In reply to fidelity101 :
One thing that I do is polish/chamfer the edge of the spring so it does not dig in to the seal. I have found that apex seals wear quite rapidly on the UNDERside and this hurts spring tension over time.
I have not disassembled an engine yet after I started doing this, but it makes me feel better.
I dug into everything yesterday and I absolutely hate side seal clearancing on the rx8 rotors. with the tapered seal its difficult to get an accurate measurement. I find myself aiming for .002" clearance but getting .0035-.005" and sometimes up to .007" if i re-measure. not fun.
I also notice that my port job sucks and has already caused 2 rubber buttons to move out of place and looks like the rear is chipping the side seal a touch, could just be bad cleanup around the port but the leading edge of each of these side seals show this wear as if its crashing into the port, I may have to spend some time cleaning up the port too.
I also wonder if I need to use the oil scraper rings because this thing has tons of oil in the intake compared to what I'm used to seeing and its a vent to atmosphere crank case so I'm not expecting any plugs or anything. oil pressure is inline with what it should be too. Time to search it up!
some of this is excess fuel from incorrect settings yes but for such little run time there was a lot of oil in the runners - there seems to be mixed reviews on this subject.
My endplay play was a bit on the high end too so I can fix that, there is a .0015" difference between the standard eccentric shaft bolt and the titanium one when torqued down which is pretty interesting. saw some signs that the rotor face had wear on it where it shouldn't be contacting as the side seals are supposed to do their job. I found 1 or 2 side seals a bit stickier than I'd like them to be.
hooray project cars!
hindsight I would have just stuck with the t2 irons and resurfaced everything and been back on the road but I went a bit off the deep end here so I need to see it through.
What you're dealing with is why I ultimately abandoned any plan to run the RX8 rotors. The slight bump in compression (9.7 to 10:1?) didn't seem to be worth the work/money involved: buy RX8 rotors, machine apex seal slots, balance rotating assembly and then fight funky side seals. I've got some plans in store for my rotors for this next rebuild :)
I had to go back through my old photos because I know I had a similar gasket picture:
This was my old setup and I don't recall the time/miles on it but you can clearly see fuel/oil on the gasket. Maybe not as much as yours, though. Did you machine the flange flat after all the welding? I've never had a manifold, intake or exhaust, with completely flat flanges out of the box. I've always taken them to a shop to be machined. I've always been told not to run the oil scrapers when using RX8 rotors in non-Renesis engines.
Yeah lessons learned the rx8 rotors aren't worth it (everyone told me this), I did see two side seal that seemed way out of spec which should explain the lower numbers in the front (plus a bad sealing apex seal) and a corner seal spring that was too soft/too collapsible. The gasket was with vacuum leak so way more fuel (oil gas) went in and when i replaced the gasket and fixed the vacuum leak (didn't tighten the flange properly and didn't goop the gasket originally). I did get the flange machined flat and you MUST use gasket sealant with the paper gaskets for it to work (from my experiences) - did this before on the S4/S5 intake manifolds in the past as well with great success.
The side-seal-to-corner-seal clearance changes so much by how far down you push the the seal it is almost impossible to "set" it so its incredibly difficult to measure but I am going to try some new seals pre cut and go from there. You really need to be able to measure the clearance from side seal to corner seal with the side seal pushed all the way down, which is impossible. best bet is to keep it level and as far down as possible but this tapered/keystone design is funky and it moves on an arc so its not a straight up and down like the rx7 seals. Mazdatrix doesn't even cut them anymore they just use the pre-cut ones from the letters on the rotor FYI.
for the oil scraper I am getting mixed results:
but I'm going to continue down the "don't use them" path.
My port job isn't as bad as I thought I was just overreacting and frustrated but I need to sandpaper the edges a bit and make sure nothing is popped up because it looks like poor cleanup had a slight raised spot/lip on the rear where it was a slip of the grinder so side seal got a bit beat up because of it.
I got some E&J solid corner seals on the way that I will play with see if they are a little oversized (or not) and tighten up that gap as well as fix the rubber button issue because of the aggressive port, if not I will save them for a future motor. I'll have enough random parts that I can put together a budget spare motor relatively easily now.
another thing I learned is that you need to add a hole in the baffle if you want to use the FC dipstick or use the FD/cosmo dipstick.
I will still be using these mediocre rotor housings too so that will not make my compression in the 120s but if I can get around 100 thats good enough for racing for a while.
I would use them because in the last allofthem engines I have disassembled, the outer oil O ring was destroyed. Mazda, aftermarket, does not matter.
In reply to Pete. (l33t FS) :
the middle oil ring then on a renesis? I dont follow or are you tearing down renesis motors often?
build attempt #3 = fail
managed to pinch/damage the inner o-ring on the front rotor and had a tiny pinhole leak (pressurized it full of water) that was making chocolate milk out of my assembly oil but the good news was I was able to fix my compression so now (apex seal spring + a few new side seals) and now that everything is marked and organized I just need to clean the irons again and do re-assembly once more so I guess 4ths time a charm!
Since this has taken so long I have just gone an ordered new FD rotor housings because I don't want to tear this motor down again for a long time, everything else is new so berkeley it might as well.
EDIT: I also added 1 piece dowels as a drop in easy solution to keep the engine from twisting as the very high rpm as the rotors tend to wobble, however the whole assembly has been balanced so that should help as well.
I will be running two of the left shown as I don't feel like modifying my front iron for the improved oil passage which moves the oil feed to the rear iron externally but this will add rigidity to the block.
