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1987 325e sedan M30B35 swap

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    Today I cleaned out my intake manifold. All the runners were coated with a layer of sludge.

    At least you can see some aluminum now.

    All clean and ready to install. I’m replacing the injectors since the engine has sat in storage for so long.

    I should also mention I installed a late model M30 starter. I had several working old style M30 starters but wanted the skinny starter Incase I had to change it later.

    Then I started on the controls.
    I picked up a manual brake pedal from my wrecked M60 e30.

    Cut up the old style shifter plate for my chassis mount shifter.

    I’m hoping to have the swap running by early December, maybe driving by late February.

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      Nice progress. What is the performance difference between the N31 and N21 cam?
      Never argue with stupid people, they will drag you down to their level and beat you with experience. -Mark Twain


        Originally posted by Bearmw View Post
        Nice progress. What is the performance difference between the N31 and N21 cam?

        I have no idea what a N31 or N21 is.

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          Today was the big day. The first start! All my hard work would be rewarded with the roar of a loud, poorly running M30!
          First I’ll go into the wiring and installing the harness. Hands down the easiest way to do this swap is with a M20B25 engine wiring harness. I picked up a 88 SETA harness from my favorite place to get parts, R3VLimited Facebook group. A quick ISO post and a PayPal transaction, I had the harness needed for super cheap. The 88 SETA is technically Motronic 1.1 but the harness is still the same as 1.3, only difference is in the DME.
          I’m running a e34 535i 179 DME. The latest and greatest DME for the M30B35, don’t even bother with the 150 DME.

          My M30B35 came from a automatic 735i so the throttle switch would need to be changed from an automatic throttle switch.

          To a manual throttle switch.

          You cannot use the M20 switch. It looks the same but internally it is backwards. So your DME will think your at WOT at idle and idle at WOT. Luckily my Brother’s wrecked 635csi is in my driveway so that part was easy to source.
          The M20 harness has the AFM located in the drivers side of the car instead of the passenger side.

          This requires trimming of the harness protective sheathing by about a foot to achieve this.

          The M20 harness uses a separate harness for the injectors/temp sensors unlike the M30 harness.

          I had to remove the harness from the plastic housing so the wires would reach.

          I know it looks like shit right now, but I do have the M30 injector plastic wire housing to make it look OEM later.
          Using the stock M20 coil.

          To get my key to work for starting the car I had to find my old Auto shifter and plug it in with the shifter in park. I need to figure how to jump this connector since I’m using a manual transmission.

          I have an extra 2 prong connector on the throttle switch/AFM/ICV portion of the harness. I have no idea what it’s for.

          With the harness completely installed I removed the fuel pump relay to prime the fuel system. Using a wire to jump pins 87 and 30 kicks on the fuel pumps.
          I also installed rebuilt fuel injectors.


          Also make sure the spark plug wires you are using have the sensor on the #6 wire.

          To my amazement the engine fired up no problem!!! The engine sounded like it had a giant cam because of all the vacuum leaks from disconnected vacuum ports, and no o2 sensor.
          Overall I was pretty excited.

          Now to finish up everything on the car.
          Shifter, clutch, driveshaft, vacuum lines, etc.

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            What's the link too? i have to sign up to see it.


              Originally posted by LowR3V'in View Post
              What's the link too? i have to sign up to see it.

              It’s my Facebook page. Try this link.


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                Today I got the exhaust system closer to completion.
                I was going to weld 2” V band clamps to each separate down tube, but then I thought I could combine both manifolds and down pipes into one piece. This way I would only need to buy 1 set of V bands.

                I cut the down pipes as soon as they turned straight.

                Followed by a dual 2” inlet collector to a single 2.5” outlet.

                I tack welded everything under the car to ensure proper alignment.
                The most important detail about this setup is that you can remove the manifolds/down pipe/ collector together. This requires no exhaust joints till after the collector. The entire assembly is a little cumbersome, but it can be installed as pictured.

                My dog Boris inspects all my work.

                All was looking good till I tightened the exhaust studs.
                The FWD manifold down pipe was hitting this ear on the engine block.

                My options were hitting the down pipe with a hammer for clearance, or cutting off that ear on the engine block. I’m pretty sure it won’t matter.

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                  Id hammer that down pipe in a little. I think that ear is for putting the engine on a stand. If you ever need to rebuild it. You might have difficulty mounting it

                  1989 325is l 1984 euro 320i l 1970 2002 Racecar
                  1991 318i 4dr slick top

                  Euro spec 320i/Alpina B6 3.5 project(the never ending saga)
                  Vintage race car revival (2002 content)
                  Mtech 2 turbo restoration
                  Brilliantrot slick top "build"


                    Got some valuable wrenching time in this weekend and squared away my shifter.
                    I drilled my chassis shifter plate to pick up the original holes for the auto shifter on the trans tunnel.

