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  1. #1

    Tore down my 03 FX140 engine but not sure how piston rings should look

    I had about 60psi of compression on each cylinder. When I pulled the plugs and dropped some oil in the cylinders the compression went up to about 140psi on each so from what I read it points to piston rings. I tore the engine apart and replaced the lower ring on one of them but I'm not sure if I did it correctly. Is it supposed to be sticking out from the piston a little? The rest seem to be flush with the side of the piston. Here's some pictures can anyone tell me if I did it correctly?
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  2. #2

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    There is a tool to insert the ring on the piston, did you use that? It's possible you struggled to put it on and you damaged the ring...having said that, ring should be sticking out slightly but not sure the extend of it from the picture. If no one replied, ask frenchy on pwctoday he knows it all when it comes to these older machines...

  3. #3

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    Its a ring expander. You can get one from any auto parts store. If you do it carefully though, you can put them on without one. Make sure any markings on the new ring are UP. But most importantly, did you measure the end gap? I blew one up by installing wrong size rings by mistake. With those compression numbers the bores may be worn to the point where a rebore is necessary.

  4. #4
    yamacruiser's Avatar
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    Yeah definately sounds like more then just rings that compression is way to low and its all even across so that kinda tells you that its wear and tear how many hours on the machine?

  5. #5
    Ski Hacks MG's Avatar
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    Please don't take this the wrong way but tearing into an engine without knowing what you are doing (or knowing what you are looking at) is not smart and can further complicate things.

    At any rate, yes, they will stick out just as shown in your photos. Next, you need a ring compressor to compress the new rings around the piston before sliding them into the cylinder. It also goes without saying that you need to know how to properly orient the rings as well as how to use the tool to slide the rings into the cylinder.

    Be extra careful not to damage the oil ring. It's very easy to do.

  6. #6
    Quote Originally Posted by CCW View Post
    Please don't take this the wrong way but tearing into an engine without knowing what you are doing (or knowing what you are looking at) is not smart and can further complicate things.

    At any rate, yes, they will stick out just as shown in your photos. Next, you need a ring compressor to compress the new rings around the piston before sliding them into the cylinder. It also goes without saying that you need to know how to properly orient the rings as well as how to use the tool to slide the rings into the cylinder.

    Be extra careful not to damage the oil ring. It's very easy to do.
    Lol I'm not taking it the wrong way. I figured you can't really get any worse than dead so might as well see what happens. I have this OCD thing with having to know how something works so I take things apart more out of curiosity than anything. I have a machine shop local to me. I bring all my auto projects to him, wheel bearings etc. I've seen quite a few lower blocks and crankshafts from car engines there. I'm thinking I might be better off having him check it out. Thanks

  7. #7
    Quote Originally Posted by yamacruiser View Post
    Yeah definately sounds like more then just rings that compression is way to low and its all even across so that kinda tells you that its wear and tear how many hours on the machine?
    170 hours.

  8. #8
    Quote Originally Posted by butterbean_29512 View Post
    Its a ring expander. You can get one from any auto parts store. If you do it carefully though, you can put them on without one. Make sure any markings on the new ring are UP. But most importantly, did you measure the end gap? I blew one up by installing wrong size rings by mistake. With those compression numbers the bores may be worn to the point where a rebore is necessary.
    End Gap? Lol oops didn't measure anything. I didn't use any tools. The rings actually went on pretty easy, except getting them sandwiched together was tricky. I know they're the standard bore rings. I got them from the dealer and I cross checked the part number and it was standard bore.

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