LIVING_SIDEWAYS

What is the best rebuild kit to get for an 87 N/A GXL or is it better to peace one together?
I have heard that racing beat makes a good one and so does Mazda Motorsports
also what parts do you have to replace and what parts should you replace
I heard the water pump and oil pump should be replaced when the motor is torn down
I just want to make sure I do everything I can do while the motor is apart and easy to get at. So any advise would be very helpful
---THANKS---

jkimbro

iTrader: (3)

My best advice would be to pull the motor apart and see what is needed...then order all of your stuff. Atkins is very popular.

LIVING_SIDEWAYS

Atkins Rotsry id only like 15-20 min away from where I live, but I have heard some bad things about them like about 40-50% of their re-builds are bad and I have heard of people taking them to court over it like one guys motor died after 10 days



I am not saying that any of this is true but I am just being careful

FCKing1995

iTrader: (3)

Atkins makes there own stuff and from what Ive heard and seen is very good. Racing Beat and everyone else as far as I know uses Mazda OEM parts. Like suggested, pull it apart and see what you need unless you have the cash to just do a full rebuild

CrispyRX7

iTrader: (139)

The sum of the parts far exceed the cost of a whole engine.

First thing you must consider is why are you rebuilding? Ate an apex seal? If so you are looking are more than just gaskets and seals. Overheated it and have a coolant leak? Could be simply a bad water O-ring failure but it could also be a warped rotor/side housing?
Smoking like a mosquito fogger? May just be bad oil control ring O-rings...or toasted rotor or stationary gear bearings.

A typical master rebuild kit runs on the order of $800-$900 NOT including any replacement hard parts that are simply worn out.

And engines with in excess of 100k mile are almost always near the end of their life from a wear perspective. The engine may continue to run well past 100k miles if left togther but once you break it down it's like humpty dumpty. If rebuilt it ain't gonna last long - 20k-30k perhaps.

Be prepared to spend about $1000 to simply tear the engine down and rebuild it. If you need to replace a rotor, rotor housing, or side housing add several hundred $$'s to that amount. For example...a SINGLE new rotor housing costs $500+

..and hence you see why in many cases the cheapest option is sometimes just to get a Mazda reman motor.

HTH,
Crispy

adrock3217

Wait. Let's say you DO need a new rotor housing, and a new rotor.

$1000 + $500 + $400 (rebuild kit, housing, rotor)

$1900...

A new reman from Mazda is what, $2600 last time I talked to Ray Crowe?

And most people, rather than buy a new housing, would just buy a slightly used one. For perhaps, $100. And a used rotor, if its not an S5 NA, will cost around $40.

Mazda reman doesn't seem like a very viable option, now, does it?


The best choice, from someone who doesn't want to waste money, or just doesn't have the skills to rebuild the motor themselves, is to buy a used, good compression motor. I'm NOT reccomending JDM motors, btw..used USDM motors, from a car or someone you can get a compression reading from prior to purchase. If you must, bring a transmission and starter/battery with you...

LIVING_SIDEWAYS

The thing is that I am doing this for my gradutation project, so the question that if it really needs a rebuild doesn't really matter. I have to rebuild it so I can graduate, and I would like to do this anyways and my car needs it so its worth it for me. So a little backround on the motor I am working on. It is an S4 and has about a 98% chance it has a bad oil seal (it smokes in the high rpm's like none other, and aslo goes through a lot of oil). The rotor housings were replaced about 60K ago but not the rotors. But about the rotors, I have heard that you can swap out the ones from the renesis. Is that possible? So I will probably take a drive up to Atkins to check them out in person and ask them about prices and stuff.

CrispyRX7

iTrader: (139)

S5 NA = $2450. Ask me how I know.

A *used* housing is going to cost about $150. Thats a decent used housing that's going to last for more than 30k miles. Want to slap together, what I've heard referred to as a ...floorsweeper... don't replace anything except gaskets and O-rings..and be prepared to flush your $1000 for the rebuild kit because it isn't going to last...that 100k mile used motor you just spent 3 weeks rebuilding.

as many a respected "rebuilder" and you might find some of them disagree. In fact some even buy the remans simply to get the parts for less than what it would take to buy them separately. Remember what I mentioned about the sum of the parts....

