Well, I'm no professional engine builder or rotary expert but... I am experienced in machining, machinery, materials, and surface treatments. In my opinion, the nitriding offers no strength. Only hardness. And with the way that works, the bare metal threads may offer more strength since hardness equals brittleness. Hardness and strength only share a union in the middle of graphs, not at the extremes.

The iron may become weaker from the removed material but not from the removal of the nitride surface of what, ~.003"?

I know it's already done so I'm a little late. Just something for you to think about. I can't wait to see your build done. It must be nice to do such a build.

 

you're probably right but we have seen machine work to these holes weaken the integrity of the base materials so i don't necessarily prefer removing material but sometimes it's just the tradeoff you have to make.

more often it is because the thickness of the bores being thinned out allowing the material to stress more, most often in the case of installing dowels since the walls are very thin in some areas after machining and they tend to oval out with the twisting forces of the engine. the amount of material removed is only about half as much as what would be removed from dowelling an engine so i'm not too worried about it.

these are also reasons why i have moved away from installing additional dowels versus using studs. less stress on the base metals, as much if not more possible surface area tension and better clamping force you can apply to the engine to hold it together to cope with the twisting motions.

the amount of material removed was roughly 2mm.

 

trial fitment checks out ok, the whole block is already machined but still missing the 3 final studs.



i think i'm going to need a spreader to ever get this thing apart...

next up is cleaning up the port on the center iron, bevelling the exhaust ports, re-cleaning the parts and paint. i need to stock order coolant and oil seals so best case it won't be going back together until mid week.

i also have no idea who "ZG" is or why he felt the need to mark the engine that wasn't together for very long.

 

sorry if you were a fan of the **** ugly baby blue paint.

reconditioned/resurfaced 100k mile turbo S4 housings(in house) which had some step wear but 0 flaking


painted and waiting for it to cure before cleaning up the paint overspray.



simple degrease of the parts(the rotor housings were bead blasted again after my paw prints soaked into them), followed by high compressed air, masked and painted. i go over all flat surfaces to clean off paint residue after a day of curing. the lettering is simply block sanded down to highlight the engine and something i feel gives it a tiny touch of detail and it stands out even with everything in the engine bay(plus i've been doing it since the beginning where i notice most people couldn't give a damn).

to keep overspray minimal i have 2 old rotor housings and an old front cover i use to assemble the shell with while painting the irons. the rotor housings are simply set side by side and cleaned afterwards with carb cleaner on the friction surface and the sealing surfaces.

i simply hate an engine that has color on everything, including crapped up bolts/threaded holes.

 

looking great brother!

 

Looks great!

 

all the materials came in today so i'm making the final 3 studs and hopefully should assemble it tomorrow.

 

coming along nicely!

 

studs are all done and beveled to make assembly easier since the final test assembly wasn't exactly easy to accomplish, i also removed about .03mm from the studs because the assembly was in fact a little too tight.

i will finish prepping the housings and irons and probably do the final assembly today or tomorrow.

 

Subbed, Thanks Ben for sharing

 

rotors: used FD corner seal springs, good condition relatively low mile FC corner seals which won't catch a nail in the side seal wear spot. the side seals were a bit all over the board from .00mm to .15mm, i could have averaged them out with all at about .10mm clearance but as long as they're within the minimum spec they're fine, i just ran out of good long side seals and didn't feel like cutting new ones. using my viton oil seals in the rotors.

oil seal carriers are also used, so long as they aren't showing more than 25% shine on the surface i consider them good as the factory spec is a little bit overboard with these.

vaseline(not crisco) holds everything together.

sorry for the pictures, my camera has been dropped one too many times it seems and the auto focus is losing its touch.



front iron with my HP coolant seals and aviation sealant on the S4 legs with viton dowel seals.



bottom half put together with used low mile re-arced(higher tension) apex seal springs. molybdenum engine assembly oil on the rotating bearings. Goopy 2mm standard apex seals installed with .04mm clearance, tight er than spec but fine considering the scalped/clearanced rotors.



a little MMO on the rotor sides for some lubrication during initial cranking.

 

center iron in place



now the studs have to go in to ensure they lock into the front iron properly.



*** end assembled, this wasn't nearly as quick as it took you to go from one picture to the next.. it took about 15 minutes tapping the housing down evenly into place over the studs, on a stock engine this is like a 3 second process. in fact it took roughly 2 hours to assemble this keg where most stock engines only take me about 30 minutes.



and this is where i leave it today, .0018" endplay first try with a thrown together thrust stack. of course the front balancer i grabbed happened to be the shittiest piece of crap i out of the stack but whatever, it has a simple job.



the studs are currently torqued to 40ft/lbs and i will double check them tomorrow to see if the block is settling or if it is just right. hand cranking the engine gave positive results so it looks to be all ok from here.

all in all parts cost was roughly $700 with mainly good quality used parts filling in the gaps(not including a good core engine). the studs and new apex seals alone took up over 2/3 of that figure just for the seal set and raw materials/tooling for the studs. i could have easily spent over $2k by replacing everything, but why... most of the components have a lifespan of 2-3 rebuilds, assuming they weren't abused.

total labor hours invested was roughly 60 hours, half of which were spent polishing the damn rotors, clearancing them, milling the block and... the studs actually took the longest to make of all the steps involved at nearly 20 hours to get the specs just right.

 

Great build pictures, always my favorite. I was wondering though. That transmission that you worked on, was it an S1 or S2?

 

Very nice Ben.
I'm technically ignorant about the rotary engine but quality work is self-explanatory.

