MincVinyl

So this is going to be a long first thread, because I am technically on my second rebuild at this point I should have started a thread a long time ago. I am going to separate this post into a History and Current Issues. I am going to try to cover all my bases of what I can remember History wise, skip to the Current Issues if you really want. Most of this is focused on the bad experiences and essential information for my current issues. I have done many other things to my rx8's along the way.
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History

Roughly 6 years summed up leading to the current issues.
Rx8 #1
I first got my #1 rx8 back when I was in senior year of highschool for a cheap $2300 from a guy in Mass about 5 years ago with 3 previous owners 115k miles. It had body damage, multiple color reds, no rust, an oil leak inbetween the two oil coolers, no issues hot/cold start, but it clearly had a blown oil seal. The seller had a new braided steel oil lines to upgrade to, and in terms of the engine the plan was to rebuild it the following summer before I started college. After buying and inspecting the car more thoroughly we realize that almost the entirety of the car had been changed in the interior, most likely from the seller who had other very clean modified cars. The car also had an unnamed exhaust system, no cat dual resonated mid pipe with what was essentially no mufflers. With the 2 cycle premix and oil control ring problems the car sounded and smelt like a snowmobile.

At some point or another towards my graduation of HS plumes of white smoke started to happen with a sweet smell that burns the eyes. The coolant jackets finally got eaten or broke, however it would typically go away after the engine came to temperature. It got the point where the ongoing joke was that I was responsible for there being no zika cases in the neighborhood. Eventually we decided to bench the car and begin the tear down. My father, brother, and I wanted to do this as a project together, which was why we did not just have a shop do the rebuild. Being a family of all mechanical engineers taking on projects we knew little about was just second nature. The house we were living in at the time had a small enough garage that with the rx8 fully over to one side, wheels rubbing the walls we could just barely walk around the car. We did have just about any random tool needed and a portable gantry crane for pulling the motor. At this time doing an engine pull took about two or so weeks, having to deal with an uneven driveway, weather, old floorjacks with a low car. Everything went well with the teardown, irons looked great, rotors needed to be cleaned, and the housings surprisingly were in good shape (we thought it may have been rebuilt before). Using a parts cleaner my father borrowed from work we spent plenty of time cleaning everything.

Here is where the rebuild kit comes into play. My father decided to go with the Atkins master 6 port rebuild kit with the Atkins Cryo Apex seals and solid corner seals ~$1500(saved roughly $160 with atkins seals instead of mazda.....but not really). After alot of research on all the tips and tricks and following the atkins rebuild guide. We cannot fully remember if my father pressed in new bearings for the rotors, but it is very possible, looking now on atkins site, they do not include new bearings with the kit. Somehow during the rebuild an apex seal did end up snapping in half while we were trying to put it in the first rotor. Which we had to call and buy another one, and clean out the rotor again to make sure no pieces were in the engine. Side seals were all made to be within mazda specs of .002-.006in (we now know most people recommend going even tighter). We went through checking all the parts are moving like they should, just like in any rebuild video we saw how the seals/springs would move. In the end everything went together as planned after that, and we ended up getting everything back into the car after a few weeks.

The first start:
Off of an optima yellow, the original battery from the seller we tried to start the engine. It would spin at about 300 rpm, but to no avail. Going down the list we thought about the basics: spark, fuel, air, compression, and timing. We went down every rabbit hole we could, which alot of it we had no problem buying new parts since non of them would really go to waste making sure a new engine has the best chance it can.

1. new plugs, wires, coils
2. new upgraded starter, optima redtop battery(highest cca we could get)
3. new fuel injectors
4. new engine harness
5. crankshaft position sensor and timing wheel (only code given from computer)

Still nothing, just a very consistent spinning motor that wouldn't turn over. We tried everything from starter fluid, to jump starting, to even push starting the car. At this point the only other thing we could think of was the computer system or maybe CAN bus messing something up somehow. So we ended up buying an ebay computer, immobilizer, keyless entry module. From our limited knowledge on CAN bus all we could really see on an osciliscope was that the signals were present and nothing looked out of the ordinary. Why not just go to the dealer? Well, we did decide to give mazda a shot and brought the car to a dealership that would have a mazda master mechanic work on the car. After about a month of driving by and seeing the car barely moved we got word back. They had issues reading the computer and said apparently someone had encrypted it. So they had us buy a third computer and wait another month. Eventually mazda told us to come pick up the car and said they will no longer work on it at all due to there being too many unmatching vin#s on the car. Of course the dealer still had us pay an absurd amount for labor that resulted in nothing and the computer. We thought perhaps the immobilizer could be screwing with something with the 2nd computer pair. Eventually spending more money to have a locksmith come and make keys resulted in the engine still just spinning. For laughs we tried just swapping computers again and found out that the original computer had the immobilizer deleted and worked with any key that turned.

