I have all hurley seals but just broke one.Is it okay to replace the broken one with a new mazda apex seal?

 

It would not be something I would do. Different seals trying to break in on the same wall sounds a little risky.
I would contact Hurley and let them know your situation. They have seemed to be pretty nice when I have talked with them about questions for clearances, etc. I would think they would sell you one seal. I doubt that this is not a common request.

 

If they are both 2mm they should have the same clearance so what is the problem?

 

Clearance is not the only thing in the picture here. Spring pressure and hardness/material composition could make for trouble. You can have good compression at all 3 seals but if you have a 20lb difference at one seal when you get it together it will make for a lot of work.
It could go together and work great. But it is a roll of the dice.

 

if they are 2mm seals, the mazda one will be 3 piece while the hurley one is 2 piece, thats just 1 of the differences

 

I didn't think there was that big of a differance between the spring ratings?I would think the springs would have the same rating wouldnt you?

Why would this cause more work?I just don't want to bother finding someone with one hurley seal and have to go through the downtime when I can go down to the dealer and just overnite a mazda seal to me?

 

If you take 3 identical seals and springs it is more certain that the same amount of surface pressure will be excerted. The surface of the seal tips "break in" on the surface. I am not certain that two diffent seals will break in the same on the surface.
What would cause more work is if this did not work very well and you had to either pull everything back apart or live with the results.
There is a lot to be said about doing something right the first time and not having to sweat it out when you go down a unbeaten path. It may work, it may not if you use different seals. It will work if you use the same. If it was me I would be in touch with Hurley on getting one seal to me. If not I would put all the same seals no matter how I went.

 

Well thanks for the advice.I emailed Hurley last night and KD Rotary this morning so we'll see what they say....I hate being impatient.

 

Everyone here that has ever put very many motors together can probably relate to this. There are times where a shortcut was taken and you cross your fingers and from the moment you start putting everything back together and do all that it takes to get it started you just sweat worrying about whether it will work.
If you use a different seal and you have my luck it won't work. Then you will be kicking yourself.
I don't like extra anxiety. Patience is an absolute neccesity with engine building.
I am risk taker, but only on certain things. Go look at my thread on my "Resufacing rotor housings". https://www.rx7club.com/forum/showth...2&pagenumber=4 If theory is on your side go for it. But be careful what you base your theory on.

 

Just got off the phone with Dave @ KD Rotary and he said that it would be okay to use one mazda apex seal and 2 hurley apex seals on one rotor.He said the only differance would be that the mazda apex seal would have a little bit more compression but nothing I could see or feel.He said he knows people that do it all the time...

He also said that he does not use Hurley seals anymore for turbo applications...

 

That scares me. The Hurley seals are a little softer than Mazda's seals. The wear rates are going to be uneven. The force applied to the rotor housing will be slightly uneven and compression will be slightly affected due to sealing differences. I want everything to be as even as possible. Just be patient and take the extra time to do it correctly. If you don't you'll hate yourself later.

 

Not to mention that the corner piece of the apex seals are different between the two seals. The hurley corner piece is much longer which wears in a different pattern than the mazda seals (narrower). your compression will definately goto **** but if you run enough boost, you can always compensate.

my .02

 

I know that I would not do it for all the reasons mentioned.