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Discussion Starter · #1 ·
I'm about to start cutting out some mock-up metal for a rotary in my GT.
Anyone got any good pics (marty's in particular) so I can compare my engine placement idea.

I'll share too.
 

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rotary

It is very simple and if you use the rotary's front bracket really no fabrication is necessary. I will try to get some pics
 

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Detritus Maximus
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AZ-
Which motor are you running? 12a or 13b (four or sixport)? Which transmission?

I have reason to ask.......:) what with a plethora of Opels and rotaries......;)
 

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same project

I am putting 12 a rotary with 5 speed into 1969gt. Had to shorten the shifter location by 4 inches.It was easy to do, just cut rod and redrill. Used rear bolt location in front.
wally
 

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Opeler
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12a vs 13b

I was wondering your reasons for putting in a 12a instead of the 13b...is it easier to mount?, easier to work on?, what were your reasons?
i was thinking of doing this swap myself, but dont have the time/money, so.....
I know that the 13b, inany form, has more power than the 12a, and with the extra 2 ports, more potential, too...so anyway...
thanks
-Rob
 

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Currently in Opel Detox.
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Discussion Starter · #6 ·
I'm using the 12a just because I had 3 of them already around from a friend who has a 79 rx. I currently have the 12a and the 5 speed using the 4 speed tail housing sitting in the GT.

I want to try to use as much of the mazda mounting design as possible. I am seeing that I will have to shorten the engine mounted bar, and the front crossmember perches look to just clear the front rack unit.

Here's what I've learned in research. the 12a with a proper carb (either a nicely tuned nikki or a weber) and the racing beat header will get it right around 125hp. I've also wired up a direct fire iginition using the later 13b ignitors and coils and tested it on the RX. My 12 also has a small streetport job which on the rotory is like tampering with the cam lobes.

I don't want to get much more power than that as I'll most likely always drive my car regularly and don't want to get radical.

I would like to go to a fuel injected 13b, but the much cheaper atkins rebuild kits for 12a and my on hand selection made the decision easy.

after giving away my 13b core, I did however have a brainstorm idea on integrating it's stock motor mounts into the gt which would take allof 40 minutes to fabricate (later on down the line I'll test my theory, or not if I'm content).

I can't wait to get my opel rolling again as I've been way to sidetracked since I decided to start taking on rx7 projects as training ground to make sure I wanted that in my GT.

And as a word of warning, the Rotary can create a horrible stench if it isn't burning its fuel well ( and rotaries do not as a rule).

Also, if you use the 12's, go premix, because I've had to adjust every RX7's oil metering device several times (drips motor oil through the carb to keep the seals lubed). These mechanical devices have some slop in them after 20 years. And the later model electronic ones may be a bear to mointor.
 

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Detritus Maximus
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The S4 13b (86-88) has fuel injection and a mechanical oil metering pump, S5 13b (89-90) has a different FI intake set up and the electronic oil metering pump. But both, S4-S5, use a separate pair of oil injectors mounted in the rotor housings. If one wanted to continue using the OMP to avoid dealing with pre-mixing oil into the fuel, the S4 FI engines are a good choice. They can be converted to carb and retain the mechanical OMP.
The front mount from the 1st gen cars can be used on the 13b (with the appropriate front cover) to make installation easier.

The stink of unburned fuel is a problem. I had to remove my cat from my 87 RX7 when the brick inside disintegrated. It smelled awful. I then bought a Bonez Superflo cat. Expensive, but well worth it, in my opinion. No more smell, meets emissions easily, and I saw no noticeable loss of power. Changed the tone of the exhaust, too. Sounds better, less 'tinny'.
 

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Detritus Maximus
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Bret-

On a related note. There is quite a furor over running synthetic oil in the rotarys (you probably already know that if your messing with RX7s).

The idea is that since the omp injects oil into the rotor chambers and that oil is subsequently burned, synthetic may be a problem since it does not burn well. Deposits may form and cause the same problem as carbon (mainly, carbon lock).

But, if you are running pre-mix and not using engine oil for rotor lubrication, then there isn't really a conflict since you have separated the two. It should be ok to run synthetic in the engine if you are not using engine oil for rotor chamber injection.
 

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Discussion Starter · #9 ·
Yes, I've seen the debate.
my 79 rx ran 240,000 on its first motor and mineral oils and the oil metering.
so, I'm not concerned about the synthetic benefit.
 
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