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Engine Rebuild and Scope Creep

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  • Engine Rebuild and Scope Creep

    I'm going to start a rebuild thread to try and motivate myself to keep on making progress.

    I bought my '88 from a local SIG member back in 2009 with 175k miles. It was Alpineweiss with a Cardinal interior. Seat leather was worn and one tiny dash crack but a great driver.
    E30 M3 by chris tsay, on Flickr

    The drivers side quarter panel has a crease from a parking oopsie by the previous owner and it had a nice collection of door dings and other paint imperfections but it looks great from 15 feet.

    Car was mostly stock with tasteful upgrades: Gustave's spark plug wires and bracket, Evo airbox, big front sway bar, front strut bar, reinforced sway bar mounts front and rear, Kosei K1, stock wheels with RA-1 and a set of HT-10 for the track, Rogue weighted shift knob, VSR center section, supersprint muffler, Bilstein Sport shocks with stock springs, and an excel sheet with maintenance records along with a fat folder full of receipts.

    Back then these cars were pretty cheap so I originally picked it up as cool car that was less valuable than the Exige and a bit more robust in off track excursions.

    So over the next few years I did preventative maintenance like replacing all the coolant components, new fuel system components, H&R Race springs, rebuilt shocks, 'crash' front strut mounts, control arms, tie rods, DTM motor mounts and AKG tranny mounts, finned diff cover etc etc. I also tried to pick off small cosmetic warts like the coolant level sensor wiring, some interior trim pieces etc.

    The motor was high miles with the usual oil leaks but I kept the oil overfilled like the PO had for track work and did regular oil changes. Somewhere in the maintenance history the PO had replaced the rod bearings about 30k miles ago when he noticed copper during an oil change, none of the bearings had spun and the bearing replacement was done in situ and I don't think the clearances or roundness of the big ends was checked. I had joined the local track (Harris Hill Road) and it saw track action at least once a month, until this happened in 2012:

    Engine seized, put the car in gear and we couldn't roll it. Got a roadside assistance tow back home and decided to do the rebuild myself.

    Now let's talk about myself. Mid-30s computer nerd, I do hardware but at a very low level. I had DIY'd most of the M3 work and done some other bolt on work on the DD Tacoma, luckily we had just moved to a place with a garage so what's the worst thing that could happen?

    Pulled the motor with a borrowed engine hoist and started the tear down and found this in the bottom end:
    #4 connecting rod bearing by chris tsay, on Flickr

    mystery solved, those are the special 30 piece Motorsport bearings... :P

    So what to do? After a few months I bought a 2.5L 'core' motor from Ron Checca, he had taken it in trade so he hadn't built it but the price was right and at that point hoarding parts seemed like a good thing to do. Supposedly it was a recent rebuild so the timing components should be re-usable, motor needs a rebuild because of detonation causing some piston damage.

    Engines on stands by chris tsay, on Flickr

    Then the scope creep started. While I've got the exhaust and driveshaft out it's only a few more bolts to drop the whole rear suspension and do some work there that I'd never wanted to tackle because it'd keep the M3 non-drivable for too long:
    Axle boots were cracked -> need to replace the bearings as they usually are destroyed on axle removal -> might as well replace the trailing arm bushings too -> I bought a 4.45 diff might as well install that too

    H&R Race springs led to some greater than desired rear camber so I'll weld in the Massive Subframe riser kit.

    While I'm talking to Lee I piece together a brake kit that will fit under the Kosei's with a set of used from brackets and calipers and new rear kit and front floating rotors.

    Along the way of course I had some seized brake lines that required new hard lines in a few places. Also while the brake system is open might as well move to a 25mm MC and plumb in an adjustable BPV.

    And might as well rebuild the PS pump, replace the sound and heat insulation in the engine bay, swap in a reinforced front subframe, and fix the frame rail paint loss near the exhaust header.

    E30 M3 Trailing Arms by chris tsay, on Flickr

    Trailing Arm Bushing Installed E30 M3 by chris tsay, on Flickr

    4.45 Ring Gear by chris tsay, on Flickr

    M Coupe Diff Cover with Yamabond by chris tsay, on Flickr

    E30 M3 rear subframe and trailing arms by chris tsay, on Flickr

    Rear Subframe, trailing arms, diff. by chris tsay, on Flickr

    !*@*#!*!* brake lines by chris tsay, on Flickr

    Tilton Adjustable Brake Proportioning Valve by chris tsay, on Flickr

    Front Brakes by chris tsay, on Flickr

    Rear Brakes by chris tsay, on Flickr

    New firewall insulation installed by chris tsay, on Flickr

    ZF power steering pump rebuild. by chris tsay, on Flickr

    frame rail surface rust E30 M3 by chris tsay, on Flickr

    Frame rail touch up and reinforced subframe. by chris tsay, on Flickr

    Messy Garage by chris tsay, on Flickr

    to be continued...

