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    Engine/head rebuild

    Where is the best place to buy the rockers, valves, springs etc etc?
    :loco:

    #2
    I would buy IE HD rockers for sure, regardless of goals.

    if you're doing a stock rebuild, any place that sells OE springs/valves will be fine. If you're doing a modified head you'll have to decide on oversized valves and of course proper springs for an aftermarket cam.
    Build thread

    Bimmerlabs

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      #3
      Not looking for anything outside of stock (building spec E30). Just looking for the names of the best places to buy parts from.

      I'd like to buy a whole head rebuild kit at some point, along with new bearings.
      :loco:

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        #4
        oh, for spec E30 I think the IE HD rockers are out then (a shame, since they're cheap and much better than stock).

        I would look into having a set x-rayed for casting flaws (pores), but you're pretty much stuck with stock other than that. tischer, pelican parts, BMA, etc. all sell stock/OE parts for decent prices. I don't think there is any rebuild "kit" though, I'd look at realoem.com and find the part #s you want to replace.
        Build thread

        Bimmerlabs

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          #5
          What would you suggest I replace on the M20 before I head out there. Car doesn't burn any oil, and I don't mind having a little bit of a "loose" bottom end. Now, I'd like to freshen up the upper end, especially valve guides and springs. Looks like the rockers on this car are prone to wear as well.

          No idea how old the engine is in the car. Car has 170k right now. inside of the motor is super clean. No ridges on the tops of the bore or the pistons.
          :loco:

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            #6
            I would just do rocker and springs as for "hard" parts
            1989 cirrisblau-metallic 325i

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              #7
              Well I was thinking doing main bearings as well just to be safe
              :loco:

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                #8
                ^ really not a huge wear issue, but couldn't hurt
                1989 cirrisblau-metallic 325i

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                  #9
                  a question thats been in my mind for a while..

                  can most mechanically inclined people rebuild an m20 without any major damage/ wear without taking it to the machine shop?

                  is it really a matter of just replacing parts in there, or do sizes and things really need to get checked?

                  im just wondering how much of it i can do.

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                    #10
                    Yes, it is pretty easy to do an engine rebuild.

                    You do need to carefully measure, remesure and re-check everything though. Most m20's I've taken apart would have been fine with just a reseal, piston rings and rod bearings + bolts. Unless there was some oil pressure loss or other failure. This kind of rebuild is easy to DIY with simple tools. The only ones you may not have are measuring tools, valve seat grinding tools and a cylinder hone.

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                      #11
                      ^ even a cylinder hone stone is easy to come by, and most valves can just be laped in place
                      1989 cirrisblau-metallic 325i

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                        #12
                        what do you usually pay a machine shop to clean and check everything, maybe even put it all together if i bring them all the bearings/ bolts/ etc..
                        ??

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                          #13
                          This is going to be for a spec E30 build, so if I don't need it, I won't get it. Haven't looked to see what the stock compression numbers are, but the engine runs pretty good right now. I don't need to build it for 2 years, but I need to start getting stuff together now, so when I actually go to get it done, I have everything and can just start.

                          Absolutely for certain, I want to refresh the upper end, just need to know what I should replace besides springs, and possibly rockers. The car is old, so possibly new valves and such, but I just don't know what goes wrong with these things. If it might break because its old, I'd rather just replace with new. Cam isn't a huge thing to me. If I'm down a couple of thousanths, as long as it won't snap, I'm good to go.

                          Back in the day when I was really serious about racing and had a bigger budget, I'd just get a new motor. Those days are over, and I'm on a budget.
                          :loco:

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                            #14
                            This is what I'd consider a 'bare bones' rebuild.

                            New Rod bearings + bolts
                            Piston rings
                            Take your valves somewhere and have them faced ($20 or so, see if they can hone your cylinders quick/cheap too)
                            Lap the valve seats

                            Everything else is inspect/replace as necessary, the bently has all the specs you need to check.

                            Valve springs/rockers isn't a bad idea, you could probably get away with just springs as every time I've broken a rocker there was piston/valve contact.

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