danny14435

Hi guys, firstly id like to say im new to all this so please forgive me if i sound a tit! I really need some advice tho. I recently purchased a 2004 rx8., the car was exceptionaly cheap as the engine had quite a bad knocking noise while under load. I did a little research and found that these engines seem to suffer with bearing wear usually causing these symptoms. So iv pulled the engine out and stripped it down very carefully. Iv found that the typical bearing failures iv read about seem to be the cause of the problem. How ever! Im now at a loss as to what needs replacing and what doesnt, i will purchase a rebuild kit and the bearings reqiured. I just need to know if the eccentric shaft, rotors or housings need to be changed as some of them dont look very clever. i know this sounds very amaturish but this is the first rotary engine iv worked on and iv bought this car for my self as a learning curve.. I wanted a change from the norm and a new challenge. Any help would be muchly aporeciated i can post pics if needed.

Thanks dan

RIWWP

iTrader: (2)

Well, I applaud you for taking the plunge. You are going to need precision tools if you don't already, to measure what is usable and what isn't. If you can, take TONS of pics of all the parts and post them up here (moving the thread to Tech), and the guys here can help you sort through them.

A rebuild kit is almost certainly going to be a must, as you will need new seals. No way around that.

olddragger

iTrader: (3)

yes --you will need to do a lot of reading and studying before the actual rebuild. These engines look simple but they are not.
As suggested please post pics--look at others examples---and we will be glad to help whenever we can.
It will be a good learning curve

danny14435

Thanks guys i will get some pics up tmoz. How precise do i need to be? i know thats a stupid question what i mean is will standard micrometers, verniers, calipers be ok or is there something more specialist i will be needing?
Thanks dan

danny14435

Hi guys, took a few photos of the internals etc some thing i personally would say are ok. But being unsure about these engines iv pictured them any way

danny14435

6-10

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11-15

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16-20

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21-25

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26-30

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31-35

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36-40

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41-45

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Last 3!

danny14435

Thats all of them for the min. Pics 25-29 are the nakerd bearings from the centre of tne rotors. all the apex seals and face seals are all intact none have broken up. This engine still ran and drove although not very well. There was copper debris in the sump pan i had cleaned that before the pics were taken but i stopped cleaning stuff nicely when i saw the bearings in the rotors. The irons that look scored in the pics still feel very smooth. The copperish glaze on the eccentric shaft also feels smooth it does look alot worse in the pics. Hope they are of good enough quality for everyone and any help would really be appreciated

Thanks Dan

olddragger

iTrader: (3)

Dan
The housings to me from what i can see in the pics are possibily reusable BUT---- you need to check for surface protrusion at the plug sites. Just use a straight edge for a gross test.
The irons---to me appear ...done? Dont use them--appeared scored.
Rotors--possible reuse depending on how they spec out.
E shaft---dont know--maybe I wouldnt.
But I really cant tell by looking at a pic

If copper was in the pan dont forget to get the oil coolers professionally cleaned--if not replaced.
Good luck!

danny14435

Thanks ragger appreciate the advice. Is there anywere i would be able to find a spec sheet for stuff such as the rotors and e shaft. And what would your thoughts be on having the eshaft skimmed and use bearings with a smaller I.D. It is only a thought altho it would cost considerably less.

The oil coolers have not yet been removed but i do have replacements for them i will still have the old ones cleaned though i think always good to have spares!

I know what you mean about the irons thats one thing that made me question myself as they look terrible but still feel quite smooth i wasnt to sure if the marks on them were something you would expect to see in these engines or not.

Thanks Dan

ASH8

Having a quick look at your pics....

IMO...

E-Shaft is gone, once it starts picking up bearings forget it, 9 times out of 10 a new or clean eccentric shaft is needed.

Rotors, the bearings are gone, Rotors could clean up OK, the critical parts are obviously where Apex Seals seat, as are Corner Seals and Side Seals, did any of these seals escape their home and go for a damaging ride, sorry I have not viewed every pic?

Rotor Housing, if chrome has peeled off (I can see some gone) then they are not within Mazda spec, some 're-builders' get away with re-using, you really are gambling if you do.

Irons, depending on how deep the scour marks actually are and if you can get them machined...

Hayward Rotary in the UK gives out good advice.

IF you want a MMC (Factory) Engine Manual (in PDF), PM me an email address so I can send to you, it will tell you all the specs, etc.

olddragger

iTrader: (3)

good advice Ash--and to the op do not attempt to rebuild this engine without the engine manual AND a lot of research. Such things as side seal clearance etc need to be addressed.

wcs

iTrader: (2)

Nice thread, good pics.
Thanks for all the work and keep it coming.

And "sub'd"
I'll now take my seat at the back of the bus.

dannobre

iTrader: (3)

Personally..I would look for a low miles wrecker engine...and use that....either for a core to rebuild....or just to put in the car. There are way too many bits buggerred in there to buy them one at a time...it will be expensive...

bse50

I have some rotors with good bearings and a clean e-shaft i might be willing to let go (i'm in italy). Also 2 housings in way better shape than yours.

With that said, i'd buy a remanufactured engine from Mazmart in the 'states. Your strong currency vs weak dollar means that you can probably get an engine with no core return at a better price than the average builder in the uk can offer

One of their engines is the route i'd personally take. The last time I did the math it was still cheaper to get a reman than rebuilding an engine here. Some rebuilders reuse parts that shouldn't be reused... Oh, and I didn't factor labor costs into the "in house" builds since i know how to do it. It's a shame but that's the hard truth.

ASH8

Got to agree with G, but, I think any gains in currency will be offset with importation taxes/tariffs, from what I know the UK has a very low 'no tax' threshold limit, I think it is only 80 pounds value coming in.

Something Dan should definitely look into though...and or get a price from Hayward???

Whatever you do don't cheap out on any of the critical stuff and that is virtually 100% of parts.

bse50

Well if he orders the engine through a shop then the should could find a way to avoid paying VAT

UK builders are hit or miss, it all comes down to how much beer they had that day!

danny14435

Wow what a response! Well thanks guys,

Ok, thanks for the input ash all the apex seals side seals springs etc were all in place (stuck!) but there is no obvious damage to the faces of the rotors altho the inners where the bearings are seated do appear to have sustained damage.
Rotor housings still have all the chrome on however i can see what you mean by the pictures but the discoloring was a build up from were one of the apex seals had stuck and was blowing by when firing i assume iv since cleaned that up. Still not sure though. I assure you though when she eventually gets rebuilt she'll be 100%

Bse. I did think about buying from america but the import taxes dont really do me any favours. And i would really like to rebuild this myself its just one of those things that iv never had the chance to work on, it gives me a break from horrid plant machinery!

Thanks Dan