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Thread: Transmission swap questions
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datsunrides
Revvin Up
Posts: 58
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posted November 11, 2007 11:25 AM |
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Transmission swap questions
OK, after searching previous post regarding swapping in a 5 spreed transmission, can I assume the following is still true? (some of the posts are fairly old) My 4 speed is quite loud in 3rd.
79'/80' RX7 5 speeds are a direct bolt in with the exception of the trans mount. Will either need to slot the crossmember or fabricate a plate for the trans mount or a combination of both. Shifter in stock location, driveshaft bolts in.
I have not found a reasonably priced clutch kit for the REPU. It would seem I could use the early GSL-SE clutch kit IF I also use the flywheel (different bolt holes on pressure plate?). This supposedly has the same counterweight? Are there any other options for a reasonably priced kit?
Thanks, Mark
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Klaus44
Redlining
Posts: 365
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posted November 11, 2007 01:52 PM |
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Transmission info. is correct.
The only difference between the stock REPU clutch, and the one in the rx-4, is that the REPU clutch cover has 9 bolts, as opposed to the rx-4's 6 bolt setup. (That, and differing flywheel weights.) The rx-4 ones might still be more abundant...?
I'd have to look up/remind myself what the other options might be, or not...
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roaddancer
Hauling
Posts: 127
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posted November 12, 2007 10:37 AM |
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My adapter plate drawing has been posted in the pictures page by someone, and it does work but is not perfect. I ran into some alignment issues in my 75 that I did not see in my 74 that I drew it for. In 20/20 hindsight plus more familiarity with metric, I suspect that the center to center of the pattern is actually 52mm, not 2 1/64" and maybe 48mm front to back centers instead of 1 7/8". I ran into some front to back alignment issues but I suspect that was differences in engine mount bolting and age of the mounts.
I have the drawing in PDF if you have trouble getting a good print of the posted pic. I didn't have that option when I originally shared the first sketch.
Before you buy a clutch kit you need to find out what bolt pattern you actually have as so many (most?)of these trucks have "lost" the original engine and may have almost anything there. When I did my conversion from the automatic I ended up with a combination that included a heavy duty clutch and a light flywheel that used the original automatic counterweights. Do check with Racing Beat, Mazdatricks, etc. for the best options. I don't endorse the light flywheel/heavy clutch if you have a high geared rear end. Mine dogs off the line but gets pretty good mileage on the highway, I suspect. Sure was fun pulling that trailer! Now with the differential from my old 74.......Wow! That would be quick!
____________
formerly
rx2/3/4/cosmo,repu,94 rx7,
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Jeff20B
Moderator
Posts: 661
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posted November 12, 2007 09:27 PM |
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Klaus, the REPU flywheels have a step. You can only use REPU discs and pressure plates with REPU flywheels.
The actual weight of the REPU flywheel is 30 pounds. The '71-'73 12A flywheels are also 30 pounds, as are '74-'78 RX-4s and '76-'78 Cosmos. Heck even the '79 to '80 RX-7 flywheels were 30 pounds.
The REPU clutch disc is 225mm and the pressure plate has heavy duty spring diaphram. Pedal effort feels kind of like a Racing Beat street strip pressure plate.
All other 30 pound flywheels used 215mm discs.
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Klaus44
Redlining
Posts: 365
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posted November 13, 2007 09:46 AM |
 Edited By: Klaus44 on 13 Nov 2007 09:47 |
Well, bugger!
Just figures you'd need to remind me that I've most likely been led astray by virtue of the fact that *none* of the REPU's I've ever owned were bone stock. As I recall (?), back when I looked at 6-bolt and 9-bolt clutches... I did not discern a difference. Perhaps this was due to a P.O. swapping out the flywheel? Who knows. One could certainly run an rx-4 clutch/flywheel in a REPU, no? That's probably what I have, mostly...
Perhaps posting a pic or three of the 'step' in question would serve to better illustrate this idiosyncracy once and for all?
FWIW: Can't verify, of course... but, rumor was, the REPU flywheel actually weighed a pound or two more... (?)
(I *do* have a flywheel weight/ID chart for the rx-7's... which kept getting lighter, ultimately to 20 lbs.)
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datsunrides
Revvin Up
Posts: 58
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posted November 16, 2007 08:49 AM |
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Ok,I'm getting confused. (not that hard to do)
What I would like to know is what combination of flywheel and clutch can I use that will bolt on. Ideally, the GSL-SE setup would be my first choice as parts seem readily available and reasonably priced. Will this work?
