sa22rally

Hi guys as some of you know im rallying a Sa22 here in denmark and i have almost no parts available for my oldschool 4 port 13b. ive searched high and low and asked alot of querstions in here to figure out what way to go so i dosnt come to a stand still in the middle of the season anymore.
Thats why ive bought a Tii engine im gonna pick it up in a few weeks. what way im able to buy parts much easier.
Ive searched the forum and found a few threads on the subject but i havent found any threads on making a Carbed NA engine with 9,7 rotors aout of a Tii engine. I did find thread where a guy asked allmost that question but didnt get any answers.

So ive got a few question wich i was hoping someone could anser but first my setup.
Tii engine
48 mm IDA weber from my oldschool 4 port im thinking 38 mm chokes to get some torque.
Rallyport from Pineapple.
Carbon seals
And i am hoping to find a set of 9,7 rotors to go instead of the 9,0
Then ive been researching the mazdatrix FAQ page and my idea is to use a 83-85 12A flywheel because the rotors weigh allmost the same and i can not get the turbo flywheel in my 86 NA trans and i have no where to get the engine balanced here in denmark.

i am planning on using my old frontcover to the the dizzy on there and running my old dlidfis setup but What about Timing the that engine? and will the cover fit?

What stuff does the Tii engine have that i need to take care of to run it with the carb?

Is there any reason you guys can think off that this engine shouldnt be much better than my old one?

Best Regards Rasmus from Denmark

j9fd3s

iTrader: (3)

well basically your plan will work. the old front cover goes right on, timing will be the same, the 9.7's go right in.

for a flywheel you can run an 89-91 non turbo flywheel, or aftermarket.

the intake bolt pattern changes too, so you will need an intake manifold, or get creative with the welder.

that is pretty much it.

sa22rally

Thanks alot i have bought the lower intake alon with the engine and borrowed a aluminium Welder wich i hope could turn out usefull.
Would a 45 mm dcoe Weber get me some better torque ore will that be to small

Kenku

Street port, stick with 48mm. 38mm or bigger chokes is about what a streetport 13B will want, and that's too small on a 45.

sa22rally

Great thanks ive Bern running 24 btc timing leading and 20 traling thats correct right?

sa22rally

What will be the safe rpm limit for this engine? With Carbon seals

diabolical1

iTrader: (3)

what's the Rally port? i looked on their site, but didn't see it listed. is it one of their bridges?

sa22rally

Sorry they Call it a race street port it should be equal to the old rallyports i now.
I bought it for my old rx4 13 B because i was told i would also be able to use it with the new 4 port engines and i get the same feeling from the Racing beat parts Numbers Can anybody confirm that.
Also i from what i Read it seams that the safe rpm of the Tii engine is 9-9500 rpm Can anybody confirm that?

diabolical1

iTrader: (3)

thanks. i saw them refer to the Rally port in the description once you choose it from the menu. however, i'm still no clearer on what kind of port it is. i don't mean to belabor the details, but i'm curious because in all the videos i've seen of Rx-7 Rally cars, they sound like bridges, but there are some people here that simply have huge streetports that they call Rally ports. so is your template a bridge or BIG street?

anyway, 9500 should be fine as long as you're still making power there. with the carbon seals, you have removed the seal chatter obstacle, so i think your next issue would be e-shaft flex, but i think that would occur well above 9500. i've never experienced it because i've never run anything that high before. perhaps someone who has can shed more light on it for you.

do you plan to clearance the rotors?

sa22rally

Yes its. Huge street port i chose it after Reading som old Papers about the rallycars and how they made a little more torque and a little leas HP.

I am planning on making an ignition cut at 8500 rpm but my old engine didnt have that and i blew up While loosing grip at about 8-8500 so if the Tii isnt stronger i will make the rev limit at 8000 rpm instead.

I havent been able to finde any Real info on clearincin rotors if i could find a good descreption i would like to do it just to be safe

diabolical1

iTrader: (3)

well, you may not have to do it at all. i simply mentioned it to be thorough. i've seen some people (that i think know better than me) say the stock Gen II rotors are good (clearance-wise) to 9000, and i've seen some people (again, who i think know more than me) say they're not. so i simply don't know. as i said, i've never run anything that high before.

here's RB's take on it: Rotary Tech Tips: Engine Rotors

on the old engine that let go at 8500, did you ever determine what happened? also, how are you cutting the ignition?

sa22rally

The old engine blew because i didnt have a rev limiter and at 8500 rpm i blew my tire so basicly the engine just did ti many rpm i didnt se how Much.

I am planning ti use my shift light to trigger a 5 pin relay ti cut the power for the ignition so that both the trailing and leading will be cut of. I Think i will just keep the rpm below 8500 .

