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05-05-2009, 09:36 PM | #1 |
Not Yet Wild
Join Date: Jun 2008
Posts: 57
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Naked Engine Questions
Well here is some engine porn fo you all.
Brief synopsis: Engine has 150PSI compression, burns oil, has a small air leak at the spark plug gasket. Pictures were taken while hoping that a new/rebuilt head would help. When putting the cylinder to TDC there is almost a small bubble of air/oil near the 11 o'clock posiiton in the pictures. At BDC you can see a film of oil on the cylinder wall as evidenced by my wet finger after wiping it off. Lots of oil seen at the top of the cylinder wall. About 1 inch above BDC it looks like the piston froze at some point (disuse)? Walls are pretty smooth, no scratches/gouges. Let me know what you all think? I'm at a 0.050 overbore already. Rering/hone? Enough meat for a G14 piston? Other options? |
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05-05-2009, 10:07 PM | #2 |
Sometime's............
Join Date: Oct 2007
Location: Tacoma Washington
Posts: 11,868
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Re: Naked Engine Questions
Those pic's look like your cylinder bore is pretty scratched to me. Let me do some checking to see if your plan will work. Dave
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05-05-2009, 11:39 PM | #3 |
Gone Wild
Join Date: Feb 2009
Location: P-COLA
Posts: 1,176
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Re: Naked Engine Questions
Valve seals, guides??? You had me at naked...
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05-05-2009, 11:50 PM | #4 |
Raised by coyotes
Join Date: Nov 2008
Location: Central Texas
Posts: 5,658
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Re: Naked Engine Questions
If you're sure the threads are bad on the spark plug I'd heli-coil it, but from the pics I'd also guess your head gasket was leaking. At .050 already I'd hone and re-ring and hope for the best, but see what Dave comes up with. If anyone can help you you more, he can!
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05-05-2009, 11:53 PM | #5 |
Gone Wild
Join Date: Feb 2009
Location: P-COLA
Posts: 1,176
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Re: Naked Engine Questions
Maybe broken oil ring??? Jus' tryin'...
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05-06-2009, 12:00 AM | #6 |
Not Yet Wild
Join Date: Jun 2008
Posts: 57
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Re: Naked Engine Questions
I've got another head that is in much better condition that I plan on swapping out.
Don't think the headgasket failed since I had plenty of compression 150PSI, I was planning on just swapping heads, but I think I have too much oil in the cylinder to start with. Is what you see a normal amount of oil in a cylinder? If so I'll just put a head on and go. Otherwise i'm thinking collapsed oil ring from sitting and pray for a hone? |
05-06-2009, 12:11 AM | #7 |
Raised by coyotes
Join Date: Nov 2008
Location: Central Texas
Posts: 5,658
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Re: Naked Engine Questions
E, that amount of oil in a cylinder sure looks excessive to me.
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05-06-2009, 07:27 AM | #8 |
Admin
Join Date: Dec 2006
Location: TN
Posts: 101,826
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Re: Naked Engine Questions
Cylinder wall looks scored pretty bad to me in the pics. Possibly a bad ring. I also agree with dirtysouth about the valve guides and seals. Might want to make sure you installed the new rings correctly. If I'm not mistaken the two top rings may be specific to each location: meaning there is a difference. I'm not completely sure about this and smallblock should be able to verify.
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05-06-2009, 08:16 AM | #9 |
Not Yet Wild
Join Date: Jun 2008
Posts: 57
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Re: Naked Engine Questions
Yep, I didn't put the rings on, so it sounds like I get to dissasemble the motor a bit more and pop the piston out.
Can this be done while the motor is in the cart, or do I have to remove the motor? Is there any way to tell if the rings are bad after looking at them? Since the piston is already at 0.050 overbore, do I just order 0.050 rings and put them on? Or how do I measure them and gap them correctly to fit the piston and cyl wall? I hopefully have a manual comming in the next few days. On the clutch, I've removed polaris CVT clutches by putting a small blank bolt into the pulley hole, and then tightening a bolt to push it out.....same concept on the yamaha drive clutch? If so anyone know the diameter of the piece at the end of the shaft needed? |
05-06-2009, 08:29 AM | #10 |
Admin
Join Date: Dec 2006
Location: TN
Posts: 101,826
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Re: Naked Engine Questions
Pull the engine, only about 5 bolts holding it in: 4 on the mounts and 2 under the muffler attaching it to the rear axle brace. To pull the drive clutch, just use an impact to remove the bolt. If you bored your cyclinder wall oversize, I would say you need to go with oversized rings. Wait to do much of anything until you get your manual.
Dave (smallblock) is going to be a good source for you here. He's probably built hundreds of these engines. |
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