Good luck to you. Either way it's a crap shoot. Even a motor with good compression can have worn bearings and grenade the day after you bought it. Ask me how I know that too. Or it could last 50k-100k miles. No one should over look the fact that 2G rotaries are 15 years old at a minimum.

All I was trying to do was caution the thread starter that rebuilding a rotary might require a little more than just replacing the water pump and oil pump, which may not be necessary.

To: Living Sideways,
Sounds like your engine would be a good project for a rebuild what being said about decent housings. If the housings are decent chances are the rotors are still within spec. Given this a simple rebuild should be right up your alley. Atkins sell reasonable kits, as does Pinapple Racing. And of course Mazda. Then there is Racing Beat and Mazdatrix although they tend to be a bit more expensive. Maybe others...I dunno. Ray Crowe at Malloy Mazda will be your best bet unless you are a Mazda Comp member. Good luck to an enjoy the rebuidl...It's a fun little project.
Regards,
Crispy

LIVING_SIDEWAYS

Thanks Crispy but about the oil pump and water pump I read that you should replace them in the Hayne's guide when rebuilding the motor. And about the RX-8 Rotors is it interchangable? because I would like to have lighter higher compression rotors. oh yea and would I have to get anything else for the transplant with the RX-8 rotors?

iceblue

Do it right. Full Mazda reman from Speed machine. Be super strict on the housings if not in that spec by new ones. Have the irons surfaced. Replace thrust bearings and main bearings.

If you just need a motor and you do not plan on doing this more often to your motors, it will pay to have someone else do it.

LIVING_SIDEWAYS

Over time most of the engine will be new before I put it in so I am not exactly worried about the full on rebuild. I have done a lot of research and just want to verify some of it. But no one is answering my question about the RX-8 rotors being transplanted, and Im just assuming that you would have to use their seals. But if thats the case I heard the the RX-8 rotor has a secondary oil seal on the centerplate for better balance and in general is just better. If thats true would I need that as well?

CrispyRX7

iTrader: (139)

I understand the RX8 eccentric shaft is interchangeable and is 1/2lb lighter than the RX7 shaft but I'm unsure if the RX8 rotors are interchangeable. There are many nuances to the parts even though they may look VERY similar. S4 and S5 rotors are not the same. S4 and S5 rotor housings are not the same. S4 and S5 front covers are not the same. Will RX8 rotors simply drop in? Maybe but I'd be willing to bet there are difference that will require some other changes to engine management givne the different location of the exhaust ports on the RX8 vs the RX7. Anyone have a pic of the RX8 rotors? Note also that if you start mixing and matching parts like this it would be very wise to have the rotaing assembly balanced. I'm curious also. Where have you gathered this info. FYI the RX8 rear stationary gear is interchangeable and offers hardened gears and a 3 window bearing for better lubrication....FWIW
Regards,
Crispy

tuns0ffun65

the btter answer is dont bother rebuilding your na nows the time to order a jspec swap, so your car doesnt suck

FCKing1995

iTrader: (3)

nows the time to find a low milage good compresion usdm engine. jspec engines so often are junk

Kyrasis6

I know for sure that the RX-8 rotors use differently designed seals that are not interchangable with other rotary engines. I believe the side seals are tapered or something like that, I forgot exactly what I read I just remembered "if you use RX-8 rotors you must use RX-8 seals on the rotors." lol.

Me personally I think if you are going to try to run an RX-8 eshaft with RX-8 stationary gears and rotors you might as well find an RX-8 shortblock and say the hell with trying to match up all the internals. I think it would be more practical trying to get it to bolt into the car than trying to frankenstein the engine but that is NOT from experience so don't hold my words.