My father tried to get some info out of Atkins, but from what I remember my father was not very pleased with how he was treated. Curious, we just opened the original computer and to our surprise water came out of it. We obviously have no idea how this happened, but there was clear indication of this causing issues with charred markings all over the circuit board like something melted. Ended up talking with the guys at racing beat alot and sent out the computer. My father mainly talked with R.B. over a few weeks and they sent the computer back after working on it a bunch for little to no cost(apparently it was still good for the most part, but they cleaned it up anyways). We are actually very very happy with racing beat for what they did and how much info they were able to give us after giving them barely anything in return. I and several friends are now mainly using racing beat to upgrade our cars. (except for that one friend who swears by his Mercedes and has likely spent more money than I have at this point just changing light bulbs) Eventually we did test the original computer on my next car and it worked perfectly fine.

It was the sad truth that I am certain of now that it was entirely compression issues with the rebuild, our best bet to what it was would have been reusing the housings. By the time we thought about doing a full compression test, mazda wouldn't work with us and we were out of time. Never did it come across our minds that the seal kit could have had issues. We had to avoid pulling the motor due to my father being in and out of the hospital with spinal problems(getting titanium plates in his neck) and me starting college(mechanical engineering). Of course the winter set in and delayed all progress.

Rx8 #2
Come the end of freshman year(no car allowed on campus anyways) I wanted to have a working vehicle for sophomore year, so I ended up shrewdly negotiating someone selling another rx8 in pretty much the exact same shape as the 1st one down to $1200 from $3700. It essentially had a bunch of really simple problems that by now we knew pretty much all the ins and outs of that are common with 110k mile rx8s. We ended up swapping most of the interior and new parts from #1 into the #2, Honestly buying a cheap parts car is an amazing feeling. Being able to snap or lose a bolt and then just walk 10ft away to grab another one. Anytime something had a problem we could swap it out with the #1's part to test. It recently had a new cat put it....the guy payed $1000 for, and the shop had butchered the o2 sensor wires and somehow the transmission wires aswell. Scam? idk, wouldn't doubt the shop scammed him considering the cat was half the OEM size with no heat shielding running 1.5in diameter pipe. I ended up swapping the midpipe I had in just for fear of restricting the exhaust so much and overheating the exhaust ports.

First problem arises a year after, the car starts to spew white smoke, sweet smell, burns eyes, goes away when engine reaches temp. Coolant jackets finally broke again, as to be expected with the mileage. I believe it was from really cold weather one day and then really oppressively hot humid weather the next day. At some point being away at college having coolant spill into the combustion chambers started to cause issues obviously. Fouled plugs every other month, hard starting after cooling down over extended periods, and a dead battery. However I would always get it to start one way or another.

My family then decided to move around my junior year, which meant any chance of us tearing apart both motors was another year or so away. With not much to lose and a strong will to test stuff to see just how long the motor could last, I decided to try the dreaded stop leak headgasket sealer.(I know, ughughugh why didnt you just drop 5-6k to have ship it across the country and have it fixed, ughgh you should have done it right in the first place idiot) Well i wasn't the one with money to spend, and we are a family that likes to do everything on our own. We may have already spent 5x the value of the car, but it was a fun constant project to us that let me learn about every aspect of the car I could. I had read a thread somewhere down the line that these guys used the bars stopleak headgasket sealer in a freshly built race engine for autocross, with great effect.(instructions say not to race engine) I figure not much to lose, if it works it works, if not I have to rebuild the engine anyways. .......Turns out the stopleak worked(use at your own risk), only issue I had with it was the driver side heat went out because the drivers side is on the upper portion of the heatercore. This meant due to an air pocket in the heatercore from low coolant(due to leaking coolant) the stopleak that reacts with air caused a blockage. So we just used a pump to unclog it to great effect. One other side effect was a new smell at higher rpm and stopleak/coolant half hardened mixture dripping out of the coolant overflow pressure relief tube. The drip would spray up into the engine bay, so to remedy this I used some vacuum line to route this drip form above the radiator/electrical components down out of the air dam. By now my family was done moving and we had built a large barn that could fit 6 cars in it, and installed a lift. (during future teardown the stopleak left slight residue is some of the coolant passageways, and a blob in a corner where air most likely got trapped in the engine. otherwise it was cool to see that it held exactly where the million pieces coolant jacket was sort of remaining.

