Years in the making: Franken Wankel! 1986 RX7

Long runners sound really cool. Mine ran all the way to the back without ever joining.

https://www.facebook.com/video.php?v=10202225435105336&l=5936655558868716775

I too have experienced rubber-band acceleration thanks to the loose LSD clutches.

yeah I replaced my blown diff with a moderately worn diff. But now I have a spare one that I can overhaul, AND I just located a GTUs diff, I need to confirm by counting the ring & pinion and price right now is make offer....

So I got some more work done recently, honestly this part should be the start of a new thread because the car is basically going to be totally different and the rotary engine build deserves its own thread .

in summary:

All irons? = ported (not polishing)

All housings? = ported/polished

Final parts required for assembly ETA? = today

Tap ALL the threads! (no seriously) especially the tension bolts, its a bitch and a half with the cast iron being so hard but it ensures even torque. Also its a good practice to get into and makes for an easier installation. When it comes to assembling these guys the minor attention to detail goes a long way (in my opinion) I hate doing it but its worth while.

Here is some comparison between a rough cut and just a scribed port:

Here are some after shots:

w/ the inserts removed:

all cleaned up with the polished inserts in (but not installed)

Here is my schedule to complete to make it before rallycross event on the 15th

It is a bit ambitious I know...

However I think if I rush to get it all done in time I will either run out of money to be able to compete or I have to only do the engine build/break in and thats it. However I still need to do these things MAJOR things before the car is back on the level:

1. Rear brake pads + passenger rear caliper

2. Assemble front bilstein shocks assemblies (RB springs + new bearings + bilstein B6 HD inserts + gutted shock tubes)

3. 6 speed swap: A. Verify driveshaft compatibility (might need to be lengthened or shortened or nothing at all!)

   B. Fabricate transmission mount,

   C. Create room for shifter in chassis

   D. Send shift knob out to be converted to wood shift knob (ball so hard) again

4. Headlights (the lamps themselves are now complete) BUT they still need to be: A. Wired up to the chassis

   B. Fabricate headlight mount brackets

   C. Fabricate splash shield for added water protection

5. Bodywork, A. Source or repair driver side fender

   B. replace passenger side fender (acquired)

   C. Replace and modify front bumper (to accommodate new lights, cut out grille, and the rallyboob aux mounting)

   D. Fill in hood where headlight cover opening is

   E. Paint both fenders, hood and front bumper

   F. Clean and paint engine bay.

6. Break in new engine, approx 500 miles of stop and go driving slowly bringing it to redline and slowly increasing load. And with daylight savings time approaching I need headlights to be able to drive the vehicle around to break it in at night and dusk hours. Also I may need to get a new steering wheel because the new seating position is HELL on my knee during transit, the best seating position in my car is WOT (and thats how you should be driving it)

7. Mount additional rally tires.

so my ideal goal is to have it all done by Dec 13th for the season ender to be a good shakedown to get ready for 2015 season.

Things left on the engine (before assembly)? 1. Port match intake manifold and gasket

1. Add brake booster port to intake manifold

2. Finish taping all the threads on the irons

3. Clean the berkeley out of everything

4. pull the old engine and salvage tension bolts/apex seals. Or verify if I need new apex seals or not

Ambitious? Now I after writing all what I need to get done I don't know if I can lol....

:(

Also i dunno why the pictures are crooked i rotated them before i saved/uploaded them... also i cant view the images on work pc what i upload. So i cant see any of your guys' sweet build pics but the descriptions sounds nice Time to find a new job! Lol

phone browsing is okay since i have a note2. I have no cable or internet or a pc/laptop at home fyi.

Need grm meet to rebuild rotary. When?

Oooooh what came in the mail (along with misc seals/springs)....

BNIB Rx8 e-shaft (includes pilot bearing/bushing and oil jets) from mazda for only $138. .6 lbs lighter and minor taper to the journal for better oiling, otherwise direct bolt in.

