how to tell if my piston rings are bad?

Posted by dsm92talonboost, May 11, 2012
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  1. dsm92talonboost

    dsm92talonboost Proven Member

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    sacramento, California
    im curious to see if my piston rings are still good or bad. i have no compression and am in the process of removing the head and take the head to the machine shop to see if i have bent valves(due to me messing up on timing). is their any way possible to check if my piston rings are still good/bad without removing them from the block? thanks in advance!
    #1
  2. BogusSVO

    BogusSVO DSM Wiseman

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    Once the head is off.

    Rotate the crank so all 4 pistons are at mid stroke.

    Pour oil on tops of all 4 pistons, about an inch or so.

    Let sit for several hours/overnight.

    If they are good you will still have equall amount of oil on top of the piston.

    If one cyl is lower than the rest, you stand a good chance of a ring issue in that hole.
    #2
  3. dsm92talonboost

    dsm92talonboost Proven Member

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    ok thank you!! your info will help alot :)
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  4. REDspydergst

    REDspydergst Proven Member

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    If your car was running fine before you messed with the timing your rings should be fine. You are probably getting no compression because you bent the valves. There is no way you can know if your rings are bad unless you fix the valves on the head put it back on and do a compression test. If your taking the head off the block to fix the bent valves and your suspect that they are bad you should just replace them. Take the oil pan off and take each piston out of the block, put new rings in the pistons and put them back on the block.
    #4
  5. Th3DooM

    Th3DooM Proven Member

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    I got another method how to check your piston rings. You need a comression tester and just some oil. you don't have to disassemble the engine, but it has to be warmed up properly. Remove your sparkplug and unplug your fuel pump fuse or all four connectors to the injectors so no fuel can get into the combustion chamber. screw your compression tester into the sparkplug hole an try to start your car. 10 cranks should be enough. The car won't start since it gets no fuel and no spark (at least the cyliner you are testing). Now read and write down the pressure you got. Unscrew the compression tester, spill some oil into the cylinder and screw it back on. Try to start the car again.

    Do this with every cylinder.If there is a big difference between the numbers (before you put oil into it and after), your piston rings may gone bad. the oil improves the compression so the numbers should be higher. If there is no significant difference, you should look at your valvetrain(seats or valves itself - yesterday I saw a head with a broken valve. this cylinder got zero comression). your rings should be okay.

    I hope you guys get what I want :) English is not my mother tongue.
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  6. dsm92talonboost

    dsm92talonboost Proven Member

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    thats the thing is im in my apartments where they dont let you work on your car haha. i can have my head off in about an hour... to where i can get away with it. heres what happened i got a full head job exept valves done cause shop told me they were still good. same with cams. i put the head back on and boom everything was fine timed it started right up well i was driving it and about ten min into my drive my transmission broke... my luck. not gonna go into detail what happened but i ended up getting a new trans act six puck clutch 12lb aluminum flywheel ect well when tightening the flywheel the engine was turning so i had a friend get a 17 mm wrench to hold the cam gears from turning well turned out the crank shaft turned and skipped on the belt causing the timing to be off well when i was re timing it i had the exhaust valves or intake valves open not quite sure. As i was turning the crank to line up the mark on the timing plate(btw i have the bsek)(and yes i fogot abut putting cyl 1 on tdc thats why i think i bent valves) and i was turning the crank and i couldnt move it all of the sudden. so i got a long breaker bar and still couldnt turn it over, so my friend helped me turn it over and we finally got it i fought that like four times. which i should of just turned the cams.. i wasnt thinking and when i ended up timing it i dont think i brought cylinder one to tdc and it was actually at bdc and i believe i bent the valves. sorry for all the RUN ON SENTENCES i'm tired and keep for getting all my puncuation.

    im familiar with this test, just have to remember im in the process of pulling the head right now. and just got my head back from the shop with new supertech valve seals and valve guides and crower springs and titanium retainers.
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  7. dsm92talonboost

    dsm92talonboost Proven Member

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    after i installed the head it did not smoke. but befor that it smoked at idle and on decel and in between shifts.
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  8. reddragon1

    reddragon1 Proven Member

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    Did you replace any of the valve seals?
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  9. liljaywizzle85

    liljaywizzle85 Proven Member

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    A cylinder leak down test will tell you if the rings are bad, plus more. They're like 40 bucks at Harbor Freight. If the rings are bad in a cylinder, you'll hear hissing from the oil dipstick tube. The kit comes with instructions that tell you everything.
    #9
  10. dsm92talonboost

    dsm92talonboost Proven Member

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    I dont have. An air compressor due to me living in my apts

    Yes. I replaced all lo them and the car ran for ten min till my trans broke
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  11. DSMTyson

    DSMTyson Proven Member

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    It won't be accurate if the valves are bent. But otherwise, yes. This is a good way.
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  12. reddragon1

    reddragon1 Proven Member

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    That was probably the reason it was smoking. I mean if it was smoking before you changed that and now it's not. I feel that is safe to ASSume.
    #12

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