The car was fine until it started having hot start issues.....(90% chance of low compression at ~125k miles) However, being a couple years down the line since I bought all of the above list, I recently have gotten/upgraded a few things

1. new battery, starter, alternator, belts
2. cleaned old plugs
3. Bennett built Ls coil kit
4. got the Sohn adapter and modified the kit to have a much larger washer fluid bottle (really great idea btw if you are tired of only getting a few squirts before having to refill)

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Current Issues

Now caught up to current time, I am at the point where it takes me roughly 2 hours to get the engine/trans dropped out of the car assuming the fluids are drained. So I am not limited in really any way other than waiting for mail to arrive. We had pulled apart both motors and cleaned everything from both engines. The current build uses:

1. rx8 #2's irons and front cover (#1s I plan to save for a turbo build concept using gsl se Housings or mess around with the original housings like in Brettus's threads)
2. rx8 #1's rotors/flywheel/counterweight/Eshaft (#2s rotors+eshaft bearings looked like they were cooked)
3. rx8 #1 stationary gears
4. New Mazda OEM housings from Mazda Swag
5. New Mazda OEM apex seals from Mazda Swag (atkins apex seals were put aside, keeping them for cleaning out apex seal slots on rotors)
6. Side seals were used from the failed rebuild(still within mazda's tolerances)
7. The Atkins One piece Corner seals were used from the failed rebuild
8. Rear main seal from Atkins kit was also reused (I believe it was actually an rx7 rear main seal, slightly different, but should have been fine from what we were told)
9. Atkins Oil pellet
10. rx8 #2 Oil regulator
11. rx8 #1 Thermostat (looked less restrictive than #2 for some reason)

First start, which required a jump from an F350 revving at 3500rpm to spin the motor fast enough to turn over. Engine got going and became steady wanting to sit at around 2500-3000 rpm. Going under 1500 made it want to die out. After running for a bit it would start to allow me to go even lower, which I was assuming that the new apex/housings were starting to seat properly. After about 2 hours of run time it was cold/warm starting on its own, but would not hot start until the temp guage was halfway down. Another issue we had was related to me fully cleaning the Lower Intake Manifold, which because of built up carbon I had missed the alignment tooth on the rack and pinion of the valves by one tooth, which was enough for the magnetic pickup to be misaligned with the motor on the exterior.(required engine to come back out and back in, but now fixed). Our original hope was that the, p2004 code intake manifold runner control stuck open bank 1, was causing too much air to be entering the engine and with lower compression when hot causing idle and hot start issues.
Main symptoms

1. Near perfect cold start (almost just a flick of the key)
2. Smooth idle when cold
3. Hunting idle between 750rpm(shaking) up to 1250rpm(smooth) changing every few seconds
4. Wants to stall at 750rpm and will stall when given a load like turning AC on or releasing the clutch in neutral.
5. Stalls after getting hot from increased revs (kept rpm under 4500 for break in)
6. Spins at 300rpm after stalling
7. Spins closer to 500rpm when temp guage starts to decline ~8-10 mins rough 20sec long start (is it from increased resistance from thermal expansion? but then how would it have low compression?)

Other symptoms (possibly unrelated to hot start)

1. Rear main seal was leaking (we replaced atkins rx7/8 one with another aftermarket rx8 seal...had a slightly smaller leak....went and bought an OEM seal from mazdatrix.....now very slight leak
2. P0420 (catalyst system efficiency below threshold) Front o2 sensor, likely from midpipe. Some thread I read included someone pointing at the water temp sensor possibly being linked somehow. (stopleak could have messed with it? We did full flush the whole system about 15 times, smelt like something died in the coolant, but cleared up now with fresh fluids)

This leak we are very unsure about, unless new rear main seals are supposed to take a while to set I am worried oil isnt moving properly. This could also mean the rotors are overheating causing compression loss. For my temp guage to read normally it would have to mean that the temp sensor is bad aswell, which is possible. Having used the Atkins one piece corners also has me wonder if they are not happy with the heat expansion of the engine and they are binding. From a quick google search I found Howzer tech's vid about his experience with the solid corners Racing Beat on their site also has an explanation about how corner seals play an important part in low rpm operations and hot starts. Where binding seals would cause problems, which makes me wonder if that is why mazda decided on the two piece corners. I plan on making a similar test to Howzer's using the current engine setup and with new corners and sides. I will post numbers in here once possible.

I have tested the compression of the current engine build with its problems, It is clearly suffering from low compression. My finger points towards either the temp of the engine, the side seal clearance, or the atkins one pieces binding. Obviously a combination of these is likely and more than possible. Note these are the corrected values to 250rpm by the tester, and around 85 psi is where engines typically have problems starting/running. Ideally I should be getting between 110psi and 150psi.Operating temp(hot after revs): 64 72 70 psi
After 10 mins(warm): 86 85 84 psi
After a day (cold): 88 89 87 psi
Mail orders I am currently waiting on,

1. New long side seals (I plan on going much tighter since a lot of different people on the forums say to go closer to .0015in instead of .002-.006in)
2. New Mazda OEM rx8 corner seals and plugs (the corners that came out of #2 had side seal grooves in them and at this point I want to see how the Atkins one pieces compare to the new 2 piece OEM corners.)
3. Temp sensor and Thermostat

My power steering also went out for some reason about a week before the initial #2 teardown. I plan on ignoring this for the most part until I get an engine that can start and idle. All the connections check out, I am wondering if it is the rack or the control unit under the computer. If anything I always have a second one in the parts car.
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Questions to find answers for

1. Is the O2 sensor p0420 code linked or just because the computer sees nothing else wrong and is reporting the decat?
2. What is possibly causing the rear main seal to leak oil?
3. Are there any other sources of compression loss I am over looking?​​​​​​​​​​​​​​
4. Very slim chance, but could the power steering in any way at all be linked to hot start issues, possibly causing an unnecessary load on the electrical system? Last i checked across the battery rarely dipped below 14v while the engine was running.