We can most certainty do that! Do a mini demonstration. Possibly teardown (of the old engine) and assembly of this one. If anyone is interested I would assume it would be a weekend. Nov 8th or Nov 15th. Right now I'm TBD on the build date because I found a snag...

There is a small area of pitting on one face of the center iron, I fear it might catch the corner piece of the apex seal. Also there appears to be some scratches that I can catch with my fingernail. Not sure if it was damaged in the move or from porting maybe it rested on a burr and dug in...

I might have to send out the iron to get lapped. Then its do I do 1 side or both sides of the center iron...

Expect daily updates on this build to see if I am progressing as planned. Last night finished tapping ALL the threads and gave an inspection/touch up on the porting.

Here are some block shots:

WEEKEND UPDATE WITH COLIN QUINN!

wait actually no. But some E36 M3 did go down...

I think I'm going to replace or resurface my center iron, I found some scratches and a small pitted area that I do not want to risk on this engine. But I did get to work on gasket matching the other ports.

One was nearly spot on, the other took a tad of beveling to correct.

Also, note the size difference in ports between the block and the manifold.

I really dislike atkins rotary products, this is one of them. This manifold would be great on a REW block, but if I could afford that I would have had a better manifold made. Not to mention the fact that they shipped it horribly and got scratches on the gasket mating surface, the part itself was quite dirty and required cleaning to get rid of all of the chips inside of the manifold and the flange area for the carb is not exactly round and the threads for the studs on one went into manifold which would cause a great gas leak. NOT happy with the quality and the price was so-so. Will not be purchasing anything from them again. I have had some minor issues in the past from them and now this is the final nail in the coffin. Do not buy from atkins, /end rant.

ANYWHORE! I got more engine parts cleaned and pulled the powerplant from the car and began my disassembly and inspection.

So this engine has had a rough 4.5 years and built on a college budget but how did it do? pretty damn well but this thing was tired. General heavy wear everywhere. I won't bore you all with the photos but step wear increased to drastic measures, I did find some other gouges on other irons but this is a good representation:

Here is side by side before and after of the rotor housings, everyone said that the RA classics are hard on housings, well I was also hard on the engine but you can see how much less dull it is now.

I was expecting more flaking, honestly it really didnt grow or change much (from what I remember)

Now the reason I tore down the engine was to re-use the apex seals. overall length/width measured out okay. However the corner pieces did not fair so well (I cannot find the 6th one) and the apex seal springs grooved the seals pretty well. Well lets just look at the photos....

The witness marks are pretty evident.

One of the apex seals looked like it was 'loosing its skin' I've never seen that before.

The corner pieces of the apex seals became peanut shaped.

Still cannot find the 6th one...

Mazda gives you additional specs for measurement, but they don't actually tell you what the dimensions should be....

Needless to say is that I cannot re-use these. Whats your opinion on these rotards?

I found these issues with the engine upon dissasembly.

1. Oil pump shows scratches (explains "poor" oil pressure)
2. Rear rotor rear face x1 side seal spring broke which cause the seal to collapse into the seal slot
3. Still cant find the 6th apex seal corner piece
4. The hole in my rotor (pics to come, more on that later) DID NOT GROW! overall rotor condition is excellent, even the bearings look only slightly more worn than when I put them in.
5. One of the coolant o-ring seals was starting to leak, very small but notable
6. Funny apex seal wear
7. Rear stat gear bearing was showing LOTS of copper, front looked fine.

More pics/details soon to come.

That is good to know that the Rx8 e-shaft is a direct drop in.

I defiantly would not reuse those apex seal! Have you thought about going with a 1 piece carbon or ceramic seal?

The hard launches could have caused the rear stat bearing wear.

Otherwise the porting looks like good work!

In reply to monsterbronco:

I figured I just over torqued the flywheel nut. To use the rx8 e-shaft you need to use the rx8 rear stat gear because of the light taper, front is drop in and/or backwards compatible.

