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  1. #1
    Supporting Member MiataQuest's Avatar
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    Questions on flywheel, transmission removal, CAS seal, and engine mounts. (1992 1.6)

    Long term I plan to modify my 1992 NA with either an EcoTec or LFX engine conversion.
    In the meantime I was considering to refine my present low-rent BEGI turbo system and baseline the car to start driving it.
    The first thing on the "to-do" list is the clutch, engine main seal, trans seals, engine mounts, and CAS seal. The reason is the transmission shifts notchy and feels like the pilot bearing is spinning the mainshaft. I also want to address some oil leaks.
    So here are the questions:
    1. I was thinking I should install a light-weight 1.8 flywheel on the 1.6 to enlarge the clutch surface area. I need to confirm that the 1.8 flywheel is a bolt on modification.
    2. Is it easier to change the CAS seal from under the car with the transmission removed?
    3. Is it easier to do a coolant re-route in the same manner?
    4. Do you need to support the engine when you remove the transmission?
    5. Should I change the engine mounts when the transmission is out or when everything is together? Buy the Flyin Miata "Mazda Competition" motor mounts?
    6. Should I get the Flying Miata Happy Meal flywheel, clutch, etc? Level 1 for a mild turbo?
    7. I was thinking CAT delete while the exhaust was off. Some people say this makes the turbo over-run? I do not understand because this is only a slight flow improvement. Then why is a 3 inch exhaust with a CAT OK?
    8. Anything else I should do while the transmission is out?

    Thanks in advance.

    BTW, I have been busy working out of the country most of the winter. I had lots of problems with the house (recent power failure, buy a generator, electrical work, blah blah) and the old Audi. I will be selling one of my Audi's in a month. That in itself should free up a lot of my time.
    I hope to get back to the "Manticore Build" this summer. (and to Rick, keep me motivated to install the MazdaSpeed type II wing)
    Last edited by MiataQuest; 03-19-2017 at 10:02 AM.

  2. #2
    6,000 rpm - mere mortals would shift HarryB's Avatar
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    1. 1.8 and 1.6 flywheels and clutches are interchangeable, but they go in sets; i.e 1.8 fly with 1.8 clutch and pressure plate, 1.6 fly with 1.6 clutch and pressure plate.
    5. That would make it much easier, I plan to do mine in the same fashion. Fresh OEM would do the trick I guess but depends on the type f driving/personal taste. I got Mazdacomp for mine
    6. YESS! If you can afford it, do it. It is supposed to be one of the best combos out there, OEM feel but can take decent abuse
    8. I would do rear crank seal and front trans seal as well. Also great chance to flush your clutch hydraulics and do an insulation job on the underside of the trans tunnel if you are so inclined. Pay attention to properly align the PPF when you put it back.

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    MiataQuest (03-19-2017)

  4. #3
    Ninja Messiah kung fu jesus's Avatar
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    Questions on flywheel, transmission removal, CAS seal, and engine mounts. (1992 1.6)

    Quote Originally Posted by MiataQuest View Post
    Long term I plan to modify my 1992 NA with either an EcoTec or LFX engine conversion.
    In the meantime I was considering to refine my present low-rent BEGI turbo system and baseline the car to start driving it.
    The first thing on the "to-do" list is the clutch, engine main seal, trans seals, engine mounts, and CAS seal. The reason is the transmission shifts notchy and feels like the pilot bearing is spinning the mainshaft. I also want to address some oil leaks.
    So here are the questions:
    1. I was thinking I should install a light-weight 1.8 flywheel on the 1.6 to enlarge the clutch surface area. I need to confirm that the 1.8 flywheel is a bolt on modification.
    Yes, and as mentioned above 1.8 FW> 1.8 clutch, no mixing the clutch/FW between the 1.6 and 1.8. I suggest a FW between 10 and 14# for drive-ability. Lighter than that can be tiresome in stop and go traffic. I prefer chromoly to aluminum flywheels for safety and reduced gear lash noise.

    Quote Originally Posted by MiataQuest View Post
    2. Is it easier to change the CAS seal from under the car with the transmission removed?
    Nope. With the trans removed, the engine may actually rock back into the firewall.

    Quote Originally Posted by MiataQuest View Post
    3. Is it easier to do a coolant re-route in the same manner?
    No. The tube that crosses behind the back of head for the reroute could hinder reinstallation of the transmission. I will share more thoughts about this below.

    Quote Originally Posted by MiataQuest View Post
    4. Do you need to support the engine when you remove the transmission?
    No. The engine is bolted to the front subframe via the mounts. The trans bolts to the spine. When you release the trans from the spine, the whole shebang has a tendency to rock backwards because the trans pivots the engine back in this situation.

    Quote Originally Posted by MiataQuest View Post
    5. Should I change the engine mounts when the transmission is out or when everything is together? Buy the Flyin Miata "Mazda Competition" motor mounts?
    No preference.

    Quote Originally Posted by MiataQuest View Post
    6. Should I get the Flying Miata Happy Meal flywheel, clutch, etc? Level 1 for a mild turbo?
    I prefer headroom on a clutch. If you have distinct, firm power goals in mind, give yourself at least 25% headroom on the clutch's ability to handle it. It sucks if you have to do it again because you find your new mods now hit the ceiling of what your clutch will hold.

    Quote Originally Posted by MiataQuest View Post
    7. I was thinking CAT delete while the exhaust was off. Some people say this makes the turbo over-run? I do not understand because this is only a slight flow improvement. Then why is a 3 inch exhaust with a CAT OK?
    If you like huffing gas fumes, delete the cat.

    Quote Originally Posted by MiataQuest View Post
    8. Anything else I should do while the transmission is out?
    Degrease, clean, paint the underside of the trans tunnel and line the front part, the cabin portion, with heat insulation. It makes a big difference. I would replace the clutch master, slave, and hose (with SS braided if haven't yet). A new, heavier clutch can expose weak clutch hydraulics really quick.

    Quote Originally Posted by MiataQuest View Post
    Thanks in advance.
    BTW, I have been busy working out of the country most of the winter. I had lots of problems with the house (recent power failure, buy a generator, electrical work, blah blah) and the old Audi. I will be selling one of my Audi's in a month. That in itself should free up a lot of my time.
    I hope to get back to the "Manticore Build" this summer. (and to Rick, keep me motivated to install the MazdaSpeed type II wing)
    Word.

    For what you want to do, and the work that it entails, I would suggest pulling the engine and trans together out of the car. I'm saying this ESPECIALLY if you don't have a lift. A lot of people groan or roll their eyes when I say that, but listen, it's super easy to fudge the clutch installation while under the car. Rent, borrow, buy an engine stand and engine crane. Pull the engine and trans together, split them when you get them on the ground, put the engine on a stand, take the trans outside and degrease, then do your seals.

    It_is_much_easier to all the work you describe above with them out of the car. You can do the engine maintenance, do the clutch maintenance, degrease the engine bay (or paint it), degrease/powerwash the engine, and a TON of other jobs with the car empty. You can install the majority of the coolant reroute with the engine out without fighting for room against the firewall. When everything is done, you can line up the clutch (far easier to do), mate the drivetrain together, reinstall into the car (on your new engine mounts). You also run less risk of the car falling on you while jostling the trans to get it to line up the input shaft into the engine. The amount of time to waste struggling to this work with them IN the car will be more than the time you spend pulling them out and putting them back in. Far less frustrating, too.


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    Last edited by kung fu jesus; 03-19-2017 at 04:23 PM.

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    HarryB (03-19-2017),MiataQuest (03-19-2017)

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