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Thread: 46 Knuckle engine

  1. #31
    Join Date
    Apr 2008
    Location
    Upper Yarra Valley, Victoria. Australia
    Posts
    829

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    After a short interval, we are back the scheduled program.

    These heads are in reasonable condition but have had some trauma in the past.
    Even though these have been run with this repair, I will check the accuracy before investing time in painting and assembly.

    P9140005.jpg

    How do I clock this head to the mill? Do I trust the head gasket surface? Do I trust the towers?
    I had to trust something so I sat the head gasket surface on some ground blocks and used the towers to clock the head with a dial indicator. The towers still have a nice machined surface and the strengthening gusset on the other side of these towers should mean a greater chance of being straight.
    Once I had the readout the same across the two surfaces, I pulled the head down to the table. I also did a vertical check of these surfaces to check that the head was square in the other direction.


    P9140001.jpg

    P9140003.jpg

    P9140004.jpg

    Now that these surfaces have been clocked in, I could check if the rocker box supports were square to these towers.
    I think the job needed to be done in this way because the towers hold the other end of the rocker shafts.
    Steve Little
    Upper Yarra Valley. Victoria.
    Australia.
    AMCA member 1950

  2. #32
    Join Date
    Apr 2008
    Location
    Upper Yarra Valley, Victoria. Australia
    Posts
    829

    Default

    Measured the diving boards with a vernier height gauge. To ensure an accurate measurement I placed the gauge in close to the fin and then out at the tip of each one.

    P9160007.jpg

    P9160008.jpg

    P9160012.jpg

    Hmm?? I could fit a cutter in the mill and make them all the same, but that would be a trap for young players.
    There are a few more measurements to be taken before ripping metal off.

    P9160013.jpg

    P9160014.jpg

    I will let you know the findings on Monday.
    Hope everyone has a marvelous weekend.
    Steve Little
    Upper Yarra Valley. Victoria.
    Australia.
    AMCA member 1950

  3. #33
    Join Date
    Mar 2009
    Posts
    539

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    I appreciate and certainly respect your approach to this repair.
    Thanks so much for showing what you're doing, Steve.

  4. #34

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    Quote Originally Posted by Rooster View Post
    I appreciate and certainly respect your approach to this repair.
    Thanks so much for showing what you're doing, Steve.
    I second that, Thanks much!

  5. #35
    Join Date
    Apr 2008
    Location
    Upper Yarra Valley, Victoria. Australia
    Posts
    829

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    Thanks Rooster and pan620.

    After setting it all up and doing a check, check and triple check the computations are as follows:

    Shaft diam 0.550 divide 2 = 0.275

    RIN Base of rocker box to top of shaft 2.210 minus 0.275 = 1.935
    RIN Diving board to top of Tower shaft 2.211 minus 0.275 = 1.936
    I reckon that is within factory tolerance.

    Now the repaired exhaust springboard.
    REX - Base of rocker box to top of shaft 2.285 minus 0.275 = 2.010
    REX Diving board to top of Tower shaft 2.287 minus 0.275 = 2.012

    P9160012.jpg

    As seen in the measurement from the Mill deck to the repaired diving board, reads badly but I took measurements from the shaft tightened in the tower, down to the face of the repaired springboard, and then measured the rocker box...it only has a difference of 0.002

    My brain wont compute, so I mocked it up three times and it slides together nicely so I think I will call it OK.

    Yeah but the difference is still bugging me!!


    I wont bore you with bead blasting and painting. We will rendevu back at this big tree in a day or two.
    Anyone got recommendations on paint to use on the heads? VHT gloss engine paint?
    Steve Little
    Upper Yarra Valley. Victoria.
    Australia.
    AMCA member 1950

  6. #36

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    I think your choice of paint depends on whether you have ethanol in the gasoline.

  7. #37
    Join Date
    Apr 2008
    Location
    Upper Yarra Valley, Victoria. Australia
    Posts
    829

    Default

    Thanks Larry. On the odd occasion I have seen odds bowser with a sign Ethanol on it but I don't think it really caught on in Australia. When we have vintage runs over here, most people line up at Unleaded which is 91 octane. I think I will go with VHT Regards Steve
    Steve Little
    Upper Yarra Valley. Victoria.
    Australia.
    AMCA member 1950

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