What apex seals are you using???

[pigeon]

Well im going to be completing my rebuild in the near future. Thing im stuck on is which apex seals to use. The motor will be ported with scope to run a medium size single (T04Z maybe), but initially will be running stock twins.
oem, pts, ecp, hurley etc etc. What are your experiences, reccomendations and thoughts?
There are a lot of mixed views on them all so trying to find out as much info as possible.
Cheers Adam.

[Bob Monkhouse]

How about Mazda 3mm seals? Or maybe ask Meester Hayward, I hear he is making them from Kryptonite (well,summat like that anyway).

[AtomicRex]

We are stocking the bendy seals and running them on our own engine.

[pigeon]

How about Mazda 3mm seals? Or maybe ask Meester Hayward, I hear he is making them from Kryptonite (well,summat like that anyway).

Ooooo i didnt know you could get 3mm mazda seals. I take it they still break under det though rather than bend like others do.
 

We are stocking the bendy seals and running them on our own engine.

Ah cool. Whats your opinion of them? which ones are you using and how are the housings holding up to them.
 
Cheers Adam

[AtomicRex]

They are the east coast seals, so plenty of people running them with no problems what so ever
 
3mm seals are kinder to the rotor housings...but you need to find someone that can machine the slot accurately!  And as you point out...if they go, they can potentially score the housing.  Not as bad as ceramic :o

[pigeon]

They are the east coast seals, so plenty of people running them with no problems what so ever
 
3mm seals are kinder to the rotor housings...but you need to find someone that can machine the slot accurately! And as you point out...if they go, they can potentially score the housing. Not as bad as ceramic :o

Whats their resistance to det like compared to that of oem seals?

[Speedworks]

3mm OEm seals can be found on RHDJapan.com

[damehyndman]

Ceramics courtesy of Carl Hayward.

[Bob Monkhouse]

If I remember correctly, ceramic seals are £200 each, though I hope I\'m wrong!! Rotary aviation in the States do 3mm seals at around $200 a set- I think- but we ended up with Mazda 3mm seals in Grants car as they were difficult to obtain.
  You might be better either speaking to Atomic Rex or Carl and get expert advice and go from there.

[BlitzBoy]

Please note 3mm dont seal as well as 2mm, you get better compression with 2mm imo

[HaywardRotary]

3mm can seal just as well as 2mm if you build the motor right with right tolerances.
As for revs 2mm are better for higher rpm,but we have run 3mm to 11,500rpm so far.
I speak from experience and not internet viewing.
Regards
Carl

[BlitzBoy]

Carl do you have a Dyno prints you can share from two engines with the same ancillaries 2mm Vs 3mm seals, be interesting to see if there are any power differences?

[HaywardRotary]

Compression can be in the same with either seal if tolerances are worked correctly.
And that is really the main criterior for these engines.
Ceramics give lower compression but wear very well in fact on one engine that was running around 430hp after 36,000 miles on ceramics there was NO measurable wear!
Our own designed apex seals are two piece as per Mazda and we can make 2mm or 3mm.

Het Mark,you must have a load of different dyno figures for various seals including Hurleys,Mazda,PTS,and of course differing compressions,what are your results with exact like for like motors and turbo\'s?

Regards
Carl

[BlitzBoy]

LOL Na no Dyno Comparison sheets Im just an internet Viewer as you say, you are a person who builds the engines so hence why I asked if you had any dyno figures for comparison.

I only drag race the things doing 10 second 1/4s, so my interest is there any benefit of having 3mm seals over 2mm in terms of performance. And from speaking from people who have engines built with both, most people go for 3mm due to slightly offering more strength and protection to DET. I was under impression that 2mm offer better performance due to less friction and weight and inherently better sealing.
Hence why I asked if you had any direct comparisons in charts to see if all this theory is true in practice or not.

[Bob Monkhouse]

Please note 3mm dont seal as well as 2mm, you get better compression with 2mm imo

As someone who isn\'t particularly knowledgeable on tuning rotarys, I find it strange that larger seals-ie. 3mm over 2mm- are actually better because larger/thicker/deeper on a piston engine means less revs and therefore less power.
      My main expertise is(well was until someone tried to murder me), two strokes. You want a two stroke engine to rev you have to go for thinner rings or shorten the stroke due to piston accelleration.(though the same applies for 4-strokes).
     An example of this would be the Villiers 210 used in Karting. It had an horrendously long stroke(70mm I think) and when you did the figures for things like mean piston speed(max 4000/min) and piston accelleration(max 160000ft/sec) this engine would be right on the limit for both and therefore used a .6mm ring.
 Most engines are quite comfortable with 1mm rings at high RPM\'s so this is where I find everything I\'ve learned over the last thirty odd years goes out the window when I find that bigger is(well sometimes)better, though detonation in a two stroke would mean a large hole in the piston.
  The rotary engine its-self I find fascinating though I am along way from understanding the sodding thing!!