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Thread: Gizzard's M38A1 Restoration

  1. #31
    Super Moderator LarrBeard's Avatar
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    Oh boy - a new toy to play with! Don't let it eat you up...

  2. #32
    Super Moderator gmwillys's Avatar
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    Sweet! The Rotacut is on my wish list. You'll have to give your opinion to how they cut.

  3. #33
    Member Gizzard's Avatar
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    Dropped the engine block, head and crank off at the machine shop today.

    IMG_2245.jpg

    Looks like the wrist pins got loose on a couple of cylinders and gouged um up pretty good

    IMG_2238.jpg

    IMG_2229.jpg


    Bubba has been busy with a pipe wrench on the crank

    IMG_2244.jpg
    Last edited by Gizzard; 06-14-2021 at 08:39 PM.

  4. #34
    Super Moderator gmwillys's Avatar
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    Keep the Bubbas away from the pipe wrenches/out of the engine bay. In all my time working with engines, I can only think of one time where a large pipe wrench was employed. Even then I cut a piece of pipe that fit the crank snout, and ground in for the keyway to hold it in place. That was to apply pressure to a stuck tractor engine, by hanging weights from the pipe wrench, and allowing pressure/lube/and gravity over time to break it free.

  5. #35
    Super Moderator LarrBeard's Avatar
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    OUCH! That really is a gouge.

    But, a good machine shop can sleeve that bore if it won't clean up. Sleeving is a lot easier and routine to a professional than it seems to we mere mortals.

    And - don't let Bubba anywhere near an old rifle with either a pipe wrench or a file ...
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    Last edited by LarrBeard; 06-15-2021 at 06:15 AM.

  6. #36
    Super Moderator bmorgil's Avatar
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    Giz, I am interested in that gouge. When you tear that down let us know if indeed the wrist pin came loose. The design of the wrist pin rod interface is a bit unique. I would be interested in how it failed. Pisser on the crank snout. No need for that ever! You would like to sit the guy down and make him understand the precious heat treating and machining process they just hacked. Well the machinist will touch that up if you ask him. Be careful there. The fit of the front dampener/pulley relies on some press fit. If its too loose it will come loose, shear the woodruff key and do other "things".

    Larry, nice barrel vice the "Bubba" had! A true craftsman, in a time before Christ was born.
    Last edited by bmorgil; 06-15-2021 at 06:35 AM.

  7. #37
    Member Gizzard's Avatar
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    There were actually two cylinders that had matching gouges.......2 and 4

    Have no idea why they failed for sure, , but the only way possible is that the wrist pin locking bolt on the rod came loose or was not tightened after bubba got a holt of it.

    Machinist called me today....needs two sleeves so far

  8. #38
    Super Moderator bmorgil's Avatar
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    On tear down were the wrist pins out of position? If not the wrist pin holes do seem to collect the stuff that gouges the walls. The other thing it could be if it wasn't the pins, would be pieces of broken rings migrating into the pin holes.

    It is very difficult to correctly torque the wrist pin bolt in the rod. The machine shop usually has an offset torque wrench to do the job. I bet you are correct. Someone just got er done, and the bolts came loose or the bolt was not tight enough from the start. I always ask the shop to hang the pistons on the rods on that style rod. The motor is on its way now. Your going to have a sweet running little 134 when you are done.

  9. #39
    Member Gizzard's Avatar
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    After further inspection by the machinist, it was definitely the the wrist pins migrating out that cause the gouges. Cyl 2 and 4 had matching gouges. We also discovered a odd rod out of the 4. Previous owner bubbanism is strong in this one.

    He advised installing a sleeve in cyl 2 ( cyl 1 has an existing sleeve that he said was in spec).....not so much for the gouges but for a newly discovered small crack which a sleeve will fix. ......cyl 3 and 4 will get bored out to 60

    Crank is at crank shop being magnafluxed and ground if acceptable
    Last edited by Gizzard; 06-17-2021 at 05:32 PM.

  10. #40
    Super Moderator bmorgil's Avatar
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    Very interesting! The importance of properly torquing the wrist pin bolt is now verified. So you are going to have all 4 bored to .060 over?

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