sdminus

Could somebody please advise me.
Thinking of having my engine re built but i have a dilema over the seals. some say i should use ceramics..... Why... Are they really that much better than stock seals..
Is there any data that i can compare on these seals
Scott

GUITARJUNKIE28

for the money, there's nothing better than the stock seals.

if you've got THAT much money laying around, the ceramics are nicer to the rotor housings and more forgiving to detonation. but for their cost, you can blow your motor up once or twice and rebuild it while you're getting it right.

IMHO, they're a race-only justification unless you've got deep pockets.

couturemarc

It all comes down to application, you can get into ceramics for $895 or less. There are benefits to ceramics in any application, not just racing. Every 2 pc steel seal that i have seen basically gives you 40 000 mi before things start to go downhill, less in high output motors. this does not happen with ceramics.

Spend the extra money upfront and get a motor that will last the first time or set yourself up on the engine payment plan and rebuild with steel seals every couple years. the extra $500 is quickly recovered IMO.

sdminus

Nice one guys.
So is there any actual documented gains from ceramics. ie can they hold more boost etc..

Scott

couturemarc

You gain about 1-3% power from the reduced friction of ceramics, they can hold upwards of 90psi boost, but so can the steel seals... they can resit knock better than steel but you can still break them. The real advantage is that they will not wear out the motor and your performance will not drop off over time like it will with steel and when rebuild time comes along you can reuse the ceramics most times and the mating surfaces will not show as much wear as with steel seals.

RETed

Too much variables (i.e. ceramic composition) unless we're talking about ONE ceramic apex seal?
Ianetti?

Ceramics can be abrasive, so making a blanket statement like "less wear" is unproven until I see proof...


-Ted

sdminus

The seals in mind are ianetti LOL !!!!!

couturemarc

I know of 4 types of ceramic seals that are manufactured today, all are of the same material and general finnish quality. The higher end seals have higher heat transfer rates than the industrial seals along with higher thermal shock resistance and slightly higher fracture toughness. But as far as i know all are made of the same material, just made by different manufacturers.

You can get your own proof by building a motor with ceramic seals, by doing research on the usage of ceramics, by calling one of the manufacturers and getting asking for testing results (but i doubt they'll give it to you), through a materials engineering degree and many other ways...

the industrial generator motors using ceramic seals require less power to spin, this is attributed to the reduced friction from the seals.... less friction will result in less wear.

GUITARJUNKIE28

i've only seen the ianettis. got any links for any of the others?

couturemarc

NRS ceramic power seals makes 2 grades of ceramic seals, the others that i know of are not available to the public and retail markets.

GUITARJUNKIE28

anyone sell them?

maxcooper

You can buy Ianetti (sp -- is it one 'n' or two?) seals from Mazdatrix:
http://mazdatrix.com/getprice.asp?partnum=01-9103-0000

-Max

BNA_ELLIS

I know someone who has used ianetti and detonated and blew his seals into about 100 pieces infact more than one now I think about.
I know of other that have used Ianetti seals and have had poor compression in comparison to stock seals & i'm sure we all agree compression=power.
I also know people using them with great results, but this is just another side of the coin to make you aware of.
One of the things I have always questioned with the ceramics, where people quote "you can run more boost with ceramics" some of the times from what I have noticed is you have to run more boost to get the same amount of power you would with stock seals because of the lower compression and as already stated
compression=power.

rgds

sdminus

Cheers, that is the exact question I needed answering

So, my next question is... what are the advantages between 3 piece and 2 piece seals, also what's the advantages between using 2mm and 3mm (apart from the obvious dimensions)

Cheers

Scott

GUITARJUNKIE28

thanks max--i meant other than ianetti though. i'm not spending $1800 unless i'm planning on putting down 4-digit horsepower

bna-- can you get a little more in depth with the compression? i was under the impression that they sealed ether as good, or better than stock.

maxcooper

3 piece
seals better but weaker
moot point since you can't get them anymore

3mm
reported to be more detonation resistant, but they aren't bulletproof (no seal is)
chatters more
doesn't seal as well
some folks have trouble with machining the rotors to accept them
allows you to reuse rotors that are no longer in tolerance for 2mm seals

I recommend Mazda 2-piece 2mm seals (the stock ones). I personally don't think 3mm seals are all that great, but a lot of engine builders like them. I would trust my engine builder and use what they recommend (even if it was 3mm seals), or find another builder if I was dead-set on using a specific seal and the builder didn't want to (no "you should have used the seals I recommended" excuse if you have problems with the engine).

