hello there !! i was wondering if anyone has had any experience with carbon apex seals and if they have used them on a strictly street engine, life expectancy? compression? these are to be used on a fuel Injected 13b peripheral port with brand new rotor housings and trying to keep them as new as possible since new housings and a PPort job was not a cheap proposition for me .Thanks

I used them in my racer. Last for years just on weekends mind you, but the housings show no wear at all. Very easy on the rotor housings, and with proper end clearance, easy on the irons. Premixing an ash free synthetic 2 cycle oil (Red Line 2 cycle oil is what I use) and the irons have never been resurfaced. Shifting at 9,600 RPM.



Of all of the possible apex seal materials, carbon is the best for housing wear. However, carbon seals wear out more as a function of air filter effectiveness and top oil use. Ceramics act about the same, but a bit more housing wear. The seals do not wear at all and are very strong.



I have no data on daily use. Maybe a year with gentle use, perhaps two years?



Worst would be any aftermarket steel seals. then stock Mazda seals. Then Mazda or aftermarket ceramics then Mazda carbon seals. Not for turbo use, just too soft, and they flake when detonated.



Keep in mind that all one piece seals need some end clearance, and that generally means poor hot start performance.



Lynn E. Hanover

Thanks for that Lynn , It will be more of a weekender and rarely driven during the week and it will be lucky if I put more than 3-5 thousand miles on it per year and occasionally revving it out hard.

Sounds like a good plan. Both carbons and ceramic are the very lightest seals available, so you get great tracking and no shudder marks in the chrome. Carbons are fine with one spring. Ceramics run two springs, (you can go way over 10,000 RPM if you have the mods right) but they cut the drag down so far that it is a bolt in 5 HP. But you need a bank loan to buy them.



Lynn E. Hanover

Rule of thumb is that they generally last 30-60k miles of street use before they're done. Mind you, apex seal life will depend on how it's driven.



I have heard of certain race applications wearing them out in 6 hours of use! At that point, ceramics start to look like the more cost-beneficial deal. Few people run their cars that hard on carbons, anymore.



Don't forget - until 1974, Mazda used these seals as OEM fit.

hi, i am new at building rotory engine i have a ? has any body use nitrous and how much on RB carbon apex seals on a brigde ported motor.

Weren't the OEM carbon seals wider than 3 mm though? I would say go for the 3mm carbons and see how they last. They are much cheaper than ceramics, and if you do end up breaking a set you can always make that switch after.