Timing Belt Trouble

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  • RoarinE21
    Noobie
    • Jul 2017
    • 27

    #16
    Also anyone know where you can rent the a leak down test kit?

    Comment

    • zaq123
      E30 Fanatic
      • Jul 2016
      • 1364

      #17
      Originally posted by RoarinE21
      Also anyone know where you can rent the a leak down test kit?
      You can build your own. Use the spark plug adapter hose from the compression tester, quick connector, 2 gauges and 4-5" tubing in between two gauges. Epoxy/JB weld a restriction inside the tube and drill 0.04 hole once epoxy is dry. All part can be found in HF or HD store for under $20.

      if you are concerned about bent valves and don't have a tester, you can just TDC a cylinder and pressurize it thru a spark plug hole with the compressor (still need a comp. gauge plug hose). If you can hear/feel the air from IN/EX, valve aren't sealing. Just make sure you can hold the crank nice and firm, the breaker bar will want to smack you with all that pressure in the cyl.

      Honestly, I'd just pull the head if you meet any major resistance during the rotation. M20 should rotate very easy even with HD valve springs and 12" bar. It will obviously resist slightly when v. springs are compressing but it will be still smooth.

      Did you ever tried to find TDC with a piston stop? If so, even with a gentle rotation you will feel when pistons meet the hard stop. Don't know how else to describe it....when overcoming valve spring pressure you will feel some a resistance but it will be very smooth (spark plug removed obviously).

      Before TB change, do you recall how it felt when you were rotating the engine to TDC?

      Comment

      • ForcedFirebird
        R3V OG
        • Feb 2007
        • 8300

        #18
        First off, you don't need two head gaskets on an m20. You just gave yourself something silly like 7:1 compression - don't even know if you will be able to get it to fire as you will be dangerously close to 100psi cranking. the m20 came from the factory with 8.8:1 which is perfectly fine to boost, or even raise compression and boost.

        What is the sharpie line in your pic? You need to put the crank at TDC, then use the tick mark located on the outside of your cam gear. The marks inside the gear are for advancing or retarding the cam.

        I suggest you take the head off, put a single head gasket back on, put the stock cam gear back on, then attempt to work on it. If it's a stock engine you are going to turbo, toss that cam gear aside. I have been putting turbos on bone stock motors for years with great results. Just o-ring the block (or stock thick .070" MLS head gasket), and put ARP studs in and the engine will easily make 400 in a daily driver and last many years so long as you don't botch the tune.
        john@m20guru.com
        Links:
        Transaction feedback: Here, here and here. Thanks :D

        Comment

        • zaq123
          E30 Fanatic
          • Jul 2016
          • 1364

          #19
          Originally posted by RoarinE21
          I couldnt figure out what the M20 valves are all supposed to look like at tdc so if anyone knows or has a picture of that that would be great[/B].
          At DTC for cyl 1: if you look at cam lobes for that cyl, they should be pointing down at the same angle from the center line. Very roughly speaking, IN lobe will be at 4 o'clock and EX at 8 o'clock position. Basically, the same position when you can measure the valve clearance properly

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          • RoarinE21
            Noobie
            • Jul 2017
            • 27

            #20
            Alright am pulling the head and going back to to one gasket this weekend. Also found my old oem cam gear and compared it to my second aftermarket one and it looks like I was right! the timing marks were inches off! the one I made with my sharpie was only one tooth haha. Not sure wtf they were thinking when they made these and advertising them for m20s besides destroying everyones valves. Well guess that solved it! thanks everyone for the feedback, sure ill be back soon with some other problems!

            heres a pic of the oem vs aftermarket cam gear, you can see the actual timing marks circled in red and the ones put on by aftermarket guys in blue:

            Comment

            • digger
              R3V Elite
              • Nov 2005
              • 5929

              #21
              shit gears are shit
              89 E30 325is Lachs Silber - currently M20B31, M20B33 in the works, stroked to the hilt...

              new build thread http://www.r3vlimited.com/board/showthread.php?t=317505

              Comment

              • RoarinE21
                Noobie
                • Jul 2017
                • 27

                #22
                Originally posted by digger
                shit gears are shit
                Fuckin amen. Moral of the story is dont buy anything ebay/amazon without checking everything about the product out first
                Or just dont in the first place:nice:

                Comment

                • zaq123
                  E30 Fanatic
                  • Jul 2016
                  • 1364

                  #23
                  Originally posted by RoarinE21
                  Fuckin amen. Moral of the story is dont buy anything ebay/amazon without checking everything about the product out first
                  Or just dont in the first place:nice:
                  Also it's expected that every time you use a part thats not OEM, everything has to be checked/rechecked and than checked again. A simple glance at those two gears side by side would have prevented this.

                  Comment

                  • ForcedFirebird
                    R3V OG
                    • Feb 2007
                    • 8300

                    #24
                    Appears it was bolted together in the wrong position.
                    john@m20guru.com
                    Links:
                    Transaction feedback: Here, here and here. Thanks :D

                    Comment

                    • RoarinE21
                      Noobie
                      • Jul 2017
                      • 27

                      #25
                      Originally posted by zaq123
                      Also it's expected that every time you use a part thats not OEM, everything has to be checked/rechecked and than checked again. A simple glance at those two gears side by side would have prevented this.
                      Definitely glad thats what I ended up doing before trying to start this thing. Guess it still woulda saved me about 3-4 hours of work and a head gasket

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