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Thread: 1981 Mazda CB 626

  1. #1
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    1981 Mazda CB 626

    I am currently restoring my 81 626 MA motor and have a couple of questions.
    What other cars in Mazda's range do the CB 626's share common parts with. I have heard that they share the same floorpan as the early model RX7's and possibly have parts in common with other models but am unsure.
    My other question is I am toying with a 12a conversion and am wondering if I can use the original engine mounts and gear box mounts?, if I keep the MA 2ltr does anyone know of any producers of aftermarket parts for the MA motor like better bearings and so on.
    If anyone can help me out it will be greatly appreciated.
    Thanks

  2. #2
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    Mate,
    Having just finished converting my 626 coupe to 13B power, forget
    what everyone else says about 626s sharing common parts with RX7s, they have no f@#&ing idea! :evil:

    Pic of 626 cross member vs RX7 cross member vs RX4 cross member.
    The RX4 cross member is used most often because it is the same width as the 626 chassis rails. This moves the motor way forward so most guys then have to fit a spacer block to try and move the block back.



    You can use:
    RX7 front strut and brake assemblies but will need to fit camber plates, and also when fitted are about an 1.5" lower than the original strut.
    RX7 radiator
    Clutch slave(providing it's not leaking)

    Parts I used from an S2 RX7:
    Alternator
    starter motor
    end and tall port centre plates
    Throttle cable(perfect length)
    Engine mounts
    Igntion coil mounting bracket
    Oil cooler
    Earth cable (battery to block)
    Starter motor cable (battery to starter)

    Parts used/adapted/fabricated:
    Complete engine cross member - made to bolt in
    RX3 front engine mount
    radiator mounting brackets
    oil cooler mounting brackets
    Radiator(3 core)
    Radiator hoses
    Oil cooler lines
    Overflow bottle extension bracket
    Gear box mount extension bracket
    Drive shaft( original 626 made 75mm longer)
    Ignition coil mounting bracket
    Throttle cable extension bracket(mounted to carby)
    Fuel regulator mounting bracket
    Entire exhaust system (DO NOT waste your time trying to adapt an existing RX exhaust system to fit. It WILL NOT FIT!!!!!!)
    Heat shield - unless you just fit an entire RX7 12A engine with reactor
    box and attached heat shield, etc.

    Just to give you an idea:










    Finished product -


    GO FOR IT and GOOD LUCK!

  3. #3
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    Sweet build Philip, that's an awesome example of the hardtop, damn I so want the metal bumper version!

    Yeah Oven, he's right, not a lot is really common despite the stories you hear on ausrotary, built one too

  4. #4
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    Keep the MA, get it to breathe properly with a good exhaust and a decent manifold and carb a bit of lowering, some good tyres and enjoy it.

    that's just my opinion anyway.

  5. #5
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    Thanks heaps for all the info.
    I think I am going to stick with the MA and fit a 32/36 Weber, extractors and exhaust as well as getting the rotating assembly fully balanced and shotpeening the rods and crank amongst other small things I think will get her going a little better.
    Thanks.

  6. #6
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    Mate, besides the baggings you hear, the MA was a brilliant engine. I've supercharged them, turbo'd them, bored them to silly oversizes etc. If only Mazda had kept it's quality into the FE/F8 2.0 litres.

    I've got a 2001 E2000, where the crappy FE died, I'm planning a MA swap into it, yeap, manifold are the other way around but least it will go on for a long time . A good friend and I, just finished a MA turbo, straight LPG with a four speed auto, bloody rocketship!

    Good idea with that work you're going to do, get the cylinder head checked and if it hasn't been done, get the casting ports welded to stop any leaking. They are the two flat 'welsh plugs' under where the cam runs. A trick too for young players that haven't had one apart b4 too, the inlet and exhaust rocker arms + the rocker shaft springs are different so don't mix them up. A little trick I do is to get some auto wire and tie it around all four rocker arms before you lift it up...otherwise the whole lot springs apart everywhere!!

    Good thing I find, with a lot of chaps in Australia doing rotary conversions, ebay has all the bits for Mazda piston engines quite cheap!

  7. #7
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    Hi, can you please explain the difference between the inlet and exhaust rocker shaft springs? As I think mine have been mixed up.
    Is it worth me modifying my alloy rockers to accept the hydraulic tappets that were in the earlier model motors as I have just picked up a set of cast iron rockers with these tappets in them that were apparently out of a 1500ss.
    Thanks.

  8. #8
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    Just to let you know, all the early motors were adjustable tappets, really wasn't until 12 valves that they got into hydraulics that and even then early 2.2l still had adjustable versions. The commercial engine versions went on for years, my 2001 E2000 still has adjustable tappets in it!

    Would you have a photo of those rockers? Yes the UB 1500 engine (1966 until bout sept 1968 then they went to the alloy type) did get cast iron rockers but they did have a habit of cracking so just make sure they haven't been welded as I've seen it done and it doesn't really work when using a larger cam. Also the series 1 1500ss and series 2 1500ss cylinder heads were differed slightly so the early motor rockers will miss your exhaust valves in a MA rocker gear set.

    Those springs are longer on the exhaust side although after years of service they end up about the same length due to the heat around the exhaust side of the cylinder head.

  9. #9
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    I have been warned off of using the hydraulic tappets I have and just use the original solid ones as the hydraulic ones apparently need to be set to a certain pre-load and thus they cause more wear on the cam and follower end of the rockers.
    If I chose to use them I was going to get my aluminium rockers drilled to provide a passage for oil to feed the tappets from the main rocker shaft and have the ends welded back up where they have been drilled.
    I am still not sure which way to go?

  10. #10
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    Quote Originally Posted by ewokracing
    Keep the MA, get it to breathe properly with a good exhaust and a decent manifold and carb a bit of lowering, some good tyres and enjoy it.

    that's just my opinion anyway.
    What do you mean by a decent manifold and carb? Would like some details with that if you would be so kind From another Mazda or some aftermarket stuff? Weber? And could I order some online maybe?

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