    1988 M3
    2007 Lotus Exige S

  • #2
    Great stuff....I love these threads.

    It is almost Deja-Vu in terms of how I started on my car over 10 years ago.

    If you are wondering, or kidding yourself....I can tell you that it will never be finished. We are chasing perfection....and we will never get will find no matter how much work you do on the car there is always something that can be improved or something new wearing out. I don't mean that to sound negative though....most of these projects are a lot of fun as long as you don't need the car for transportation and you can walk away for a while when you want (or need) to.

    I will be following with interest.


    • #3
      I definitely feel you on the mission creep. I'm a sucker for "while you're in there" tasks.

      So your project began with the need for a new engine, but you've done everything except for the engine to this point, correct?
      Alles Beste!

      B. Wheaton
      1989 E30 M3, Owner since June 2000
      2008 E61 535xiT - The DD and work horse

      Register your E30 M3!


      • #4

        My wife has caught on "You're working on the wrong side of the car Chris!"

        My rationale was I didn't want a freshly rebuilt engine sitting for a while before I started it up, but maybe I'm just scared :P

        I think I'm at the point where I've gotten all the chassis worms I've let out back in the can so I can focus on the engine, plan is to tear the 2.5L motor down over Thanksgiving so that I can drop off the block, crank, rods, and bearings off at the machine shop. I'll be using these guys as they are local and have a good (but not inexpensive or quick) reputation:

        The head will go off to E-Ticket Motorsports and the cam box to VAC for clearancing. Also before I can drop stuff off at the machine shop I have to get my bearings treated at WPC and back, the intention is to have the shop clean, inspect, and measure out all the bearing clearances and assess the bore so that I can order new pistons and I'll do the assembly. I've got the Evo main bearings on hand just waiting for the rod bearings to show up. I also decided to splurge and bought all new timing chain guides.

        On the electronics side I've talked to a couple of vendors and I think I've found someone that will retail me the computer and build me a custom engine harness. In the worst case I could do it all on my own as I'm pretty far down the rabbit hole for wiring tools. I'd need to buy a DMC crimper + positioners, a nicer AMP crimper, and a wire stripper to get the jacket off of multi wire bundles but I think I've got the rest covered:
        Wiring tools by chris tsay, on Flickr

        I also have to finish designing the adapter boards so I can interface the Aim MXL Pista to the stock wiring without cutting any wires. I am planning to do this while I'm waiting for the machine shop to finish.
        Screen Shot 2015-10-12 at 10.20.35 PM by chris tsay, on Flickr

        An earlier part of the plan was to install a surge tank but I don't want to drill any holes and the plumbing is pretty tight in the stock main pump location so I'm going to let sleeping dogs lie and just go ahead after replacing all the rubber hoses over the tank and to the expansion tank and install a dedicated relay for the main fuel pump. I do still need to modify the engine bay side of the fuel feed and return hardlines to accept AN-6 connections as the fuel rail I have is AN.

        Adapters will be sourced from Swagelok, if you need to go from 8mm hardline to AN-6 you need this:
        SS-8M0-R-6 SS Swagelok Tube Fitting, Reducer, 8 mm x 3/8 in. Tube OD

        followed by this:

        SS-600-6-6AN SS Swagelok Tube Fitting, Union, 3/8 in. Tube OD x 3/8 in. AN Tube Flare

        completed assembly is ~2.5" long, they don't have a 8mm to 6AN direct adapter, nor a 5/16" to 6AN direct adapter, I guess it's not a common thing in industrial applications.

        Untitled by chris tsay, on Flickr

        Completed Main Fuel Pump Relay Harness by chris tsay, on Flickr

        Completed Main Fuel Pump Relay Harness by chris tsay, on Flickr

        Untitled by chris tsay, on Flickr

        Cams, buckets, and rods. by chris tsay, on Flickr

        1988 M3
        2007 Lotus Exige S


        • #5
          Some other things that have gotten done is repair of the ABS connectors in the engine bay, as most of you have probably experienced they get brittle and literally crumble if you touch them.