On the rx8 shaft the main journal diameters are approximately one-half thou smaller, and there is a one-half thou taper in the rear main journal.

However the rx8 rear stat gear does not have the o-ring groove like the rx7 ones do. The renesis block has the o-ring in the side housing, most people just use RTV. I sent out my rx8 stat gear to get machined to match the rx7 condition so I can just use an o-ring. I don't trust myself with RTV that much haha.

Carbon would be a good choice but then I might as well go full bridge and balance the engine and I'm not willing to spend that money and I don't need that power. Also the carbon apex seals aren't so good at cruising speeds

Ceramic would be good too but you generally need brand new housings and those seals are VERY expensive.

Also I just realized that my old images are no longer being hosted? so I have to re-upload those.

Also also, here is the photos of the hole in my rotor that has been in there the whole time.

weird!

Question for ya...

How much of a power increase can you expect to get out of a streetport? The engine in question is an S4 NA with the stock confuser / stock timing. It does not have any accessories (except alt and water pump). It does have a good quality exhaust and RB header.

Is 160 hp or 165 hp a decent guess?

Thanks!

Rob R.

Also, is a CAI worth anything on these cars?

In reply to wvumtnbkr:

yeah if compression is good a catless exhaust on RB header and a good streetport should yield that.

the stock intake tubing/elbow is pretty free flowing not much gains in it, People usually just stuff a cone filter and make a cold box for it, maybe get a headlight cover vent too.

What do you have to do a lot in rotary building? Cleaning and measuring! and it sucks, trust me.

I am working on this build a master spec sheet so you can record EVERYTHING. Basic measuring tools required? 1. Dial indicator on magnetic base. 2. feeler gauges as small as .0011" 3. Micrometer 0-1", 1-2" and 2-3" 4. T gages 1.5"-2" (ish) and 2.5"-3.5" (ish) 5. digital or analog calipers

Like I complained about atkins before ALL of the corner seals were .00105" undersized (diameter spec) but I chalk that up to my equipment precision or squeezing the mic too hard. Needless to say I am going to run them.

A seal case is handy in these instances too, mazda wants to charge you a billion dollars but go to any walmart or Meijer or lowes and etc and you can snag one of these for about 7 bucks.

My apex seals wear out on the backside before the frontside, and wear thin before they wear short.

Means need better air filtering. Measure your apex to rotor slots real close, tighter is better.

In reply to Knurled:

The old engine rotors were a bit wide. great candidate for 3mm but new rotors are much tighter.

Right now its just do final cleaning on all the parts because I need to wait until payday for apex seals.

fidelity101 wrote: So this engine has had a rough 4.5 years and built on a college budget but how did it do? pretty damn well but this thing was tired. General heavy wear everywhere. I won't bore you all with the photos but step wear increased to drastic measures, I did find some other gouges on other irons but this is a good representation: Here is side by side before and after of the rotor housings, everyone said that the RA classics are hard on housings, well I was also hard on the engine but you can see how much less dull it is now. I was expecting more flaking, honestly it really didnt grow or change much (from what I remember)

Okay, that line on the far side of this picture looks like a crack. Is this a normal wear pattern? Would you reuse this iron?

I just took apart an old motor I had that was known bad (front apex seal and housing damage). All of the irons have this same situation. Is this normal?

Also, I have heard about people talking about "flaking" What is it and where is it? How much is too much?

Thanks!

Rob R.

I haz more questions if that is okay?

Where do you get the specs for determining if parts are good or not? Where do YOU get rebuild parts?

No worries! We are all here to learn right?

