RX_Speed_7

ok so I'm building a bridge port 13b for my FB, I'm thinking of using the RA Super Seals off http://www.rotaryaviation.com/ but I want to know if anyone has used them before??

SirCygnus

iTrader: (1)

they are awesome.

84stock

iTrader: (5)

Ruined the housings on a previous motor one of an engine builder friend of mine did.

680RWHP12A

i tried a set on a 13B with good condition used housings and the motor never made good compression. when i called them they said you should only use these seals with new housings

Liborek

If you planning high RPM operation....don´t ever consider it.

Kentetsu

I have heard great things about Goopy Seals. They are doing some amazing things with high compression turbo motors. Might be worth looking into...

Here's a comment posted on Sterling's site, regarding a motor they are building for him:

Hello Guys

Sorry that I have been so quiet but I am on the road much of the time and well you know the PC is time consuming.
I will respond to a few of comments.

Sterling's engine will be built using oversize 12A Goopy Apex Seals & Solid corner seals . Our intention is to have .001 of clearance on all wear parts on rotor. We manufacture both a stock size 12A seal which measures .115 and a oversize seal @ .118. This is due to the fact that 9 out of 10 used 12A rotors are out of tolerance in the area of the apex seal slot.
They are shaped like a V from all the years of use where the apex seal slopped back and fourth thus leaving outrageous clearances when reusing them. Our seals also have a proprietary coating on all surfaces that lower the (COF) coefficient of friction.

Our main objective with these tight clearances are high compression #s.
We @ Goopy Performance have built a 12A engines with all used parts except the wear parts and have obtained
#135 of compression.

Good sealing characteristics are key ingredients to high compression #s that will eventually reflect a good Vacuum or how Sterling puts it "Signal"
Tight clearances also help to isolate the Apex Seal SPRINGS from the actual flame in the combustion chamber.
This is a big issue with turbo motors with not only the over all radiant heat from the engine affecting the spring but the flame front distorts them even more to them eventually relaxing and loosing their deflection.


Over the years i have observed many rebuilds using both new and used components and its evident what engine is built right and which one is compromised.
One indicator is to see where the car idles at, fuel consumtion MPG etc
Ive seen some rebuilds where they have a hard time idling under 1200 RPM
Another indicator is if the spark plugs have to be replaced often.
And another is the amount of emissions out of the exhaust.

Although the induction system Ie:carburetor plays a big part, a better signal/vacume is always a plus.+++

On the Break-in issue, we recommended somewhere between 300-500 where new bearings are used and 200-300 where they are reused. New Mazda bearings have a film that either has to be removed prior to using or allow it to come off gradually while breaking in.

Now our Goopy Apex Seals and Goopy Corner seals the break-in is not as an issue as with the rotor or stationary bearings.
We have had Drag racing customers with absolutely no break-in time in Nitrous cars with no issues but to them high RPM's is everything so the idling, MPG spark plug replacing becomes a non-issue.


We appreciate all your questions and coments.

Goopy Performance.
God BLess
Here is the link to the thread if you want to check out the whole thing. They sound like great guys.
http://sterlingmetalworks.com/bymc/index.php?topic=91.0


.

RX_Speed_7

ya because I'm using 74 13b housing with s4 rotors and 12a irons

gsl-se addict

iTrader: (3)

I call BS on this number. Here is why:

12A engine has 9.4:1 compression ratio. This is determined mostly by the dish on the rotor face. The shape of the housing is also a factor, but that is going to be fixed for us unless you totally redesign the engine. This ratio is based on the volume ratio between the time where you have max volume on your intake "stroke" and the time where you reach TDC (min volume). It has nothing to do with leakage from the seals. Leakage and only make the effective CR smaller.

So, let's crunch some numbers. At sea leavel, atmospheric pressure is about 14.7 psi (actually little bit less). So, at a CR of 9.4, the pressure in the chamber would be:

14.7 psi * 9.4 = 138.2 psi

Now, you say that this is on par with what they got, so what's wrong? Well...remember your gauge does not read 14.7 psi when you just have it out in the open..it reads 0 psi. The difference is psia (absolute pressure) vs. psig (gauge pressue), so you need to subtract 14.7 psi from the above number:

138.2 - 14.7 = 123.5 psi

This is the maximum value that we would expect to see during a measurement. At higher elevation, it will be lower. There are also slight variations in atmospheric pressure due to weather changes, but that would have very little impact.

Someone who reports #135 compression on a 12A has either modified the dish to increase the CR or is just flat out full of it. I would say the latter in this case since they are trying to sell you something. Higher numbers can be seen in a 13B since 9.7:1 and 10:1 compression ratios are available. These guys talk about quick break-in and performance applications, but they don't tell you how durable these seals are. We know the stockers are good for about 200k miles and hold up fine in a lot of performance applications. This is why most experienced engine builders will say to stick with OEM.

For apex seals, OEM is still best. Mazda has a lot more time and $$$ into R&D than any of these shops. The stockers will work great and last a long time in just about any situation. You can also get carbon or ceramic for performance engines. Carbons are good for high RPM applications, but tend to have a shorter life. The ceramics are great in almost every way (except for your wallet ).

sen2two

iTrader: (10)

I always use RA Super seals. never a problem...

now many people have had a problem in the past. but thats all fixed now. they had outsourced making them to keep up with the demand. they were always sold out. they are now back to doing it all themselfs and never have problems anymore.

use the RA seals. you cant go wrong.

bad 83

iTrader: (3)

Good call Kent. The stronger the Apex Seal material, the quicker the wear on your housings. Its just physics at that point. I have torn down engines with factory seals at 150k plus miles and the chrome is either gone or almost gone from the top of the housings and they were good running engines with descent compression. Unless you have experiance with building this engines and know what to expect from them, don't get snowballed by some "E-Bayers" out there.

I personally like the chyro hardened seals from Atkins, but I know the housings will wear faster. I also expect the seals will hold way more boost than the factory seals. I use the seals that fit the application, and I know what to expect out them.

Kentetsu

Very interesting. Nice catch Kent.


"I've told you a million times that you should never exaggerate"!

Manolis_D

iTrader: (2)

They're junk, don't use them. I built a motor with them, then saw some pictures of 10k old rotor housings with RA seals (scrap metal after the 10k), so pulled the motor apart, sent the seals back, and ordered a set of mazda 3mm seals instead.

Check this out:
http://www.riceracing.com.au/apex-seals.htm

Liborek

I´m glad you posted this link. I can´t even think about how many apex seals thread I read through... Its always the same. Real experienced people like Crispeed, RICE... always suggested mazda OEM stuff...or ceramics if you have money...

Back to the OP. You still didn´t specified your goals. If you are going for high RPMs N/A and not trash housings go with carbons or ceramics.

PercentSevenC

I've been impressed by the regular, non-hardened Atkins seals. I forgot to set my timing after getting the Camden installed and detonated hard my first pull (as in, the detonation was audible). No sign of damage. Plus, they break in a little better to used housings.

PvillKnight7

iTrader: (16)

If you want a reliable daily driver stick with the stock 2 piece seals and stock corners. Use the rubber insets if your ports allow it. Build it right the first time.

http://www.fc3spro.com/TECH/MODS/ENG...OTORS/apex.htm

http://www.riceracing.com.au/apex-seals.htm

Siraniko

iTrader: (13)

I only use factory seals. I heard good things about RA super seals but I havent seen any proof that it will outlast the stock seals as in total mileage (ie, 100K miles or so).