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Is my cylinder head ok?

Posted by John Mark Dongon, Mar 13, 2019

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  1. John Mark Dongon

    John Mark Dongon Probationary Member

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    Joined Feb 7, 2019
    Stockton, California
    20190313_183225.jpg 20190313_184054.jpg 20190313_175235-1.jpg Im on a budget and decided to resurface using sand paper. The problem is when I shine a flashlight I can see very little indents across the surface. Is this bad or is it ok? I would keep sanding but I'm afraid of over sanding.
     

    Attached Files:

    Street Build 124  1

    1997 Mitsubishi Eclipse Spyder GST
    automatic · 2G DSM
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  2. DSMPT

    DSMPT Proven Member

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    Joined Jun 12, 2014
    Mexico, Arizona
    You should check the flatness before sand it. it would be depending on the result. Check it as below.
    If the flatness is within the spec then it would probably be fine if you use a composite gasket. But you definitely should bring it to a machine shop to re-surface, if you use a MLS gasket.
    Head flatness.jpg
     

    Street Build 681  2

    1998 Mitsubishi Eclipse GSX
    awd · automatic · 2G DSM

    Drag Race Build 490  1

    1990 Mitsubishi Eclipse GSX
    awd · manual · 1G DSM
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    steve and John Mark Dongon like this.
  3. motomattx

    motomattx Proven Member

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    wampum, Pennsylvania
    Never ever use sand paper on a cylinder head, especially aluminum heads, you would be better off leaving it alone and wiping it clean with acetone, that being said as long as you didnt screw it up with the sandpaper too much it should be ok, you do have what looks like some detonation damage in one cylinder I see so that tells me that it was knocking at some point, you might want to find out why.
     

    Drag Race Build 2K  13

    1995 Mitsubishi Eclipse GST
    fwd · manual · 2G DSM
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  4. pauleyman

    pauleyman DSM Wiseman

    4,949
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    oklahoma city, Oklahoma
    Have that thing decked. Its cheap.
     

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    1997 Eagle Talon TSi AWD
    awd · manual · 2G DSM
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  5. hopwoodp

    hopwoodp Proven Member

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    Oak Harbor, Washington
    I’d do what Pauleyman suggest. I was there with a 2g head not long ago. I checked for flatness in accordance with the manual, it was out of spec. I took a decent 1g head and had it worked. Spent $400 for deck, clean, valve job/grind, new seals, etc.

    I wouldn’t skimp on something like this. This is the heart of your car.
     

    Street Build 486  10

    1995 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  6. John Mark Dongon

    John Mark Dongon Probationary Member

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    Stockton, California
    I didn't sand too much and one of the pistons was chipped upon disassembley so i think that's what caused the detonation. So it should be ok to use in this condition despite the detonation?
     

    Attached Files:

    Last edited: Mar 14, 2019

    Street Build 124  1

    1997 Mitsubishi Eclipse Spyder GST
    automatic · 2G DSM
    Loading...
  7. DSMPT

    DSMPT Proven Member

    316
    79
    Joined Jun 12, 2014
    Mexico, Arizona
    That's a lot but how does the piston top look like? If those detonation marks on squish area are caused by you, probably you see them on piston top, too. You might have run too lean, too much boost, too advanced ignition timing, low octane gas, etc etc. So just be careful about that with the new engine.
    If you have never run like that or if you don't see any marks on piston top, then there is a possibility that it's from previous owner.
     

    Street Build 681  2

    1998 Mitsubishi Eclipse GSX
    awd · automatic · 2G DSM

    Drag Race Build 490  1

    1990 Mitsubishi Eclipse GSX
    awd · manual · 1G DSM
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  8. ThunderChild

    ThunderChild Previously tametalon92

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    Rathdrum, Idaho
    It's like $25 bux to have a head surfaced. Personally I wouldnt run that head as-is.
     

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    1997 Mitsubishi Eclipse Spyder GST
    fwd · manual · 2G DSM

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    manual · 1G DSM

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    awd · manual · 1G DSM
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  9. John Mark Dongon

    John Mark Dongon Probationary Member

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    Joined Feb 7, 2019
    Stockton, California
    It's from the previous owner I only had the car for about a month before it started to make a constant knocking noise. As my uncle inspected the car we noticed the coolant tank was empty so I've been running without coolant for over a month+ however long the stupid previous owner was running the car.
     

