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DIY : Engine Rebuilds (Speciofically BMW S54)

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    DIY : Engine Rebuilds (Speciofically BMW S54)

    So I'm going to attempt to rebuild my own engine for the first time.

    Interested in any stories from people who have just said "fuck it" and rebuilt their own engine. I'm doing it for self interest, and to try and keep costs down (yes, if I fuck up I'm aware I could be up for ALOT more...)

    Engine/Car history.

    *Car was bought as a cheap E46 M3 - 230,000km. Came with books and serviced by BMW till about 220,000km.
    *Car was always intended to be tracked and leaned on.
    *It's been overheated a few times in search of a better lap time.
    *Performance wise, it's never missed a beat... Reliable enough to come away from all track days with a PB, clocked a 1.10.9 at Wakefield last time out - so it's still got power there.
    *Now has 245,000km & about 12-14 track days on it since I've owned it.

    Decided it was time to do a compression test, I noticed some water marks in the engine bay, suggesting coolant had been pushed out of the expansion reservoir.

    Coolant gas check from the same reservoir came back negative.

    Compression test (cold... just forgot to warm it up) was 105/105/147/150/149/149 (ideally they should be around 175 - on a warmed engine)
    -crack in head gasket between Cyl1 & 2 obviously.

    So : Plan is :
    -Redo compression test on a warm engine
    -If it comps up to 170ish & within variance tolerance to each good cylinder...
    *Have head machined & serviced, new head gasket, new rod bearings and bolts, new main bearings, new timing chain & guides, new water pump, new water hoses, sensors.

    Just curious if anyone else has had a crack at building their own engine, regrated it ? Or actually got something out of it.

    Ps. I have access to a few mechanic mates, so the tech help and specialist tools are there when I need them, but remember.... Doing this mainly for the experience.

    Yes... Pro BMW technical stuff and this and just pay a workshop... No...
    Panzer Wagen

    M-Cars follow the idea that power should be felt & not seen

    I've built so many of my own engines. Once you have done this one you will look back and wonder wtf you were worried about. Best thing I did was get friendly with a machine shop. I used them for the machining along the way and then I just used to ask them stupid questions whenever they popped up in my head.

    Manuals are good, you need good reference materials. Also when it's all said and done you doubt yourself at every oil drop and bit of smoke and waiting for oil pressure to get up first start etc etc. Take your time. Know what you are doing ie follow the manual. That's an enthusiast car so there should be loads of info out there. Clearances for bearings and piston ring gaps are all out there. Follow your manual and go for it.

    You can download engine build sheets so when you do it measure everything and write it down. It gives you a reference for later.

    Wait till you get to breaking in the new engine. How to run in an engine. Everyone has an opinion. They all contradict each other. I've done the cheapest dirtiest rebuild known to man and broken it in by doing a big 11 down my street and a track day a week later and it was fine and still is to this day.

    Few problems you are bound to come up against.

    Measuring tools are expensive. I borrowed them from friends the first two times I built engines.

    The piston ring compressor to suit your bore instead of the adjustable ones are worth their weight in gold.

    Its way easier putting it together with someone helping.

    You really need a clean place to build it and lots of table or bench space.

    Sorry I know nothing about bmws. Pity you are not in wa. That machine shop that helps me had a guy working there that used to answer my questions. Raced an e30 full bmw nut would be really helpful at this point in time.


      Oh cool.

      Yeap... All measuring tools available. I'll invest in some myself though as well.

      Machine Shop is one thing which I really need. Not sure if I need to buy into the hype of a machine shop with a good rep, or "you must only goto a shop that knows BMW engines, as anyone else will fuck it up"

      Again, few mates are into drags and will be able to get some feedback on the machine shops available around here.
      Panzer Wagen

      M-Cars follow the idea that power should be felt & not seen


        all of this^^^

        Its been fucking years, and I was only doing L series dattos and Kents and an RB out of a patrol, but non of the engines I built blew up.

        Agreed you need a heap of space.

        Take plenty of pics to. Right from the start.
        .... because every driver experiences the destructive potential of the effortless surge of power available through the smallest of body movements.

        Dr Hoon

        DrNick is king!!!! No, Mark Webber is now! Long live the king!... hold on a minute mate, Ricci is in charge now


          I bought my first car as an 17yo, and promptly blew it up a few months later (Datsun 1600). Didn't have money to pay for engine rebuild. Bought a Gregorys manual, borrowed dad's tools, pulled it out and rebuilt it. Worked fine, I enjoyed doing it and have built many since.

          Originally posted by AndyMac View Post
          Not sure if I need to buy into the hype of a machine shop with a good rep, or "you must only goto a shop that knows BMW engines, as anyone else will fuck it up"
          Nah, if you're doing most of the work yourself, the machine shop will only be doing general machine work (boring cylinders, machining valve seats, decking block, grindgin crank, head, etc). No difference between doing that work on my old Datsun engine or your fancy BMW engine. Pick one that you're happy with - its always good to find one that is happy to do stuff like measure up your bits for you to determine what you will need, on the understanding they'll get the job oce you have bought all the bits (tip - measure up, buy pistons, bearings in the sizes you need, then take it all to the machine shop along with details like clearances for them to do their bit)


            Originally posted by AndyMac View Post
            Not sure if I need to buy into the hype of a machine shop with a good rep, or "you must only goto a shop that knows BMW engines, as anyone else will fuck it up".
            The previous owner always took my 36 to a workshop that specialised in BMW. They still managed to completely fuck it up - and sent him the bill for fixing said fuckup.
            Just find a good machine shop, no matter what their specialty is.

