Guys thinking of rebuilding the engine in my 91 vert...any suggestions where to go to buy a rebuuild kit...thanx!

 

Most kits I have seen, and I mean complete kits, run about $1000-1500. If you want ceramic apex seals, add another $1000.

 

It's an n/a engine so it's not as critical... you are not throwing a bazillion hp at this motor. One thing I will warn you about though: aftermarket soft seals generally don't fit as well as OEM, and the kits tend to just throw the pieces into a bag without labeling.

You can do RA, Atkins, OEM, whatever. Just make sure you put it together right and that the parts you are reusing are in spec.

If I were you I would tear the whole engine down and inspect everything before you go buying anything though. For instance, you could need new bearings or you could have a trashed housing.

 

I agree, my motor had 159k on it when I got it rebuilt. It still ran but it was worn beyond recognition. My engine still has the asbestos gaskets that came stock. If it is a DD, use OEM and stick with it. Mazda has spent millions, if not more, on the wankel rotary engine.

My original motor ingested a spark plug insulator at 150k miles and still ran like a top, but the seals and the housings where worn beyond recognition. If you want reliability and not tons of power, get the OEM stuff and some new rotor housings. It'll last you a long while. Hell, my motor still took me to work every day and never failed on me, yet I only had 50 psi per rotor face on both rotors. I replaced the engine just as a prophylactic measure.

 

Sound advice

I found my front housing unuseable, my rotor questionable enough that I replaced it, stationary gears need new bearings, etc

 

I heard somewhere that you can use the 81-82 12a gasket kit for the coolant seals. Saves you ~100$.

Never actually tried it but I'd think is possible since people make franken 12a's all the time with 13b irons and 12a center plates and all kinds of mix-matched stuff.

 

thanx for the advice....i was thinking of street porting it as well while is apart, but i might have to go with experienced professional to do the job, sounds a little complicated for me to do lol....unless there is a thread that shows you what to look for on the housing and rotors to see if they are damaged lol!!!

 

There are a couple rotary rebuild dvds you can buy. I have the one from atkins. You should check out the archived threads on this forum and other rotary forums. Use the search engine in these forums will get you to where you need to be....but you'll have to do some reading.

Here's some good videos from pineapple racing
http://www.rebuildingrotaryengines.com/

Some websites to checkout
http://atkinsrotary.com/http://atkinsrotary.com/

http://www.pineappleracing.com/http://www.pineappleracing.com/

http://racingbeat.com/http://racingbeat.com/

http://mazdatrix.com/

http://www.banzai-racing.com/

There are a few other rx7 and rotary forums and sites to checkout, but i'll get in trouble for posting competition. Google rx7, rotary, 13B, FC3S and a few other rx7 references and you'll turn up lots.

 

Thanx justjeff

 

Also, consider the measuring tools you'll need to reliably check tolerances and their associated prices. It may not be much more to just have a shop do the work for you. Most shops charge roughly 2400 for an S5 NA rebuild parts and labor, not including removal and reinstall.

 

^ measuring tools? digital dial calipers and a set of feeler gauges are all you need for a build like this... that's like $25 total? and technically you do need micrometers to check bearing clearances and housing warpage if you want to do that. but you don't really need expensive ones, just ones that go down to thousandths of an inch. Most likely you will only change the bearings of they are showing copper, and you'll change the housings if they have chrome flake. So the micrometers really aren't "needed" for a build like this.

You can check eshaft endplay with a feeler gauge so you don't even need a dial indicator. See http://www.rebuildingrotaryengines.c...tting_end_play video at about 2:45 .

Of course nicer tools are preferable, but you can do a solid non racing build without them. The only thing you need to be really mindful of is the eshaft endplay and the side seal to corner seal clearance. Both can be checked with feeler gauges. And side seals can be filed with sandpaper: http://www.rebuildingrotaryengines.c...ing_Side_Seals

 

https://www.rx7club.com/general-rotary-tech-support-11/what-apex-seal-use-916777/ Just in case you dont want to click it here it is.

I cannot seem find to a thread posting the popular companies without arguable product discussions. I'm trying to match the correct person with correct apex seal and add feedback from the community along with the compines to help someone find the right apex seal. So here we go.

DISCLAIMER: None of the following information is original to me, I compiled the information from forums, including this one. This is to use for someone who wants to see a quick comparison for the popular companies side by side. I’m using general information and product information along with community feedback.


Rotary Aviation(RA): Makes kits used biased on engine types seal thickness and must have add-on’s to promote longevity.