    Street Build 124  1

    1997 Mitsubishi Eclipse Spyder GST
    automatic · 2G DSM
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  10. amsrn13

    amsrn13 Freelancer

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    danbury, Connecticut
    People get caught up on the flatness of the deck and dont take The Ra into consideration. Ra is short for Surface roughness. It takes a significant role in head gasket sealing. Sand paper is not the correct way to surface a performance engine. If you plan of just getting the engine to run with a composite gasket will it work? Maybe... I just dont understand why people choose to take shortcuts when they are unnecessary. Having a head serviced is cheap, as cheap as buying the supplies needed to hand sand the cylinder head. Do it correctly or dont waste your time
     

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    1992 Eagle Talon TSi
    645 whp · 498 lb/ft · 1G DSM
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  11. DSMPT

    DSMPT Proven Member

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    Mexico, Arizona
    I agree with you about the RA and definitely having the cylinder head decked wouldn't cost much..
    No offense but I don't think the best/better way is always "necessary" for everyone. Just clean the block/head surface and use a composite head gasket would be fine as long as if the both surface is clean and the both side flatness is within the spec. and especially if the OP just wants to make the car running again for daily use. Just hope he didn't over-sand. If the flatness is out of the spec then no choice, has to be surfaced.
    I would have completely agreed with you and would say the same thing if the OP mentioned that he wants something good or planning to modify the car to have high horsepower or go faster etc etc. But as the OP clearly mentioned at the first that he is on a budget.. So I assumed he is not planning to modify the car much. I would be surprised if the OP is planning to build a high horsepower car.
     

    Street Build 681  2

    1998 Mitsubishi Eclipse GSX
    awd · automatic · 2G DSM

    Drag Race Build 490  1

    1990 Mitsubishi Eclipse GSX
    awd · manual · 1G DSM
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  12. amsrn13

    amsrn13 Freelancer

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    I guess my point is budget or not having a head milled is cheap.....very cheap in fact. What happens when he spends all that money rebuilding the engine to have to tear it all apart because the headgasket doesnt seal?. Do it correctly, youll be glad you did
     

    Street Build 2K  20

    1992 Eagle Talon TSi
    645 whp · 498 lb/ft · 1G DSM
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  13. nismojones

    nismojones Proven Member

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    Metro Detroit, Michigan
    I’m not sure if it’s the lighting in the pictures, but inspect the spark plugs threads, I don’t see any on No#1?
     
  14. DSMPT

    DSMPT Proven Member

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    Mexico, Arizona
    What you say is right. I was always telling my customers like what you say, the better or the best way. It doesn't make sense to me neither to take a risk for saving a little money and time. It is not worth, compared to the time and money that they would lose. But I learned that sometimes it doesn't fit with some people's case.
    My point is our way is not always the only way to go, even if we think it is not ideal or the best. There are people who really don't need, don't want it or maybe can't with some reason.
    To check the flatness according to the factory service manual and not to have the head milled if the flatness is within the spec is also a correct way.
     

    Street Build 681  2

    1998 Mitsubishi Eclipse GSX
    awd · automatic · 2G DSM

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    1990 Mitsubishi Eclipse GSX
    awd · manual · 1G DSM
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  15. amsrn13

    amsrn13 Freelancer

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    hey Ay
    In many cases you can just slap another composite gasket on and go. The fact that he mentioned his head has pitting , more specifically around the sealing surface of the combustion chamber to me means this method will not work. The pitting might not even come out with machining. I think his only option is machining and a composite....Hopefully those pits arent to deep
     

    Street Build 2K  20

    1992 Eagle Talon TSi
    645 whp · 498 lb/ft · 1G DSM
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  16. donniekak

    donniekak DSM Wiseman

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    I tell my customers I only follow best accepted practices. I refuse to put a compromise build out there with my name on it.
     

    Street Build 3K  0

    1991 Eagle Talon TSi AWD
    manual · 1G DSM
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  17. DSMPT

    DSMPT Proven Member

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    Yes as you said most of case it would probably seal if the conditions are met and installed correctly. Of course there is a possibility that wouldn't seal well. It is almost impossible to distinguish exactly with just some pics. And still the best bet is to have it milled.

    Obviously, I am not recommending to compromise. I am saying is there would be an another possibility that would work. But right, what you tell your customers is the same thing as I was telling to my customers. I had refused all customers who wanted to compromise a lot or dreamt to build a high horsepower car with only cheap used ebay parts. So I quit. I don't work anymore since where I live is mostly like that. But I do understand that they had their own reason that sometimes not to be able to do as I believe.
     

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    1998 Mitsubishi Eclipse GSX
    awd · automatic · 2G DSM

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    1990 Mitsubishi Eclipse GSX
    awd · manual · 1G DSM
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  18. motomattx

    motomattx Proven Member

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    wampum, Pennsylvania
    It will live, and hey there was a time when I used sand paper on things like that when I didnt really know why not to myself, and here I am someone that turned out to be a top notch lead tech that has taught others the right way in the shop, I have done much worse so dont worry about it, I just want you and anyone that reads the thread to know not to do that, it causes way more harm then good.
     