LIVING_SIDEWAYS

I tried to post something earlier but I let it sit to long and it logged me out. So ill just repeat it. To FCking1995 and Tonsoffun95 read the hole thred before you coment, so until then kepp your ignorance to yourselves. TO Crispy- I read some post on this form a whie sgo about someone who did it. It could all be a lie, but I can see how it is possible as well, but I will try and dig it up for you. Also what would be better the FD rear stationary gear or the RX-8's? Are you sure about that you would need new engine management for the translplant? They run excesively rich as we all now. So leaning it out won't hurt. But the balance part I can understand completely. Would you have to have a custom balnace weight, but then what about the eshaft pully? would it work with the new e-shaft? and if you have to do that would everything mount up?=( what a sad day this is. - ANd there isn't anything nessecarily bad about mix and matching parts. Thats how you find out whats better and whats not. It is just how you do it, and making sure they will work together

FCKing1995

iTrader: (3)

hey dick... i was commenting on the guys post i quotes, saying that its better to get usdm, not jdm... so keep your smart *** comments to yourself

LIVING_SIDEWAYS

Yes it is true that JDM's are generally bad but I didn't say anything and no one else did. Because I know that it is common knowledge and there is no point in stating it So I didn't.

FCKing1995

iTrader: (3)

aight then. i was pointing that out to the guy i quoted, then i get smart *** comments from you. but whatever

LIVING_SIDEWAYS

I have been doing some research on the Renesis, and I am not seeing Why you can't swap out the internals

CrispyRX7

iTrader: (139)

Since you piqued my interest I did my own research
Drawing my own conclusion the RX8 rotors will fit but it's not worth it.
1) The side seals are different so if your use the RX8 rotors you must use the "FE" sideseals
2) the apex seals are different so either machine the rotors to fit RX7 apex seals or you would need to source RX8 apex seals as well
3) the RX8 rotors are thinner (hence the lighter weight) but more fragile. Ever see a dented rotor...it's ugly.
4) The higher compression 10:1 RX8 rotor vs the 9.7:1 S5 NA rotor will require additional engine tuning (fuel management) to take advantage of the benefits of higher compression rotors.
5) The RX8 rotors have a beveled side to permit "timing" for the side housing exhaust ports. This is fine but if you loose an apex seal not only will you destroy the rotor housing but also the side housing as the apex seal debris gets jammed in the beveled area of the rotor and scores the side housing.

Mazdatrix has done extensive prototyping with frankenstein RX7/RX8 motors and have not been able to demonstrate appreciable power gains by using the RX8 rotors.

As for me I will be rebuilding my 13B REW block shortly and plan on using an RX8 e-shaft and front and rear stationary gears. The RX8 stationary gears being hardened and having a 3 window bearing. I've a few questions about the thrust bearing races when using the RX8 front stationary gear with an RX7 front cover but from what I can tell, apart from the lack of a rubber o-ring, the rear stationary gear is a direct fit.

All I did was a simple search on "RX8 rotors" BTW and read the first 2 dozen threads.
FWIW,
Crispy

LIVING_SIDEWAYS

Hmmmm from what I have read all the main components from the FC's to the RX-8's are interchangable (except rotor houseings and such). The RX-8 still is the "same" (to a certain extent) as the RX-7's. --It came from it and it is basically made and designed better. Not to many drastic changes. --Other than the exhaust ports moved to the side. Most of everything is interchangable. --There is no reason to mess with the feul management compression doesn't affect that it obviously just compresses what you have further. The power gains are not always the greatist. --The thing is generaly all used rotors you get are old and used. --So for one if time is taken you can make it reliable, and to do this I am going to "blue print" this motor. --For apex seals you can use RX-8 racing ceramic seals. --And from what I have read use the stock corner seals from the FC. --But I think that no one else has blue printed the motors so I will try it. --I will also be getting the E-shaft and I will try and find something about the front stationary gear and the front cover. --And after the build is done just making sure it is balanced it should be fine for testing.

CrispyRX7

iTrader: (139)

Let me know how it turns out!
Regards,
Crispy