometimes get a seized piston unstuck by just turning it backwards by hand via the flywheel. Then you pull it back as far as possible , then onto the starter box and normally the full rotation is enough to get it fired back up and on track. You should maybe look into running the motor via the cyrul method for a tank or so to get things flushed out and get it loosened up a tad more.

Just a thought.
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Old 04-15-2007, 07:43 PM   #12
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I did take the engine out of the car and I couldnt even turn it over with a pair of channel locks with the flywheel still on the engine. My only other guess is the engine shut down with the piston half way up the sleeve. But after I cleaned the engine from the gum it turned over fine
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Old 04-15-2007, 09:24 PM   #13
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Quote:
Originally Posted by tony montana
I did take the engine out of the car and I couldnt even turn it over with a pair of channel locks with the flywheel still on the engine. My only other guess is the engine shut down with the piston half way up the sleeve. But after I cleaned the engine from the gum it turned over fine
Yeah thats what a seized piston is , at least when it gets jammed , its normally towards the top of the piston where it pinches off. Ive had some really overly tight seizes. Taking apart the car is last resort.

Normally tapping on top of the piston seems to be the best as far as quickness is concerned. As for stress on parts not sure , but its not good to have a hot piston cooling to near tdc inside the sleeve either. This is what causes it to loose pinch.
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