Tad

Hi,
well i've been learnin up on my rotary engine info,
and I think i've got a pretty good understanding of how it works now(thanks to howstuffworks.com hehe)

Anyways, my engine blew on my FD a while ago(had to sell
it alittle while after ), there was somethin funky goin on with the coolant system, and it overheated badly.

So I'm wondering, what exactly is it that happens to the engine
when it overheats that causes it to break, or rather what part of it breaks?

THANKS!

artguy

there are coolant seals that have a tendency to cook rather easily...not to mention warped rotor housings etc...

j

luneytune

The owners wallet! And maybe his heart?

Tad

OOhhh, coolant seals,
i get that... too bad though, seems like something
mazda coulda fixed pretty easily, although I guess they would
have had to diagnose that at least by 94

cash money

insuffiecent radiators are also a factor that causes overheating

when it overheats, temps. get real high and in the metal starts to warp, such as the rotor housings... like art said

luneytune

Mazda has been in the Rotary game since the 50's and ended up teaching the Germans how to build a Wankel engine they couldn't build themselves including NSU and Mercedes. The big problem Apex seals and Coolant seals - Mazda tried graphite and sintered alumnium apex seals and ended up with good old cast iron alloy and beat the Apex problem. Then came coolant seals - very long, around the whole rotor travel area - subjected to flames on one side and hot coolant on the other but only about 5mm thick - this is a very hard engineering feat to overcome. The first Mazda Rotaries failed because of apex and coolant seals and dumb owners that new nothing of the expansion of aluminum and Iron in close vicinity (didn't warm them up properly) with the RX-4 and Cosmo the Apex seals were licked but the coolant seal could go on for another 10 years before materials can be incorporated that can stand up to abuse of overheating.

Key is don't overheat your Rotary Engine

Tad

Aaaah,
it's all so much more clear now!
so I guess the coolant seals kind of run between the different
pieces of the engine?(like rotor housings and such).
I do think it's suprizing apex seals hold up as well as they do though!
they are such small, thin, pieces of metal to contain the entire combustion process

"insuffiecent radiators are also a factor that causes overheating"

grr, next time one of the best rotary mechanics around
tells me he highly recommends having my radiator replaced...
i'd better listen... DOH!

I guess I'm too used to driving stuff like my 88 hundai,
lord knows when(if ever) the oil/coolant was changed on that car

Tim McCreary

Something that people tend to forget is that the engine is made of dissimilar metals. If all the parts were made of aluminum or another similar metal, the metals expand with the same properties and rates of expansion. The chances of having a seal failure would reduce.

When Aluminum heads were just beginning to become standard, everyone was having head gasket failures and cracked heads around 75K miles. This was due to the fact that head gasket would not allow the head to "float" when expanding at a different rate than the block. New technology with the head gaskets now allow this to happen. But remember that the head does not actually mate to the surface of the block. Rotary engines rotor housings and side plates mount against each other with a little O-Ring sealing the chambers.

There has been gains in O-Ring technology and there are better than factory alternatives now.

Tim McCreary