    Drag Race Build 2K  13

    1995 Mitsubishi Eclipse GST
    fwd · manual · 2G DSM
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    DSMPT likes this.
  19. DSMPT

    DSMPT Proven Member

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    Mexico, Arizona
    Maybe should think it vice versa. The detonation caused the damage. So you should figure out what caused the detonation and try not to bring the same issue to the new engine.
     

    Street Build 681  2

    1998 Mitsubishi Eclipse GSX
    awd · automatic · 2G DSM

    Drag Race Build 490  1

    1990 Mitsubishi Eclipse GSX
    awd · manual · 1G DSM
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  20. ThunderChild

    ThunderChild Previously tametalon92

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    Ok, I'd love to know who's running around with these supposed engines on a belt-sander, 220 grit cylinder head finish. Not saying someone out there hasn't, (my uncle missionaried in Kazakhstan for years, and had to have their Trooper head done, guy set the head on a big disc sander, albeit 4 times...) but I doubt there's many guys/teams using that practice that are running 8s, 9s or better.

    Not trying to be a deal, but i gotta call B's on it.

    Either way, op needs to send his cylinder head in to be decked at least, which is only 25 bux or so, and to pressure check is usually another 20-25.
     

    Street Build 309  7

    1997 Mitsubishi Eclipse Spyder GST
    fwd · manual · 2G DSM

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    1992 Eagle Talon TSi AWD
    manual · 1G DSM

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    1992 Eagle Talon TSi AWD
    awd · manual · 1G DSM
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  21. donniekak

    donniekak DSM Wiseman

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    I can tell when I surface heads or blocks if they’ve been done wrong before. With a sander they’ll always be tilted and the wrong ra. If they’ve been rol loc’d Or hand sanded you can see the waves in the surface after the first pass.
     

    Street Build 3K  0

    1991 Eagle Talon TSi AWD
    manual · 1G DSM
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  22. ThunderChild

    ThunderChild Previously tametalon92

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    @Crackerman I guess if it works for you in that application, go nuts, but comparing a pomegranate to a cumquat when talking about surfacing cylinder heads isn't really relevant. Aluminum vs cast iron, huge I6 vs small I4 etc... There's no direct comparison, and you even said yourself you wouldn't do it to your dsm.

    non-descriptly stating that using a belt sander is a decent way to surface a cylinder head to someone not as knowledgeable who is asking for help on their 4g63 powered car, when you're vaguely referencing a completely different application is not what I'd call helpful.

    I appreciate that it works for you and whoever else you know running that style surface, but please don't go spreading that around as if it's even remotely ok for these cars.
     

    Street Build 309  7

    1997 Mitsubishi Eclipse Spyder GST
    fwd · manual · 2G DSM

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    1992 Eagle Talon TSi AWD
    manual · 1G DSM

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    1992 Eagle Talon TSi AWD
    awd · manual · 1G DSM
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  23. Joe Gekko

    Joe Gekko Proven Member

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    Kingwood, Texas
    Did you sand it by moving the sandpaper with your hand, or did you have the sandpaper glued down to a piece of glass or something to ensure flatness, and move the head over the sandpaper?
     

    Street Build 1K  0

    1995 Eagle Talon TSi AWD
    manual · 2G DSM

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    1995 Mitsubishi Eclipse GST
    manual · 2G DSM
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  24. tk106

    tk106 Proven Member

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    A9D2D6CD-73EA-4805-8E63-3988D88A00D4.jpeg 7F9DBD41-8A87-4C44-AF9E-D06EBF1CBE00.jpeg
    This is my head and it’s back together running fine. It’ll give carbon something to grab onto. Should be fine otherwise. Just make sure there aren’t sharp spots since that might cause hot spot for knock.
     

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    1992 Eagle Talon TSi AWD
    awd · manual · 1G DSM
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  25. Old Mitsu Tech

    Old Mitsu Tech DSM Wiseman

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    Newburg, Missouri
    Ok. We all try to save money. I get that. However, we aren’t qualified machine shops. There’s more to heads than flatness. Are your guides within spec? Is the flatness within tolerances? Ate there invisible cracks? And a whole cornucopia of other things they check for. Next question. Do you want to risk pulling the head again if it’s not right? It’s like buying insurance. I’ve been doing this a lot of years. I take mine to the machine shop. I want guarantees. I don’t have the calibrated machinery to guarantee a proper finished product. You might ask them to check your work if having them to do it is unacceptable. Just my 2 cents.
     
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