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#92906 - 11/25/17 03:05 AM Inline 1979 Mazda RX7
strokersix Offline
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I will be pulling the original rotary from an RX7. The car is in real nice shape. The owner just wants the engine and I keep the remains. So I'm looking for suggestions on what to do with the car. Installing a v8 seems to be a common swap. Car is rear wheel drive.

Question for this crowd: What would you do with this car? I think an inline swap would be interesting but it looks like there is no room for an inline of more than four cylinders.

The right answer for racing is probably a v8. The right answer for daily driver is probably leave the rotary in the car but the engine is claimed for another purpose. Looking for suggestions. The smart answer is probably to sell the car and use the money toward a different project... Considering possibilities at this point. What would you do?

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#92907 - 11/25/17 07:17 AM Re: Inline 1979 Mazda RX7 [Re: strokersix]
CNC-Dude #5585 Offline
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There have been several land speed cars with inlines in them, both straight 6 and straight 8's and even several Flathead Ford transplants in to RX-7's and other later sports car bodies. Since your close to the Ohio Mile races, it might open up the possibilities for you in that venue if you are interested in that type of thing. You would never be competitive with the later 250's or 292's, but with the earlier Stovebolt's, GMC's or even Straight 8 Buicks or Flathead Ford for the vintage classes you could have a better chance with the sleek body lines and aerodynamics of the RX-7 to set a record or two.
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#92908 - 11/25/17 10:14 AM Re: Inline 1979 Mazda RX7 [Re: strokersix]
strokersix Offline
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Was thinking more of a street car but that is interesting. Expect significant structural mods to fit a stovebolt or straight 8! Hmmmm. Thanks

v6 and 700r4 or something along those lines seems easiest but not remarkable. Car is currently auto trans.


Edited by strokersix (11/25/17 10:16 AM)

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#92909 - 11/25/17 11:00 AM Re: Inline 1979 Mazda RX7 [Re: strokersix]
CNC-Dude #5585 Offline
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I'll go ahead and beat Marc to the punch and say you can always do an Atlas 4 cylinder swap. The 2.4L Ecotec makes 182 HP in stock trim.
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#92910 - 11/25/17 11:59 AM Re: Inline 1979 Mazda RX7 [Re: strokersix]
panic Offline
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RX7 with the Toyota 2JZ L6 engine, which (although heavy) is fairly short compared to later and larger L6.
https://www.google.com/search?q=rx7+2jz&ie=utf-8&oe=utf-8&client=firefox-b-1
I doubt an older L6 will be easier (longer and heavier except for Ford 250), and I would bet against an L8 unless the bellhousing is in your lap.
For size, the very low deck height of the Ford 5.0 etc. makes lots of vertical room, the Buick/Rover V8 is shorter but wider, an LSX is lighter.
The smallest package is a modern 3.5 etc. V6 DOHC from a RWD (FWD are cross-axis) Nissan, Lexus, Ford, Chevy, almost 300 hp stock.

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#92911 - 11/25/17 12:27 PM Re: Inline 1979 Mazda RX7 [Re: strokersix]
strokersix Offline
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panic, what vintage/application Chevy DOHC v6 and trans combo would you suggest? I would keep my eye out for a complete donor car.

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#92912 - 11/25/17 12:29 PM Re: Inline 1979 Mazda RX7 [Re: strokersix]
strokersix Offline
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was thinking about the Atlas 4. Aren't they a physically tall engine? Hood to steering rack clearance.

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#92913 - 11/25/17 12:52 PM Re: Inline 1979 Mazda RX7 [Re: strokersix]
panic Offline
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The question is "how to transplant the electronics from the donor engine to the RX?". Any GM or Ford will be easier than Toyota.

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#92914 - 11/25/17 12:55 PM Re: Inline 1979 Mazda RX7 [Re: panic]
CNC-Dude #5585 Offline
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Most any OHC engine is taller than an OHV inline engine. The challenge for the RX-7 is a really short front profile and hood line. But that's why they make hood scoops.LOL
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#92915 - 11/25/17 03:39 PM Re: Inline 1979 Mazda RX7 [Re: CNC-Dude #5585]
efi-diy Offline
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Originally Posted By: CNC-Dude #5585
I'll go ahead and beat Marc to the punch and say you can always do an Atlas 4 cylinder swap. The 2.4L Ecotec makes 182 HP in stock trim.


