Midwest 7's

iTrader: (4)

in my rotary experiences i have torn down about 15 12a's and old 13b's with the 3mm seals. never seen a broken apex seal.
in the 5 S5 13b's ive torn down every one of them had a broken apex seal on one rotor.
anyway, just wanted to say that our first gens have fine motors from the factory.

diabolical1

iTrader: (3)

well ... i'm not contesting that our engines are awesome, but i've torn apart some older (3 mm) engines and found the apex seal broken. from my experiences, it wasn't a common occurrence, but it did happen.

i just want to put that out there before someone ignites another of those "2 mm vs. 3 mm wars ...

trochoid

iTrader: (6)

Aw come on, let's start something today, I'm in the mood. I think the biggest problem with the 2mm seals was going to the 3 piece set up. I've torn down some S4's and the top half of the seal had disappeared. Bottom half was razor sharp. Don't stick your finger in the exhaust port when this happens to feel the seals, ouchy.

Alex-7

Even though I've been drunk every time I've seen a motor torn apart at midwest 7's place I must say he speaks the truth.

Nevar seen a bad apex seal on a 12A or 3mill 13B. Always a bad seal on FC motors. Always.

IIRC many of the 12A seals have still been in useable spec after over 150 thousand miles.

Rogue_Wulff

The 3mm seals are 50% thicker, and theoreticly, 50% stronger, than the 2mm. They can break, it's just a lot rarer..........

mbaha

I think strength is square function so 2^2 = 4 and 3^2 = 9 and (9-4)/4= 1.25 so a 3mm seal would be 125% stronger than a 2mm seal

REVHED

Were the S5 motors turbocharged ones?

Alex-7

All N/A.

Tranquil

iTrader: (1)

Yes, there was an S5 Turbo II.

Midwest 7's

iTrader: (4)

the ones i have tore down have all been n/a.
i just did 3 last night and each one had a fucked up rotor.

trochoid

iTrader: (6)

On the 1st gens I usually see the housings just plain worn out, chrome gone.

The second gens have usually popped a seal and chewed up housings, and usually with fewer miles on the clock. Almost always the rear seal has gone.

Michael_Rudy

ya, every 12a i have taken apart is missing massive amounts of chrome, and most of them have multiple broken apex seals, lots of the housings have massive gouges in them too

REVHED

No **** Sherlock.

I was asking if any of the ones he tore down were Turbo.

Matty's first 1st Gen

I've gone through 3 engines in 2 years, all from apex failure, of course they were all used engines, but i'm not happy with apex's in general, and also I see alot of chrome flaking on my engines, what am i doing wrong?

Nicholas P.

iTrader: (1)

Matty's first 1st gen.

their is a bible for the 1st gen. follow it!

its all in the car manual. order it online.

LokiRx7.1

iTrader: (1)

Just got a 12A with 180,000 on the dial, runs REAL strong. I am very impressed, this is my third 7 and so far all of them have been N/A 12A's. I love them, I think they stand out in reliablity with the best of them. I have no doubt the engine needs to be rebuilt, but since it is running so good it is being relagated to DD until I can afford to rebuild it properly.

85rotarypower

Well, when my original 12A went out, it took out a rear apex seal on startup. Cranked the engine over and when it caught, it snapped the apex seal in half. The rotor and housing were both damaged, but there was no chrome flaking and no odd wear. This engine had about 275K KM on it as well. Thats about 180K miles. The bad thing about it was that the engine was real strong still and the insides looked pretty good when I tore it down. It would hold a rock solid idle at 800 rpm and would rev out to 7K without a problem.

The engine I have now, an S4 13B N/A, currently has about 60K KM on it, but I know its goin to need rebuilding before that number doubles. The engine has to go through tuning on a carb, so things aren't going to go too well for it at first.

peejay

I can't find good 12A rotor housings anymore, they're all junk because the 3mm seals eat housings. Just because the engine was running doesn't necessarily mean the housings are any good, iron seals will seal remarkably well against a chrome-free sheetmetal insert But not for very long.

I've never pulled a 2mm seal engine apart with worn out housings, just debris damage. That almost guarantees that every core FC-up engine has at least one useable rotor housing.

This hurts to say but I might be going 13B soon, just so I can get cheap parts.

peejay

Overrev the engine, and you'll break a seal or two. The other downside of the 3mm seals.

85 FB

Hey, c'mon now. 13B's are great. I feel so damn lonely thinking I'm the only one with a stock 13B. And, what size seals would my rotary have? 3mm? Or, 2mm?

peejay

If you have anything made between '74 and '85 you have 3mm seals.

Anything '86-up is 2mm.

Midwest 7's

iTrader: (4)

thats funny, my experiences are the exact opposite.
pm me if you need 12a housings, i might have some i can spare.