CaymanRotary

Detailed story! I hope you are able to solve your issues with your engine. As for your questions:

1: P0420 typically means the cat is bad or you are already running catless. If you are still running a cat, it's good practice to take it down and inspect for any clogging or damage.
2: Rear main seal is leaking oil due to either the seal being bad or installed improperly. It shouldn't be leaking at all, it's a serious problem.
3: Compression loss is due to worn out or improperly installed replacement parts. There's really nothing else it could be.
4. I've had power steering issues in most of the RX-8's I've owned. You could try cleaning the connectors of the power steering harness and those of the connectors attached on the car. You should also clean both grounds. This can usually fix the issue but if it doesn't, and installing a new PS computer doesn't work either, you will likely have to replace the rack. I'm at that stage now with one of my cars. Can't be anything electrical so I will need to source a replacement rack.

MincVinyl

@CaymanRotary
New OEM corners and sides should be here this weekend, so most likely by next week I will be re-stacking the engine.

1: I am catless due to the original seller of the car being scammed by an exhaust shop, so it is likely that the P0420 code is from my decat. I figured I might aswell include this incase it ties into one of the other issues for some odd ball reason.
2: I am going to check the rear main seal again once we put in the new OEM corners and side seals. We think something might not be right inside the engine oil flow wise, considering we have tried 3 different rear main seals at this point.
3: I find it hard to believe that Seals were improperly installed multiple times, I am almost certain the one piece corners are the issue. Most likely binding from expansion when hot.
4. All connectors have been checked, this time around I am going to swap the PS comp with my other car's unit. If anything I can pull the rack out of the other car.

CaymanRotary

1. Yea, its because its catless, you will always get this code. Just disregard.
2. Are there any chips in the metal mating surfaces? That can cause an issue with sealing.
3. It could also be the irons or housings. If they have any scoring that can cause compression loss even with properly installed seals. Make sure these are inspected for any scratches or scoring. You will also want to ensure the rotors themselves are also in good condition.
4. If you cleaned and ensured good connection between the harness and the rest of the car it could also be that computer. Swap it out and hopefully that solves the issue.

Good luck!

MincVinyl

There was no scoring on the irons, the housings were new oem ones with no markings or damage of any kind, with new mazda apex seals. I will take pictures once it is cracked open this week

CaymanRotary

Its unusual to get failing numbers on a fresh rebuild. Something isn’t right or missing. Or injectors or any other holes into the housings are not sealed in properly. Pictures will definitely help, it’s hard to say.

TeamRX8

iTrader: (25)

rebuilding a rotary engine is simple they said, it only has three main moving parts they said ...

MincVinyl

Facts, it is fun messing around to see how changing different things affects the car. Figure it is best to mess around with a shitbox rx8 and try different things before I find a rust free shell to build up.

MincVinyl

This teardown took roughly 4 hours or so. At a certain point it is nice how every bolt doesn't put up a fight anymore.


We are having a hard time believing that we have put the rear main seal in improperly 4 times. The oil leak wants me to believe that there is pressure behind that seal causing the leak because of something else in the engine.

All of the irons are in the same condition. There is nothing you can feel on the surfaces, even though you can visually see the wear pattern.

The thing we noticed when taking out the rotors was that every corner and side seal fell out, which makes me want to believe I need to go tighter on the gap this time around.

These are the new Mazda OEM seals that came out of the engine, about a tank of gas has run through by now. Each seal seems to have this buildup on them.

MincVinyl

We found what was causing the rear main seal leak. When we were deciding what iron to use, we left the O-ring that goes between the rear stationary gear and the iron in the iron from the other engine.

While we had the engine apart we also saw that the bearings didn't look in great condition so we have replaced those aswell.

Other than that we put the engine back together with new mazda corners, sides, and springs all around. The side seals we went with a tighter tolerance of .001in to hopefully see a jump in compression.

