double springs for apex seals?
 

Can you double spring the stock seals or does it have to be an aftermarket seal?

If I went with the hurley double spring race seals would the smallest size be 3mm? I am assuming that the standard hurley seal doesn't work with the double springs either or am I wrong?

Ok I believe I have gotten a little confused. The hurley website indicates that the racing tip seals are not available in the 2mm size, and the longlife tip seals are not available with double springs. Thanks for all of the input gmonsen.

Hey Gordon!
I'm using factory OEM 3mm Apex seals that come in 85 and earlier 13B's that also use one spring per seal.

crispeed
87TII
9.67@141mph


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gmonsen, are you saying that 2.5 mm will fit fine without machining? The longlife racing tip seals with double springs are available on their website in 2.5,3,3.5 mm sizes.

...........and a little birdie told me that apex seals springs only play a part when the engine is not going and when it is running at low rpm, the rest of the time, it is the exhuast gas pressure under the seal that is holding it in place.................

HWO, fill us in on what you stated a little more clearly.

Actually Gordon!
Everyone is just trying to state their opinion on what they believe or have experienced.I don't see why you have to refer to name calling just because you don't agree with that person's opinion.If you want everyone to respect your opinion here you'll have to return the same.Remember respect is not given,it's earned.

crispeed
87TII
9.67@141mph

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I do not claim to know every thing??? (Gordon) but I do know alot when it comes to apex seals and proper clearances that need to be run in high pressure and high rpm engines.

The biggest cause of seal float or chatter at high PMEP's is the "delay" in pressure build up underneath the apex seal lagging behind the pressure build up in the cambustion sector, this causes the seal to bottom out in it's slot...infact the amount of gas pressure load on the seal 13B (3mm) out does the spring seal by a long way...It takes about 20kg maximum pressure to compress twin springs of the biggest strongest you can fit, where as there is about 240kg of force acting against the seal!!!!!!!!!!! In a v'high hp application.

When the seals are clearanced properly (or have custom spec as mine do) they do not suffer from a pressure build up delay, hence they do not bottom out in their groove causing breakages and or detonation.

The problem is improper apex seal clearances, you cannot put in a strong enough seal to rely on this alone...gas pressure does all the work real work in a rotary engine. The srings "only" real function is to be there at low rpm "cranking speed" and in the Hurley case? curing a problem assosiated with Rotary Engine builders inexperience with retarded pressure build up under the apex seal due to inadequate slot or inaccurate clearancing procedures?

Regards.

Hmm, looks like that little birdie has posted an indepth thing on the matter in fact.
I suggest you stick to cyber shooting games gorden, they may be more productive, at least you'd know what it was you were hunting.

I still say there is an attitude on this forum that is held by a number of people from one country in particular, that anyone who doesn't originate from that country, doesn't have a clue. And every god damn time it happens, someone ends up with egg on their face, lots of names get hurled and it generally becomes crap. Lets not have that happening in this thread, keep it civilised.
Just cause you have 'big name' rotary workshops in the US, it doesn't mean they have discovered every trick in the book. I dont claim to know all the tricks in the book, i probably dont know half of them, but i take the time to talk to guys like cris and peter to hear what they have found out from their years of playing with our beloved engines.

Cheers
Shane

Gordon, seal spring failure is more a thermal over load issue.

When the rotor temp gets so high that it will cause the spring to loose its tension, I pay close attention to the jets size in the crank as to provide enough rotor cooling along with oil temp monotoring.

I am not aware of any standard based 2mm 3piece seal chatter issues even on engines making over 800bhp....I have used the Iannetti seals you talk about and they are excellent, the main advantage I find though is that cause there is no corner piece it will let you run bridge ports "big ones"

Hey Peter!
Some people still just can't accept the fact that it dosen't matter what type of apex seals or springs or whatever they are using, won't make a shit of a difference if it's not clearanced properly or if the motor is not well tuned.It's funny how many people instead of attacking the actual problem of poor tuning and engine blue printing techniques try to cover it up by saying the OEM parts were not design for a certain application.Kinda like the person who keep blowing a fuse because of a short and instead of finding the short just keep on replacing the fuse with a higher amperage one. https://www.rx7club.com/ubb/smile.gif

crispeed
87TII
9.67@141mph


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This is a little ridiculous. All I was trying to figure out was about double springs,and my question has been answered. I do however like the idea behind the hurley seals, and realize that anything will break if not tuned properly as should everyone. Poor tuning is what occured in my case,now that I will be rebuilding it only makes sense to make the engine a little better. I also am aware that the stock parts will work fine for my application, however it is just a matter of preference to try something different.

loss of seal spring tension is cause spring steel will loose it's spriginesss above a certain temperature, as is rapid apex seal wear/bowing due to ferrous materials loosing it's hardness at elevated temperatures...too high rotor housing water temp and or too high rotor oil temp and or too high combustion chamber temp.

Apex corner breaking or corner seal breaking is usually happening after long use and is a fatigue issue, it is very common with one piece and two piece seals. The reason for the three piece seal is that it does allow relative movement of the apex element when it rocks from one side to another with out loading up either the seal itself or the corner plug (when using the expansion type plug with rubber insert).

