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Thread: low compression

  1. #1
    Hybrid booster 4cefedomni's Avatar
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    low compression

    cyl 1, 90 2, 90 3, 125 4, 75 on the way home from the track my cam end cap blew off on the hi-way and i lost 2 quarts of oil i think it blew because of lots of blow-by also it blows oil out my turbo seals making a big cloud when i'm under boost this is all new it wasn't happening before( well it was but before it was the o-ring gone on my pcv valve letting boost into the crankcase)what can i do to bandaid this while i build my other motor?
    you can't polish a turd! [COLOR="Red"][FONT="Arial Black"][/FONT][/COLOR]13.67@100.11

  2. #2
    Hybrid booster 4cefedomni's Avatar
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    Re: low compression

    i just drove it and it accelerates fine no smoke but on deceleration it blows smoke and lots of it it also only blows smoke after i go quite high into the boost. if i only go 5psi or so it doesn't smoke on deceleration.
    you can't polish a turd! [COLOR="Red"][FONT="Arial Black"][/FONT][/COLOR]13.67@100.11

  3. #3
    Hybrid booster
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    Re: low compression

    Recheck you PCV system (the valve) and make sure it's not sticking open. Also, you "could" have either a cracked piston, blown seals or just really worn rings. I'd try to stay out of boost until you get that other engine built up. What does your boost gauge read for vac at idle and decel?

  4. #4
    Hybrid booster 4cefedomni's Avatar
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    Re: low compression

    i have good vacuum like 20in/hg at idle and even more on deceleration the car runs really well it just blows smoke on deceleration one of my pcv isn't sealing very well i can blow the wrong way through it a little but thats the one that goes to my intake pipe right after my airfilter.
    you can't polish a turd! [COLOR="Red"][FONT="Arial Black"][/FONT][/COLOR]13.67@100.11

  5. #5
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    Re: low compression

    FWIW, your rod bearings probably took a heck of a beating when you lost that 2 quarts of oil. A set of "band-aids" would run you $25 and a couple hours time.

  6. #6
    Hybrid booster 4cefedomni's Avatar
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    Re: low compression

    okay this is screwed up if i take off my oil filler cap it smokes but there is definately gasses coming out the hole. if i take off the pcv system at idle it smokes and it creates suction. so if i release pressure it smokes if i remove the vacuum adding more pressure it smokes WTF. it doesn't smoke under boost but as soon as i let off the throttle huge cloud. i thought it might be turbo seals but my intercooler pipes have no sign of oil in them on either side of the intercooler and with them disconnected and my hand in front of them if i rev it no oil so i don't think its the turbo seals unless its the turbine seal and no the compressor seal.
    you can't polish a turd! [COLOR="Red"][FONT="Arial Black"][/FONT][/COLOR]13.67@100.11

  7. #7
    Hybrid booster
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    Re: low compression

    Hmm.... here's a thought. Take your valve cover off and take a look at the PCV cap/cover (or whatever the hell it's called) that's on the inside of the valve cover. See if it's sealed properly, if not, unscrew/clean it and use some black RTV and reseal it and tork it back down. I'm just throwing out ideas but something is definitely not right.

  8. #8
    Hybrid booster 4cefedomni's Avatar
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    Re: low compression

    tomorrow i will pull the oil pan and have a look at the cylinder walls i may have cracked a piston ring or something, something is causing all this smoke
    you can't polish a turd! [COLOR="Red"][FONT="Arial Black"][/FONT][/COLOR]13.67@100.11

  9. #9
    Hybrid booster 4cefedomni's Avatar
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    Re: low compression

    the blow by was caused by really worn cylinders the pistons can be rocked back and forth alot by hand so this engine is done i guess until i build my hybrid
    you can't polish a turd! [COLOR="Red"][FONT="Arial Black"][/FONT][/COLOR]13.67@100.11

  10. #10
    Buy my stuff!!!!!!!!!!! :O) Turbo Mopar Vendor turbovanmanČ's Avatar
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    Re: low compression

    Thats what I was going to say, youv'e cracked a piston or its just plain worn out.
    1989 FWD Turbo Caravan-2.5 TIII, GT35R, auto, a/c, cruise, pwr windows/locks, fully loaded with interior and ran with full exhaust. RETIRED FOR A FEW YEARS! 12.57@104 :O)
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  11. #11
    Hybrid booster 4cefedomni's Avatar
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    Re: low compression

    yup shes worn out the pistons look great but they are loose. do you think the smoke on deceleration was due to this or are there other problems like valve guides or something?
    you can't polish a turd! [COLOR="Red"][FONT="Arial Black"][/FONT][/COLOR]13.67@100.11

  12. #12
    Buy my stuff!!!!!!!!!!! :O) Turbo Mopar Vendor turbovanmanČ's Avatar
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    Re: low compression

    Quote Originally Posted by 4cefedomni
    yup shes worn out the pistons look great but they are loose. do you think the smoke on deceleration was due to this or are there other problems like valve guides or something?

    It could have valve guide issues, no way of knowing unless you get the head checked or install new valve seals.
    1989 FWD Turbo Caravan-2.5 TIII, GT35R, auto, a/c, cruise, pwr windows/locks, fully loaded with interior and ran with full exhaust. RETIRED FOR A FEW YEARS! 12.57@104 :O)
    1984 Chev Getaway van, 6.2 Diesel with a remote mounted turbo setup burning WMO-For sale.
    2003 GSW 2.0L TDI, auto, fully loaded, modified, 360K-wife's.
    2004 GSW TDI, 5 speed, fully loaded, modified.

    Aurora ignition wires for sale. Link to info

    Super60 roller cams or custom/billet cams. Link to info

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