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1G Low compression new engine

Posted by 98 dsm, Apr 3, 2020

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  1. jed344

    jed344 Supporting VIP

    706
    100
    Joined Jan 10, 2008
    Waterville, Iowa
    By chance does the motor have cams? cams with a lot of overlap and aggressive can lower cranking pressure. For instance my motor is 10:1 and with different sets of cams and overlaps I was able to swing compression anywhere from 125-190. What was ring gap and PTW?. My motor is built a lot looser then most but it is built to make a lot of power. Built loose with cams with a lot of overlap could explain it.
     

    1K  38

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  2. SasaniFab

    SasaniFab Freelancer

    2,245
    660
    Joined Dec 1, 2013
    danbury, Connecticut
    when I built my motor I noticed a variance in compression when adjust My cam gears with gsc stage 2s , what didn’t change was the variance between cylinders. When my compression lowered is was even between cylinders
     

    Street Build 3K  20

    1992 Eagle Talon TSi
    645 whp · 498 lb/ft · 1G DSM
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  3. jed344

    jed344 Supporting VIP

    706
    100
    Joined Jan 10, 2008
    Waterville, Iowa
    That is true and I should have said that. My cylinders are always within a few psi of each other. Just the overall can swing a lot.
     

    1K  38

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  4. motomattx

    motomattx Proven Member

    2,336
    980
    Joined Dec 9, 2010
    wampum, Pennsylvania
    I'm just not, if things aren't broke why try to re-invent the wheel? the tried and true methods for seating rings were around for many decades, rings and cylinders haven't changed, why mess with seating methods?
     

    Drag Race Build 4K  24

    1995 Mitsubishi Eclipse GST
    fwd · manual · 2G DSM
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  5. jed344

    jed344 Supporting VIP

    706
    100
    Joined Jan 10, 2008
    Waterville, Iowa
    What method do you prefer? I have always broken motors in with sort of moto man method. I always check compression and leak down during break it and within very short time rings seal.
     

    1K  38

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  6. 98 dsm

    98 dsm Supporting Member

    58
    26
    Joined Mar 8, 2009
    milaca, Minnesota
    Sorry it took so long to reply. Head gasket multiple failures on #2. Im at fault i took the head of thinking i forgot a dowel "i didn't" i never made sure the L19 were seated all the way into the block before re-torqueing. Head was warped, i pick it up tomorrow. Cylinders look great. 8:3:1 wiseco piston eagle h beam rods. Composite hg with arp L19
     

    156  4

    1990 Plymouth Laser RS Turbo
    fwd · manual · 1G DSM

    Drag Race Build 203  8

    1991 Eagle Talon TSi AWD
    awd · manual · 1G DSM

    Street Build 152  7

    1990 Eagle Talon TSi
    13.805 @ 99.67 · 1G DSM
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  7. 98 dsm

    98 dsm Supporting Member

    58
    26
    Joined Mar 8, 2009
    milaca, Minnesota
    Yes i have cams hks272/264
     

    156  4

    1990 Plymouth Laser RS Turbo
    fwd · manual · 1G DSM

    Drag Race Build 203  8

    1991 Eagle Talon TSi AWD
    awd · manual · 1G DSM

    Street Build 152  7

    1990 Eagle Talon TSi
    13.805 @ 99.67 · 1G DSM
    Loading...
  8. 98 dsm

    98 dsm Supporting Member

    58
    26
    Joined Mar 8, 2009
    milaca, Minnesota
    So my head was done yesterday. Before i left to pick it up out of curiosity i asked for total height of the head. The head has been milled a total of 22 thousands. Aera service limit is 15 thou. 7 thousandths over block has also been decked unsure how much. My question is should he have measured it before milling? Im assuming the head is junk?
     

    156  4

    1990 Plymouth Laser RS Turbo
    fwd · manual · 1G DSM

    Drag Race Build 203  8

    1991 Eagle Talon TSi AWD
    awd · manual · 1G DSM

    Street Build 152  7

    1990 Eagle Talon TSi
    13.805 @ 99.67 · 1G DSM
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  9. 98 dsm

    98 dsm Supporting Member

    58
    26
    Joined Mar 8, 2009
    milaca, Minnesota
    Update: Brought him a new head . Ordered farrea beehive springs, bronze guides, and hks head gasket! Crossing fingers
     

    156  4

    1990 Plymouth Laser RS Turbo
    fwd · manual · 1G DSM

    Drag Race Build 203  8

    1991 Eagle Talon TSi AWD
    awd · manual · 1G DSM

    Street Build 152  7

    1990 Eagle Talon TSi
    13.805 @ 99.67 · 1G DSM
    Loading...
  10. 98 dsm

    98 dsm Supporting Member

    58
    26
    Joined Mar 8, 2009
    milaca, Minnesota
    update : resolved. everything's been back together for a few days compression tested 150 on all 4. felt gasket and heat don't play well. also fixed my wiring headache, i appreciate everything you guys
     

    156  4

    1990 Plymouth Laser RS Turbo
    fwd · manual · 1G DSM

    Drag Race Build 203  8

    1991 Eagle Talon TSi AWD
    awd · manual · 1G DSM

    Street Build 152  7

    1990 Eagle Talon TSi
    13.805 @ 99.67 · 1G DSM
    Loading...
  11. TK's9d2TSi

    TK's9d2TSi Supporting Member

    3,092
    1,208
    Joined Sep 11, 2017
    Cincinnati, Ohio
    It was a new hg?
     

    381  3

    2000 Jeep Cherokee Sport - Classic
    awd · automatic · Misc Vehicles

    426  4

    93 Civic 4 Door -sold-
    fwd · manual · Misc Vehicles

    Street Build 3K  6

    1992 Eagle Talon TSi AWD
    12.2 @ 120 · 1G DSM
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  12. Sniffbooger

    Sniffbooger Proven Member

    137
    38
    Joined Apr 12, 2020
    Torrance, California
    Wow... Thats seems like super low compression... especially for a new engine!
     

    Street Build 257  8

    1998 Mitsubishi Eclipse GST
    fwd · manual · 2G DSM
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  13. 98 dsm

    98 dsm Supporting Member

    58
    26
    Joined Mar 8, 2009
    milaca, Minnesota
    yes new headgasket both times. sorry btw, i never seen i had replies.
    150 seems low? or prior to tearing it down?
     

    156  4

    1990 Plymouth Laser RS Turbo
    fwd · manual · 1G DSM

    Drag Race Build 203  8

    1991 Eagle Talon TSi AWD
    awd · manual · 1G DSM

    Street Build 152  7

    1990 Eagle Talon TSi
    13.805 @ 99.67 · 1G DSM
    Loading...
  14. Sniffbooger

    Sniffbooger Proven Member

    137
    38
    Joined Apr 12, 2020
    Torrance, California
    Sorry I was referring to this post where it says 120 psi...
     

    Street Build 257  8

    1998 Mitsubishi Eclipse GST
    fwd · manual · 2G DSM
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