Mazda RX8 Engine Life?
Mazda RX8 Engine Life?
Author
Discussion

MElliottUK

Original Poster:

844 posts

233 months

Thursday 8th March 2007
quotequote all
I have seen you can pick up some high mile rx8's quite cheap now. How does the Wankel engine hold up with high millage.

80,000 Miles? would the engine be knackered by then?

will they go to 120,000 miles + ?

Thanks

scoobylicious

122 posts

251 months

Thursday 8th March 2007
quotequote all
Make sure the engine has been rebuilt before you buy at this mileage.
I was looking at RX8s a few months ago. The dealer said this needs to be done around 60K (IIRC) to replace the blades on the rotors. Not as expensive as you might think though.

Great car, I really liked it, nearly bought one until the police found my stolen scooby.

MrFlibbles

7,774 posts

304 months

Thursday 8th March 2007
quotequote all
scoobylicious said:
Make sure the engine has been rebuilt before you buy at this mileage.
I was looking at RX8s a few months ago. The dealer said this needs to be done around 60K (IIRC) to replace the blades on the rotors. Not as expensive as you might think though.

Great car, I really liked it, nearly bought one until the police found my stolen scooby.


Even some of the RX7s stretch on to 80k odd...I'm surprised that Mazda havent managed to sort the durability for the RX8...

Stu R

21,419 posts

236 months

Friday 9th March 2007
quotequote all
I thought the RX8's were meant to have tougher rotor tips? Hence a lot of the RX7 boys talking about using them on their rotaries. Shame if they're not much improved

RobDickinson

31,343 posts

275 months

Friday 9th March 2007
quotequote all
Bollox, RX8 engines are good for 150k miles without a rebuild.


Tips are hard, the seals in the RX7 that went pop (rubber) have been replaced by cast iron ones.

If in doubt get a specialist to do a compression test.

Biggest issue is the CAT. There often toasted and need replacing. Bet you can get one for 10k now, if youc an stand the 18-22mpg there superb cars.

brap_brap

753 posts

230 months

Sunday 11th March 2007
quotequote all
RobDickinson said:
Bollox, RX8 engines are good for 150k miles without a rebuild.


Tips are hard, the seals in the RX7 that went pop (rubber) have been replaced by cast iron ones.

If in doubt get a specialist to do a compression test.

Biggest issue is the CAT. There often toasted and need replacing. Bet you can get one for 10k now, if youc an stand the 18-22mpg there superb cars.


If by "tips" you mean the apex seals, they're not really any harder, and in fact are actually shorter significantly.
What makes them SEEM tougher is the fact they don't have an exhaust port to constantly ride over unsupported.

I'm currently having my FC rebuilt with RX-8 internals and I had to regroove the seal slots to accept a deeper RX-7 seal
for that very reason of riding the exhaust ports. RX-8 seals aren't tougher, they're just subjected to less stress.

Just my humble opinion as a concurrent 3x rx-7 owner.

RobDickinson

31,343 posts

275 months

Sunday 11th March 2007
quotequote all
The actual tips on the RX7 sat in rubber housings which perished due to heat & life.

The same parts on the ernesis are cast iron, the apex seals themselves are different, but not all that much, the housing they live in, and the problem for the RX7, is changed.

Brap_Brap

753 posts

230 months

Sunday 11th March 2007
quotequote all
RobDickinson said:
The actual tips on the RX7 sat in rubber housings which perished due to heat & life.

The same parts on the ernesis are cast iron, the apex seals themselves are different, but not all that much, the housing they live in, and the problem for the RX7, is changed.


Maybe they did in the rx-2, rx-4 era.... not it the last 20+ years. The apex seals sit on springs.
Go have look at some rebuild kits....

FD http://racingbeat.com/resultset.asp?P (full kit)

FC http://racingbeat.com/resultset.asp?P (not in an FC either)

FB? Same thing... go look if you want.

You don't have to take my word for it, but as someone who owns 3 RX-7's concurrently
including a rotary race car, , I know of what
I speak.

How many rotary engines have you owned? (5 for me)
How many have you rebuilt? (2 for me)
How many have you disassembled? (2 for me)
How many seasons have you raced a rotary powered car? (2 for me)

I hate to say it, but you're talking out your ass here.

If anyone wants to see a tie-breaker in this disagreement here, go ask Adam at rx7specialties.com
what a "rubber tip housing" is and you'll get laughed at.

I rest my case.


[edit] Here's a pic of the seals and springs EXACTLY as they fit into a
rotor tip groove. http://rx7specialties.com/productpage

I further rest my case.

Edited by Brap_Brap on Sunday 11th March 20:29

RobDickinson

31,343 posts

275 months

Sunday 11th March 2007
quotequote all
Guess the RX8 book I have isnt quite truthfull then.. I bow to your superior knowledge...

Brap_Brap

753 posts

230 months

Sunday 11th March 2007
quotequote all
I'm sorry. I didn't mean to sound crass at all! LoL
It's just that I'm a HUGE lover (and defender) of rotary engines
and I get a little defensive of them at times. People like to
put them down.

On another note to the orignal poster, there are some advisable
things to do for prolonging a rotary engine life....