Once back together we were having similar issues trying to start as we did with the previous rebuild. This time we could check the compression (cold freshly built, no break in) and we were getting 80-85psi all around. Previously with the Atkins corners(broken in) we were getting 88 89 87 psi (cold). These numbers still seems low for new mazda OEM:
1. Apex+springs
2. Housings
3. corners+springs
4. Sides+springs

I am unsure at this point where we are losing out on compression. I feel like I am running out of options to change around. Unless there is something that is being kept secret behind the scenes from every engine build video that I have seen where I am putting something in slightly different and that is enough to cause issues.
Rotors?
Irons?
Tension Bolt Torque? (using 28ft-lb)
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One thing we have been doing is using Vaseline on all of the surfaces and to keep the seals in. We have been using hylomar on the water jackets, making sure none of it squishes into the rotor cavity. This time around we are wondering if the vaseline is gunking up the spark plug and fuel injector ports. So we have done some deflooding and cleaning of the spark plug ports and fuel injector ports. To me I cant think of a reason for the vaseline to hurt the compression, but I suppose the hylomar could cause issues with the seals if it got into the seals on the rotors. Could this be the gunk we saw on the new apex seals previously?

Ant_1026

I’m sure one of the seasoned vets will chime in but I was under the impression that you need to check compression on a hot engine after everything has expanded to where it would be (or close to be) under operating conditions.

CaymanRotary

You can check it cold but the numbers will be skewed higher than they are when the engine is hot. 85 is very low unless it wasn't adjusted to 250 rpm.

MincVinyl

Yeah normally you would check compression within 10 mins of operating temp and should be around 85-90psi for like a bare bones just barely starting(wont hot start). Since the engine wont start I took the cold numbers to compare to the previous cold numbers I took just incase.

MincVinyl

Yeah the 85psi (320rpm) was the non adjusted with I want to say 80-82psi (250rpm) adjusted. Which is low compared to the ~90psi(250rpm) from the Atkins corners build (2 tanks of gas broken in).

We already cracked the engine apart again, and my guess was right. Since we wanted to try a really tight gap on the side seal clearance, the tight gap caused the sides and corners to bind after spinning. It also appeared that the hylomar was being sucked into the combustion chamber, which i'll try to get pics of tomorrow. There were a few deposits on the rotors that make me wonder if spinning the engine was enough to suck in some of the hylomar from the coolant jacket areas, or if tightening down the torque bolts just squished some hylomar in. I also plan to cut down on vaseline and use it only to hold the sides and corners in for install.

CaymanRotary

That makes sense as a common issue in rebuilds is the springs/seals binding. You want to ensure all side and apex seals can move freely. As the engine expands when it heats up, if the seals are binding, it will cause compression loss. Sucks you have to keep taking the engine apart...

MincVinyl

At this point it only takes like 3-4 hours to get the car from running condition to having the engine in pieces, so it really isn't that big of a hassle. Dealing with the coolant getting everywhere each time is the hard part because there really isn't a good way of us clearing out the engine. We were actually wondering/joking about putting a coolant drain on the cold side of the engine somewhere.

If anything I'd rather do a bunch of trial and error on my renesis before I try to do a rew or a gsl-se/ren hybrid. You know, how tight of a tolerance can we go on the sides or how should the corners feel, things like that. Its painful to read random forum posts about "the side and corner seal gap should be this XX" and then the good ole "well actually they can be this YY" or the guy that says "Its actually best if there is no gap at all, some people have actually machined the corner seals to allow the side seals to go into them" I'm at the point of just doing my own tests to see how tight i can get them without binding, I'll probably end up between .001in and .002in for a side corner gap this next attempt. This last one I went as tight as I could where if you pushed on a seal it would return without binding, but I think even if one doesn't bind the whole face of the rotor can potentially bind if it is pressed in at the same time.

jcbrx8

MincV,

Kudos for taking on the adventure of a rebuild. I rebuilt mine...self taught, and am currently at ~16k miles turbo'd, and going strong. Fwiw...I stuck to Mazda tolerances...rather than opinions proffered by self proclaimed "forum experts", and used sufficient...but minimalist lubricants.

It's a great learning experience, can save a good deal of $$, and result in a solid engine, but it's not for the faint of heart, finance, patience, or attention to detail.

All the best.

MincVinyl

Well good news. This time around the engine started up quick enough I was barely able to let go of the key. Sadly we didnt record since we thought it would still take one or to goes. It had trouble idling with the clutch not held for the first 20 mins or so, but improved as of now. The engine already hot started several times very well. Tomorrow I am going to try to get some vids and do some compression tests hot/cold+front/rear

This Current Build:
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New Mazda Oem Parts

• S1 Housings (previously broken in from last build attempt, 2 tanks of gas)
• RX8 Apex Seals (previously broken in from last build attempt, 2 tanks of gas)
• Side seals (0.001in to 0.002in corner seal gap)
• 2 piece Corner Seals
• Springs all around
• Stationary gear bearings
• Flywheel nut (we had to cut the other one off)
• Air intake Vacuum elbows (I am suprised how much harder these are to put in and take out now that they are new, I wonder if when they get old and brittle do they shrink causing vacuum leak issues)

120k miles Parts

• Irons (all from my second engine)
• Rotors (from my first engine with newish bearings)
• E-Shaft (from first engine, the second engines rotating assembly got cooked pretty good if you did not read the original post)
• Counterweight and flywheel (from first engine

