Announcement

Collapse
No announcement yet.

The Silver Buick's 1969 Firebird OHC six project.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #31
    Show us the Aeromotive pump install on the Skylark. Are you going to be controlling the pump with the MS, or with the Aeromotive controller?
    BS'er formally known as Rebeldryver

    Resident Instigator

    sigpic

    Comment


    • #32
      Love the body lines of these cars. Body cleans as it looks?
      Si vis pacem, para bellum

      Comment


      • #33
        Early visit from Santa!

        Dan

        Comment


        • #34
          Sweet - did you get the thanksgiving discount?

          I would clean up the sharp edges in the head combustion chambers before you bolt it all down.

          I can't believe with all your plethora of skills and experience you're still using plastigauge - pony up for some mics, bore gauge, and dial indicator! Even the cheap stuff is way better than relying on plastigauge.
          There's always something new to learn.

          Comment


          • #35
            Yup, I got the thanksgiving discount. It's what forced my hand versus waiting until Feburary or March. I still have to sort out what I'm going to do with that much pump on my Skylark's engine. Will probably have to pony up for the Aeromotive PWM controller to down grade the flow. There will probably be some re-engineering of my Skylark's fuel system again.

            I'm going to leave this head more or less alone. Next month when I am in CA I am dropping off a head that will get the good treatment with some chamber re-shaping.

            Plastigage, meh. I have a good set of mics, two pretty nice dial calipers, two dial indicators but no bore gauges for either the cylinders or the rod/main journals. I'm more or less an engine assembler at this point and simply wanted an idea of clearances, basically a magnitude of order measurement, which was easily achieved. Besides, by the time I'm measuring out to the fourth decimal point even me measuring with a dial indicator the measurements are suspect IMO.
            38P likes this.
            Escaped on a technicality.

            Comment


            • #36
              You could have bought -.001 bearings for that motor and returned the clearances to almost stock specs.

              Sealed Power part numbers: (From Summit)

              Mains: (Z) 4124MA1
              Rods: (Z) 2020CP1

              Even though the rear main's oil groove and holes are not right for the OHC, they do work. For your "throw-together" motor they'd be fine. For your EFI motor, have the rear main bearings worked on to get them right.
              Last edited by OHC 6 Sprint; November 28th, 2012, 02:58 PM.
              38P likes this.

              Comment


              • #37
                The service manual said the same thing =P

                The good motor will certainly have tight clearances. I'm kind of curious as to the effect of the ~40*F temps on the measured clearances.
                Escaped on a technicality.

                Comment


                • #38
                  Originally posted by TheSilverBuick View Post
                  I'm kind of curious as to the effect of the ~40*F temps on the measured clearances.
                  Little to none. For what you have to measure with: Less than none.

                  It's all cast iron and steel (except for a relatively thin layer of babbitt) which have roughly the same coefficient of expansion - about ~6 ppm/*F.

                  Your delta T is -110 [-40*-70*]. You have an average set of dimensions like 2.300 & 2.306 and 2.000 & 2.006 for each bearing pair.

                  2.300 shrinks to 2.298482
                  2.306 shrinks to 2.304478

                  The difference (diametral) is 0.005996" versus 0.006", a "change" in your .003" gap (per side) of only -0.000002"

                  I did ignore the babbitt thickness. This layer - primarily Tin - has a coefficient of expansion of about 13 ppm/*F, slightly more than twice that of the steel & Iron. The thickness of the babbitt is probably like .010", so its total change in thickness over the temperature change is a whopping -0.0000143" (smaller) per side. This effectively opens the "per side" gap from 0.003" to 0.003012".

                  Bearings, fits, clearances and your motor oil are all designed to work within a specific operating temperature range. The values in the service manual for room temperature measurements have already taken this into account.
                  38P likes this.

                  Comment


                  • #39
                    Originally posted by OHC 6 Sprint View Post
                    Little to none. For what you have to measure with: Less than none.

                    It's all cast iron and steel (except for a relatively thin layer of babbitt) which have roughly the same coefficient of expansion - about ~6 ppm/*F.

                    Your delta T is -110 [-40*-70*]. You have an average set of dimensions like 2.300 & 2.306 and 2.000 & 2.006 for each bearing pair.

                    2.300 shrinks to 2.298482
                    2.306 shrinks to 2.304478

                    The difference (diametral) is 0.005996" versus 0.006", a "change" in your .003" gap (per side) of only -0.000002"

                    I did ignore the babbitt thickness. This layer - primarily Tin - has a coefficient of expansion of about 13 ppm/*F, slightly more than twice that of the steel & Iron. The thickness of the babbitt is probably like .010", so its total change in thickness over the temperature change is a whopping -0.0000143" (smaller) per side. This effectively opens the "per side" gap from 0.003" to 0.003012".

                    Bearings, fits, clearances and your motor oil are all designed to work within a specific operating temperature range. The values in the service manual for room temperature measurements have already taken this into account.
                    Now that's a solid answer to my question, my lack of engineering is showing. As I've said, I'm not the sharpest tool in the shed, but I'm persistant. Hopefully my bumbling through this first round doesn't run you off.
                    38P likes this.
                    Escaped on a technicality.

                    Comment


                    • #40
                      I'm actually a Plastigage fan - as a final check. You use the mics, etc, etc. but as a last chance the Plastigage costs almost nothing and takes just a few minutes. If you (or the machinist) made a measuring error (it can happen even to the best) you'll catch it before parts are ruined.

                      So no, you don't count on it but.......

                      Dan

                      Comment


                      • #41
                        Found this site this morning. This guy built a manifold for his Triumph GT6 essentially like what I want to do on my engine.
                        http://www.teglerizer.com/fi/GT6_man..._manifold.html

                        Last edited by TheSilverBuick; November 29th, 2012, 09:42 AM.
                        38P likes this.
                        Escaped on a technicality.

                        Comment


                        • #42
                          that's a lot of work!

                          Cute little 14 lb injectors
                          My fabulous web page

                          "If it don't go, chrome it!" --Stroker McGurk

                          Comment


                          • #43
                            So you'll be fabbing up your own system for the OH6?
                            Thom

                            "The object is to keep your balls on the table and knock everybody else's off..."

                            Comment


                            • #44
                              I want too. No guarentee of success as I really am not good at fabrication.
                              Escaped on a technicality.

                              Comment


                              • #45
                                Originally posted by TheSilverBuick View Post
                                I want too. No guarentee of success as I really am not good at fabrication.
                                note his use of really thick aluminum? that is the secret to success
                                Doing it all wrong since 1966

                                Comment

                                Working...
                                X