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Project Big Blue

Discussion in '6.9L IH & 7.3L IDI Diesels' started by Thewespaul, Dec 8, 2019.

  1. Garbage_Mechan

    Garbage_Mechan Garbage Mechanic

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    Booyah I know Ra is quoted on head specs and is a surface finish quality measurement could you explain how it is measured?
     
  2. ifrythings

    ifrythings Full Access Member

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    A few weeks back I watch this video from FTE member TooMnayToys that explains a lot about Ra and required surface finish

     
  3. Booyah45828

    Booyah45828 Full Access Member

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    With a tool called a profilometer. It basically drags a stylus across the surface and calculates the Ra based off the movement of the stylus.
     
  4. Booyah45828

    Booyah45828 Full Access Member

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    As far as walking away from a machine shop that doesn't have one, I don't know if I'd do that. A good machinist can get the right surface finish without needing a profilometer. It's nice to have one to get an exact number, but when you're working in a 20-30 window, a good machinist with sharp tooling can get there without worry.

    To be honest, I've seen more issues with flatness causing head gaskets not to seal then incorrect surface finish.
     
  5. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    I've run into this before too.
     
  6. Garbage_Mechan

    Garbage_Mechan Garbage Mechanic

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    On the RMS I had some engines back in the 80’s that were very sensitive to head surface finish. Had to run pure graphite head gaskets on a very smooth surface.

    On the IDI head surfacing I have ran into the issue with the precuts being hard. The shop that used to do mine used an actual surface grinder. He was very careful to be sure the precups were tight....if one came out while grinding it would likely explode the wheel (and destroy the head)
     
  7. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    Far from horrible, with a head surfacing machine unless you change to a brand new insert every time you go over a prechamber you’re just going to have visible marks where the cutter passed over the inconel and back into the cylinder head and they aren’t noticeable to the touch on the surface, just visible on the surface. These aren’t mls gaskets and aluminum heads that require a mirror finish for sealing, what’s most important is the flatness, the surface finish can be cleaned up with lapping stones and prep tools which I did for good measure, on top of the copper coat to seal any imperfections with the block surface and 150 ft lbs on the studs, shouldn’t ever, ever have to come apart again
    :Thumbs Up
     
  8. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    Well she’s a runner, just did a first fire and it lit off pretty easy. Did my compression check while priming everything and actually picked up some compression on most cylinders with having the heads shaved, with my highest now just being shy of 500 psi. Getting the accessories and intercooler kit in tonight for a first drive in the morning!
     
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  9. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    So will you be able to get it on the dyno with the quarantine?
     
  10. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    Unless things change I can still get it run at truck source diesel where the truck was originally ran stock since the city considers them an essential business and still allows their employees to travel. Engine is coming along, hooking up the exhaust and setting the rad in now. 46B6CF08-71EB-430B-A76F-FD5D0FECECAB.jpeg
     
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  11. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    Exhaust and rad installed with fan and fan shroud.
    B9B3964B-A5FA-4D2D-88DB-F97B54F050D0.jpeg
    Intercooler piping installed with over flow tank, topping off fluids for another startup and to pressure testing the cooling system.
    82E83D17-3D06-4040-B958-97F94A0EF505.jpeg
     
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  12. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    All set for a test drive in the morning 87D22D68-643E-42E8-9244-F6B389F6EFBE.jpeg
     
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  13. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    I agree. I think that they're an essential business too.
     
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  14. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    Took the truck out on a loop around the shop and it’s been perfect so far, engine is nice and quiet, turbo sounds great and trans is shifting well. Going over fluids and clamps then going to run it out to the fab shop in town. E2B1893E-E48D-4D28-8CD7-A73D75395E72.jpeg
     
  15. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    Well back to the shop and nothing much to report, truck drives great, ac is cold and the ride is nice. Didnt really get on it much, it might have touched 20 psi once merging onto the highway at part throttle but plenty of power to move the truck around with ease without hardly any pedal effort. Im catching up on my inbox while the truck cools off then I would like to adjust the timing and drop the fipl voltage down half a volt, this new trans shifts very snappy and the triple disk converter is significantly lower stall than the stock converter so its taking some fiddling with the fipl setting to keep the trans shifting in the engine's power band, without making part throttle up shifts uncomfortable.
     
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