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All just std grade equipment. It was the square bit on the breaker swivel that broke, in this case. The adapter was fine (apart form having the said square bit stuck in it).
Originally Posted by justnspace
I've got that nut busting tool of you need it
Hoping to avoid breaking/cutting the nut. We'll where the 3/4 drive bar gets me first.
Had my dad throw together an offset adapter plate for the Dorito spinner.
Should make maneuvering it on the stand much easier, as it'll center the weight on the stand.
Just need to get a few spacers/thick washers & longer bolts to push the engine outward a bit, as the engine-side plate contacts the dipstick tube.
Looking forward to starting teardown on it.
My measurements were a bit off & the adapter plate hits the dipstick tube.
Will need to either drill 4 new holes a bit further inboard, or get some thick washers/spacers to push it outward enough. Will have to mock it up & see if there's enough room to drill new holes without interfering with the standoff to the engine stand plate.
Picked up some extended bolts yesterday & am using the 'legs' from the engine stand plate as spacers.
Un-luckily, the 4 holes are 2 sizes. The M12x1.5 were correct, but the M10x1.5 are not. So the adapter is currently mounted with just 2 bolts. Hoping to have time today to swing into the store & get some M10x1.25 for the top 2.
Should be able to get it up on the stand [finally] this weekend, after breaking the flywheel nut loose.
It's been a bit stalled recently, as I've been waiting to get to work on the engine & need a welder to finish up the frame.
Once the frame is finished, re-assembly can commence
The Dorito spinner is mounted up on the stand & the flywheel bolt has been removed.
Just need to pull the flywheel & can start breaking down the engine.
Prior to above post, I had my father-in-0law help me tote the keg outside & broke the flywheel nut loose. 3/4" breaker bar & a 3' cheater, and I had both feet in the air, suspended by the bar. A couple bounces & a loud ping later & it broke loose.
Got it up on the stand & got the flywheel removed, thanks to a video by Pineapple Racing, on the right spot to give it a smack with a hammer.
A couple hours' work (and a decent cut in my palm where the wrench slipped while breaking loose the tension bolts) later & she's an exploded Dorito spinner.
Cursory first look, nothing looks awful inside. Need to get it all cleaned up & do some more thorough examination. The rotors are a bit sludgy, to the point that the apex seals didn't fall out when removing them from the housing.
Fingers crossed that she's rebuildable without needing to replace much, other than seals/springs.
Pretty amazing that an entire short block is only about 20 major components.
Need to get some good degreaser & a suitable parts washer container & start cleaning things up.
But, just in a single rotor:
Rotor
3 (2 piece) apex seals
2 springs per seal
6 side seals & springs
6 corner seals & springs
4 rings around the e-shaft bore & springs
E-shaft bearing
Drive gear
Assembled, the 13B short block is somewhere between 200-225lbs. Lots of iron in it. The rotors weigh about 10lbs each, flywheel is something like 24lbs.
For comparison, a Ford 302 short block weighs in around 250lbs
In college, had a friend with an FB RX7 with a dead Wankel. He swapped in a 302 & the car only gained about 50lbs.
Wow, didn’t realize how heavy 2 rotors wankels considering how small in volume they are.
really cool project, please keep posting updates as they occur
colleague had a 1983 RX-7, light car about the same as my 2G Prelude Si with about the same power. It handled well for a solid rear axle
Got out to the garage a bit over the weekend & got the front rotor torn down. All seals & springs removed.
All of the apex seals were cracked in half, laterally. All of the seals took some work to remove, and they're supposed to be free-moving in their slots. Broke a couple of the side seals as well trying to pry them out.
Cleaned up the rotor a fair bit & need to get to the rear rotor. Then it'll be the housings & making the call on whether it's salvageable or if buying a used/running engine is more worthwhile.
Got out to the garage a bit over the weekend & got the front rotor torn down. All seals & springs removed.
All of the apex seals were cracked in half, laterally. All of the seals took some work to remove, and they're supposed to be free-moving in their slots. Broke a couple of the side seals as well trying to pry them out.
Cleaned up the rotor a fair bit & need to get to the rear rotor. Then it'll be the housings & making the call on whether it's salvageable or if buying a used/running engine is more worthwhile.
Are there repair parts for these or do you need to salvage them from wrecks?