Do you Think i will be able to make descent low end torque with this engine thinking about 38 mm ore 42 mm Chokes

diabolical1

iTrader: (3)

well be careful. i recently read this (post 54): https://www.rx7club.com/build-thread...1043356/page2/

the 38s will give you better low end, but i wouldn't discount using the 42s. every engine and setup is different, so who knows? yours may be able to use bigger chokes. start with the 38s when you get everything together. document everything. then do the same for the 42s.

j9fd3s

iTrader: (3)

i think if you just had a hard cut @8500, and the engine just turned off, its probably ok. but the stop/start of a traditional rev limiter isn't good if you spend a lot of time hitting it.

its almost better to over rev the thing

peejay

I run steel 2mm seals past 10,000 all the time. I put my engine in the car in mid-2012 and it's done maybe 65k kms since then. Compression is going away but this is because the chrome is flaking off of the rotor housings. (old worn '84 housings, the Turbo II have much MUCH better chrome!)

I have been steered away from carbon 2mm seals as they apparently do not have any good lifespan. Far shorter than 3mm carbon seals.

DO NOT USE A REV LIMITER. Rev limiters (under load) kill rotaries! Increase the oil pressure, teardrop the oil holes in the eccentric shaft. Clearance the rotor sides a little bit - an additional .05mm per side at the tips is sufficient. Without clearancing you are good to ~9500 or so. With clearancing you get another thousand RPM. The scary part is the clutch and flywheel spinning that fast!

sa22rally

Great guys thanks for the advices any info on how to teardrop the Oil channels?
I tried Reading the Racing beat info on clearincing but i guess something is lost in translation because i still dont understand it

I actually remember Reading about the problem with ignition cut i guess i just have to control my self

Any other advises on the project is appreciated im picking up the engine next weekend i tried porting some old irons for the first time to Day pretty booring but i guess it went okay.
AS a side note in the future if one of the housings needs to be changed does it have to be another Tii housing ore what is the differences

diabolical1

iTrader: (3)

well, having read RB's stuff when i looked it up for you, i'm a bit confused myself. i understand the process, and i've seen it done in an Australian rebuild video. however, they never once mentioned the e-shaft and all this time, it was my understanding that basically it was the shaft flexing because it has these two, oil-filled cows on either end of it, causing them (at high RPM) to make contact with the side housings. i will be taking a second look at this stuff now for my own curiosity, if for nothing else. sorry, i sometimes ramble when i get excited/confused ... but yeah, you're basically taking measurements (rotor housing, lands, and sides) to determine if the rotor sides are narrow enough to avoid contact and machining them to suit.

for the teardrops: https://www.rx7club.com/rotary-car-p...y-port-489429/

project7s

iTrader: (5)

I noticed mentioned above using non turbo rotors for the slightly higher compression, but according to racing beat you get get the same power by using the turbo rotors and just advancing the timing a couple degrees. Has anyone else done this?

j9fd3s

iTrader: (3)

i've seen a coupe of turbo engines run NA, and they seem to do ok power wise.

Mazda published a power vs compression ratio chart in the early 80's and going from 9.4 to 9.0 is a pretty small difference. i think what misleads people is that the compression number is a 9 and not an 10,11 or 12. piston engine guys get all worked up about raising compression to like 12.5:1, but if you did that in a rotary you'd probably loose power.

Rub20B

I would also just first give the 9.0 a try. just make sure bearings are rx8 or FD ones and have enough clearance. rear main bearing is first what will fail when you massively over rev with insufficienct clearance and or oil pressure.

If you stay with normal aux venturis (not annular) I think there is no need to go to small choke of 38mm. with 51 IDA and 44mm chokes our PP was very streetable at any rpm if the load was reasonable. (no not driving 30 kph constant in 1ste gear)

sa22rally

hi guys so i finally got the engine build and startet right up no problems at all.
i went with 9,4 comp rotors. fd oil regulator modified front regulator. no gasket on front cover and 38 mm chokes in my old 48 mm ida.
i ended up tig welding some "ears" to the old style 4 port manifold and portet the crap out of the center iron to fit everything.
i pluged the injectorholes in the centeriron with 18 mm bolts so that i could port the entire runner with no holes ore edges, it worked very well as i also threaded the to small holes with 4 mm thread that goes from the gasket area and all the way 3 mm into the 18 mm so that the 4 mm and 18 mm will hold eachother in place iff the locktite gives up. .

Next question how much do i need to brake in the new carbon apex before dyno/racing. the housings whas not flawless but very good. im going the dyno in 2 weeks very exciting stuff

how about the timing should i just set the timing 24 btdc at 4000 rpm? im running dlidfis. maybe closing the difference between leading and trailing

j9fd3s

iTrader: (3)

i think i would run like 18 degrees of timing, until i get to the dyno. i'd also run 42 venturis

sa22rally

Okay great what would be timing maximum / minimum. And what should i do with trailing ?
What about Breaking in the Engine is 200 miles enough?

j9fd3s

iTrader: (3)

i think 200 miles is enough, i'd like more, but it probably doesn't need it.

for timing, i'd see what it likes on the dyno, you should end up around 24, but start low. you'll pick up a lot, and then the gain will flatten out, and you wanna run the part before it flattens out. so if you ran 15 degrees, and it made 100hp, and running 18 degrees, made 120hp, running 20 degrees might only make 125hp, so you'd want to run 18. make sense?

sa22rally

Yes very great and excatly what i was looking for. Thanks alot i Will get back with resultat after dyno i hopping 200 with good torque