          Sourced some chassis side pigtails off of eBay and used some Raychem MiniSeal Crimp Splices and some DR25 to repair the body side harness. The MiniSeal splices are awesome but expensive (about $1 each in quantity of 100) and require a specialized crimper. I bought this one:

          One end crimped, getting ready for the other end. by chris tsay, on Flickr

          E30 ABS wiring repairs by chris tsay, on Flickr

          E30 ABS wiring repairs by chris tsay, on Flickr

          Also used the same to fix a crappy wiring fix I did for the Coolant Level Sensor years ago:
          Bad wiring repair job. by chris tsay, on Flickr

          Completed miniseal crimps by chris tsay, on Flickr

          1988 M3
          2007 Lotus Exige S


          • #6
            Chris, welcome to the M3 world. Ironhead was oh so correct in that you are never finished. The super good news is that look at all the new tools you have bought and will buy.
            Good luck and keep us posted.


            • #7
              Some parts showed up today from Blunttech: Timing chain components, top and bottom end gasket sets, front wheel hubs, misc electrical, and rod bearings.

              parts! by chris tsay, on Flickr

              With the rod bearings in hand I'll be shipping a set of red and blue Evo main bearings and stock size rod bearings off to WPC for treatment. Here's a picture of an Evo guide bearing:
              BMW S14 Evo Guide Bearing by chris tsay, on Flickr

              Coating at WPC is $4 / half-shell + shipping to and from their facility in California. The S85 and S54 guys seems to favor WPC over Calico, I like that the color coding on the bearing is still visible after treatment. Maybe it's snake oil but it's cheap in the grand scheme of things.

              1988 M3
              2007 Lotus Exige S


              • #8
                More scope creep / distractions.

                When I first purchased the car in 2009 the cover to the Aux Fuse Box was missing. Coincidentally Lotus uses the same box and cover so that gave me a lead on the part numbers:


                So I ordered 61131382197 from the local BMW Motorrad dealer, ECS has it for about $13. If you want the box also it’s part number is 61131382196.

                When I went to install it I cracked the mounting tabs on the little fuse box, cue the sad trombone sound. I tried extracting the terminals with what I had on hand but was unsuccessful and put it on the back burner.

                Over the years as I’ve acquired terminal extractors for other projects I’ve tried them on the fuse box terminals but none worked. I finally caved and bought a set of terminal extractors, #20 worked for this task:

                Terminal Extraction Tools by chris tsay, on Flickr

                E30 M3 Aux fuse box terminals by chris tsay, on Flickr

                E30 M3 Aux fuse box terminals by chris tsay, on Flickr

                E30 M3 Aux fuse box terminals by chris tsay, on Flickr

                Unfortunately the old terminals aren’t seating perfectly in the new fuse box and the new terminals I bought in my last part order don’t fit either. I had ordered 61131358924 but it’s a little too wide. Looking at Jake’s terminal and plug housing post:

                I think these are the right ones:
                02 Double leaf spring contact 0,5-1,0MM˛(SN) X 61131370691 $0.62
                02 Double leaf spring contact 1,5-2,5 MM˛(AG) X 61131370692 $0.68
                02 Double leaf spring contact 2,5-4,0MM˛ X 61131370693 $0.68 ENDED

                It’s not critical as the fuse box is unused and if I add any other electrical loads in the engine bay I’ll be running new dedicated wiring.

                I did take some measurements while the terminals were free:
                E30 M3 Aux fuse box terminals by chris tsay, on Flickr

                E30 M3 Aux fuse box terminals by chris tsay, on Flickr

                E30 M3 Aux fuse box terminals by chris tsay, on Flickr

                Then tidied it up:
                E30 M3 Aux fuse box terminals by chris tsay, on Flickr

                1988 M3
                2007 Lotus Exige S


                • #9
                  double post.
                  1988 M3
                  2007 Lotus Exige S


                  • #10
                    You will find the terminal extractors to be money very well spent.

                    My car is now a mix of the stock type wiring terminals and mil-spec stuff. I wish I could convert everything to mil-spec....once you are over the hump of having to buy the mil-spec crimping tools....that stuff is so vastly superior in every other way.

                    Some of the stock in the C101 connector...are absolutely impossible to extract without a very application-specific tool. I tend to buy every extraction tool I can find....and I still run into situations where none of them really work very well. The connector for my WB02 sensor was a perfect example just yesterday....there was nothing I had that would extract the terminals. I wound up having to cut it off and start over.