I suppose this is why masda used this design in the 787B 26B car? (In ceramic form)...When I used one piece and two piece seals I would have the failures you are mentioning after a fair period of running or after a bout of detonation.

With the three piece there is no such problems, as an example I had a wastegate failure on a customers car ans it cause very intense detonation in his 3 piece 2mm engine (as loud as a machine gun!!!!!) I thought it boke every seal in the new engine I built, the only damage was a broken rear end plate!

I examined the seals under a microscope and they had no cracks at all, I reused the seals.

DAMMM!!!!!!!!
I thought AUSSIES knew too much! https://www.rx7club.com/ubb/smile.gif
Or was it KIWIES had no idea! https://www.rx7club.com/ubb/smile.gif
Actually it's the damm YANKEES! https://www.rx7club.com/ubb/smile.gif

crispeed
87TII
9.67@141mph

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Hey Gordon check your PM

crispeed
87TII
9.67@141mph

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gordon, I have some data to send you....

send me your e-mail add at

riceracing@ozemail.com.au

and I will e-mail it back to you.

Hi Rice Racing,

I'm a bit confused by the idea that apex
seals lose their tension due to overheating.
Most spring steels won't lose their temper
below ~600F (give or take), so for the spring
to be subject to that temp (when it's
protected by the seal) seems unlikely to me.

Even with exhaust gas flowing into
the seal area, the quenching effect of the
rotor (which I think would stay below ~300F)
should be enough to cool the gas significantly.
At the least, if the rotor did get really hot, I'd
expect to see signs of oil coking on it.

Is it possible that the percussive loading that
the spring/seal sees during detonation events
mechanically relaxes the spring?

BTW, if you're posting technical data to
Gordon, would you mind either posting it on
the forum, or emailing it to me also?

Thanks.

David, dbreslau@mit.edu

Gordon you're really funny https://www.rx7club.com/ubb/smile.gif
But at least you're diehard ROTARY LOVER!!!!!

crispeed
87TII
9.67@141mph

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Once apon a time, in a land of cyber place. there was a thread about efi systems, which had more things said than grace. Everyone was there Peter, Cris, Matt and me too. There was another person there from a different land aswell, and no matter how many facts were put under dere nose, they couldn't seem to read between dem lines. Now is it me, Cris and Peter that this thread is starting to look very similar.

Remember thy 2 commandments.
There is no subistute for a good tuner and a properly built engine.
and
Its not boost which kills 'em seals, its uncontrolled combustion.

PS: Find that short in your wiring, fuses begin to cost a lot over a period of time.

signing off me hearties
The Dead Pirate Rotang
https://www.rx7club.com/ubb/biggrin.gif

Here is a spanner in the works!

The engine that I popped in February was due to excessive combustion temps; but here is the spanner!

The side seals were gone (I had burn marks on the sides of the rotors where the combustion was leaking in) and the exhaust sleeve was melted so bad it looked like a bear had been chewing on it!

The apex seals I was using, composite chrome moly doodads from Canada, were only slightly scratched from unknown causes! They were cracked or chipped or anything! The corner seals had been flattened but the double apex springs were fine...

https://www.rx7club.com/ubb/cwmsmilies/cwm41.gif

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http://users.bigpond.net.au/ajc13b/sig.jpg

Did the exhaust sleeves close off the exhaust ports in any way?
What actually happen to the side seals? Did they break or did the springs loose it's tension?
Where on the Apex seals were the scratches?

crispeed
87TII
9.67@141mph

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[This message has been edited by crispeed (edited May 28, 2001).]

Gordon, the e-mail addy for you and your mate does not work, I sent crispeed an e-mail at the same time no probs...

Any way, below is my diagram for what I am saying....also to answer your email the seal force does get thrown outward, but also inward as it approaches the minor axis (near the plugs and the intake side)..it needs gas pressure to function properly along with spring pressure.

https://www.rx7club.com/ubb/image_up...s pressure.jpg


[This message has been edited by RICE RACING (edited May 28, 2001).]

The stock 2mm 3piece seal is double spring and is very strong....I have used all types (except Hurley) including my own manufacture and have found the std 2mm seal to be the best, sure it does not last as long as an Iannetti but you will need to rebuild the engine due to side seal wear long before the apex seals wear out or fail.

Here is some temp distribution data for your mate?

One is of a normal temp (cooled adequate rotor) the other of an overloaded rotor in which it suffered loss of spring tension, resulting in no loss of performance...only engine could not be restarted once stoped

normal rotor

https://www.rx7club.com/ubb/image_up...rotor temp.jpg

too hot rotor (600F = 315C)

https://www.rx7club.com/ubb/image_up... hot rotor.jpg

Localized temperatures vary alot and it is very possible for a great amount of heat transfer to occur with over worn parts, as in AJC13B case due to worn ends on his side seals causing a large quantity of v'hot gas transferring too much heat into the corner seal and hence to the side seal spring causing it to loose it's "spring"....

Loss of "spring" is mostly attributed to overheating of the spring, this is mainly cured by increasing the oil flow rate into the rotor to help cool the rotor and it's sealing elements, same for the rotor housing.




[This message has been edited by RICE RACING (edited May 28, 2001).]