Super Seals

Information:"RA Super Seals are made of the same base material as classic RA seals. They then go through an extra process to make the seals even more resistant to high heat conditions. This secondary treatment process gives them a distinctive black color." - Rotary Aviation (http://www.rotaryaviation.com/2_mm_apex_seals.htm)

Use: High power, Large boosted applications comes in both 2mm and 3mm

Feedback: From many threads I have read it seems that 80% of people said, that the seals took detonation extremely well but left “chatter marks" and sever scaring to the housings, however; the life of the seals were short lived because of compression. A few threads reportedly had flat spring.

Conclusion: Good for large horse power where detonation will be a problem and would prove good to a drag car.

Classic Seals:

Information:"RA Classic Springs are suitable for use on all cars EXCEPT true high performance race cars" - Rotary Aviation (http://www.rotaryaviation.com/2_mm_apex_seals.htm)

Use: Most all street cars and stock rebuild applications Comes in both 2mm and 3mm
Feedback: It seems people were happier with the classic seals, they lasted 50-80 mostly without compression drop, common causes wee coolant leaks and oil leaks that forced the rebuild. Left chatter marks, not as bad the Super Seals, but never the less still there.

Conclusion: Used for the average rotary owner, street car minded. Still reported to leave chatter marks, but held detonation well.


PTS(Performance Tested Seals)- Sells the "Unbreakable" Apex seal

Information: "Performance Tested Seals (PTS) have developed a product especially for you that are guaranteed not to break in an engine, giving you an advantage over other racers.

•Seals do not wear the housings or rotors.
•Tested under race conditions, high boost and high RPM.
•Seals available for 2mm and 3mm for 12a, 13b and 20b rotary engines." - Performance Tested Seals (http://www.performancetestedseals.com/)

Use: For Race applications. but used in non race cars

Feedback: From the multitude of posts I have read it seems that the majority of people who used these seals were pleased. The seals will not damage the housings; they will bend, in some cases right out of the rotor, seemed more of a clearance issue, personally. These seals are rumored to "blow", left to cool then reused and worked like new. People have said that these are "Race only" seals because they work, but at the expense of the housings. It seems that people are split.

Conclusion: Not Ceramics but in my opinion from reading not has "hard" as the Super seals. Another seal for someone who is worried about detonation, and housing condition.


Atkins Rotary - "Atkins Rotary, where we not only love the rotary, we live it!For over 30 years, Atkins Rotary has been rebuilding Mazda rotary engines, working and designing parts for improved performance, durability and reliability."

Information:"We make many of our own parts including but not limited to: apex seals, thermal pellets, solid corner seals, high performance pulleys, intake manifolds, exhaust flanges and superchargers, all of which have been tried and tested by David Atkins and his professional championship winning racing career." Atkins Rotary (http://www.atkinsrotary.com/)

Use: Stock to high power rotary cars

Feedback: SPLIT by far. Probably the most tossed around names, Atkins seems to have problems with their rebuilt engines and seals."In addition to their failure to be good business people, I have heard of more instances of Atkins failures than any other brand."- jeff48. Others have said that their seals have survived horrible boost spikes and detonation and are still in use.

Conclusion: Seem to be more negative the positive, luck of the draw.


Racing Beat - Racing Beat is devoted to the research, development and manufacturing of Mazda and rotary engine performance products.

Information: "Racing Beat's 1986-92 Non-Turbo (2mm) Race Apex Seals are specifically designed to replace the stock cast iron seals in engines operating near, or above, 8,500 RPM" - Racing Beat (http://www.racingbeat.com/FRmazda2.htm)

Use: N/A ONLY. Must be used with the Racing beat springs and kept away from detonation.

Feedback: Works how it is designed to, as long as it is used how it is designed to.

Conclusion: Great if it is used as a N/A replacement and high RPMs.


NRS-Ceramic Apex Seals have been approved for the Formula Mazda Series and for good reason.When you want the best, you get Ceramic Seals.

Information: “They are kind to the hard chromed surface of the rotor housing and reduce friction as well. They virtually eliminate seal groove wear. They are several times stronger than any steel seal and handle detonation better. They weigh approx 5.5 grams each as compared to 14 grams for steel. That's almost a 2 ounce weight savings on two rotors!! Increased torque, increased reliability and just try to wear these out! Stronger than steel, lighter than steel, less abrasive than steel, less friction, negligible wear, reduced rotating mass, housing friendly and almost unbreakable” – NRS (http://www.nrsrotorsports.com/index.html)

Use: All Rotary applications,

Feedback: People seem to love these seals. The only two things bad about them are the price and that in large detonation they can break. They leave no marks on the housings are stronger than any other seals, I have yet to hear or read anything bad against them.

Conclusion: If some detonation may occur and price is no issue these are the seals for you.



I covered a few of the popular companies. Just to emphasize why I did this again, this to provide a side-by-side view for people looking to find THE BEST APEX SEAL FOR THEM AND THEIR APPLICATION. As most of us know it’s not so much the seal then the person not correctly matching the seal with their application.