I went ceramic (1-piece 2mm Ianetti) since there were doubts floating around about both the then-new Mazda 2-piece seals and the Rotary Aviation seals. Both of those seem to be working fine for people now, but I didn't want to be a ginea pig so I opted for the proven (but expensive) ceramics. The 1-piece seals should be harder to break than multi-piece seals, but they don't seal all that great as evidenced by my low idle vacuum. The car starts easy, feels great, and made decent power on the dyno, though, so they must be working okay. Judging by the power band (peak power on dyno @7700RPM, which is where we let off the gas), I think my port job is pretty big, so that may be part of the low idle vacuum as well.

-Max

GUITARJUNKIE28

ahhhhh one piece...no wonder they didn't seal so well.

for any street car, i think RA with stock springs, or just mazda 2-piece seals can't be beat in the cost-to-benefit ratio.

Erdin

The sealing problem isn’t that much of a problem as every one thinks I have recently had my engine compression tested and it was hiting 7 on the front rotors and 5 on rears which was a surprise for me because I am using 3mm 1 peace ceramics with solid corner seals. The engine has about 7000 miles on it now what I will say is it takes a lot more time to rune the engine in I think I did about 3000 miles before it had run in. That my to cent anyway.

Zero R

iTrader: (1)

I pretty much use stock mazda seals, unless the customer asks otherwise. I have used atkins seals as well without bad results. I think ceramics are good for racing and esp. NA aps. They are not indestructable and when they do go the kinda cause alot more damage from what I've seen. I wouldn't rush into them.

GUITARJUNKIE28

but when we're talking about sealing, are we talking about cranking compression numbers, or the ability of the seal to seal at speed?

at 5000+ rpm, there's basically NO time for any significant leakdown of the combustion gasses, so i'd think a one piece wouldn't make much difference at all..but poor sealing (not poor, but maybe not "as good") down low may make the car a bit testy to start under some conditions.

maxcooper

I hope you are right about there being a difference in sealing while the engine is revving versus low-speed sealing at idle. It seems like differences in seal float (due to weight and spring stiffness) could make a difference there. The ceramic apex seals are lighter than steel and the springs are heavier, so perhaps they do seal better at high RPM, despite my 1-piece seals sealing worse at idle RPMs. My car is easy to start and idles okay, and if it stays the way it is now I don't see any problems with the 1-piece ceramic seals.

-Max

GUITARJUNKIE28

then i guess it doesn't make a big enough difference to matter--unless you're really bitchy.

i've seen cars with blown apex seals idle like crap, but as soon as you get them in the upper rpm range, you couldn't even tell the difference. one guy i know dyno'd at 207 with a bad apex seal (standard corner chip), and only 212 with all good seals.

i really don't know how much it matters up top.

couturemarc

correct, the ceramics will show less seal float at high rpm.

They seal as good or better than any other seal on the market, BUT they will not wear into used housings like a steel seal will so new housings are imperative. Ceramics also have a much lower thermal expansion rate than steel so this allows for tighter tolerances/clearances than steel seals.

NRS is also the only ones offering cermet coated springs that will NOT wear out when using ceramic seals. Typically stock or performance un-coated springs will wear out and get shorter and eventually provide poor spring pressure on the seals. With the ceramics being lighter they do not have the same cetrifugal forces that the steel seals have.

When properly clearanced with cermet springs nothing beats ceramics with perfect housings.

*Erdin* if you are getting low compression readings at 7000mi then i suspects your springs are worn out, that is the typical life span of uncoated springs.

*guitarjunkie* Try and look at rotor housings that have run the seals that you are looking at getting before you buy. I've seen hundreds of housings and by now i can tell you what seals were run in the engine by looking at the wear on the housings (most of the time ). There are few seals on the market that won't destroy your housings. If they are scrap or marginal housings then go for it, if you like your housings and don't want to buy new ones in a year be careful.

Seal float is the biggest problem at high rpm and causes bypass, in general the higher the seal weight the worse the problem.

GUITARJUNKIE28

i suspect the seal float is the main reason the rx8 seals are shorter--lighten them up.. since that engine was designed to spin 9k.

GUITARJUNKIE28

i suspect the seal float is the main reason the rx8 seals are shorter--lighten them up.. since that engine was designed to spin 9k.