White_FC

Now I may be having a bit of a mental blockadge at the moment... but what balancing issues would you have if you connected two 13b shafts with 90deg. sepparation and fired it 1,3,2,4? as in, call rotor 1 0deg, R2 would be 180deg, R3 would be 90deg and R4 would be 270deg.





Because making the shaft can't be as simple as that. Connecting them is no big deal at all and theres even plenty of room to put a middle bearing in there.



Just seems to me like a fairly easy way to make a 4 rotor 90deg. eccentric shaft?

(i know the rest of the motor would cost a packet)



What is the reason people dont do this?

crackheadmel

Scan of Scoots 4 rotor setup if it helps ya guys



[attachment=28528:attachment]



[attachment=28529:attachment]



-Jacob

mike_rudy

This is a pic of a 4 rotor 10a e shaft, i am thinking of building my 4 rotor 12a this way, with just adding the secind shaft at 90 degrees, but i am still contimplating running it 2 rotors firing at the same time, with that ignition system would be much easier to make and the engine might produce more torque.

Jeff20B

The engine wouldn't sound very good if it sounded like two 13Bs reving up together. Go for the 90° seperation instead for that awesome 26B sound!



Oh and by the way, the ignition is quite easy to figure out at 90°. I helped a guy work out some solutions yesterday as he plans on MegaSquirting his.

mike_rudy

could you possibly reveal some of that info on the timing/ignition of the 4 rotor set up??, i am not going to have mine fuel injected, but either going with preditor carbs, or runn the biggest holley i can find

Jeff20B

Ok. We all know that a rotary with late leading sparks tends to run better than one with single leading sparks, regardless if trailing if functioning or not. Or at least I do. Anyway, it would be very simple to set up an ignition system for a 4 rotor engine which has two leading sparks per rotor face, one every 180°, on each rotor. Very easy.



You could modify a distributor for direct fire late leading (known as wasted spark on piston engines), but I'm not sure how you'd do trailing at this time. The reason why trailing wouldn't be as easy to do compared to leading is because trailing can only have one spark per rotor face while leading can have two, and since two rotors will always be 180° apart, these two can share one pickup in the dizzy IF the reluctor also has four teeth.



This is theory and speculation, but if you're better at math than me, you'll see the confusion clear up after I explain how I'd personally run a 4 rotor with a carb (in other words, no ECU). You could do a late leading direct fire ignition system with just one '81-'85 distributor. It's very easy, or atleast that's what my ignition sense is telling me. The only mod it would need is to reposition the stock trailing pickup to 135° away from the stock leading pickup instead of 185° or whatever it usually is. The two rotors at 0° and 180° would fire on one pickup and the other two rotors at 90° and 270° would fire on the other pickup.



This is infact easier than my 20B modded dizzy which required three pickups spaced 120° because no two rotors could share the same signal. It all has to do with the geometry of the 4 tooth reluctor and the pickups' cores in relation to each other (hence the need for 135° spacing instead of 90° or whatever, since the reluctor's teeth are spaced 90° apart).



You could use two 2nd gen leading coils for their dual spark outputs if desired, hooked to a J-109 ignitor as in a typical 2GCDFIS installation, or you could share the pickup output in parallel to two ignitors, then to two coils, then to two spark plugs as in a typical DLIDFIS installation. Yep, either a grand total of both stock J-109 ignitors in their stock locations on the dizzy housing, each hooked to a 2nd gen leading coil, then on to both 180° offset rotor pairs, or four J-109 (or other) ignitors, detatched from the dizzy housing, hooked to four coils, and then to the four plugs.



If I were you, I'd just use two 2nd gen leading coils and both stock J-109s on the dizzy housing (don't forget to keep the ballast resistor in the circuit). Very simple, less to go wrong. Read up on the 2GCDFIS project (20 minute direct fire upgrade on a 1st gen) for more info.



I'm not sure if the above is typed very clearly or not. I'm also not 100% sure my math for 135° pickup spacing is correct. You'll definitely want to give it some thought before proceeding.

diabolical1

it sure sounds like it ...

CletusFD3S

off topic but.... on a 4 rotoe do they use 12a center plates between rotor 2&3 and rotor 3&4?

mike_rudy

i am just using another center plate to basicly conect the 2 engines together with stationary gears on both sides. What we are going to do is use 2 front stationary gears cut the flangers off get them both machined down so the gears will stick out either side the right amount, then we are going to have a step cut in so they will interlock then have a groove cut in and have them welded, and spline/weld in onto a chromolie pipe thatwill be a bit bigger then the hole in the center plate, then spline and set screw that into the center plate

guitarjunkie28

he'd do a 4 rotor, but not a real ems?