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S52 Head on a Z3 M52TU block?

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    #16
    On the block? 36998356 and 28-6S-1. Yeah, it must have been swapped. Now I just have a pointless car sitting in the garage. Gotta start dismantling it to make up the loss.

    Currently building a badass coffee table
    Random stuff on insta @kevanromero

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      #17
      Originally posted by Chilezen View Post
      I am getting mixed results here.
      I just saw I'd been quoted here...

      If you don't need the strength, don't bother with ARPs.

      However, Time-serts in ANY aluminum block are a good idea. Second and subsequent re-torques have a much higher failure rate in aluminum than steel. The combination of friction and stress, and stress corrosion cracking over time before the engine was disassembled, can cause the aluminum threads to give up when you tighten a bolt into them.

      Replace the threads with steel = problem solved permanently for as many times as you want to take the engine apart.

      stripped out threads, damaged threads, blown out sparkplugs, stripped thread, stripped out theads, helicoils, BMW sparkplug repair, repair BMW sparkplugs blew out with time-sert, thread repair problems, spark plug BMW blown, blew out BMW sparkplug, stripped theads, threads stripped out, threads got stipped out of BMW sparkplug, repairing stripped threads, thread repair kits and inserts, repairing sparkplugs threads, sparkplugs threads have stripped out, screw thread inserts for striped out threads, automobile threads blown out, motorcycle threads stripped out threads, not helicoil use time-sert thread repair, screw thread insert, inserts for screw threads, screw thead inserts have stripped out


      My Cadillac Northstar has benefited from this. These engines are notorious for losing head bolt threads ~100k miles. The time-sert repair is time-intensive, but 100% effective and eliminates the problem completely.

      ALSO:

      If your iron block will clean up with a 0.010" (0.25mm) overbore/overhone, that sounds good to me. Iron "seasons" over time, which means that your used iron block will be more dimensionally stable than a used aluminum block. You can pay for nice machine work to the iron block and the resulting engine will run better longer...

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        #18
        Can confirm. my iron block M20 has like 350,000 miles on it now, lol. Doesn't burn oil, no piston slapping noise, compression etc. is all good, and I've beat the crap out of it over the years. It had 225k miles on it when I did the build.

        But if you can't save it, I'd just get an M54 or N52 rather than try to frankenstein something together from a bunch of broken motors.
        Build thread

        Bimmerlabs

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          #19
          Originally posted by The Dark Side of Will View Post
          However, Time-serts in ANY aluminum block are a good idea. Second and subsequent re-torques have a much higher failure rate in aluminum than steel. The combination of friction and stress, and stress corrosion cracking over time before the engine was disassembled, can cause the aluminum threads to give up when you tighten a bolt into them. Replace the threads with steel = problem solved permanently for as many times as you want to take the engine apart.
          It is my assumption/understanding that head studs would avoid this problem, because you wouldn't be stressing the aluminum threads any time the head is replaced. You make an excellent case for time-serts, and I totally agree they are recommended, but I still don't see why a stud can't also circumvent the issues with aluminum threads. I see a time-sert as being a stud with a hole in it, in which you tighten a bolt into, rather than tightening a nut onto.


          Originally posted by The Dark Side of Will View Post
          If your iron block will clean up with a 0.010" (0.25mm) overbore/overhone, that sounds good to me. Iron "seasons" over time, which means that your used iron block will be more dimensionally stable than a used aluminum block. You can pay for nice machine work to the iron block and the resulting engine will run better longer...
          The extra weight of the iron is why I sought after the aluminum block. What would the price different be in machining an alu vs iron block? I thought they would clean up the same, with the same services done to them.

          I may come off as stubborn but I'm honestly just curious.

          Currently building a badass coffee table
          Random stuff on insta @kevanromero

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            #20
            Originally posted by Chilezen View Post
            It is my assumption/understanding that head studs would avoid this problem, because you wouldn't be stressing the aluminum threads any time the head is replaced. You make an excellent case for time-serts, and I totally agree they are recommended, but I still don't see why a stud can't also circumvent the issues with aluminum threads. I see a time-sert as being a stud with a hole in it, in which you tighten a bolt into, rather than tightening a nut onto.
            In one engine I have taken head off like 4 or 5 times without issues. So replacing bolts it's not problem for the aluminium block or threads. Problem is overheating the block because failure in cooling system. Your temp gauge might show something like 120degrees C (250F) when it's overheating but the block around the cylinders can be way hotter. Causing the block yield strength to suffer and when you take off the head -> threads are stripped or will be stripped when you tighten the bolts next time.



            So no matter what you do, try to avoid overheating the aluminium blocks. Once you overheat one badly, it's practically piece of junk metal.

            And the problem with the studs is that the aluminium threads can't take the extra force that you can apply with the non-stretchable hard studs. They will strip. So you can't torque those hard as with steel block and the clamping force will be about the same as with stock bolts. So studs are basically just waste of money.

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              #21
              Random, but how far can you over bore an M52 aluminum block with iron sleeves? Or would you just resleeve it if the cylinders were scored?

              Currently building a badass coffee table
              Random stuff on insta @kevanromero

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                #22
                BMW uses platted cylinder liners not sleeves. So you would have to find someone to replate after boring. I've heard of it being done on motorcycle cylinders but never on an engine block.

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                  #23
                  With nikasil/alusil coating, you need to replate the surface again. Which isn't cheap or easy. So BMW doesn't even offer oversize pistons for nikasil/alusil blocks. But for blocks with steel liners, bmw offers 0.25mm oversize pistons, so that"s what bmw considers is safe overbore. For cast iron block, bmw offers 0.5mm oversize pistons. http://www.realoem.com/bmw/enUS/show...diagId=11_6044

                  There is no need to replate bores in aluminium m5x blocks with steel liners after boring. Regular honing is enough.

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                    #24
                    Awesome! So I found two blocks nearby. I confirmed the castings end in -219. Both are $300.

                    One is just the bare block, and the seller says his machinist determined one cylinder to have a bit of scoring, and the rest are out of round, but can be brought back to spec with a .30 cut. He doesn't know if the deck is flat. This block is almost 2 hours away from me though.

                    The other one is a long block. It's been sitting outside for a year, and clearly has oxidation on the block/head. The intake is off so I assume at least one of the valves are open to the elements. The seller has no knowledge of its condition; he just wants it gone. I'd have to buy it to see the condition of the cylinders. This guy is local; 20 minutes away.

                    Which would you choose?

                    Third option is a long block for $700, but that seller doesn't list any information at all.

                    Currently building a badass coffee table
                    Random stuff on insta @kevanromero

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