                    Using the stock type is also frustrating because sometimes it is difficult or impossible to find the correct size for the specific wire gauge you are you have to kind of find a way to make it work. It's like you can get them for 10-12 gauge wire.....or 18-22 gauge wire....but nothing in-between.

                    I imagine by now you know all this though....

                    I keep wanting to buy a PDM and rewire the whole car....just haven't quite taken that plunge yet.
                    Last edited by Ironhead; 11-22-2015, 11:01 AM.


                    • #11
                      Yeah, the stock wiring and connectors pales in comparison to the mil spec stuff. I'm going to be tooling up to do Deutsch DTM / DT / DTP soon because that's what I'm specing to interface the dash and other accessories into the new engine harness, I used milspec wiring and shrink etc. for the fuel pump harness and it was great to work with.

                      If the carpet of the car ever comes out (never say never) I would have to think long and hard about rewiring the chassis harness with a PDM. After the car runs and I recover a little financially I'm going to get the interior leathers redone in GAHH but I don't plan on pulling up the carpet. Except maybe to fix that one exhaust heat shield stud that has rusted out...

                      Cleaned up the garage today in preparation to tear down the 2.5L motor.
                      Untitled by chris tsay, on Flickr

                      HT10 pads dust a lot, didn't wash the car before I pulled the motor so I maintained that 'fresh from the track' patina.

                      Connected the fuel pump relay harness trigger connections to the stock main fuel pump wiring underneath the rear seat and re-installed all the upper and lower rear seat cushions:
                      Untitled by chris tsay, on Flickr

                      Using a stock wiring grommet cannibalized from a tail light harness of eBay means I get a nice sealed interface to the underside of the car, you can see that grommet in-between the two connections I covered in DR-25 for insulation.

                      1988 M3
                      2007 Lotus Exige S


                      • #12
                        Tore the 2.5L motor apart today. No big surprises other than the first intake cam journal looks pretty ugly.

                        On the good side, the timing components look very low mileage with hardly any grooving and the guide rail is merely yellow and not a deep red like the one from my 180k build. Going to squirrel those away for a rainy day.

                        I've got a flickr album of the teardown here:

                        Found an A100 Evo Cam Gear:
                        Cam gears! by chris tsay, on Flickr

                        Cam Journal Cap damage:
                        ugh. by chris tsay, on Flickr

                        And the Cam Box side:
                        intake cam journal. by chris tsay, on Flickr

                        The Cam Journal looked fine but I forgot to take a picture. My suspicion is that the damage happened prior to the build I just ripped apart. I've got another good cam box but do you guys think this is serviceable?

                        Also whoever put this thing together forgot the two o-rings (07119906328) in the Timing Chain Tensioner Guide:
                        no o-ring! by chris tsay, on Flickr

                        Anyways, took me a leisurely 4 hours to tear the motor down taking tons of pictures.

                        1988 M3
                        2007 Lotus Exige S


                        • #13
                          I would suspect the camshaft was put in dry with no lube and the damage was done prior to oil pressure arriving. To repair it would take some considerable amount of work the cap/cam housing would have to be line bored and a shell made to bring it back to original diamater.
                          Lucky you have a good replacement in stock.

                          E30 M3 1987
                          Mini Clubman GT
                          BMW E36 323 Msport
                          Toyota Corona
                          KTM 200EXC
                          Honda CB50 (1979)


                          • #14
                            Yeah, cam box is junk. Emailed the SIG and MarioL thought the same thing. Since I'm an OCD hoarder anyone got a cam box they want to sell me so I still have viable spares of everything?

                            Spent a little time today stripping the last bits off the block before it can go to the machine shop:
                            RMS carrier
                            Oil Restrictor Jet
                            Coolant block drains on the intake (17mm bolt) and exhaust (19mm bolt) sides

                            Gustave had some great pictures on removing the jet, since his website I think is gone again here's a poor replacement:
                            Oil Jet Removal by chris tsay, on Flickr

                            Oil Jet by chris tsay, on Flickr

                            Also used a similar contraption to remove the upper timing chain guide:
                            Upper Chain Rail removal by chris tsay, on Flickr


                            1988 M3
                            2007 Lotus Exige S


                            • #15
                              Sigh, today the treated bearings from WPC were supposed to be delivered. UPS shows them as delivered but they are not on the the doorstep so seems that someone swiped them.

                              Two complete sets of Evo main bearings, red and blue, and a set of rod bearings. WPC treated. Very frustrating.

                              1988 M3
                              2007 Lotus Exige S