                    As you can see the holes are elongated so I can fine tune my shifter position without having to cut and re weld my selector rod again.
                    Here is the selector rod.

                    I had to shorten it about 3.2” for my G240. I think it’s an original 325e selector rod.
                    1st gear

                    2nd gear

                    3rd gear

                    4th gear

                    5th gear

                    Gotta say it’s pretty satisfying rowing through all the gears. I do need to replace the shifter joint on the transmission input rod, it is super wore out and causing a great deal of play in the shifter.

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                      My car spent all of it’s 217,000 mile life as an automatic which meant the driveshaft was about 7” short.
                      Real OEM says the auto 325e driveshaft is 52.25”. A manual 325e driveshaft is 58.38”.
                      And a E36 325i manual driveshaft is 59.52”. I’ve heard from somewhere you can use the E36 driveshaft but it requires flipping the CSB around.
                      I found a 1988 325i driveshaft locally for $200. The Seller said he sent it to a driveshaft shop to have the CSB replaced and re balanced. The U joints felt solid even though they were the original ones.

                      Compared to the auto shaft.

                      One small problem was the CSB was the wrong size. I guess somewhere between 87 and 88 BMW changed the CSB size.
                      I could of swapped the CSBs but since this one was new I just drilled some new holes in the mounts and used some large self tapping screws.

                      Yeah I know the screws aren’t as strong as the threaded chassis inserts. If they end up ripping out I’ll put a rivnut in the CSB mount. They seem pretty strong compared to the stock CSB bolts.

                      This driveshaft was a little bit short so the splined slip yoke had to be extended about 1.75”

                      Not ideal, but it will work.
                      I’m so close to test driving this turd. Just need to put together the cooling system and sort the pedals.

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                        I did something similar on my swap.

                        The screws won't rip out - there's not a lot of pressure on the CSB - just look at the rubber supporting the bearing - it is really soft / flimsy.

                        Be sure to check the alignment of the shaft before you drive it - the 88 on CSB has shorter legs so the alignment is probably a bit different. It'll vibrate like crazy if the driveshaft isn't straight.
                        My e30: OEM+ with M30B35


                          1987 325e sedan M30B35 swap

                          Time to sort out the pedals.
                          Disgusting auto pedals.

                          Sexy manual pedals.

                          Many people think you need a manual pedal box when doing a manual swap, and I’m here to tell you that isn’t true.
                          The only difference between the auto and manual pedal box is the provision for a clutch pedal spring.
                          A quick search on r3v proves that many remove this spring when it breaks, proving it unnecessary. You can swap your pedals from auto to manual without swapping the pedal bracket.
                          New pedals.

                          New slave from a 318i.

                          Lines hooked up from the clutch master cylinder.

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                          Last edited by st.petebiodiesel; 12-12-2017, 05:06 PM.


                            I am proud to announce that my car moved from it’s resting place on the side of my house under its own power!

                            Couldn’t run it for long since I was still waiting on my radiator. Which I received today.

                            Just a cheap $95 eBay radiator. I couldn’t use the one I had because it didn’t have the channel at the bottom for the rubber mounts.
                            I was going to hook up my heater core but the pipes in the engine bay are pretty corroded. So I’ll move that to a project for another day.
                            I borrowed some coolant hoses from my Brother’s E24.

                            The lower radiator hose had to be modified.

                            I’m going to build a mount bracket for the stock early e30 coolant reservoir on the drivers side of the engine bay. I know I could just buy a late model e30 reservoir but I could spend that money better elsewhere right now.
                            My car was blocked in by my Brother’s wrecked e24 which currently had no front suspension. So I moved it.

                            Even without an engine/trans e24s are really heavy.
                            Test drive was a little loud with no exhaust system other than the down pipes. I think these engines run better with some exhaust pressure also.
                            Warmed up it runs pretty well.

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                              so the radiator will sit on those brackets and you'll use the stock plastic mounts on the top?
                              also, how close is the pulley to the rad? I had to ditch my ac/power pulley. Too close for comfort.


                                Originally posted by LowR3V'in View Post
                                so the radiator will sit on those brackets and you'll use the stock plastic mounts on the top?
                                also, how close is the pulley to the rad? I had to ditch my ac/power pulley. Too close for comfort.

                                Yeah it uses the stock rubber doughnut mounts.
                                I have about 3/4” of clearance from my pulleys.

                                If I used a 535i radiator I bet I could use a engine driven fan.
                                Needed to swap the M30 cluster temp sensor.

                                For an E30 cluster temp sensor.

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