Announcement

Collapse
No announcement yet.

Specific Questions For Making a Stroker M20

Collapse
X
Collapse
 
  • Page of 2
  • Filter
  • Time
  • Show
Clear All
new posts
Previous 1 2 template Next
    #1

    Specific Questions For Making a Stroker M20

    Okay, so I replaced the rod bearings in my M20B25 ('89 325is) and that lasted for all of 30 min. before it started knocking again. Oh well, it was worth a shot. Cost me $75 and my own labor. But I did learn a lot about these cars in the process.

    So, the car has left me no choice but to do it right this time... haha.

    I figure if I'm going to get another block, I might as well gain some displacement while I'm at it.

    The car currently has:
    IE Short Tube Headers
    Cobbled up 2.5" mufflershop/stock IS exhaust
    MarkD 93 octane 7000RPM chip
    19lb Mustang Injectors
    Cat Cams 285 degree cam (this is what I was told by PO, but I haven't checked)
    KA Motors Intake
    Mild headwork (I don't know specifics as it was performed 2 owners ago)

    I would like to create some sort of stroker motor using the head I have now as there's nothing wrong with it.

    I did a ton of reading up on this including reading this entire thread: http://www.e30tech.com/forum/showthread.php?t=48288 all 39 pages.

    As I see it, there are two options that interest me:

    1.) Super ETA bottom end (block, crank, rods, and pistons) with my cylinder head. That's supposed to give a CR of 8.5:1, down 3 tenths of a point from the stock 325i 8.8:1.

    2.) M52 Crank (84mm stroke), ETA block, rods, and M20B25 pistons. That supposedly gives 9.5:1 CR and 2.8 liters. Much more friendly to my NA motor, as I have no plans to turbo this thing.

    Now for my questions, I'll number them to make it simple:

    1.) How much does the head need to be shaved (if at all) for each of these options to obtain the stated CR? I do not know how much the head has already been shaved (again, if at all). I suppose I'd need to know the rocker cover surface to deck surface measurement of a stock head to find out.

    2.) For option #2, I've read that a "simple sleeve for the oil seal" is required on the crankshaft. What the heck does that mean? Front or rear? Or both? Where does one obtain this sleeve or must it be custom made?

    3.) For option #2, I've also read that there "may be some IM shaft machining required". Again, what does that mean? I'd like to have more concrete info regarding this.

    4.) If I go with option #1, how noticeable will the drop in CR be? With the cam and chip, will I be hurting performance noticeably with the lower CR? I think of 8.8:1 as already quite low.

    5.) I gather that SETA cars were only made in '88. Was it an option or were all '88 ETA cars 'super'? Did they have extra hp and torque or were they rated the same as all other ETA cars?

    6.) How hard will it be to find a SETA block w/ internals and what kind of prices should I expect?

    Thank you very much for any help and advice! :)
    '89 BMW 325is Zinnoberrot / '88 VW Jetta GLI 16v Tornado Red / '89 VW Jetta GLI 16v Tornado Red / '89 VW GTI 16v Bright Blue Metallic / '91 BMW 325i Black / '91 BMW 325i Sport Black / '92 VW GTI 16v Black / '92 VW GTI 16v Montana Green / '01 Audi A4 Avant TQM Silver Metallic / '01 VW Jetta GLX VR6 Black
    Tags: None
    #2
    I built a 2.8 with the m52 crank - I cut the counterweights down, mostly to remove weight but also for clearance. Have it balanced after

    I did not have to shave the head at all, used a stock i block and all bearings.

    Yes, you need an oil sleeve machine to fit the M20 timing cover seal. MM or IE may sell this? comparison as to what it needs to look like on the left.



    You may need to cut the piston skirts. I used early i pistons which have taller skirts on them. I cut these down as low as possible to reduce weight. Again all were balanced.

    SETA is basically an e engine with an i valve train installed.
    '87 325ic, powered by S50.

    Comment

      #3
      Originally posted by e30rapidic View Post
      I built a 2.8 with the m52 crank - I cut the counterweights down, mostly to remove weight but also for clearance. Have it balanced after

      I did not have to shave the head at all, used a stock i block and all bearings.

