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Engine building questions...LONG

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  • Engine building questions...LONG

    As of right now, im still waiting to hear from 4spdz34 about the $500 heads he owes me. In the mean time, i pulled my heads off the motor and brought them to Napa Machine shop. I have delt with the guys there before, and have brought heads and blocks to them with good results. Well, turns out when the engine overheated last summer, i warped the heads and pushed a few of the valve guides down. So, to make these heads usefull again, they want $475-500 to pressure check them, replace all the guides, 5angle job, some bowl work and port work, machining, and beed blasting. Not a bad deal, but i dont want to spend ANOTHER $500 on the heads. So I, or someone else needs to this guy and get my damn heads......thats another matter not to be discussed here.


    So, we started bullshiting around about the idea of the 2.8L crank inplace of the stock LQ1 crank. I never have seen hard evidence that this would work, and knowing from what other people say, the blocks are the same. So we matched a 3.1L head gasket to my 3.4L head, and the bolt holes lined up, and we checked part numbers on the 2.8L crank bearings from a 1988 Blazer and the 3.4L crank bearings from a 1994 cutlass. they matched up. So i guess that is enough proof for me that it would all work. Concerning the stock crank, he said that polishing cleaning and making sure the crank is within specs would be $45, and then ball honing the cylinders to create a new crosshatch pattern for the new rings to seal was around $30 or something.

    Since I am turbo charging this setup, what would the benefit of adding the 2.8L crank be...besides destroking the engine and pulling higher rpms????

    We then talked about work done to the block. He said, with an all stock bottom end, it wouldnt have to be balanced, that it should be pretty close to perfect. I figured it would be wise to replace the bearings, and piston rings since im this far into the engine already.

    Adding the 2.8L crank would require new balancing then correct?

    He reccomended replacing the stock pistons with aftermarket ones if I put in the 2.8L crank. He also said that shot peening the rods wouldnt do alot for this engine being that its a later model engine compared to old V8s and stuff. That to me sounds like he is contradicting everything i have read and been told about the rods. He said being that its newer, there shouldnt be very many casting flaws to deal with.

    Is he correct about this?


    www.cardomain.com/id/topless94style

  • #2
    RE: Engine building questions...LONG

    guys at napa dont know what they are talking about, they think they do and they just make up a bunch of bullshit. i say stay away from napa, far away.

    Jake
    GM Goodwrench Tech - GM Certified

    1991 Pontiac Grand Prix GTP - 3.4L DOHC , 5 Speed Manual Transmission , Turbonetics 62mm turbo, Turbonectics Evolution Wastegate , Turbonetics Raptor BOV , Large Front Mount Intercooler , AEM Methanol Injection , Car is running at 11PSI currently with methanol injection.

    Runs 13.4 In the 1/4 with a 3 second 60 foot

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    • #3
      RE: Engine building questions...LONG

      With the 2.8 crank, you will definitely need custom pistons....or custom rods....or both. If you use the stock pistons and rods, the pistons will be down in the cylinder bore 0.150".

      Marty
      '99 Z-28 - Weekend Driver
      '98 Dodge Neon - Winter Beater
      '84 X-11 - Time and Money Pit
      '88 Fiero Formula - Bone stock for now

      Quote of the week:
      Originally posted by Aaron
      This is why I don't build crappy headers. I'm not sure, I don't know too much about welding.

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      • #4
        RE: Engine building questions...LONG

        This is what im doin right now. dohc block, 2.8 crank, 6" rods and a set of customs pistons
        1984 Indy Fiero 3.4L
        13.7 sec @ 98 mph
        *ALL THROTTLE AND NO BOTTLE*

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        • #5
          RE: Engine building questions...LONG

          Yes You WILL need custom pistons with the 2.8L crank. There is no 3.4L bore sized stock piston with the proper Piston Compression Height. The 2.8L has the wrist pin Lower on the piston compared to the 3.1L/3.4L pistons.

          As Marty said. Your stock pistons would be down in the block by .150inch. (not good) Otherwise your looking at a set of custom rods with a 5.85 inch length to them to be able to use the stock pistons and have the deck height the same. (cheaper to buy pistons)

          I agree with the "stay away from napa" comments. Go to a competent engine machine shop.
          Colin
          92 Sunbird GT, 3200 Hybrid 13.99@ 95.22 (2004)
          90 Eagle Talon TSi AWD 10.54 @ 129mph.

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          • #6
            RE: Engine building questions...LONG

            Im not worried about these napa guys, ive done work with them before, and so have many of my friends. Ill end up doing hte valve job/guides by my self, so the only realy work they will do is machine the heads bake the block and do a new cross hatch pattern for the new rings. Ill probably not go with the 2.8 crank because i dont have the money right now for a set of new pistons. As far as part shops around this area, this napa i go to by far has some of the best guys i have delt with compared to the other ones i have been to.


            www.cardomain.com/id/topless94style

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            • #7
              RE: Engine building questions...LONG

              well all the napa guys i have ever delt with were complete morons who thought that they knew everything when in reality they knew nothing.

              Jake
              GM Goodwrench Tech - GM Certified

              1991 Pontiac Grand Prix GTP - 3.4L DOHC , 5 Speed Manual Transmission , Turbonetics 62mm turbo, Turbonectics Evolution Wastegate , Turbonetics Raptor BOV , Large Front Mount Intercooler , AEM Methanol Injection , Car is running at 11PSI currently with methanol injection.

              Runs 13.4 In the 1/4 with a 3 second 60 foot

              Comment

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