AcidAngel7477

iTrader: (16)

man, ive alway's dreamed about a 3 rotor 12a but this is awwsome.

:AA:

Jeff20B

iTrader: (13)

Final payment should be sent some time this week. That's it for now.

teddyrx2

iTrader: (33)

man this build is hot any updates on pics and stuff?

warwickben

iTrader: (1)

man i would kill to be able to have a 4 rotar 12a, id throw it in a 94-98 mustang to have plenty of engine room get the adpater plate from www.rotaryshack.com and use the z rated t5 tanny. o man i wish i had enough money for that.

Jeff20B

iTrader: (13)

Do you drive a newer car? That's where your 4 rotor money went. Newer computer? Furniture? Clothing? Food? See a pattern?

mikewoodkozar

I am glad that you dont have one then... Mustang with a 4 rotor... a waste

warwickben

iTrader: (1)

hey say what you want about mustangs iam a ford guy and a mazda guys.
me and my buddy own a 1984 rs turbo 2.3L capri (fox body mustang with different fenders ect). any ways me and my buddy where jokeing that after we convert it to dohc with a volvo head if we get beat buy honda well both take loans out to make a 4 rotar.

to answer my hero's(jeff20b) question

Do you drive a newer car? nope 1994 mercury gandma car lol. 1980 rx-7 summer car.
Newer computer? nope mac g3 laptop
Furniture?nope
Clothing? dickeys and x mas gifts lol(i never bought under wear in my life)

most of my money go's to my folks i moved out when i was 18 and moved back in when i was 20 to help them out. i pay 75+$ a week and pay for oil and and water ect.

jeff id pay money just to see your motor and to talk to you.

Jeff20B

iTrader: (13)

Don't put me on a pedestal. It's been a while since I thought about the 4 rotor so I'm a little rusty.

All the info is in this thread. If you can't find the answer here, or maybe on nopistons, the question hasn't been asked yet.

The next thing I need to do is mod a distributor for direct fire leading on all four plugs. It will be like DLIDFIS x 2. There will still be two leading ignitors, but each one will trigger an FC leading coil, for a total of four outputs; two sparking together every 90°. L1 and L2 together and L3 and L4 together 90° later. Does that make sense to anyone?

gsl-se addict

iTrader: (3)

Jeff,

On the e-shaft, how are the lobes laid out? Is it 90* separation between 4 rotors, or is it like 180* (rotors fire in pairs)? What's the order if separated by 90*?

I think you could mod the dizzy as you said. It just depends on how the e-shaft is setup on how to do it. I haven't looked at the 4 rotor stuff, so I am unsure on the firing sequence.

Jeff20B

iTrader: (13)

Kent, they are 90°. I wouldn't have wanted to do this project if they were 180° because it would end up sounding like two 12As reving together. It wouldn't have the awesome unique 4 rotor sound.

The trick as to why I can get away with my ignition set up this way is because the rotors are phased 90°. Since the dizzy spins half of eccentric shaft speed, if I space the pickups 135° degrees apart, a reluctor tip will pass by one pickup at its normal time, sparking two plugs. Then 45 distributor degrees later or 90 eccentric shaft degrees later (same thing), a reluctor tip will pass by the other pickup located 135° after/225° before the first one, sparking the other two plugs.

The engine will still sound like a real 4 rotor much the way a direct fire 12A sounds like an FC in that it still sounds like a rotary, but smoother. It's obviously burning fuel at the trailing edge of the rotor that would have otherwise gone to waste out the tail pipe. Otherwise it wouldn't affect the exhuast note like it does.

Direct fire accomplishes more with less. No need for a cap and rotor, you get all the benefits of the 2 rotor engines such as easier starts, smoother idle, more power, less emissions etc. All without the need for additional pickups, a timing computer, multiple ignitors and coils, complicated wiring mess and so on. Just a relocated pickup in the dizzy, two GM HEI or similar ignitors, two FC leading coils, a little bit of wiring and that's it. Easy, uncomplicated, more reliable, less to go wrong, less to troubleshoot later. I wouldn't have it any other way.

z-beater

I couldn't agree with you more Jeff. Less complication = less mess.