It's too bad this level of quality makes no economic sense on a NA engine.

 

sure it does, plus you don't need to buy the studs on an NA engine.

 

short of studding and high boost/RPM clearancing the rest is actually included in our most basic rebuilds priced at $1450-1600. the only difference between n/a and turbo is i opt for the goopy seals in the turbo engines where the n/a engine get atkins seals because i just feel they last longer as a tradeoff where the goopy seals can handle much more abuse. i will probably raise the turbo engine prices slightly to reflect that but i still haven't had time to change the website so i'm honoring the prices listed there.

but i'm still trying not to make this feel like an advertisement otherwise i might have actually cleaned some of the crap off the floor and taken some more photogenic pictures.

 

"Our"?
There's more than one of you?

And why are "we" not accepting overhauls at this time?

 

our- as in me and the business, sometimes i just say it to make myself feel more important i guess, lol. every once in a blue moon i will have someone help with their own engine but 99.9% of the time it's just me here.

still booked up with work and want to get caught up a little bit more before taking on more. there's been an RX8 here for a new hybrid renesis engine(peripheral 5 port exhaust, 6 port intake) and turbo fabrication for about a year now that is getting to priority level even though most everything is coming out of pocket without any deposit so of course that needs to get paid for soon. of course this build just tacked on more time that i was hoping to push back a little longer, but i'm never not busy so it had to get squeezed in somewhere.

i've had that note for about 3 months now, no matter when i think i'm getting close someone walks in the door and offers up a rebuild so it has just been re-upped for that time as it's just hard to tell someone who comes in personally that i don't have the time and they have no alternatives but to wait for an unaccounted for timeframe.

i also put the note up because we(me and my gf) planned on moving to florida, possibly back to california, or elsewhere early next year but so far the house hasn't moved but i'm still trying to plan for it. after moving i want to set up the new shop to accomodate building off my basic principle and begin building the prototype caterham 7, starting with a 2 rotor and then moving to the 4 rotor version.

my FC was actually offered and accepted to be bought for $10k which included a new engine but of course the buyer ran into financial difficulty and backed out but i planned on this anyways, just changed the configuration around a little since i guess i'm now planning on taking it with us. for a customer this engine rebuild would run about $3k minus a good core engine, mainly for the studding and a small chunk allocated for the clearancing. but someone who would pay that cheddar for an FC engine would probably pay a few hundred more for more new hardware, for me it's no huge problem since i can have the engine out of my FC and torn apart in a few hours(there is 0 accessories on the engine aside from an alternator and water pump, as i always say: "simplification is your friend").

so yeah, i've been a little busy along with the 20B here awaiting a rebuild and several more rebuilds coming in soon. i should just hire and train someone but i'm too thick headed for that.


and i agree, most of this wouldn't be necessary for a naturally aspirated engine.

 

to a point, this is a good problem!

i think caterham rotary is a florida project, i imagine registration for that in CA would be a nightmare, and a lot of your customers would be back east too, but i don't actually KNOW that, just opinion

 

Ben is the man..

 

no pictures of the assembly under the front cover, that's all simple anyways.

set the engine to 5*ATDC with my custom 5/20ATDC degree wheel.



grabbed a random hub and pulley off the shelf to see if they match, in this case not even close. of course it is about 10 degrees retarded but that would be like running 5 degrees of advance at 15psi short of spending the time and risk of retuning the timing curves that is just lost power all around. you could wind up with the reverse on an FC hub/pulley combo which advances the timing 10+ degrees, not good and is why i do this procedure.



so i grabbed a match set that came off an original engine that i knew should be accurate, which it was despite the crappy picture.

 

awsome build Ive been wanting to start my 1st rotary build. Alot of good pics and info keep it up.

 

sorry i missed this, it was a series 1 Aisin transmission, the S2 supposedly fixed a number of issues with the Aisin by building the transmissions by Ford and designed specifically for the rotary car rather than a truck transmission simply adapted to it.

 

i've heard about the different pulleys of the Gen II, but actually seeing a photo of how off they can be is just downright frightening. it validates my practice of keeping most of my stored engines fully assembled until it's time to work on them. so generally speaking, i don't mix parts in a build (at least not parts like pulleys, stacks, flywheels and such).

what's the deal with the differences? what brought them about?

sorry, for the aside, but i just thought this particular phrase/concept was bloody hilarious.

i never really had much LOVE for Ford, but i do consider myself a huge fan (since childhood) of the Escort (Mk 1 and 2), Cortina (Mk 2 and 3), RS200 (Group B soldier), the Mustang (minus the mid-70s to mid-80s) and late '80s T-Bird. I've also started a new love/respect for the F-series trucks.

that said, the thought of Ford fixing a problem, their's or anyone else's, tickles me.

 

i believe there is a difference between the turbo and n/a hubs/pulleys being machined differently but that is just speculation, it could be a difference between JDM and USDM pulleys. i've never spent much time verifying which pulley combos came off which engine to know 100% for sure. all i do know is that i have seen engines that were builkt from a box-o-parts that had this issue, when it comes to turbo engines it could result in repeated failures. usually i can tell if there is a problem anyways, if the cas isn't in the default 30% forward position then there is an issue with timing on or off the engine. most times i can time an engine to within 2 degrees without touching a timing light.

i was also never a fan off ford and their connectors from the 80-90's, or their ability/passion to rivet their cars together.. a necessary tool being a drill in your toolbox is a little discomforting to do simple jobs. but ford owns mazda so i guess their bailout in the failing tranny department was a necessary evil.