twinturborx7pete

iTrader: (3)

Ok, i have sooo many people telling me to get different apex seals and its driving me nuts so here i go.. i'm gonna ask the poll?!

94touring

Well if you don't have bad wear on your rotors and there is no need to mill them out, stay with 2mm seals. If you have money to burn and can justify it go with the ceramics. I personally like the hurley 2 piece seals over stock, they have heavier duty springs that are suppose to help eliminate seal fluttering in the higher rpms, and are less prone to spring collapse.

twinturborx7pete

iTrader: (3)

Ya i'm swinging to the Hurley 2 piece 2mm if i can... most of my friends run them, but a friend here in town who rebuilds rotaries swears by the stock mazda seals...

94touring

The stock seals seal slightly better due to the 3 piece design, however I found that they also wear harder on the rotors since they can begin shift around slightly, it was very obvious that once the stock seals begin to wear the rotors the problem only gets worse. I was forced to mill my rotors to 3mm on my last engine, and can say that the 2 piece have a very small chance on shifting around, or at least thats how it appeared to me. The difference in sealing abilites has to be little to none anyways, and hurley says that their seals and springs will give better sealing in higher rpms, while stock seals may begin to flutter. When I compared my stock seals with my hurleys, the hurleys were much 'beefier' over stock and appear to be able to withstand more abuse. They will blow up just as easy with leaning conditions, as will any seal, but gives me some peace of mind.

R Xplicit

go to the rotary performance section. there is an outright perfect discussion regarding that same issue that has been going on for a few months. there are some huge words being tossed around in there ;-)

it basically boils down to who you trust, on the forum, and who is doing to engine in the first place. most of the tuners have a predetermined choice, depending on their experiences...

louis

Brian P

You'll need new housings if you are going to use ceramic seals

94touring

Is that because they don't wear into used housings like other material seals? Not that I don't believe you, but i'd like to learn more about it.

rotorbrain

ceramic is hard. you are right about the wearing in. the metal apex seals are soft and can therefore be worn it with no problem. if you use ceramic seals with used housings all the little crevices in the housings will go un touched. the ceramic just doesnt wear. you can rebuild your engine time and time again using the same seals. . . given you dont blow them up!!! i believe star racing did this with there engines.

paul

RX7Elmo

i'd say go with the 2mm mazda seals unless you see a good reason to change from that.

Danny

Bill B

iTrader: (1)

Stock Mazda seals 2 or 3mm will work just fine don't listen to the hype from all of the "brand name experts" .

paw140

If this is true, then how do you explain an engine with low compression? Worn side seals?

Fd3BOOST

iTrader: (7)

stock 2mm all day long

peejay

That's because they work fine right up until the point that they practically fall out.

A few years ago, dude i know in Canada (don't know if he's on the Forum or not) reported tearing down a T2 engine for a preemptive rebuild and found that the apex seals had lost 2/3rds of their original height!

If he hadn't decided to rebuild it as preventative maintenance, he would have merrily kept on driving it until it failed catastrophically.

The nice thing about rotaries is also the bad thing about rotaries: Much of the time, they run great right up to the moment they die, and then they die with no warning.

stinkfist

I pulled a running 13bt apart to port and rebuild. I found the apex seals to be 2 mm shorter than stock.

Mike

hypntyz7

Bullshit. I take engines apart on a daily basis. It is easy to see that apex seals wear down a lot. Stock seals have a triangle corner piece. When new, this piece comes to a perfect point. As it wears (and they DO wear, a LOT) the point becomes a flat spot that gets wider and wider with age. In fact, just by looking, you can estimate the mileage on an engine by the width of the flat spot, since this is equivalent to the wear.

Bottom line,when you have metal on metal, there is NO way to prevent friction and wear. IF a man could do that, he would be a billionnaire, because every corporation in the world would be after him. You're telling me you can break the laws of physics by building a motor in which metal parts dont wear?? :

Tell me this...you start off with apex seals of X height. They dont break. Then one day all of the sudden one breaks, even on a bulletproof engine like a nonturbo rotary. IF the seal never wore, why then did it break? Don't tell me detonation, or even abuse, I have seen engines blow without either being present. IT broke because of wear. As it wears, it gets weaker. Duh...

Nathan Kwok

Another update to this thread, Mazda is now using 2-piece seals as the stock apex seal. You will find them on all new remans.

rx713bt

iTrader: (4)

I can send you about 20 apex seals that are worn to the service limit based on the FSM. I think they are worn to .250". New they are over .300". You still don't think that's called worn?


-Jeff

rx713bt

iTrader: (4)

Exactly. That is one of the ways to estimating the amount of wear on an engine and determining what is usable. I've only taken apart and/or rebuilt about 50 engine in my lifetime and that's what I see.

-Jeff

dubulup

so you guys are arguing a statement made almost a year ago???