I'm looking to get an RX-7 but have heard that the apex seal needs replacing a lot. However no one I talk to gives any answer to how often they need replacing or fail. I've looked through the archives and cant really find any answer.

Does anyone know how often apex seals need replacing or fail? Or how often do you guys replace them?

 

The Apex Seals are an integral part of the combustion process, and therefore shouldn't need to be replaced any more than you need an engine rebuild, for regular driving that is. Somewhere between 100-200k miles maybe less.

 

Ask the same question of piston engine owners, and see what they say about piston rings.

 

Thanks for the input.

 

If i can remember correctly the apex seals are weak points of the rotary engine. If i dont run mine for a good ammount of time, the car ends up having an oil spot underneath it. Nothing too big, but an easy fix. Run it.... they should seal up just fine...

 

What?
Apex seals would have nothing to do with oil leaks.
Check your oil pan seal.

 

Your apex seals will be fine as long as you keep oil in your car.

 

What kind of RX-7? If it's a turbocharged version (T2 or 3rd gen) the engine's apex and coolant seals do live a harder life. While the apex seals typically last longer than the coolant seals, any detonation or preignition will shatter them. Something to consider if you intend to tune it for more boost and power.

In an NA RX-7, the apex seals last much longer. NA rotaries tend to last as long or longer than piston engines.

Dave

 

I'm looking for a 3rd gen FD.

How hard is it to change out coolant seals? Do they require an entire rebuild like the apex?

 

The coolant seals are between the housings and irons, so replacing them requires "unstacking" the whole short block. It's basically the same amount of work, and if you're already in there, you might as well replace as much as possible.

 

you should be able to tell if your apex seals are bad. it might not idle correctly and you will have a major power loss.

 

a good way to tell if its coolant seal vs. apex seal is... and this happend to me.

everytime you start the rx7 up if it billows nothing but white sweet smelling smoke out the exhaust... ur consantly having to unflood the car... and u overheat everynow n then! only way i could get my temp down before it overheated and ruined the engine was get out, pop the hood and slowly ease the radiator cap off with lots of pressure under it... and 3rd degree burns later because i let it slip once. trust me i rather have a blown apex seal and rebuild then warped coolant seal!

so yah just thought i would share!

and a lot of time if the engine is running like it has a blown apex seal it can be a leak in the vaccuum lines learned that one too!

 

yeah mine smokes more than i do.. it likes to blow white smoke rings too. i plan no changin the coolant seals soon and while im doing that i figured i would chang the apex and oil seals as well sense i already have it apart.

 

Thanks guys, this helps a ton in my decision making.