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Tech: 348 - 409

Discussion in 'The Hokey Ass Message Board' started by DeucePhaeton, Mar 7, 2008.

  1. DeucePhaeton
    Joined: Sep 10, 2003
    Posts: 977


    I did this back in the early 80s when I rebuilt the ole 348 for the Impala. As the "W" motor fans know the deck angle to the cylinder bore for these engines isn't perpendicular to one another. So how does one install the pistons into the cylinders after a rebuild? >A< You can run down to your favorite AZ and purchase a 348/409 piston ring compressor. Ya, sure.. >B< Get a few of your favorite buddies over for a install party with a half dozen flat blade screw drivers. I don't recomend this! >C< Try it by yourself with the kids outta shouting range. Or >D< Takes a little preplannning but I used a piece of black pipe and bored it on a lathe to a couple of thousands under my finished bore diameter. Squared up one side to the bore and milled the other to the proper 17 degree angle of the deck. Use a standard piston ring compressor on the square side. Worked like a champ.
    I'm sure there are other ways but it's how I skinned the cat.

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    Joined: Jun 2, 2002
    Posts: 9,638

    Classified's Moderator

    How much for it? :D

  3. Candy-Man
    Joined: Mar 21, 2006
    Posts: 1,702


    Saves breaking rings ?
  4. Tony
    Joined: Dec 3, 2002
    Posts: 7,286


    I was thinking the same thing, that or, how much to rent it for a little while??:D

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  5. Ricola
    Joined: Sep 8, 2007
    Posts: 100

    from MN

  6. DeucePhaeton
    Joined: Sep 10, 2003
    Posts: 977


    This is for a +.060" 348. So it's 4.183" or so.
  7. Hell, I need it too. I'm doing a 348 +.060.

    I promise I'll return it. I've been dodging this job for awhile just because of the ring compressor issue.

    Rental fee? Deposit ....... I'll give ya' the title to my '40 Ford Pickup!!!!
  8. Larry T
    Joined: Nov 24, 2004
    Posts: 7,932

    Larry T

    I didn't know it was that hard to install pistons in a 348/409 without a ring squeezer. I've had good luck just squeezing the rings as they go into the cylinder. The further they go into the cylinder the further around you squeeze them until they're all the way in, if that makes any sense.
  9. DeucePhaeton
    Joined: Sep 10, 2003
    Posts: 977


    Dragging up old threads....
    How'd this work out for people? Did anybody have one made? What did it cost?
    Joined: Mar 22, 2006
    Posts: 2,041

    from OHIO

    What bore size is that one....Ive got a use for it..Lol
  11. DeucePhaeton
    Joined: Sep 10, 2003
    Posts: 977


    I figured you had the resources to make your own.
    I can loan it to you when I send your T-shirts ---- :eek:
    Answer to the question is, I built it for installing my 348 +.060 Pistons way back in 82. I installed used Jahns that measured out to be +.058" with wear and IF I remember right it was bored -002" from that dimension. I just used it to install my new Egge pistons which are an honest +.060" is it still works.
    Last edited: Nov 23, 2011
  12. Truckedup
    Joined: Jul 25, 2006
    Posts: 3,798


  13. 48 Chubby
    Joined: Apr 29, 2008
    Posts: 1,016

    48 Chubby
    Member Emeritus

    When a 348/409 is bored it should also be counterbored. If the bore goes .060 over then the combustion chamber (it's in the block) also goes .060 over. Then you can use a standard band type ring compresser seated at the bottom of the counterbore. Beyond where the ring squeezer sits, its just like any other engine. I've built a few of these, no problem.
  14. I was expecting to have trouble putting my pistons in because of all the stories I heard about the W motor being hard to install pistons/rings. But I had no trouble at all. Mine was bored .030 and I used a standard ring compressor. I had no problem.
  15. DeucePhaeton
    Joined: Sep 10, 2003
    Posts: 977


    Since the combustion chamber is determined by the pistons and it cylinder, how much does this lower the compression? Probably not much but have you done the math? How deep (dia) is the counter bore?

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