Completely overbuilt and out of budget 200hp motor on the way.
UPS had a delay and I missed my weekend window opportunity so I ended up making a jig to help the porting and prevent me from making a mistake because of trying to hold the housing and port much more stable and less awkward but first tape up all the sensitive surfaces to protect them and make cleaning easier later once the housings did arrive.
I do hate tearing into new housings was tempted to run them as is but I got a better template for my needs from Australia via extreme rotaries from John Blanch Racing. I didn't like the flexibility from racing beat or mazdatrix and the pineapple racing ones were better focused for turbo spooling instead of NA power. This one was a nice sweet spot and not too big so I can have some torque (possibly).
this is better suited for my non turbo application and doesn't really change the port opening but increases the duration for more overlap. Here is the port marked on the FD rotor housing.
and a rough cut done hopefully get a chance to get these inserts swapped out for my printed inconel ones and get this motor assembled this weekend - the EGR port needs to get welded still (underneath the insert) then do a deep cleaning on these housings then it should be ready to rock!
fun fact, the factory inserts are inconel as well but they have 2 holes in the insert to flow for the EGR port, the printed ones I am using are a different grade of inconel and are smooth radius with no holes for air to escape to other areas of the housing.
Out of curiosity, why did you go with two drilled dowels? Can't the lower one be swapped to solid with no additional work required?
In reply to infernosg :
I don't think its going to make much of a stiffness hollow vs solid in my non turbo application, this one is less weight which was the main reason even though its small savings and was a tad cheaper.
In reply to fidelity101 :
I figured it'd be weight. Who'd you get them through? Since my rebuild keeps getting pushed to the right I'm considering ordering a pair myself. I'm aware of Pineapple's but they're more expensive for two drilled dowels vs one solid and one drilled.
In reply to infernosg :
I got them through pineapple, I had called them to get clarification on ordering as the site didn't show 2 drilled being orderable with the way it was setup.
Plug the hole and tap the hole for m6 thread to use set screws instead of rollpins. good with and without the printed inserts.
these came out much better than the other housings.
this is no longer a frankenwankel - its truly a dankenwankel now.
4ths time's a charm I guess - passed the compression and coolant pressure test so were good to go!
Renesis Rotating, fully cut
Custom streetport (a mix of templates)
Cosmo 13B RE front/rear irons
20B center iron
FD housings w/ printed inserts (Inconel 718)semi solid dowels
Printed metal intake/exhaust manifolds
Haltech elite
EFI Hardware ITBs
Looks good. Should be a fun engine. I'm jealous since I'm still waiting for parts. Probably should start cutting side seals though. Funny thing. I ended up with two drilled dowels as well from Pineapple. Ordered a set last week but was informed the solid ones are backordered. Since I have a "low-powered" N/A build they gave me two drilled dowels for the same price.
Plugging the EGR ports is always something I wanted to do. Not sure if there's any benefit other than keeping some carbon out of various engine parts. Short of going with an aftermarket insert like you did is there another option?
In reply to infernosg :
racing beat offers this service but its pricey, I mostly did it to keep exhaust gasses out of the oil pan because it tends to dilute the oil more with fuel which is difficult on these motors anyways so any little bit helps.
Chips offers a nice package where he machines the housing to match the titanium insert otherwise mazdatrix has titanium inserts off the shelf that look like this one. I'm not so sure on the titanium choice for that part of the motor inconel seems like a much better idea, the weight savings is pretty minimal and the thermal properties of the inconel are far better than titanium and won't oxidize with the heat cycles but people use them so its hard to say.
some fun pre in car shots:
4th times a charm!
It started up on 7/5 and I put about 200 miles on the break in so far, got some more miles to work in the sub 5k window then start working the 5k+ break in, try and do about 500-700 miles on the break in and then do an oil change and start floggin it.
working on a new hood so I can keep rain out and improve my radiator cooling, I can still use this current one as a backup if need be but the plan will be to hack up an aluminum non turbo hood.
from what I can tell its way too loud, I will need to add a 2nd muffler, definitely likes the higher rpm and climbs the RPM very smoothly once it gets going. Haven't done much "high RPM" because of the break in but were gettin there!
YES
In reply to ¯\_(ツ)_/¯ :
yes with many delays and scope creep it is finally ready and leak free!
this motor actually only has the rotating assembly in common with what I tried to build in January.
with a new motor came a new intake manifold (and a modified exhaust manifold, again) but it also means a new hood, for obvious reasons, so without consideration of anything here is what I got cooking...
step 1. get an aluminum hood:
step 2; cut the hole for the intake and then add a roof scoop... backwards (even though forwards looks more cool)
step 3. add race louvers and gratuitous amounts of gorilla glue liquid nails:
step 4. more paint. more glue and then eventually add the hood pin latches
ta da!
a little over 220 miles on the break in, starting to climb RPM and increase load. Compression is okay but it could be better but there also is a lot of overlap in this motor like a bridgeport so that may be some of the reason, compression should increase with break in as well. moral of the story, rx8 sides suck.
now that im not allergic to the weather I can increase the miles and get to brapping.
custom parts have custom problems.
I need a bigger crimp on the cable or a smaller bushing, at WOT it likes to pull right through the bushing...
3d printer to the rescue again!
Looks great!
and by 3d printer I mean zip ties and shrink wrap, looks to have solved the issue.
forgot to post the pic:
also its time to put the stripes back on this hood, its far too naked at the moment.
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