I am not sure if this has been answered, but what is the expected weight of the engine?

On a side note you should have come south last night. Gavin and I drove north after the meet. I would have given you a ride in the turbo.

gsl-se addict

iTrader: (3)

So the order is 1-3-2-4, then? If so, then just like you said. 1,2 are 180* apart, 3,4 are 180*. 2 FC coils (1,2 together) (3,4 together) firing every 90* of the e-shaft should do the trick. No need to mess with trailing. That would greatly complicate things for little or no benefit.

FB_drifter_X

heavy or not that car will be badass!!!! what i could do i had a 26b...

Crit

iTrader: (6)

Jeff, do you think that a 1-2-3-4 firing order would twist the e-shaft more than a "traditional" 4-cylinder firing order where it's all mixed up? I wonder if it would impact your actual timing or if the deflection would be negligible.

Jeff20B

iTrader: (13)

z-beater, about 128 pounds more than a 12A. To put it in perspective, a 20B weighs about 75-80 pounds more than an S5 T2 short block.

Maybe next time.

Kent, yep.

L1 0°
L3 90°
L2 180°
L4 270°

Trailing is not worth the effort.

Crit, I don't know and have no opinion.

warwickben

iTrader: (1)

jeff i reread the whole post and your making me want to say f@#k putting a 12a street port in my car to replace my old 12a and make a 24a. can you post every part needed to do this so i can price it out , included seals ect liek little mundane parts so i can try to figur eout how much it would cost me.


any way thanks for makeing this thread iam going to go reread this again to fully under stand .

IronMonkeyL255

This is such an amazing project.

I can't wait to see it running.

Unlike others here, I don't want one. While I think it's awesome, I would hate to take away from the uniqueness of your build. I'll stick to 2 or 3 rotors and a crapload of boost.......

warwickben

iTrader: (1)

iam just got done rereading this again and man i wish i could do this. maybe ill buy a part here and there and in 2015 ill have a full motor. iam more of a welder fab guy then a motor guy. iam lucky cause my best friend went to uti ect, so he helps me out with my car and i do all the metal work on our race car.

its funny in the 2.3L turbo mustang world converting it from sohc to dohc with a volvo dohc head in there eye's is there holy grail in muchthe same regard as what your trying to do jeff20b.
the reason that i think its funny is that to do it is pretty dam simple, just slot a few oil holes to make them line up better, add a block of metal at the back end of the head.


any ways didnt mean to get off topic, i think your the man jeff20b. i think its cool that your showing how to do this and that it can be some thing real for us frist gen guys.

for now iam going to throw a street port 12a in have fun with my little rx7. i can not wait to see more pics ect.

Jeff20B

iTrader: (13)

I wonder who else here will do a 4 rotor.

notveryhappyjack

iTrader: (4)

is this going in your pesonal car or someone else ?

can't wait to see it, I hope it stays in Seattle!

Jeff20B

iTrader: (13)

Someone else.

Seth1884

cant wait to see how this goes... i've got a small dream of buying a 7 as my "play" car here in a good few years... the thought of a 4 rotor is just wonderful. really really intrested in how your build goes. hope the best of luck with everything on it! i'll be following this

risingsunroof82

iTrader: (3)

Do you have an estimated time that you think this will be done?

ultimatejay

iTrader: (1)

^

What he said. Looks like you have plenty of projects but no time to finish any of them. hehe.

vipernicus42

iTrader: (4)

*laughs* Jeff finishes projects. He finished a freakin' awesome black FB with a body kit and 13b w/ 2bbl carb that was amazingly done and the bugger he built it for decided to sell it!

Jon