Items/Techniques used

• Used various dremel bits to clean all side/corner/apex seal grooves completely free of any buildup.
• For the Irons cleaned, polished runners/ports, hand lapped using a granite stone and lapping compound
• Slight dabs of Hylomar blue on the inner coolant jacket. Spread outwards away from the combustion chamber. More Hylomar on outer coolant jackets
• Used engine assembly grease only on the bearing surfaces and to just hold in the side and corner seals. NONE applied anywhere in the combustion chamber to avoid potential flooding of the plugs >> spinning engine >> no start.
• Super-glued the Apex seal assist corner pieces back together like how they came from Mazda. This was painful but well worth it, making sure to have NO glue residue on any faces of the seals or else there would be binding.
• Placement order was Iron > assembled rotor > run apex seals to align corners > Silicone on legs (on the clock from here to avoid any chance at added thickness with solidification) > assembled housing > shaft > apex seal > large spring slide down slightly > small spring slide down all the way > dowels >next iron > repeat
• Dipped tension bolts in some oil, and tensioned to 30ft-lb in multiple stages following the proper order. Still working quick to ensure the Silicone does not solidify and create any potential thickness
• Continued to use the hylomar in some extra places to ensure no leaks. Ex: around the dowels, the Sohn oil metering kit, the water pump, All of the coolant lines coming in and out of the engine.
• New 5w20 Royal purple engine oil
• Idemitsu premix for the sohn kit (I will post a pic of how I modified my kit, because it held only one or two squirts of windshield washer fluid and was tedious to fill)
• End play was at 0.0025in within the recommended 0.002-0.004in range

First start

• Near instant 2.5krpm then down to 1000rpm. Eventually very smooth idle at 800rpm, very little engine/trans shake.
• Blue smoke at first, lasted about 2-3 mins (signs of oil burning off)
• trouble idling with clutch released in neutral, lasted 15-20 mins
• Thin grey/white smoke in engine bay, lasted 10 mins or so

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We found that it was much easier to get the flywheel nut on when the engine stand was held down, instead of having 4 people trying to hold it steady. A while ago my brother also fabricated a simple bracket to prevent any rotation.
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Issues still present

• Power steering is still out. We are on the second module already I believe. The harnesses are all good, so it is the rack or the computer unit. I have two racks so I am not to scared about finding one, and the computer unit is only a hundred or so.
• Still keeping eye on idle and hot starting, probably going to drive around the neighborhood a lot. We didn't run it for more than an hour, but it did appear to hot start better before we closed up for the night.
• I think the AC compressor/ idler pulley has about had it (120k miles)
• the fuse box/ air box/ battery box/ computer box/ coolant resevoir are all in terrible shape at this point, but working
• The guage cluster has static crackling when the key is put in the "ON" positon occasionally. (old issue)

Un4gvn_rx8

I just recently rebuilt my 2005 rx8 6port with all atkin seals/internals and I still have low compression. Anyone have an idea what I could have done wrong. I even had rotors machined to fit rx7 apex seals. Please any ideas. I need help befor I lose interest/money in it lol thanks y’all

myon

MincVinyl, thanks for sharing. It sounds like your last rebuild went a lot better, congrats! What do you think was the big difference for compression between the earlier rebuilds and this last one?

MincVinyl

Sorry I haven't made an update in a while with the final results, someone in my household passed away and I have also started a new job since my last post. First I am going to compare the atkins seals rebuild we had running before against my current mazda oem build.

120+psi = Excellent
110+psi = Very good
100+psi = good
85+psi = Fair, but falling below mazda's standards
80-psi = Hot start issues and lack of power

Atkins Seals - Apex+1pCorners+Sides after a full tank of 93octane shell gas
Operating temp(hot after revs): 64 72 70 psi
After 10 mins(warm): 86 85 84 psi
After a day (cold): 88 89 87 psi

Mazda Oem(from Mazda Swag) - Apex+RX8 Corners+Sides after another full tank of 110octane(smells great btw)
Operating temp(hot): 91 98 90 psi
After a day (cold): 106 104 105 psi

(might redo this hot test since I started having issues with the pressure transducer after this one, either that or the 90/91 is a corner seal binding between these chambers. Wear in on its own????
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Now to be honest this test isn't completely conclusive saying that it was the atkins seals that were the issue. When we got the new side seals, we clearanced them to 0.001 instead of the .002-.004 that mazda recommends. Likely getting them that tight without binding is what is truly making up that compression. At the same time from an engineering standpoint I could also see that the one piece corners could cause issues with binding when hot due to expansion, without that 2 piece insert like how mazda designed it originally for this engine. I do see the use for one piece corners in higher power builds for sure.

To get my compression higher I think the next step would have just been to get new rotors and have them fully balanced/clearanced/lightened. There was some play in the apex seals that I can only imagine is causing some sort of compression loss. By my next engine I will most likely have bought my 3rd hopefully rust free rx8 and will be looking to do a rew swap. I will probably need to find a rotary tuner that is in new england by then.
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Other issues fixed:

Power steering - it was the module under the computer that just needed to be swapped out. Dad bought a random ebay one without telling me and it worked out. It did turn left really fast for about a week, then it started to balance out between turning left and right.

