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Index > Engine/Drivetrain > Thread: do the 80's rx7 13b engines work easily w/ a 74'
Thread: do the 80\'s rx7 13b engines work easily w/ a 74\'

Posts: 4
posted November 12, 2002 06:15 PM

do the 80's rx7 13b engines work easily w/ a 74'

I just received a 74' repu. it needs a new engine but all i can find are rx7 13b engines. are these the same ones that come in the truck all ready? if not, is it easy to put one in> do i have to convert ne thing? thanks alot

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Too Many Rotary Websites
Posts: 206
posted November 13, 2002 09:09 AM


The mid 70's 4 port motors are different from all RX-7 engines... The TurboII engines are 4 port, but they are different, as are the 6 port 13bs.

If you wanted to use a 4 or 6 port 13b from a 2nd gen RX-7, you can... but you have to do a little more work.

1. take the front cover from your current mid 70's engine, and swap it onto the later 80's 13b. It should fit, and allow you to mount the engine in the stock location. You could also swap out the oil pan from your 70's 13b onto the 80's.

2. Get a manifold and carb (from racingbeat) http://www.racingbeat.com/resultset.asp?PartNumber=18045#

3. Get a larger fuel pump (from racingbeat too)

There are other options too... you could take the entire fuel and electrical system out of a RX-7 doner car, and splice it into your REPU.

Or, you could do a custom Haltech setup like I did.. I swapped in a 90 RX-7 TurboII motor with a haltech controlling the fuel injection. It's still in the debug stage, but looks very promising!

The best way to predict the future is to invent it!
-- Tom Matano

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Posts: 1672
posted November 13, 2002 11:34 AM

can do a frankenstein too!

If you really want a 4 port 13b, you can also get a 12a, dissassemble it, and use it's front side, intermediate, and rear side housings. Get a Rx-7 GSL-SE 13b and take it's rotor housings, e-shaft, front counterweight, and flywheel and assemble the motor with the REPU front cover and oil pan. Now is a great time to take your REPU rear oil pressure regulator and shim it 1/8" and to get 80-85 PSI oil pressure (stock is 70).

Keep in mind the intake ports on the Rx-7 are smaller than the 74-75 tall intake ports. So the frankenstein motor will make less power. Unless you take this excellent opportunity to port the intake and exhaust ports and make some good power!!!

74 REPU Lawn Green
81 Rx-7 racecar. 12a J-

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