Got out to the garage a bit over the weekend & got the front rotor torn down. All seals & springs removed.
All of the apex seals were cracked in half, laterally. All of the seals took some work to remove, and they're supposed to be free-moving in their slots. Broke a couple of the side seals as well trying to pry them out.
Cleaned up the rotor a fair bit & need to get to the rear rotor. Then it'll be the housings & making the call on whether it's salvageable or if buying a used/running engine is more worthwhile.
Out of curiosity, what are the apex seals made of? Spring steel within a steel core?
Are there repair parts for these or do you need to salvage them from wrecks?
Most is still available from Mazda, and there are a ton of aftermarket solutions.
Originally Posted by Legend2TL
Out of curiosity, what are the apex seals made of? Spring steel within a steel core?
OE is cast iron, I believe. 2 piece seals with 2 springs under each
Aftermarket solutions are: aluminum-filled carbon, and ceramic, maybe a few others.
Install process is to place the rotor into the housing, then insert the long part of the apex seal into the slot, followed by the long spring, leaving a gap to then insert the short spring. Seat all of that fully & apply the small corner bit on the end.
You can just make out the 'channels' for the springs on the bottom of the seals, below.
There's also 1-piece seals, but they're $$ & for much higher power (FI, lots of boost) engines that I'll have in here.
Got a comment on my build thread on the Locost forum that a user thinks he has a full set of seals & springs that he'll send me if he can find them
That'll save me ~$4-500 on the build.
Thought my apex seals were all broken, length-wise.
Turns out, Mazda has gone back & forth between 2 & 3 piece apex seals. So, looks like mine may be fine after all. Supposedly, in N/A applications, the 3 piece seals do a better job of holding the seal than the 2-piece, which tend to tilt within the seal channel & can allow some loss of chamber sealing.
2-piece seals appear to still be there preference & OE spec for boosted engines.
Do I spend the $ & just pick up an RX-8 Renesis 13B-MSP, which will bolt up to the rest of my drivetrain, of spend almost as much refurbing my early 80s NA RX7 13B-S4 engine...
If I go Renesis, I doubt my pretty old Haltech (E6k) will work on it, and I've read that the high-po Renesis (6 port) needs some fairly advanced engine mgmt to run properly (need to manage the variable intake ports). Not sure how feasible it is to run the OE ECU in the Lotus.
Alternatively, I could go 4 port Renesis, which is much simpler, but de-tuned a bit.
6 port Renesis: 246hp & 9k redline
4 port Renesis: 206hp & 7200 redline
Torque is the same for both options
Both options make more power than the 13B S4 I have right now. 146hp
If, the apex seals are good on mine, at minimum I need:
Side seals & springs, apex seal springs, corner seals & springs (maybe not all 12), intake manifold & tb.
Not sure if the plate that is in place will work with the partially complete dry sump system the previous owner was planning to use.
If I go MSP, I'd just need to cut out the crossmember in the chassis, to make room for the (surprisingly shallow) oil pan, and possibly add some bracing in place of it, and fab some engine mounts.
Both options are going to require a custom exhaust, header at minimum.
The easy route has my thinking MSP, and sell the short block S4 I have (or keep & build it into a hotter option for later ). There's a 4 port MSP (automatic) locally for $1k with everything on it, would just need a clutch/flywheel, and use ForScan to bypass the immobilizer.
No chance of an LS fitting in this thing without major redesign on the chassis.
I don't even think an LFX V6 would fit, and both options are $$$. My dad is looking, casually, at either an LS or LFX to drop into his W108 Mercedes 280SE, if he decides to keep it.
It's a rotary. Whatever version you choose will need to be rebuilt
I vote 4 port or rebuild what you have. 206hp will be just as fun in that chassis as 246hp. Just keep it simple and get it running. After a while, if you crave more power, look into swapping out.
True, the 4 port is a lot easier to manage with a standalone ECU (supposedly a Speeduino can do everything needed).
200hp in a <1500lb car should be pretty spirited. That 9k rpm screaming Dorito would be awesome, though.
Then slowly build the S4 into a mighty brap-brap spinner.
07-06-2021 | 03:36 PM
Major components, it's surprisingly few.
). There's a 4 port MSP (automatic) locally for $1k with everything on it, would just need a clutch/flywheel, and use ForScan to bypass the immobilizer.