Check engine light for P0420 went away - Still have no cat, I did manage to also get mazda edit and I am planning on trying to mess with removing the codes aswell as bumping the omp maps to use more oil across the board. Lowering the Fan temps. I do also want to look at the dwell times since I have the LS coils.

The only oil leak so far is actually from one of my sohn oil adapter bolts shearing inside the front engine plate. Hopefully I have time before winter to deal with this.
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Future Buy Plans:

Full Racingbeat Headers + dual resonated midpipe + catback
JDM 5 speed trans
S2 Rx8 Diff
Tein Flex Z coilovers + Racingbeat Sway bars
Enkei kojin wheels + need New tires by then
Engine block heater????? For new england in the cold. I heard REC talk about excessive bearing wear on the rx8 in the cold, which I could see on both my engines ----------------
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@Un4gvn_rx8 Obviously there are thousands of variables that we could talk about. Did you get new housings aswell? DId you gap the side seals correctly, there should be a 0.002in-0.006in gap between a side seal and corner seal? Do the side seals and corner seals all compress at the same time and return naturally? Did you use an excessive amount of Vaseline/lube in the combustion chamber and are clogging the spark plugs>>flooding? Are you following the proper tension bolt pattern when closing the engine? I mean you can read through my whole experience, there is plenty that went wrong.
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@myon Yeah the current engine is doing well, honestly I was hoping for a higher compression. Again I think I need new rotors if anything is to improve. Compression wise the biggest difference I saw was making sure the side seal gap was done properly(asumming no seal binding, which is what I think the issue with the atkins rebuild was having). You would imagine that the majority of the compression depends on the life of the Housings+Apex seals, before we heard from shops like atkins and many people online that there is a good chance we could reuse old side seals. So the trick is to be able to get as tight of a tolerance as possible without any binding occuring when ALL the seals on the side of the rotor are compressed at the same time. Numerically I found it will be between 0.001-0.002in from a side seal to one of the corners. Perhaps if people didn't try to drive these engines till they absolutely died like I did, doing a simple rebuild with just apex seals every 40-60k miles wouldn't be that bad honestly. For me it would take two weekends to just swap out the seals. (Ignoring the near 2 months it took mazdaswag to ship). The other major gain that I would have to imagine would have been the new housings, but I dont have any compression tests between those builds

I am curious if my compression will end up increasing after I hit about 1000 miles, the supposed break-in mark that people seem to like. I read up on race teams that don't understand why people even break in their rotaries since there are few reciprocating parts. I suppose everything we have just spins and wears from the get go.

myon

I've also read about the magic break-in period and increasing compression, and I understand the logic and reasoning behind it. But I have done 3 rebuilds the last year (my story is quite similar to yours) and all of them have had 3 issues:

1. Low initial compression (70-80 psi, corrected to 250 rpm).
2. Decrease in compression after break-in (~65 psi after 200-400 miles)
3. Side seals breaking... (went for 0.002 clearance first time, so I increased to 0.004 on the last rebuild but it broke again. My suspicions is the the rotor have experienced knock or something mechanical and the side seal groove has pinched)

I have used complete new seals all around, new housings and lapped irons. After opening the engine up again I have not seen any major wear on the housings, but some scratches on the irons due to parts the side seal breaking off and dancing around in there...

I've re-lapped the irons each time and hardened them again (note: remove all freeze plugs and replace them after hardening, I learnt that the hard way).

I have two major suspects to the low compression I am getting:

1. The irons being uneven, they are smooth to the touch and "look good", but I fear that they may have "valleys" from wear and un-even lapping. Will measure that more precisely in the next tear down. These valleys could leak out compression between the side seal and the irons, that's the theory at least.
2. Apex seal clearance. The apex seal groove on my rotors have a very very slight v-shape. The clearance is within tolerance but it looks to me like the apex seal have an excessive wiggle room.

I intend to run boost so I am using solid corner seals, which could be a reason for the lower compression, but other than that I can't see where else the compression could go apart from the two suspects I have listed. My plan is to lap the irons with a real lapping machine and machine the apex grooves, possible also go for the full depth apex seals when I'm at it.

I can imagine that the experienced guys here are laughing a bit at all these rebuilds and wasted money... I would have turned to a serious builder if there were any here in Sweden, but since there isn't any I thought I might as well learn by trial and horror xD And so far it has been a lot of horror. Broken side seals, freeze plugs popping loose, brass plugs in the oil system leaking, etc.

Thanks for sharing your story and what you have learnt. Sorry to hear about the loss, hope you're doing alright.