Mark
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sparky
Redlining
Posts: 299
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posted November 16, 2007 10:06 AM |
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I have been going through the same torment...flywheel compatibility. I'll probably find a light weight after market flywheel and use appropriate counter weight. What ever series your rotors are use the counter weight from a car with automatic transmission. Remove the CW from the torque convertor/flywheel. The Mazdatrix website has some good info and photos for flywheel compatability and identification. Good luck.
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Brad
Rotorhead
Posts: 1672
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posted November 16, 2007 10:31 AM |
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aftermarket flywheel and clutch
golden rule is the rear counterweight has to be matched to the rotating assembly (rotors, eshaft, front counterweight).
repu uses the same weight heavy rotors as 84-85 13 gsl-se. so, if you have stock repu rotating assembly, you can use gsl-se rear counterweight, flywheel, clutch.
sparky or 510, i have the big socket and heavy duty 3/4" drive breaker bar + homemade flywheel stopper to take the flywheel off if u need to borrow it.
my repu came with rb aluminum flywheel. the motor revs up good. 1st gear is a little touchy but not a pain, especially starting from a stop. for most people the RB light steel flywheel is a better bet but man, this motor loves to spin up. and spin down.
brad
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datsunrides
Revvin Up
Posts: 58
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posted November 16, 2007 06:33 PM |
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Ok, is this correct? As long as I use the counterweight that is currently on the engine, I can use whatever flywheel/clutch assembly (RX4/RX7) I can get for the best price. I just want to have all the parts to do the swap in a day and have no suprises without having to pay for the stock repu clutch kits I can find.
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sparky
Redlining
Posts: 299
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posted November 16, 2007 06:57 PM |
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Mark,
If you have a manual transmission then there is not a counter balance weight on the engine. The balance weights are only on engines with automatic transmissions. Based on brads info I think the best way to go is with a flywheel from a GSL-SE rx-7. Buy a clutch/pressure plate kit for the 84-84 rx-7. Check out these links. I found them very helpful. Check out the video for flywheel removal.
Good luck.
http://www.mazdatrix.com/f-writng.htm
http://www.mazdatrix.com/faq/flywheel.htm
http://www.mazdatrix.com/faq/Rcounterweights.htm
http://www.mazdatrix.com/faq/flywheelremoval.htm
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Jeff20B
Moderator
Posts: 661
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posted December 01, 2007 10:08 AM |
Edited By: Jeff20B on 1 Dec 2007 10:10
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I was going to use a GSL-SE flywheel with stock disc and ss pressure plate, but decided to try a Camden supercharger. As a rule you must use a flywheel one step lighter to make up for the additional rotating weight of the SC. I don't have the SC yet, but I do have the light steel flywheel and auto rear counterweight. Also the special bolt set. I think I'll go with the light steel flywheel since it will probably feel more like the GSL-SE flywheel when the SC goes on. I'll just put up with the reduced weight in NA mode for a while. :)
Sorry klaus, no pics, but it's not difficult to tell the difference. I also weighed my REPU flywheel and it was 30 pounds. Not 31, 32 33 etc. It was right at 30 pounds.
To make sure, once I pull the stocker off my engine, I'll weigh it again. This 30 pounds is the weight of the flywheel only. The rest of the weight is from the disc and pressure plate.
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kansei
Redlining
Wankelized
Posts: 423
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posted December 01, 2007 11:56 AM |
Edited By: kansei on 1 Dec 2007 12:03
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According to Mazdatrix...
A stock GSL-SE flywheel will work on any pre-'86 stock 13B engine. Rather than trying to determine what flywheel you have by weighing it (can be rather inaccurate, depending on your scale), just use Mazdatrix's flywheel ID chart (http://www.mazdatrix.com/faq/flywheel.htm). The stamped ID numbers are a sure-fire way to tell what you've got (if you have a post '78, anyways). All '74-'78 13Bs were the same.
Also, when I looked into this issue earlier this year, Mazdatrix also told me the flywheel's built in 'counterweight' has nothing to do with balancing the rotating assembly- that is handled by the front counterweight. What matters for balance with respect to the flywheel is *where* the weight is distributed in the flywheel.
Neal.
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jfaplanet
Redlining
Posts: 356
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posted December 03, 2007 03:08 PM |
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weight
I know from experience if you use GSL-SE rotors, you connot use an S4 flywheel and weight. You must use the GSL-SE flywheel and front weight. It had a bad vibration till I changed it. Good luck guys and Neal had a good point about Mazdatrix flywheel chart. Also Kevin Landers has some good info on front counterbalance weights on his website. http://www.rotaryresurrection.com/1stgen/tech_rotor_counter_info.html
____________
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
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r.com/
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