      Yes, you need an oil sleeve machine to fit the M20 timing cover seal. MM or IE may sell this? comparison as to what it needs to look like on the left.

      You may need to cut the piston skirts. I used early i pistons which have taller skirts on them. I cut these down as low as possible to reduce weight. Again all were balanced.

      SETA is basically an e engine with an i valve train installed.
      Whoa wait, you built the 2.8 out of the "i" block w/ "i" connecting rods? Everything I read said to use the "e" block and rods with the "i" pistons.

      And if you had to cut the counterweights down to prevent them from contacting the piston skirts with a 135mm "i" rod, how would the 130mm "e" rod ever work?

      I looked for the oil seal sleeve on MM and IE but didn't see one.... did you have yours custom made?

      Also, what's your compression ratio now?

      Anyone else who wants to chime in on the SETA questions I have, please do.

      Thanks.
      '89 BMW 325is Zinnoberrot / '88 VW Jetta GLI 16v Tornado Red / '89 VW Jetta GLI 16v Tornado Red / '89 VW GTI 16v Bright Blue Metallic / '91 BMW 325i Black / '91 BMW 325i Sport Black / '92 VW GTI 16v Black / '92 VW GTI 16v Montana Green / '01 Audi A4 Avant TQM Silver Metallic / '01 VW Jetta GLX VR6 Black

      Comment

        #4
        Originally posted by Cinnabar325is View Post
        Whoa wait, you built the 2.8 out of the "i" block w/ "i" connecting rods? Everything I read said to use the "e" block and rods with the "i" pistons.

        And if you had to cut the counterweights down to prevent them from contacting the piston skirts with a 135mm "i" rod, how would the 130mm "e" rod ever work?

        I looked for the oil seal sleeve on MM and IE but didn't see one.... did you have yours custom made?

        Also, what's your compression ratio now?

        Anyone else who wants to chime in on the SETA questions I have, please do.

        Thanks.
        you can make your stroker however you want! VAC and IE sell kits.
        you dont even need the super eta motor to do it. you can take any eta motor and put the 885 head on it. it fits. the eta pistons are flat, i pistons aren't. so your compression drops, everything i read says you loose minimal torque but gain A LOT of top end. the things i read from people who have done it say they love it.
        you can also do the revers. take an i motor and put the bottom end on with i internals.

        also read something about a guy taking his stock eta head and an 885 head to a machining shop, had them machine the stock eta head "into" an 885, stroking his motor but leaving his compression alone.
        definately cool!

        Comment

          #5
          Originally posted by devon.818 View Post
          you can make your stroker however you want! VAC and IE sell kits.
          I understand that I could technically do this in a million combinations if I was willing to use custom pistons. But, although I want to do this 'right', I'm also trying to do it on the cheap. That means using factory BMW components, nothing custom.

          I know I could do a stroker with a normal eta block too, but that would result in a CR of 8.2:1 or so. Too low for me. Even the 8.5:1 of the SETA setup is lower than I'd like.
          '89 BMW 325is Zinnoberrot / '88 VW Jetta GLI 16v Tornado Red / '89 VW Jetta GLI 16v Tornado Red / '89 VW GTI 16v Bright Blue Metallic / '91 BMW 325i Black / '91 BMW 325i Sport Black / '92 VW GTI 16v Black / '92 VW GTI 16v Montana Green / '01 Audi A4 Avant TQM Silver Metallic / '01 VW Jetta GLX VR6 Black

          Comment

            #6
            Originally posted by Cinnabar325is View Post
            I understand that I could technically do this in a million combinations if I was willing to use custom pistons. But, although I want to do this 'right', I'm also trying to do it on the cheap. That means using factory BMW components, nothing custom.