            And what Dave said. ^^


              Building an engine of some kind is a right of passage for a car guy I reckon.

              I've built 2 engines and had good success.

              Extremely rewarding.


                S54 isn't the ideal engine for a first-timer rebuild but don't let that scare you off.

                They do require a few special tools but you can make or improvise alternatives.

                Make sure you do a lot of research on Vanos system and do a full rebuild. Buy this guys kit and follow instructions:

                Oh and it will need crank and big end bearings.


                  Go for it, it ain't rocket science

                  From your list I see no mention of bores/pistons, in that case I would not remove the pistons from the bores. You may contemplate a bearing roll, removing each main bearing one at a time without removing the crank from the engine. Look it up on Youtube.
                  " Racing cars don't have doors. Toilets have doors" : Keke Rosberg


                    It does feel good once it's all together and started up making all the right noises.

                    Go for it, and take plenty of photos during removal of odd bits and the arrangement of springs, washers and spacers.
                    Jason Broadhurst

                    Someone once asked me if they could use my mower. I said "sure, so long as it doesn't leave my yard"


                      Biggest problem is going to be needing valve locking and alignment tools to refit everything timing chain and cam timing related. Theres no fancy block/bore coatings to worry about as the S54 is a iron block, but the bore spacings are pretty tight if you have any issue with roundness, especially since you think its gotten hot a couple times. There are companies that have been sleeving them though if you come across issues, you probably wont find another spare block in aus easily, so it'll probably be worth pulling it all down and measuring before you plan on doing anything first. You wont get more than maybe 10 thou over out of the block without sleeving as they really arent designed for it.

                      Id be buying a 87mm torque plate for machining though, and if you are going to upgrade all the fasteners to arp stuff, especially the mains, id buy it all before machining so you can fit the mains and check to see if it needs line boring. Long engines and the added torque of the arp bolts can see some distortion through the caps as they are pretty narrow. Normally you can probably get away without torque plate on a cast block, but it's added peace of mind after its already been run hot and beat on. It'll need facing for sure, so all that combined is probably a good start for finding a good machine shop. If they arent asking questions about the condition of the block, line boring the mains, bolt upgrades, etc, then it's probably not the place to use.
                      Originally posted by Buford T. Justice
                      This happens every time one of these floozies starts poontangin' around with those show folk fags.


                        Thanks Madhatr - awesome post/feedback.

                        I've managed to buy some good measuring tools (measuremax from Hare & Forbes), and the cam alignment and locking tool off eBay (

                        Hopefully the machine shop I'm using will have the torque plate, will confirm.

                        Engines from the UK seem to be about $6k delivered... Food for thought
                        Panzer Wagen

                        M-Cars follow the idea that power should be felt & not seen


                          Ok. cool. That makes it a little easier if you have the timing/locking tools.

                          Even if you arent comfortable building the engine, Id say go ahead and pull it down yourself and start cleaning up any parts/covers/etc you want to reuse. Just take photos as you go and grab yourself some plastic zip lock bags and some cardboard boxes and bag up things as you go and throw the bags into seperate boxes for each area of the motor. Example one box could be cylinder head, so it will have all your cam parts, followers valve gear, etc related parts bagged in it. Each bag belongs to a specific part or component you removed, each box is an area. Make sense? I used to just bag things up and throw it all in a box before I started working on amusement rides, now it makes even more sense to not only bag things up into specifics, but also to divide those bags up into areas or components too. Makes it easier to track down something missing, or to sort through only a dozen or so bags looking for fasteners, instead of a giant box full of everything (even through its labeled).

                          Im pretty sure a torque plate from m50/m52 works as they normally have a greater bore than than what the motor actually has, so they can fit multiple models that share bolt spacings. Surely someone in the bmw community will have one, all those workshops out there. Otherwise, even VACC sell them for like $350, so they have to be out there somewhere cheaper than that.

                          Is that 6k for a rebuilt bottom end or just another engine? If it's used, im pretty firm on believing in the devil you know. So if it came down to rebuilding what I have, vs buying another basically unknown proposition, ill always try to budget for sticking with what I've got. You know what you're in for.

                          Id check with precision international for parts like bearing and ring packs before looking overseas too. They distribute king and glyco brand bearings, including the racing ones, along with elring stuff for vrs kits and even cometic gaskets. Some of the prices have been pretty good too.
                          Originally posted by Buford T. Justice
                          This happens every time one of these floozies starts poontangin' around with those show folk fags.


                            only tips I would give are use a good machine shop who know their shit, get them to do the measuring and machine work on the crank/bearing/rod/piston clearances and balancing. Likely you will have to clearance rings yourself (time consuming so probably too expensive to pay the shop?).

                            1000000000000% buy either a non-adjustable compressor set for the exact size piston you are installing or one of these in the right range;

                            I have used the adjustable one before and its great. Im sure the solid non adjustable are even better. You can press the pistons in with your fingers, this allows you to really 'feel' the rings slide into the bore. Someone not experienced can have a rings snap too easily with old school compressors and a hammer technique.


                              Hey Andy. As above. When you start stripping it, zip lock bags with very specific labelling. It might feel tedious while you're doing it but when you come back in a year or two (I'm deliberately pessmistic on this subject) time to put this all back together you'll be thankful you took extra care with bagging and labelling all the little parts.
                              - Gary

                              97 Mitsubishi Lancer Coupe 1.8 (cheap and cheerful motoring)
                              16 Honda Grom (MSX125) Snail racing would be faster