A rotary engine has something we rotorheads call an OMP. (Oil Metering Pump)
The purpose of the OMP is to shoot a very small amount of oil
into the fuel/air charge so that the apex seals are lubricated.
Since a rotor housing is hollow, this is THE ONLY factory way
to lubricate your apex seals. There is however another way and also a
better way. (note: this oil spray is ALSO acting as a coolant to the rotors)

Your OMP will draw oil from the oil pan. Obviously this can get dirty
and lose viscosity. Sludge in the oil can also affect the efficacy
of the OMP. If it is possible, and budget provided ADVISABLE to make the
OMP get it's oil from a FRESH and CLEAN oil resevoir. One way to do this is
to buy a used washer fluid resevoir, mount it in the engine bay, and draw
the oil from there. If done that way, the oil will not only be clean, but it
will also be cooler allowing for more rotor face cooling. (ceramic coating also helps)

Something else advisable is to pre-mix your fuel with a wee bit of 2-stroke
oil. IE: the two stroke oil you mix with gasoline.

This has the added effect additional lubrication to the apex seals as well as
making sure you wont blow your seals should the OMP fail. Some guys on rx7club.com
use pre-mix exclusively in leu of their OMP.(and it works) I dilute my mixture by 2/3rds and use it
in addition to the OMP to be on the safe side.

One last note.... DO NOT use synthetic oil in a rotary engine! I cannot stress that enough.
While synthetic oil is a superior lubricant, it SUCKS as a coolant, and oil in a rotary is AS MUCH
a coolant as a lubricant, if not more so. Just go with a good natural oil, suck OMP oil from a
different resevoir, and pre-mix the petrol. (unless MOT emmisions test is that day, then use straight gas)

I wont count my '82 FB in the following claims as it's a rebuilt bridge-ported engine, but I will
make claims to my two "stock" RX-7's....

My 1985 GSL has 195K Km's on it.... in excess of the 80K "miles" stated in this thread... 80k miles? BOLLOX!
It's still running strong, and it's compression is way above that of Mazda's "time to rebuild" specs.

My 1988 GXL is currently having it's engine rebuilt. I blew the apex seals at 226K kilometers. AGAIN, that's
FAR beyond the stated "80K miles" mentioned in this thread. 225k to 250k would be the expected life of a well looked
after rotary engine in an RX-7. I would assume things are even better in the RX-8.

If I can inject my own bias here.... don't buy a RX-8. Buy a FD RX-7 instead. The 7 is faster, sexier
and only has 2 seats so that you only have to give a ride to your GF and not her ugly friend too.

RobDickinson

31,343 posts

275 months

Sunday 11th March 2007
quotequote all
Brap_Brap said:

If I can inject my own bias here.... don't buy a RX-8. Buy a FD RX-7 instead. The 7 is faster, sexier
and only has 2 seats so that you only have to give a ride to your GF and not her ugly friend too.




Unless you want one car that can seat 4 & has some practicality, the stuff I got in my RX8 was quite impressive for a coupe.

Also (IMO) the RX8 handles better & stops better (as standard) than the 7, though if I had the choice I'd own a 7 too. Seems to be a fair amount of 7's here and am looking forward to picking up a nice late model one oneday.

Will dig out the RX8 book and find that section Iw as refering too later...

Brap_Brap

753 posts

230 months

Sunday 11th March 2007
quotequote all
RobDickinson said:
Brap_Brap said:

If I can inject my own bias here.... don't buy a RX-8. Buy a FD RX-7 instead. The 7 is faster, sexier
and only has 2 seats so that you only have to give a ride to your GF and not her ugly friend too.




Unless you want one car that can seat 4 & has some practicality, the stuff I got in my RX8 was quite impressive for a coupe.

Also (IMO) the RX8 handles better & stops better (as standard) than the 7, though if I had the choice I'd own a 7 too. Seems to be a fair amount of 7's here and am looking forward to picking up a nice late model one oneday.

Will dig out the RX8 book and find that section Iw as refering too later...


I hope you can find one "clean" if you do pick up a 7. There's a lot here in Kanaduh but it's almost impossible to
find one that's not been messed with. Before deciding to buy my TVR I was in the market for an FD but I just couldn't
find one that was untouched.

Mind you, if I lived on your side of the pond, a rotary would be out of the question altogether due to your
high fuel prices. As it stands now, I was only getting about 350 kilometers to a 17 gallon tank, and that was
before the porting and 550cc injectors.... I'm going to hate seeing how bad it is once I get my engine back in this week.
Good thing I'm only paying $0.82 Cdn a litre! (about 35p/L)

RobDickinson

31,343 posts

275 months

Sunday 11th March 2007
quotequote all
Man I live in New Zealand. Plenty of top jap imports & cheap fuel...

Brap_Brap

753 posts

230 months

Sunday 11th March 2007
quotequote all
This was the 7 I had my eye on before deciding on TVR...

http://66.49.219.41/bird.htm

FD, single turbo, caged, lightened....

You're right, JDM has some nice offerings! What's normal for NZ? RHD or LHD? Just curious.

RobDickinson

31,343 posts

275 months

Sunday 11th March 2007
quotequote all
RHD, and no emmisions standards I already drive a Jap import (forester) anyhow.