Hope this helped and include anything I missed!

 

I will quote this for truth, but I am OCD as hell.

 

I stressed over quality of tools to get for clearancing parts. I finally got some Harbor Freight. For my purposes they will do just fine, but I wouldn't trust their life span given experience and reputation of Harbor Freight.

Dial Indicator and magnetic base $20
Micrometer $20

but like Arghx said, I've gotten the most use out of my feeler gauges to check clearances between seals and grooves on the rotors.

Micrometer told me what I expected to find...that my side seals were barely worn at all

I used the dial indicator and base to check wear on my irons and also thrust play on my turbo

 

I just installed an S5 block into my S4, I rebuilt the block while it was out of the car.

I went with the cheap $315 gasket kit from atkins, as well as new apex seals (also atkins). I replaced both housings, as well as the rear iron. All in all, I've got $1000 into the engine, including buying the engine, all the rebuild stuff & the newer (went with used housings) and a new clutch kit.

If you do the build yourself, you're gonna save a BUNCH of money, and honestly, I'm only 22, so I don't have a ton of experience by any means. If you've got the time & the extra 1500 or so laying around, do it

 

It seems that no one has taken there experience into account. As I posted earlier you want to match your power and build with the proper seals. Going cheap or extremely expensive is not the correct way to choose the seals you need. If you buy any seal you will probaly end up rebuilding your engine in ~10k miles if your going stock. Food for thought.

 

well i got a quote for the rebuild by a pro....damn thats alot of money!!! for that amount ill take a lost and by a rx7 thats is ready to go.....I need to learn how to rebuild these damn engines!!! lol
thanx everyone for their advice...i was wanting to street port it but i might just stay stock and use it as my dd....

 

Our S5 N/A base rebuild cost is $1500, all the seals replaced 12mo/unlimited mileage warrantee http://banzai-racing.com/store/rotar...e_rebuild.html

 

I bought the basic kit from RA, re-used the side seals and some other internal parts. The kit was ~$500, used housings were like $200. Engine runs excellent with 105psi /rotor last time I checked (large streetport). It didn't blow up though the apex seal springs had flattened out causing high clearance b/w the housing. I'm satisfied, considering I won't be shooting for any HP records.

 

thanx for the info Banzai and khan...will be making a decision very soon!!! Hey Khan was the mpg on the street port?

 

Yeah, it gets expensive when you factor in R&R. My rebuild from Rotary Performance cost $5000. Needed new housings and front iron, plus got new injectors and they ported my exhaust, which they did for free because they are nice guys.

My MPG went up with extended highway driving, just ported exhaust ports and the intake ports left alone. Now on the street, I lost about 1 mpg. No biggie. Chris at RP told me that the biggest restriction on an NA is not the intake ports, but rather those nasty diffusers in the exhaust. They cut those out with a plasma cutter and ported my exhaust ports for free. He told me it was good for 15-20 HP, with a slight drop in city MPG and slight increase in highway MPG. Like I said, my city MPG went down about 1 mpg so not too bad for 15-20hp.

I wanted to do a mild street port, but the $5000 price tag was killing me already and couldn't afford the extra $500 to do the street port. Oh well, my new engine with the ported exhaust makes tons more power than my 160k mile engine running 50psi on each rotor face. We used 3 window bearings on the mains from the FD and also the latest FD 2 piece seals from Mazda.

 

I encourage you to learn more about rebuilding them. I've owned different verts for the last 10 years or so, this is my first extensive engine work and rebuild and I'm loving it.

Having hardly ever touched the internals of a 13B, watching the rebuild videos was a little confusing. I couldn't visualize the individual parts fitting into the whole. All the individual trees cluttered up seeing the forest as a whole kinda thing. Once I got the engine out and started getting my hands dirty it all made sense. Point being, the engines are more simple than they appear in the videos.

One thing to take into account is that alot of the knowledgeable guys are building track cars so their advice is going to be on the extreme side.

Example: the bearings on my stationary gears need to be replaced. All the advice I got on the bearings was to replace the whole gear with RX8 and FD gears because they are hardened and the bearings are better. Sound advice mind you. BUT I don't have access to alot of other rotary guys in my town, don't have access to spare parts. And I'm not building a 10k rpm track car with high power or boost. Not saying I won't follow the advice if I see a good deal on used gears, but it's not high on my list of priorities.

Point being, you'll get alot of extreme advice that is solid but may not be your best choice. You **** up doing your first porting of irons or housing and that's one more added expense. If you **** up porting and don't realize it till the engine is reassembled...well you get my point.

 

racing beat carbon seals

 

No, NO. Carbon seals are not for street driving or longevity. Are you just trying to troll this guy into another engine rebuild 10k miles from now?

 

^I believe it was a joke off my post about extreme advice