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  • Engine: More Crankshaft questions

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ID:	1740075You will remember that the crankshaft broke in Lark VIII girls 1960 259 V8 from others threads

    After working with the parts people we have found there are no Short nose crankshafts and have aNOS long nose crankshaft to install the 1960 Engine

    I was given a spacer washer and a exploded parts drawing to show were the washer goes. Also was given two different style bolts to hold the harmonic balancer on, and to use the one that fits.

    Is there anything more to doing this installation of the crankshaft? We have all new bearings for the crank and the rods.

    We have not taken the cam out or disturbed it, and plan on just replacing the crankshaft. Is there any reason to do different?

    We have read the shop manuel so far all looks straightfoward, Do you have any more comments regarding this job.


    Thank you,
    Husband of Lark VIII girl.

  • #2
    Something caused the crank to break.
    Whatever it was, and whatever shrapnel there is from the crankshaft, is floating around in your engine.
    Are you planning on just changing the crankshaft and bearings and not going through the rest of the engine?
    Is the engine out of the car?
    HTIH (Hope The Info Helps)

    Jeff


    Get your facts first, and then you can distort them as much as you please. Mark Twain



    Note: SDC# 070190 (and earlier...)

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    • #3
      Engine is out of car, pan cleaned, engine was clean inside, took valve covers off, planning on blowing out oil passages with air, and rebuilding the oil pump. new oil filter.
      Also will use engine assy. lube and oil with zinc already in it. Before this happened engine was running great, was rebuilt some years ago.

      Husband of Lark VIII girl

      Comment


      • #4
        Why not hot tank the block, and replace the cam bearings...
        You are so close to a quality rebuild now.
        One chip of metal stuck in there could ruin all of your hard work.
        Also, worn cam bearings are a source for low oil pressure.

        Not nitpicking, but just doing a value judgement.
        HTIH (Hope The Info Helps)

        Jeff


        Get your facts first, and then you can distort them as much as you please. Mark Twain



        Note: SDC# 070190 (and earlier...)

        Comment


        • #5
          I will have to agree with Jeff, on this. I have mine down now, for a rebuild. Someone had "rebuilt" it, and I gave it a try in my 53. Got 2000 miles out of it. Oil pressure was not what I wanted. Tore it down and it had a worn crank. It had new pistons,mains, rod bearings, heads, and valves. BUT, I decided to go all way back to bare block. The cam and bearings were not replaced and the cam gear was worn bad. The chance of foreign debri is just too great to risk in your engine with a broken crank. It's gonna take me a while to get up cash to build, but i don't wanna do it again if I can help it.

          Comment


          • #6
            The best advice has already been posted, SuEllyn. The best advice now is to take it! BP
            We've got to quit saying, "How stupid can you be?" Too many people are taking it as a challenge.

            Ayn Rand:
            "You can avoid reality, but you cannot avoid the consequences of avoiding reality."

            G. K. Chesterton: This triangle of truisms, of father, mother, and child, cannot be destroyed; it can only destroy those civilizations which disregard it.

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            • #7
              More to the point, who told you there were no short nose 259" crankshafts? It's the most common of all V8 crankshafts. Here on the forum you can't turn around without tripping over one. I'd bet a WTB would bring out a dozen within a week.

              jack vines
              PackardV8

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              • #8
                I've got a 259 crank that anyone can pick up here in Mass for free. Needs turning from standard/surface rust...

                Comment


                • #9
                  Originally posted by Lark8girl View Post
                  Engine is out of car, pan cleaned, engine was clean inside, took valve covers off, planning on blowing out oil passages with air, and rebuilding the oil pump. new oil filter.
                  Also will use engine assy. lube and oil with zinc already in it. Before this happened engine was running great, was rebuilt some years ago.

                  Husband of Lark VIII girl
                  I understand all the logic behind a total rebuild, but if it was "running great" before the crank broke, I'd simply fix what is broke: replace the crank, with new rod & main bearings; hone the cylinders with a ball-hone and install new rings, and NEW oil (under no circumstances re-use the old oil). This is about what woulda been done in the 1960s, if you'd have taken the car to a shop for the same problem.
                  If it ever broke again, I'd short-block it.

                  Comment


                  • #10
                    Why did the crank break? I would at least want to check the main bearing saddles for alignment, and line-bore the block if they are out.
                    Gord Richmond, within Weasel range of the Alberta Badlands

                    Comment


                    • #11
                      Originally posted by gordr View Post
                      Why did the crank break? I would at least want to check the main bearing saddles for alignment, and line-bore the block if they are out.
                      If it broke due to block alignment, a person could probably discern that by inspecting the old main bearings closely, if they are still in tact. For example the upper bearings, if there is significant wear, uneven wear, or mis-matched wear when comparing all five. If evidence pointed in that direction, check the line bore. Also, the crank itself may reveal clues, i.e. evidence of an old crack that later spread.

                      Comment


                      • #12
                        Hi Lark girl,

                        In the picture provided it appears like a fairly smooth typical fatigue failure starting at the rod journal fillet, which then progressed over over many miles and deepened with each firing cycle, until a fairly small section was left that was just too small to "take it" any longer and broke all at once.

                        1 - Could you take some close ups adjacent to the busted area?
                        http://www.hmgem.com.au//uploads/00160.jpg

                        What condition was the rubber damper insert on the harmonic balancer?

                        I'm especially interested in the radiuses at the edges of the rod and main journals of the old crank, and if there are any indications of a weld repair having been done on that main or rod journal. Or, corrosion pitting.
                        Corners instead of fully developed radiuses, and sketchy uncontrolled metalurgy that is part of most any welding process quickly add up to make a formerly good crankshaft VERY vulnerable to fatigue cracking in the most highly stressed areas, which are usually the rod journal fillet in the "overlap" region.
                        http://www.evolution-fea.com/pics/so...sses_Iveco.jpg

                        In the picture provided it appears like a fairly smooth typical fatigue failure starting at the rod journal fillet, which then progressed and deepened over time with each firing cycle, until a fairly small section was left that was just too small to "take it" any longer and broke all at once.

                        2 - I'd be inclined to check the new crank for cracks using the wet method magnetic particle method ( MAgnaGlow).
                        Also be critical of the quality of the radiuses and lack of rust in the journal fillets/radiuses.
                        For a passenger car we should be able to "get away" with less than excellent radiuses, but your crankshaft did not break for no reason.

                        3 - Do the pistons have pitting near the edges?
                        http://performancetrends.com/Definit...nation-Lrg.jpg
                        How to the rod big end bearing and main bores look, behind the bearing inserts?
                        http://images.thesamba.com/vw/gallery/pix/1030646.jpg
                        http://www.stle.org/images/dev/fretting.jpg
                        That can be a sign of running with heavy detonation, whose sharp pressure spikes can increase crankshaft stress considerably. Also head gasket, main bearing caps, rod and crankshaft bearings suffer
                        Last edited by Dan Timberlake; 07-28-2013, 11:40 AM.

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                        • #13
                          Thank you to everyone who replied

                          The engine is now at the machine shop for Hot tank, and magnaflux, and will have the cam bearings replaced and cam installed there. Will also have the crankshaft bearings line bored. All the bearing saddles looked good. All the cylinders looked really good, no edge or marks.
                          and Lark VIII girl is happy with all this.

                          Husband of Lark VIII girl.

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                          • #14
                            Be very sure to maintain stock distance between cam and crank when reboring the mains. This is only critical in engines using gear drive cams.

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