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Trust machine shop and buy new heads or hold out for a second opinion??

Discussion in '6.9L IH & 7.3L IDI Diesels' started by Grant Cdebaca, Nov 19, 2020.

  1. Grant Cdebaca

    Grant Cdebaca Registered User

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    Hi everyone. First post. 1990 e350 non turbo started chuffing, occasionally ticking/knocking, eating oil, comp test showed 400-450 all around except for #1, which was 200. Still had good power with no smoke, but the idle was rough and the chuff/tick was getting worse. Rockers, pushrods, lifters all looked to be without any flaw, so i took the heads off and brought em to a place called Cylinder Head Exchange in Sylmar, Ca.

    They got back to me in a couple hours saying that both heads were cracked on the intake seats of #5 and #6 and that there was nothing they could do. Said that i should find new heads elsewhere. Went back to pick them up and although they marked the two cracks, i cant see anything. I cant see anything at all on #6 and can barely make out an almost microscopic line about 1/8" on the seat of #5.

    Im unsure where to go from here because both of those cylinders had good compression, and the shop didnt provide any info beyond those cracks. The shop seemed professional, but maybe it was the wrong place for a strip/advise and i should get a second opinion? Or should i just bite the bullet and buy some rebuilt heads?

    Also, if surface cracks can be so invisible on the heads, id assume it would be the same for the block. Any tips for inspecting the block mating surface. I still havent cleaned either side since removing the heads.
     
  2. Philip1

    Philip1 Supporting Member Supporting Member

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    The microscopic hairline crack would put your head out of commission. They are often repairable (depending on how bad it is) although not all machine shops will be willing to do these repairs. To check the block, the best way is to use crack detecting dye (https://www.amazon.com/dp/B00XLW4BRC/ref=cm_sw_r_cp_apa_fabc_RBXTFbFV46BV7) or magnetic detection (https://www.amazon.com/dp/B077QR2GRG/ref=cm_sw_r_cp_apa_fabc_eDXTFb83VM0QP). If those are a no go and you cannot take the block to the machine shop for inspection a good flashlight and a good eye would be the best option.
     
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  3. Koch13351

    Koch13351 Full Access Member

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    I see you are in Southern California, as am I. I recently had a set of 6.9 heads completely done up by Southwest Engines in San Bernardino, and they are second to none in my opinion on their attention to detail on the specs and making sure the process is done right. Look them up and give them a call.
     
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  4. homelessduck

    homelessduck Full Access Member

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    The machine shop I use takes me in the back and re-mags my heads if they are cracked so they can show me exactly where they cracked..
     
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  5. Booyah45828

    Booyah45828 Full Access Member

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    If #1 was your dead hole, how's the cylinder/piston/rings look for #1. What did the valve, seats, and guides look like on that cylinder? The compression is going somewhere, if you can't find the loss in the head or gasket, then it's got to be in the bottom end.
     
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  6. Grant Cdebaca

    Grant Cdebaca Registered User

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    Thanks everyone. All cylinders and piston heads look good, including #1. Not sure about the rings though and I’m not going to be pulling this engine to check. Unfortunately all the valves/springs/etc were left in a box without note of where they were in the head. Some valves have more wear/play than others and one has a pretty banged up stem crown. The guides seem to all have the same amount of very slight play when I check with the same valve all around. It seems like tracking down some rebuilt heads is the way to go.

    Y’all might get a kick out of my one man extracting method. I know removing these heads in a van is a bit of a dark art.

    5757FB0C-A1BC-4286-A818-48B1D829B12B.jpeg

    BBECDCCF-8006-4AD4-99B6-46706C552DB9.jpeg

    E508663D-557B-45F6-B9AE-FA76A4BD2B0C.jpeg
     
  7. Grant Cdebaca

    Grant Cdebaca Registered User

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    I forgot to add that before I took the heads in, I could feel some noticeable play in the #1 exhaust valve while it was still loaded.
     
  8. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    That's probably where your compression went to. That valve wasn't closing straight and wasn't seating completely. The exhaust valve guides is one weak spot in the 7.3.
     
  9. genscripter

    genscripter Full Access Member

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    I know exactly how you feel. pulling the heads in the van is an art.

    [​IMG]


    [​IMG]

    we made a steel tube extension for my shop crane to make lifting the heads easier.

    The hard part for you (as a one-man operation) is reinstalling them without scuffing the HG's. I'd ask a friend or neighbor to help line up the front of the cylinder head while you align the rear. By yourself, it'll be really tough.


    I did a write up about it: https://www.nickpisca.com/diesel/en...i-head-gasket-job-without-pulling-the-engine/
     
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  10. genscripter

    genscripter Full Access Member

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  11. Grant Cdebaca

    Grant Cdebaca Registered User

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    Nick! I’ve read your write up so many times man! I don’t think I would of had the confidence to do the job without it. I almost rented a crane before I went with the 2x4. I’ll definitely have an extra hand for the install.

    You ended up getting heads from diesel cast welding right? Do you remember what their price range was?
     
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  12. lotzagoodstuff

    lotzagoodstuff Supporting Member Supporting Member

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    You van guys have my utmost respect. I really like vans, right up to but not including working on one :eek:
     
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  13. Grant Cdebaca

    Grant Cdebaca Registered User

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    Ya I’ve been pretty bummed out at times working on this thing, but you get kinda good at it after awhile. I also got it a lot easier not having a turbo to work around, and the dog house has its perks. I’m sure I’ll be eating these words in a week or so...
     
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  14. riphip

    riphip Supporting Member Supporting Member

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    I would have to have a tall enclosure with 2 post lift to remove box from frame. Can't be that many frame bolts. I reek EASY, no matter the cost, sometimes. Only if it is repetitive usage tho
     
  15. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    I have to agree. I HATED working on vans. Working on them is probably the #1 reason that I won't own one. Now if I was rich and could just pay someone else to work on it, that may be a different story.
     
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