The line on the picture of the side housing? that is just wear from the corner seals digging into the side housings. Typically referred to as step wear, very common and happens parallel on each side of the iron typically opposite to the intake port but when its bad there its also noticed on the same side as the port. This is normal wear.

flaking is on the rotor housings:

1. Measuring tool required: Vernier calipers or Ruler.

2. Width of chips.

Replace if chipping extends inward more than 2mm (0.08 in).

extreme example:

Literally from the outside of the housing inward the chrome comes off. Happens much worse on 85 and earlier engines. Ask Knurled he probably has some good photos.

more details/photos here: http://mazdatrix.com/faq/rotorhsg.htm and http://www.rotaryresurrection.com/2ndgen/tech_housing_wear_guide.html

Here is where I get my specs: (foxed.ca has lots of manuals) http://foxed.ca/rx7manual/manuals/1988FSM/30_TECHNICAL_DATA.pdf also rotary aviation and atkins rotary overhaul videos but they get their specs from the FSM too. Pineapple racing used to have GREAT videos on their website but some server issue has caused them to go bye bye for the time being. I contacted them a while back to see what happened but they said they are slowly recovering them and hope to release a DVD. Haynes/chiltons also has good specs etc.

This place is also good for how to properly measure for the specs: http://www.turborx7.com/rereplacement.htm

Where I get my parts:

1. Mazda

2. Pineapple Racing

3. Rotary Aviation

4. RX7club.com (2nd hand parts)

5. Craigslist (2nd hand parts)

6. GRM?

7. Banzai Racing (odd end misc stuff)

8. Racing Beat

I've gotten parts from mazdatrix and atkins but I don't shop at atkins anymore fromv various 'bad' experiences and mazdatrix parts are usually higher priced OEM stuff than I get through the racer discount. Also any of their mazdatrix branded parts I thought were sub par. Mazdatrix has some good resources though.

Rotary resurrection is a good resource for info to. I think the owner is kind of an ass hole (or comes off that way on the forums) but usually he has good points and tend to agree. I don't like dealing with parts with him because I feel like he is extra screwing you labor price wise for basic machine shop services or just parts price in general. This is my opinion though.

all in all the people who do rotaries right are mazda, and I generally just follow what they do.

That flaking is what you normally see when you pull a 12A apart with any significant miles. I think the rotor housing is the primary wear item. Sick thing is, they run just fine, then you pull the engine apart and half the chrome is gone. I had one core engine that was worn through the sheetmetal insert into the aluminum in a few spots. Yowch.

I've never seen an FC rotor housing anywhere near as bad as a "good used" pre-86 rotor housing. My current engine (GSL-SE rotor housings) went together with maybe 1mm chrome missing around the edges... it's up to 1/2" on the rear rotor housing, from what I can see with the borescope.

Yeah the housings i pulled from this last engine would be a great candidates to get resurfaced.

PROGRESS!

So according to my schedule I need to be breaking in my engine this week. Well that's not happening. 2 Major setbacks:

1. I need apex seals and lack the funds for them (until later this month) Plan to order Friday and have them by the 21st.

2. I was gifted a t2 oil pump, I had not actually inspected it until recently, its bad. so a new one is in the mail ETA Monday the 17th :(

Well I got too drunk this weekend (two 30th birthdays for friends) to be able to accomplish relatively anything important on the car so I did what any sane GRM'er would do and use up one of my sick days and wrench!

It was a glorious Monday (weather wise) to do bodywork! Since I can't assemble my engine I need to get onwards with the various other tasks I need to accomplish.

Step 1. Remove wiring harness and then POWER WASHER!

Well it kind of sucks but you can see the different between the left and ride hand side with 5 minutes of scrubbing with degreaser and that sweet brush.

Step 2. Remove E36 M3ty fenders and front bumper to mount headlights!

Kinda looks like a sil-80 all naked :) After all the same company that made the sil-80/silvia lamps made these J30 ones too.

all lit up (low beam only)

With the EU spec prescription on passenger side (EU Driver side) and SAE spec prescription driver side, with general aiming it came out pretty good considering all the science and math that I skipped to do this;

I just wired them up to an old PSU from a PC, you jump 2 pins and BAM instant DC power supply, I recommend anyone to have these in their garage as handy shop equipment for testing electronics. Safer than a battery with jumper cables (for you and your electronics). I still have to integrate these into my existing body wire harness (which may get some revamping due to this) but mounting the ballasts actually is really easy, I have great areas to work with for easy R&R.