MincVinyl

@myon Sadly the side seal issue that you describe seems to point at the irons. Which of course you would only know by experience if they are bad. If you are breaking side seals id check the port areas to see if there is any burring happening. On my engine I did a very minor port job to just clean up the ridges. To be safer with a tighter 0.001 side seal gap I beveled the closing edge all around using a Dremel tool. As for extreme damage like broken seals being tossed around, id be curious what damage they caused. I also hand lapped my irons with a lapping compound and a large granite slab......lots of elbow grease.

If you plan to boost, honestly going with a rew block is the way to go. Read up on Brettus's 450hp renesis and see that in the end it will be a much greater headache even with experience than buying a rew block.

MincVinyl

Update to the update I never posted,

Power steering went out again. Using a multimeter everything checked out. the connections all checked out even from the module to the rack. This lead me to believe that it wasn't the wiring or connectors above the radiator.(proved to be wrong....maybe) For some reason we had previously swapped out the module under the ecu and power steering would be back for a month or so. Just to rule out the useless connector, I went ahead and cut it out entirely and just crimp connected and heatshrinked the wires back together.

Turns out the power steering came back on, so we shall see if it goes out again.

MincVinyl

Figure I post a closing update for this thread

As of right now the only ongoing issue with the car is rust. All codes are gone and so far everything mechanically is functioning.

Kinda had a buffer zone of income due to high demand of work due to covid + lots of overtime + Grave/night shift + delayed student loan payments. I plan on looking for a low mile/low rust shell, so many of these mods will carry over. Most of these following mods happened just because I figured I might as well do X since Y is out of the way.
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NEW MODS

• Rear forward suspension arms + toe arms
• Front upper and lower A-Arms
• Energy suspension Poly Bushings front rear + rear knuckle bushings (Doing the fronts is near impossible with 120k mile A-Arms)
• Front/Rear Racing beat Sway bars + adjustable end links
• Tein flex Z coilovers
• Rx8 Performance Poly+Aluminum Engine mounts
• Various Suspension Cam bolts + anti seize
• JDM 5 speed trans from J-spec Auto
• Front/Rear Powerstop calipers
• BrakePerformance Slotted rotors + Ceramic pads (honestly I'm not too happy with how the ceramics won't grab till I'm 50% on the brake pedal.....and yes we have bled the brakes 3 times)
• Mazda Edit + Tactrix >> Lowered fan temp, Blocked Cat DTC+Air pump, Bumped the OMP rate, LS coil Dwell map(was quite a read to find)..... Currently trying to learn more about fuel/ignition mapping/data logging
• Rewired the powersteering
• Fixed Air bag sensor above radiator (its great to have a parts car)
• Re-leathered the stock shift **** (plan on making it have the 5 speed pattern)
• Rust Repaired and Repainted front subframe
• K/N filter (I actually didn't want the K/N filter, someone else bought it for me since it was all any of the local stores had)
• Royal Purple engine/trans oils

I probably forgot about some, but we happened to get all of this done just before the car was up for inspection>> Passed.
Engine is running well, ~105Psi all around planning on doing another compression check at 5k miles.

Here's some pics:


Honestly since I was already doing the calipers+coilovers dropping the subframe+engine+trans was 10x easier compared to taking out the engine mounts and dropping just the engine+trans. Honestly I thought about getting new uprights, but decided not to since I would have to wait a few more weeks for shipping.

Ended up cleaning up just about any exposed bolt I could see.

Got to trim down the supply of various half used rustoleum cans my father has been storing.

This is the power steering connector that was the culprit. Turns out when I checked it with the meter I would see a connection across it, but after getting annoyed I just decided to cut the plug out and hard wire everything back together. Which the plug is kind of unnecessary since the harness can just unplug from the power steering rack.

Here's everything tossed back together. The front A-Arms still don't have the energy Poly bushings. Since I ended up buying new arms I didn't feel like cutting new bushings and sleeves to fit the poly bushings.

These sleeves are the reason I bought all new front arms. Apparently missed these on the first go around and messed up one of the Poly bushings. at 120k miles I didn't even notice the sleeve. The sleeves also didn't just come out like the instructions said. We had to use the mill to get them out.

I was actually a little worried, because the coilovers and the RB swaybar were about half an inch away from each other. This wasn't an issue once the car was back on the ground rolling.

I think next I'll be doing the rear subframe whenever I get around to buying a S2 diff. Concept is that the 5speed has a more even gearing, but is longer. The more aggressive S2 diff would shorten the overall gearing back up for overall acceleration.

~60K mile JDM 5 speed from J-Spec Auto came in disturbingly clean. With an extra Upgraded starter(I now have 4). New slave. JDM 4 port flywheel and clutch assembly

JDM 4 port Flywheel on the left .... US 6 port on the right

JDM 4 port Flywheel on the left .... US 6 port on the right

JDM 4 port Flywheel on the bottom .... US 6 port on the top

JDM 4 port shifter on the left .... US 6 port on the right
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Godspeed if you made it this far