Ha!

The 2.9l Atlas in stock form make 185hp and 190 lbft.

The manual bellhousing will accept asian (sp ?) transmission out of some of the jap sports cars.

They accept turbo charging well and being all aluminum - not to heavy.

As long as you retain the GM drive by wire throttle body you can fab any intake you want.

Limeswap can take care of the efi harness/reprogramming for you.
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#92916 - 11/25/17 04:12 PM Re: Inline 1979 Mazda RX7 [Re: strokersix]
panic Offline
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V6 vs. L4
The V6 is wider than an L4, but less than a V8 because the bank angle is 60 rather than 90.
A V6 is narrower than a V8 with the same deck height.
A V6 is lower than an L4 with the same deck height.
A V6 is shorter than an L4 by at least 1 bore pitch distance. Engine length (minus the front accessory drive and bell housing) is roughly the number of cylinders in 1 bank (V6 = 3, L4 = 4) plus the width of 1 connecting rod (use 1" if not sure). The V6 will be at least 4" shorter.
A modern V6 is well balanced: 60 bank + 60 pin offset, the L4 requires counter-rotating balancer if over 2.2 liters.

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#92924 - 11/27/17 05:49 AM Re: Inline 1979 Mazda RX7 [Re: strokersix]
gbauer Offline
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What about a boxer engine from a Subaru? It's been a good 2 decades since I last tinkered with an RX7 but if I recall hood height is a premium. I don't remember the available width, however.

A WRX engine puts out 300hp or so. It'd be a real rocket! Even in NA form it would certainly scoot it.

That said the real joy of driving an early RX is the lightweight feel of the car. Maybe you could find a modern rotary from a new RX? They put out a lot more power than the old ones.

Found a newer one here: https://cpprohomeoh.car-part.com/image?seller=3519&partGUID=3519-1-147607&vehicleGUID=3519-1-V1744&display=2009%20Mazda%20RX8%20Engine%20Assembly-Stock%23%20002534

Granted it'll cost you a pretty penny once all done but it might be the same or less than another swap and would keep it in the family, retain the balance of the car, and be far more reliable than the old RX-7 power plants were (apex seals, if I recall, can be replaced on these).

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#92927 - 11/27/17 12:26 PM Re: Inline 1979 Mazda RX7 [Re: strokersix]
strokersix Offline
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Hmmm, that's interesting. This car has what appears to be a generous engine compartment and trans tunnel. Mechanically it looks like a great swap candidate.

Took a closer look today. I could not figure out how a 79 RX7 has the later 13B engine instead of the early 12A. Someone did a real nice job swapping it in. Then I saw disc brakes in back. Hmmm. This car is 1989, not 1979! I don't know Mazdas...

Did I mention it's a convertible too?


Edited by strokersix (11/27/17 12:27 PM)

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#92928 - 11/27/17 01:51 PM Re: Inline 1979 Mazda RX7 [Re: strokersix]
CNC-Dude #5585 Offline
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For simplicity sake, you could always put a rotary back in it. You can now add multiple rotors to the package and have a 4 or 6 rotor engine, instead of the 2 rotor the 12A or 13B has and make close to 1000 HP and add a turbo and have fun.
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#92929 - 11/27/17 02:17 PM Re: Inline 1979 Mazda RX7 [Re: strokersix]
stock49 Offline

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Originally Posted By: strokersix
Then I saw disc brakes in back. Hmmm. This car is 1989, not 1979! I don't know Mazdas...


You might check out the guys over at Hinson Motorsports

Looks like they have a kit for a vee-thing swap.

If you are looking to stay inline how about a Swedish solution like a Volvo T5 with a Getrag M90? Pre-99 has no VVT so the electronics should be lighter.

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#92954 - 12/05/17 01:40 AM Re: Inline 1979 Mazda RX7 [Re: strokersix]
strokersix Offline
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Update in case anyone is curious. I decided that I would rather put the effort toward a different project. Dropped the front subframe with engine and trans out of the car yesterday. Going to have the remains hauled off for scrap.

This car was loaded with options. Fixing and keeping all that electrical stuff operating was going to be an ongoing problem. Stripping it all out and making it into a race car would be more fun but I have lots of other projects.

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