Since then I have removed the headlights and cleaned it once more. right now its time for masking and primer for the engine bay. Then paint.

Hood modification and fender/bumper primer/paint should be done this week or at least by end of next week when final parts arrive. All misc other engine parts have been cleaned and put into dry temp control storage (IE, the guest bed room in my house that is vacant, pics to come later)

More updates when progress progresses further more soon.

Well today was payday so that means order up apex seals, about 375 with tax/shipping from mazda... (and that's with mazda racer discount)and they should arrive mid next week. Oil pump arrives Monday. This weekend I will focus on body work. I am iffy on replacing/painting fenders right now since winter is about to hit and getting paint to stick will be a bitch. Also not sure how to attach the bottom part of the fender to the chassis since they are all smashed and rusted. Might just kind of repair them a tad and re-attach them for winter. And worry about the body work come march when its at least in the 50s again (maybe) I will most certainty replace the front bumper I have since it is required with the new headlights. Maybe it wont look so ratty but just ratty enough for winter abuse/break in driving and ice racing...

This weekends' agenda:

1. Clearance side seals. organize seals.
2. Fiberglass/sand/primer hood.
3. Spray bomb engine bay.
4. Integrate/modify wiring for new lights.
5. Modify front bumper.
6. Create splash guard to protect bottom side of headlights from moisture.

Since this thread has kind of turned into an impromptu informative group, here is some more knowledge. This post will focus on the water pump housing. N326/N327 Is S4 rx7 and N350 is S5 rx7. You must use the pump to the corresponding pump housing. S5 has an additional water pump bolt. Both WP housings are interchangeable on the irons (even on the renesis). If you use the S4 water pump housing you have better pulley clearances so I usually stick with this one, also the thermostat housing is aluminum and is more robust. Now onto the good stuff.

Issue #1 Stock sending unit is located in the rear iron, and its garbage. Its some weird thread and there isn't enough room to drill it out and retap for 1/8 NPT for most gauges.

Issue #2 mechanical fan is for the birds, and toggle switching it is also for the birds (I'm guilty of this for a while)

Ways to correct this, modify the water pump housing. Depending on your application you may or not need the factory CLT. its about 1/4" thread. I decided to drill it out and tap it for 3/8ths" NPT for the fan thermostat switch. This switch is a 1 wire unit that will be the ground to my relay that will turn on the electric fan. (I love ground side switching) Location shown here:

The other one next to it is an S5 for reference, the flat spot on turbo models I believe is drilled and tapped for the turbo coolant line. Either way that is also a good location for sending units.

This is the back side of the WP housing, you can remove this tube but my carb has the option of being water cooled so I may utilize this outlet and run it to the carb then the outlet of the carb runs to the rear iron which has the same nipple, I think this area is used for cold start or goofy ass stock throttle body. This location works great for 1/8th NPT or oversize it to 1/4" use the adapter. I don't run an airpump so I am going to use the front boss area where the airpump bracket would cover. Use a drill press and make the area a bit more open/flat then go in and drill and tap for water temp gauge sending unit. (mine broke upon removal from old housing, also this is much cleaner than prior condition) and boom you're done!

here is a handy chart for what pipe thread v drill size required from my local hardware store:

ETA rebuild? Nov 21st

Well according to my schedule, I bad at schedules. Had some hicups with parts but that should be straightened out by this weekend. Now that engine work was not progressing it let me focus on body work since for me to break the engine in, I need to commute in it and since daylight savings time I need headlights. Its allllll coming together now.

1st order of business on the body work. engine bay!

here is also kind of where I shoot myself in the foot, I am not a body mechanic I don't know paint but I do spray bomb really well. This is no exception. Some areas reacted because I used lacquer acrylic paint from duplicolor, some oil based enamels might be hidden underhood and various other stuff so some areas look funky but its all gonna get dirty soon anyways.

