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Thread: Removing Flywheel
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Rotary_Pickup
Hauling
Posts: 117
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posted August 14, 2004 04:00 PM |
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Removing Flywheel
I'm in the process of rebuilding my RX-7 12A. This is my first rebuild. I'm having problems getting then flywheel nut off. I was able to get the front cover nut off. Is there some sort of tool I can buy that will hold the flywheel?
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KansasCityREPU on RX-7Club.com
85 GSL
77 REPU (1/1/2004)
75 REPU (7/10/2004)
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jfaplanet
Redlining
Posts: 356
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posted August 14, 2004 05:30 PM |
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Yes
There is a tool to hold the flywheel. Check out Mazdatrix.com they sell 2 different ones. I made my own by drilling a couple of holes in a 3 ft bar of steel. The two holes align with 2 of the holes that hold the pressure plate on. Once bolted on the bar allow you to hold the flywheel in place. If you need pics I can send you some. Good luck.
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74 REPU "Red"
74 REPU "Jethro" "TII"
74 RE-Courier vert
79 SA-SE(aka deathtrap)
79 SA-SE-FC (project
turbo)
http://home.bellsouth.net
/p/PWP-crgj
TN Forum:
http://tnrotary.10.forume
r.com/
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Rotary_Pickup
Hauling
Posts: 117
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posted August 14, 2004 05:57 PM |
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Thanks for the email photo. I'm going to make one tomorrow and give it a try.
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KansasCityREPU on RX-7Club.com
85 GSL
77 REPU (1/1/2004)
75 REPU (7/10/2004)
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Mazdarx605
Redlining
Posts: 314
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posted August 18, 2004 01:51 PM |
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I just use a impact gun and a large socket.The flywheel never spins with that.Then I put the nut back on a few turns and give the flywheel a good smack with a 2-3lb hammer on the outer edge,and it will spring right off.Good luck.Remember to have that nut on there when you give the FW a smack so it doesn't fall on your toes or hit you in the head.
Chris
74 REPU green w/ac(not working yet)
83 RX-7 limited edition"soon to be parted:>("
New:>) 04 RX-8 nordic green base 6 speed
92 Cummins turbo diesel(the work horse)
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Rotary_Pickup
Hauling
Posts: 117
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posted August 19, 2004 11:28 AM |
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I'm going to brake out my impact wrench (got to find it first). I did purchase a Craftsman 2 1/8 3/4 inch socket. I had to also get a 3/4 to 1/2 adapter. I also made a brace to hold the flywheel. I used my floor jack handle to make to brace.
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KansasCityREPU on RX-7Club.com
85 GSL
77 REPU (1/1/2004)
75 REPU (7/10/2004)
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brad
Rotorhead
Posts: 1672
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posted August 19, 2004 03:16 PM |
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I used 4 foot steel angle iron for my flywheel brace. 2 holes drilled in it to bolt to flywheel.
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-brad-
74 REPU Lawn Green
81 Rx-7 racecar. 12a J-
Bridge
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Jeff20B
Moderator
Posts: 661
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posted August 30, 2004 12:11 PM |
 Edited By: Jeff20B on 30 Aug 2004 12:11 |
I use a 3/4" 2 1/8" impact socket with a 3/4 to 1/2 adaptor and a 1/2 impact wrench. I've done a few flywheel swaps/engine rebuilds so far and they've all been great.
I also use the Mazdatrix flywheel stopper for when I'm dealing with clutch bolts and the flywheel nut. I know it's not totally necessary when impacting the flywheel nut, but it doesn't hurt. Scroll down a little. http://www.mazdatrix.com/FTOOLS.HTM
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'74 REPU
'76 Cosmo
'77 MG Midget 13B
'81 RX-7
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Rotary_Pickup
Hauling
Posts: 117
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posted August 30, 2004 12:31 PM |
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I found that my impact wrench is not large enough in power. I took the engine to a shop near my house and they had no prolems. Didn't even charge.
I tore the engine apart on Sunday. I found a large chuck missing from one apex seal and a large piece of metal gone from the rotor in that same spot. The rotor housing was also trashed because of this. The other rotor housing had a large amount of chrome missing in one area. Now I'm in need of some good rotor housings. I have another motor that has good rotors and seals, but it over heated and now leaks oil. I'm hoping the rotor housing are not warped or at least can be milled.
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KansasCityREPU on RX-7Club.com
85 GSL
77 REPU (1/1/2004)
75 REPU (7/10/2004)
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Jeff20B
Moderator
Posts: 661
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posted August 30, 2004 02:00 PM |
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The aluminum rotor housings can't be milled. Only the side plates can be lapped if necessary.
The correct word you're looking for is crush. When aluminum gets hot, it expands. This is all well and good untill the overheated engine cools down. The aluminum has a tendency to move a little when it gets hot, and being held by the cast iron side plates and tension bolts, it can't really get much wider than 80mm. So what happens is it sort of moves in other directions. What you're left with is an engine that will either leak water or oil or both. You may notice some exhaust pressure building up in the radiator as well.
My friend overheated a 13B I built for him for his REPU. The (orange) coolant seals had deteriorated (black ones seemed ok). I didn't even bother to measure the crush on the rotor housings, but they're sitting on my work bench, and I recently got a nice digital caliper... Anyway, I threw in another set of rotor housings and another gasket set and the engine is now my daily driver. Total cost was $200 ($50 for each rotor housing and $100 for a gasket set). I even did a little porting. :)
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'74 REPU
'76 Cosmo
'77 MG Midget 13B
'81 RX-7
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Rotary_Pickup
Hauling
Posts: 117
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posted August 30, 2004 06:00 PM |
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Thanks for the info. Knowing the overheated housings are trashed will save me a lot of time. I'm tempted on going to the junkyard and finding some core 12A engines. I thought I would "practice" rebuilding my RX-7 12A before tackling the 13B in my 77 REPU. My concern is that I would end up with more overheated cores. Is there any way to validate the usability of the rotor housings (other then the obvious missing chrome or scoring)?
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KansasCityREPU on RX-7Club.com
85 GSL
77 REPU (1/1/2004)
75 REPU (7/10/2004)
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Jeff20B
Moderator
Posts: 661
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posted August 30, 2004 08:51 PM |
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Yes, there is one other way. In the FSM (factor service manual), it says to measure the width at the top of the rotor housing. It should be very close to 80.0mm for a 13B or 70.0mm for a 12A. It then goes on to say that you should compare that measurement at the top to three places down by the spark plugs. If any one of those places are .06 smaller than the measurement at the top, you need a new (or good used) rotor housing.
I just dug up my '76 Cosmo FSM and it shows the four places to measure.
A) at the highest point in the peritrochoidal surface of the rotor housing.
B)Just a hair above the middle point in the figure 8 part of the rotor housing (where it sorta poke out above the leading spark plug hole.
C)At the top of the leading plug hole.
D)Near the bottom of the leading plug hole.
A picture is worth a thousand words, but I hope the explanation is enough to get you started.
By the way, the the chrome edge is not exactly where to measure the width. You're actually supposed to move outward onto the aluminum but not quite into the recessed area where the coolant seal sits. Does that make any sense?
One set of rotor housings I have weren't quite up to 80mm wide at the top. They were 79.something. Again, I just made sure that they weren't crushed by checking for the .06mm difference. They were within it. :) The apex seals have a little triangular end peice which allows them to conform to different rotor housing widths within a limited range. The side seals and corner seals can also seal up to a limited range of rotor housing widths. Not all rotor housings are precisely 70mm or 80mm when new.
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'74 REPU
'76 Cosmo
'77 MG Midget 13B
'81 RX-7
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