Rotary Aviation apex seal report
 

I just tore my engine apart which had about 20k miles on it running Rotary aviation apex seals and springs. I was slowly losing compression until it got bad and I took the engine apart. Found some of the apex seal springs flattened, same with some corner seal springs. Also 2 brken corner seals. I did run a little lean in boost sometimes, and expierenced detnation. Which could cause this, so I understood.

When I took a close look at the rotor housings I found chatter grooves running all the way around the rotor housing. They are light but are on the whole housing. They get deeper on the part between the exhaust port and the spark plug holes. I dont know if the apex seals caused this or what. I will post pictures of it tonight.

Who did the rebuild? Did you use the RA springs as well? Tracy admitted that the springs were reliable up to stock boost levels. How much boost were you running? The springs may be the cause of the chatter marks because of them not putting the right amounts of pressure against the apex seals causing them to float. I'm no expert but that sounds logical to me. Also if you broke 2 corner seals that was either some major detenation or your side seal clearence was too tight.

Chatter is usually caused by overheating or lack of lubrication.

I never overheated the engine. Temp was always around 90C according to the wolf3d. Lubrication was fine, I premix about 1 ounce per gallon of gas. When I took the engine apart everything had a film of premix on it so lubrication isnt the problem either.

Did you use the RA springs?

yes, read the first sentence, he used both seals and springs.

how much boost were you running? i'm using both seals and springs too, now i'm kinda wishing i just used mazda stuff...... oh well, it'll take quite a while for me to hit 20k anyway. i'm running 15-16 psi though.

harrison

Here are some pics. I was running 8 psi, but leaning out. I just ordered some new corner springs and mazda apex seal springs.

Do you guys think I can sand this smooth, because I was told by someone it would work. The grooves arent very deep, just not smooth.

You and me both, I think when the funds are available again. My motor will likely be coming apart, and the RA seals/springs will be replaced with Mazda parts.

Agree...
I'm using the RA seals and mazda sprigs. I'm actually at 18 psi T70 no problems... Kaboosky made 520 whp @19 psi with that set-up ... though, neither kaboosky or myself have get 10K so time will tell...

BTW I sanded the housing with 320grit sand paper for about 15min each and they turned out like new. I ordered some new mazda apex seal springs and RA is giving me a new set of seals if I send them this set so they can look at them.

Can you tell me please the difference between RA Apex Seals from Mazda Apex Seals??? I would like to understand better the information I have... :bigthumb:

The Mazda seals are compatible with the housing surface,it appears the RA ones are not.

No thats not it. The RA springs are not heat treated like the Mazda ones. The RA springs are best used in a NA application.

I once had made some apex seals from machine tool steel.These scored the housings like the RA seals have.Because of too much friction,the apex seal would 'weld' itself to the housing surface and tear off a tiny piece of tip,which scored the housing.This left lots of scoring and very little compression,because the seals were incompatible with the housing surface.

You either use Mazda OEM (Ferrous or Carbon) or you use the BEST quality Ceramic Seals (like NRS, that I personaly specify and supply to many shops), everything else in a steel type is a piece of shit and will fuck your housing and rotor slots very quickly or they will distort like plastic as soon as conditions get hard....

Expensive lesson to learn.

Were these new rotor housings? What did RA say when you talked to them (i.e. have they actually changed anything in their seals, or did they just send you another identical set?)

Sounds like it's time to tear apart my brand new motor... :(
-Manolis

This is chatter !!!!

Those housings clearly show apex seal wear on them, which is not a good sign.
They actually remind me of housings which Hurley seals were used on.

I've got RA seals and my housings are all scored up like that too, not chattered but scored. The engine had 8k miles on it and the housings looked almost perfect before I used the seals.

I'll probably use OEM Mazda seals next time.

Yeah thats the same way mine looked as well, and I run 100:1 premix all the time...Something material wise is just not jiving...

the pictures you posted dont seem to appear to have chatter but what id does that is abnormal wear of the housing. somoone mentioned running hot or not enouf premix, (you gauge could be off) constat exposure to heat can cause this especially if you are runing lean this is even more so.
was this by any chance the early batch of the RA seals? i build some engiens with these seals and srpings one of which is a local friend who we dynoed at over 420whp and 16-17 psi of boost and his engine sounds good so far (yes the sound of the engine can tell you a lot)
i have read a lot of the these RA this RA that but to tell you the truth i have yet to read one convincing review that shows the seals or springs at fault.

actually, chatter marks are caused by over revving. the apex seal lifts off the rotor housing and slams back down causing an indentation. rotor housing grooves run perpendicular to chatter marks. over revving also causes flattened apex seal springs.

i have seen those same marks in your picture in stock mazda engines using mazda seals. can you feel an indentation on the housing.

Well obviously these arent chatter marks but apex seal wear on my housing. Its been mentioned many times now. I ran more than enough premix. 1 ounce per gallon of gas, when I took the engine apart everythign had a coat film of premix. I dont see how my housings get that screwed up over a month of driving. Thats right I only drove it with a turbo for a month, and thats when I screwed up the springs and started losing compression.

I totally agree! I only use Mazda seals.I did try some Iannetti one piece seals,they gave not enough compression,no more wheel spinning on throttle.
Chatter marks are across the housing,where the one shown has score marks right around,they are not chatter marks.The springs probably collapsed because the apex seals were way too hot,too much friction.

Yea this sucks i dont know what to do. Maybe I can sell the set of new seals and springs I get from RA for $150 or so and get some mazda seals?