Photo took several cans of this stuff:

Time to go down the lacquer rabbit hole...

Lucky for me a dollar store nearby was selling this stuff on the cheap. $1.89 per can to be exact, which was good because it didnt cover worth a dick and took tons of coats and I bought out the entire supply, probably spent about 25-30 dollars on spray paint.

So I didn't have any sawhorses or stands so I grabbed stools from the old restaurant I used to work at, they just ordered some new ones in and gave me the old "beat up" ones for free. and they work great (covered with painters tarp) I sure as E36 M3 wasn't going to make any or buy any, thats for sure.

I repaired the driver side fender and I had a minty fresh passenger side to prep. MY car was ORIGINALLY blue, these fenders were both originally red and the passenger side had certainty been repainted before.

after a few coats:

I utilized my compressor by spending about 15 bucks on a harbor freight sander and I had a bunch of 120 grit laying around still from the original burban repaint/bedliner project. so that worked out.

Here they are all primed up:

I have an rx7 for a roommate and she's kind of a douchebag, she doesn't pay me rent! In fact... she takes up my space and charges me money, what a country!

Some parts await final cleaning still before they can enter the dry/heated storage/pre assembly room/future roommate room???

ANYWHORE! back to the bodywork. Obviously the new lights required some body changes. fenders took minor trimming (unseen) the gaps for the pop up lights on the hood need to be filled and the front bumper needs to be seriously modified. Luckily I have a spare white bumper (which got cleaned, sanded and primed) and after ruining the prior bumper I had pretty good idea of measurements for hood pins and where to put what. and spare parts. Bitches love spare parts.

Obviously this is not going to work, front bumper wont mount like this and it looks jank.

Here is a close up:

a sharpie works well on what I need to trim and where, pretty close though... Normally the FTP (flash to pass) lenses or clear dummy lenses go here. Those were missing from this bumper, like most are 2nd hand these days...

Passenger side is trimmed (about 90%) and driver side is stock. Also, I made sure the rallyboobs would fit with the new holes I drilled, everything looks kosher.

Here is the teaser shot, headlight covers need trimming and the hood is only filled/sanded still needs to be primed and only the low beam/low beam function is being utilized. I mocked up the wiring diagram at work today to make this work, gonna need a fuse box from a junkyard or make my own power/relay distribution box with room for 5-7 std bosch/tyco relays. Anyone have suggestions???????

in this photo the fenders and bumper are primed FYI.

Oh herro, look what came in the mail today... overnight parts from Japan? I don't think so jesse, week long journey from Ontario... California! Thank you mazda also they were really expensive. $55.55 each :/

This week-weekends plans? finish the hood and get a HF spray gun and hope I dont berkeley the paint up, never used one before. wish me luck...

I dont want to spend 60 dollars on spray paint cans and run around everywhere and with this whole enamel/acrylic/lacquer/oil/water based Im giving in and buying a quart of duplicolor's lineup of championship white, it seems to be everywhere and most whites tend to match my paint pretty well. Oh also the meijer by me is having a clearance on nearly everything automotive body related so I snagged 6 giant cans of duplicolor lacquer acrylic clear for $1.37 each :)

then finish engine pre cleaning and pre assembly. Stay tuned... or don't - I really don't care. its nice to have a build blog that follows how this car has progressed for my own interests :)

Got the headlight covers trimmed up at work (I love having access to even a small machine shop) then got them attached (rivets) to the fiberglass, seems sturdy... enough.

Yup, totally have an rx7 for a roommate...

Today I am going to get some cleaning done (house and car parts) then tomorrow is paint day!

I ran out of the duplicolor primer so I found some rustoleum which didn't have ketones in it but I think thats a propellant, it didn't say enamel so I assume its a lacquer? No idea. Lets see how it goes...

If you don't want to spring for a HF spray gun right now you can borrow one of mine. I can't even recall what they are, last time I used them was to paint my race car in 1998!!! Note sure where your new place is, but I'm in Beverly Hills.