Cool_ManX

I want change my rotors (S4 1987-88 TII 2mm) for rotors of one engine 13b 1984-85 3mm ,, i want install apex seals RA 3mm in that's rotors and install en my engine S4 TII 1987-88 is can possible?

Cool_ManX

los rotors s4 (87-88) are 2mm

Cool_ManX

no, the car was released, S4 TII 87-88 , S5 TII 89-91 and 86 NA

ddub

No. The s4 and s5 rotors used 2mm stock, the GSL-SE rotors (13b 84-85) used 3mm.

Yes the rotors can be used in your motor.

Cool_ManX

Can I swap my S4 rotors for 13b 84-85 3mm rotors?

Hi to all!
I'd like to swap my rotors (S4 TII, 2mm) with those of a 13b 84-85 3mm and so install RA 3mm Apex Seals . Can it be done easily or am I missing something?
Thank you for your time

TwistedRotors

iTrader: (3)

What the hell are you talking about!?!?!
S4 and S5 rotors both use 2 mm seals. They can be swapped, but they have different compression ratios so you'd have to swap both rotors.
To the original poster, I don't know if you can use 84-85 13B 3mm rotors in an S4.....aside from higher compression, they may also have different balances.
-John

KNONFS

iTrader: (14)

It can be done.
They will be high compression, and heavier.

ddub

Yes it can be done. Higher comp = more power but you'll need better tuning. Heavier = more initial torque off the line, less up high.

You'll need the proper counterweights to do so.

totallimmortal

why do you want to use those rotors? why not s5 turbo rotors?

ddub

Because GSL-SE rotors are higher comp and have more initial torque off the line?

Cool_ManX

Because GSL-SE rotors are higher comp and have 3mm apex seals.... don need to prepare the rotors of s4 for 3mm
: http://rx7.com/store/rx7/fcengine_internals.html

RotaryResurrection

iTrader: (8)

Sure. You can use any 13b rotors in any 13b engine. From a structural and engineering standpoint anyway. Different weights and compression ratios affect tuning and power levels differently though, so in that respect you need to put more thought into it. BUt yes, all you need are 2 matching rotors (weight codes within 1 letter of each other, a, b, c, d or e), the matching front and rear counterweight. Since the SE never came as a turbo model, it uses only the smaller nonturbo diameter flywheel. You cannot use this on your turbo drivetrain, and your stock s4 turbo flywheel will throw the asembly off balance a bit. You'll have to acquire an automatic ctwt from a GSLSE (new or used) and run an aftermarket flywheel to make this work properly.




All 86+ rotaries use 2mm seals. All 85 and prior rotaries use 3mm seals. Unless theyve already been modded by the aftermarket for use with other seals.

Where the hell do people come up with this ****? Do they just scribble various responses down, put the papers into a hat and draw one out, then post it here?



Yeah, they'll fit right the **** in there.

NOT.

BTW, I have actually DONE this before in one of my old engines. IT does make pretty damn good low end, and still makes nice top end too. High compression turbo engines require close attention to tuning, though. I eventually broke the rear iron dowelpin landing under the oil filter (due most likely to detonation) and had to tear it down.

You *do* know that you can mill out any 86+ rotor and use that, as well, and they'll be lighter weight? You can still make good low end power with them.

jreynish

iTrader: (2)

spreading misinformation is really bad on this forum I can understand his frustration!

ddub

@ Kevin! That was awesome

But yes, misinformation is BAD, because if no one steps in to correct the misinformation then the person will think it is fact, and do things wrong.

NZConvertible

The smartest thing to do would be stick with the rotors you've got. A good, hard ping will still break a 3mm seal, and you're supposed to tune your motor to eliminate detonation, not build your motor expecting it. The newer 2-piece 2mm seals seal better and cause less friction, both of which increase power.

VII

Good call!

Cool_ManX

thanks...


Forget it.... bad Idea...

gotrotors?

The 2mm vs. 3mm debate has gone on for a long time, but the bottom line is, 3mm seals are more resistant to detonation than 2mm seals. If this is not the case, why would rx7 Specialties...one of the largest volume builders in the world, reccomend and use nothing but 3mm seals. In the time i worked there, I NEVER saw an engine built with 2mm. Bottom line, do the 3mm seals. And to eliminate any problems later, stick with your turbo rotors, or try to get your hands on s5 turbo rotors, as they have a slightly higher compression ratio (9.0:1 as compared to 8.5:1 on your s4 rotors. Im sure there is a machine shop somewhere near you that can mill your seal grooves out for you . Either that or send it away to one of the major places that do it (racing beat, Rx7 Specialties, Pineapple...etc....)



Good luck with that.

RotaryEvolution

iTrader: (30)

especially with internal engine questions, it could be a costly mistake..



as for why those people sell 3mm only, whenever you go to mcdonalds they always ask you if you want an upsize correct? they make more money off of doing it and they likely have it burned into their head that 3mm is better for all applications which is wrong, they should offer a choice but apparently don't.

gotrotors?

Well, rx7 specialties does offer and stock 2mm seals...but nobody usually wants to use them, as the 3mm are not really that much more expensive....and for most ppl, the piece of mind that you get with a 3mm as compared to a 2mm is worth the extra cost. I think he charges 60$ per rotor to mill to 3mm...and the set of seals is like....40$ more or something. So you end up spending 200$ extra...and you have a bigger safety net because of it. Sounds like a good deal to me. Im doing everything to my block, including Pinning it, corner clearancing, 3mm, and 3 window bearings. Its all about reliable for me.

And im thru

NZConvertible

They key word there is "more". So to be strictly correct, you would say "3mm seals are more resistant to detonation than 2mm seals, but they are not resistant to detonation in general". As I said above, one decent ping and it's all over.

If I was a total cynic, I could suggest they only did it to make more money from customers. But I'm only a little bit cynical...

But the facts are that the 2mm 2-piece are in other every way superior to the old 3mm seals. If you have no detonation (and you shouldn't), then there are no advantages to 2mm seals, only disadvantages. It should be noted that quite a few noted rotary drag racers, who run higher boost levels than any of us would dream about, use factory 2mm seals.

Bukwild

I went with 3mm seals because I plan to run 15lbs on the street and I just wanted the extra protection incase I got a bad tank of gas.

Aaron Cake

iTrader: (1)

Because it's cheaper to get old, worn rotors milled out for 3MM then it is to buy 2 new/good used rotors?

rx7_turbo2

Bingo!

jreynish

iTrader: (2)

You hit the nail on the head for that one!



BINGO we have the truth said very candidly right there.