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Strength of the 2.7 vs 2.5 bottomend?

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    Strength of the 2.7 vs 2.5 bottomend?

    I blew two 2.7 engines in 2 weeks! Is it bad luck or should I be running 2.5 bottomends. I have not taken them apart but they both had over 200,000 miles and it was not the timing belt (new) but it seems like the main bearings.

    The real question is: Strength of the 2.7 vs the 2.5...are they the same main bearings etc.???

    Ideas?

    Thanks
    Chuck

    #2
    you need to learn how to drive...
    ///Alpinweiß II 24v 91' 318is, Alpinweiß III 99' 323i, 04' Yamaha R6 SE for sale, 00' VW GTi, 83' El Camino BURNED, 01' P71sold, 92' Miatasold

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      #3
      Originally posted by asubimmer View Post
      you need to learn how to drive...
      quoted for truth
      Need a performance chip for you BMW? Shoot me a PM and I'll get you taken care of!!
      Taylor- Follow me on Instagram @e30_fiend


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        #4
        Other than the crank shaft, a 2.7 and 2.5 block are the same.

        I suspect that the main problem is the 200k on the short blocks and wear on the bearings. If not totally destroyed, check the crank on one of these for wear and rebuild the bottom end.
        The car makes it possible, but the driver makes it happen.
        Jim Levie, Huntsville, AL

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          #5
          You're just unlucky. There is no information at all that suggests that 2.7 bottom ends are any weaker than 2.5 bottom ends.

          '88 325is
          VP UT of Austin Autoholics
          BMWCCA 380364

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            #6
            Originally posted by asubimmer View Post
            you need to learn how to drive...
            +2
            "God created turbo lag to give V8's a chance" Taylor D.

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              #7
              Originally posted by asubimmer View Post
              5kwatson needs to learn how to drive too cause his shit blew up too...
              Originally posted by Ferdinand
              I carry a cheap pressure gauge in my glovebox with which to manually check my tire pressures, but I keep forgetting that in the USA glovebox space is sacred as it is reserved exclusively for the purpose of storing handguns.

              DIVING BOARD DIVISION DIVISION IDIOT

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                #8
                Yeah, its not the engines dude, its you. learn to drive the car.
                sigpic

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                  #9
                  Learning to drive.......please help

                  I am ready to learn how to drive. Would someone step forward and guide me as to what to do? Should I keep the revs under 2000? Warm the engine for 2 hours before bringing above 2000? Maybe if I had an automatic trans it would help. Maybe I should hire a driver. Change the oil every 1000 miles? Remove my synthetic oil?
                  Ideas please?



                  Thanks,
                  Chuck

                  Comment


                    #10
                    Originally posted by Chuckcruzin1986 View Post
                    I blew two 2.7 engines in 2 weeks! Is it bad luck or should I be running 2.5 bottomends. I have not taken them apart but they both had over 200,000 miles and it was not the timing belt (new) but it seems like the main bearings.

                    The real question is: Strength of the 2.7 vs the 2.5...are they the same main bearings etc.???

                    Ideas?

                    Thanks
                    Chuck
                    I would have at least done the piston rings and rod bearings while the engine's out. When the block was on my stand, front/ rear main seals;piston rings/rod bearings were done in like an hour?? Bad idea to put in a motor that you have no idea of. Could have at least pulled the oil pan and check if there were any play in the rods...

                    Justin


                    '89 325i - Totaled... good bye my love...
                    '87 327i budget stroker - SOLD!!!
                    '92 240sx - ca18det powered drift toy - SOLD!!!
                    '89 325i - coupe - NEW daily
                    '96 Audi A6 Quattro- Grocery getter/baby hauler
                    '99 Busa - weekend wheelie monster

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                      #11
                      Whats up with all of the new retards. That ask questions and get there answers and feel the need to be smart ass pricks? ITs your driving 2.7 are tough my 2.7i took a beating
                      and it was a juckyard shortblock
                      84 318I Delphin RIP
                      87 325IS delphin 24v Sold
                      89 325 Alpineweiss

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                        #12
                        I think this is the best advice

                        Originally posted by slo325i View Post
                        I would have at least done the piston rings and rod bearings while the engine's out. When the block was on my stand, front/ rear main seals;piston rings/rod bearings were done in like an hour?? Bad idea to put in a motor that you have no idea of. Could have at least pulled the oil pan and check if there were any play in the rods...

                        Justin

                        I am going to tear down one of the engines and build it as you have recommended. No more installing used engines.
                        Thanks
                        Chuck

                        Comment


                          #13
                          If the crank shaft doesn't have score marks, you need to measure each journal to check for wear before fitting new bearings. That is several measurements with a micrometer around and across each journal. If worn, the crank can be re-ground and over sized bearings used.
                          The car makes it possible, but the driver makes it happen.
                          Jim Levie, Huntsville, AL

                          Comment


                            #14
                            I turn my 2.7 crank past 7000rpm on a daily basis

                            being junkyard engines they may have already been dead when you got them, or very well near it. crank/rod bearing problems are pretty uncommon on the M20.
                            Build thread

                            Bimmerlabs

                            Comment


                              #15
                              Originally posted by nando View Post
                              I turn my 2.7 crank past 7000rpm on a daily basis

                              being junkyard engines they may have already been dead when you got them, or very well near it. crank/rod bearing problems are pretty uncommon on the M20.
                              I was thinking the same thing. A quick survey would show just how reliable the M20 bottom end is.

                              I think the OP just has bad luck!

                              Closing SOON!
                              "LAST CHANCE FOR G.A.S." DEAL IS ON NOW

                              Luke AT germanaudiospecialties DOT com or text 425-761-6450, or for quickest answers, call me at the shop 360-669-0398

                              Thanks for 10 years of fun!

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