            I know I could do a stroker with a normal eta block too, but that would result in a CR of 8.2:1 or so. Too low for me. Even the 8.5:1 of the SETA setup is lower than I'd like.
            isn't there another crank from a diesel you can use?
            i know i didn't help much, probably just added more questions than answers.
            good luck, subscribed

            Comment

              #7
              Originally posted by devon.818 View Post
              isn't there another crank from a diesel you can use?
              Yeah, 524td crank. But that's tougher to find. I really think the two options I listed up top are my best. I just need to sort out these questions.
              '89 BMW 325is Zinnoberrot / '88 VW Jetta GLI 16v Tornado Red / '89 VW Jetta GLI 16v Tornado Red / '89 VW GTI 16v Bright Blue Metallic / '91 BMW 325i Black / '91 BMW 325i Sport Black / '92 VW GTI 16v Black / '92 VW GTI 16v Montana Green / '01 Audi A4 Avant TQM Silver Metallic / '01 VW Jetta GLX VR6 Black

              Comment

                #8
                oh btw the head doesnt "need" to be shaved, but if you are doing it right, then have it hot tanked and shaved, i was told its under 200 for that.

                Comment

                  #9
                  i ran the 325e rod with the 84 mm crank and i pistons
                  '87 325ic, powered by S50.

                  Comment

                    #10
                    Originally posted by e30rapidic View Post
                    i ran the 325e rod with the 84 mm crank and i pistons
                    Got it, that makes more sense to me. Do you think I would need to cut the counterweights down and/or trim the skirts on the pistons if I used the later "i" pistons (I'm assuming '89 has the later versions)?

                    Any more info the crank spacer please?

                    And you didn't need to modify the IM shaft at all?

                    Thanks!
                    '89 BMW 325is Zinnoberrot / '88 VW Jetta GLI 16v Tornado Red / '89 VW Jetta GLI 16v Tornado Red / '89 VW GTI 16v Bright Blue Metallic / '91 BMW 325i Black / '91 BMW 325i Sport Black / '92 VW GTI 16v Black / '92 VW GTI 16v Montana Green / '01 Audi A4 Avant TQM Silver Metallic / '01 VW Jetta GLX VR6 Black

                    Comment

                      #11
                      The 524td crank has the same stroke as an "e" crank, only difference is the diesel crank is forged not cast. I've never heard of anyone destroying an "e" crank from too much power.

                      It's really all about your budget and what you want to do with the final product.

                      Comment

                        #12
                        Are super eta rods different than "I" rods?
                        Originally posted by Gruelius
                        and i do not know what bugg brakes are.

                        Comment

                          #13
                          Originally posted by KenC View Post
                          Are super eta rods different than "I" rods?
                          Yes, I believe the eta rods are the same as the super eta rods. I believe both are 130mm? And I think the 'i' rods are 135mm. Not positive about that.
                          '89 BMW 325is Zinnoberrot / '88 VW Jetta GLI 16v Tornado Red / '89 VW Jetta GLI 16v Tornado Red / '89 VW GTI 16v Bright Blue Metallic / '91 BMW 325i Black / '91 BMW 325i Sport Black / '92 VW GTI 16v Black / '92 VW GTI 16v Montana Green / '01 Audi A4 Avant TQM Silver Metallic / '01 VW Jetta GLX VR6 Black

                          Comment

                            #14
                            Originally posted by Cinnabar325is View Post
                            Yes, I believe the eta rods are the same as the super eta rods. I believe both are 130mm? And I think the 'i' rods are 135mm. Not positive about that.
                            he is right. A super eta is a complete rotating assembly form an e with an i valvetrain. Essentially the 2.7 stroker people talk about.

                            here is the crank spacer...and where I picked mine up from. Some companies do make them
                            http://www.r3vlimited.com/board/showthread.php?t=153911


                            no mods necessary to the oil shaft with the smaller crank weights. not sure about the need to cut the skirts of the later i pistons.
                            '87 325ic, powered by S50.

                            Comment

                              #15
                              Originally posted by Cinnabar325is View Post
                              Yes, I believe the eta rods are the same as the super eta rods. I believe both are 130mm? And I think the 'i' rods are 135mm. Not positive about that.
                              OK thanks. We're building a 2.7i soon and plan to use a super eta block, but swap in I rods for a higher compression ratio.
                              Originally posted by Gruelius
                              and i do not know what bugg brakes are.

                              Comment

                              Previous 1 2 template Next
                              Working...
                              X