Is my engine damaged?
 

This is my first rotary engine so I don't know what a damaged rotary engine sounds and feels like.

The engine was a brand new engine from Ray @ Malloy. It had approx 5k miles on the clock. My ecu is an Apexi Power FC and I was running wg pressure at the time (12psi, peaking at 15psi then coming down to 13-14psi).

We were tuning my car on the road AFR, EGT, knock count and other values all seemed ok. We had already done most of the tune and the car felt smooth at idle as well as wot pulls. I hit the 8k rev limiter at 3rd gear then near the end of fourth gear at 7500rpm the car felt flat like it hit the rev limiter. I backed off instantly and the car felt rough at lower revs, pulled to the side and started idling rough and stalled. When I restarted the engine it was again idling rough but at over 2000rpm it became smoother. It still drives and no excessive blue smoke from the exhaust, however it sounds like there are some light metal sounds coming from the engine.

I will check the spark plugs and fuel system and do a compression test but I am worried about damaged apex seals etc.

Would my engine still start, idle and drive if something internal was damaged?

I'd do the compression test first and report back. I hope it work out for you.

Probably a warped/chipped apex seal. Like he said ^^ next order of business is a compression check.

I would also advise against running the engine anymore before you do a compression test. If you damaged an apex seal it's absolutely raping the inside of the housing and causing further damage.

I just like Gordon had this same issue back in the day... I was doing a pull on the E-Way and as soon as got off the gas I had the same rough idle. Ended up going lean on the rear rotor & needed a rebuild. Like everyone said compression check then rebuild. Good luck bud.

sounds like a chipped apex seal. were you running AI? OE seals work well w AI for their app which is 255 hp FW.

the newer more malleable apex seals probably would not have broken...

good luck,

howard

Sorry to hear this...sucks for such a low-mileage engine.

What turbo are you running? Factory twins?

From the combination of symptoms, I would guess broken seal.

From my own experience on my 1987 Turbo II, I can tell you that these engines will run even with significant banging/metal noises for at least a few minutes at a time, so just because it will run does not mean it's OK :( My car would start and run for about 15 minutes with a bang/tap noise - turned out it was a spun bearing.... rebuild time.

Check all the easy stuff like plugs, wires, MAP sensor, boost hoses, etc... but I really think that the metallic noises are a big clue that you may have a blown engine, so get a compression test done.

B

Thank you for all the replies and wishes guys. I am really disappointed at this stage. I feel like all my hard work went down the drain :(

Some of you may remember my build thread called "Mission Impossible" because it really felt impossible at times trying to build one of the three FD3S in the country, I had to deal with finding parts and information/knowledge as well as naysayers and haters while trying to hold the rotary flag high.

We will do the compression test next week and I will report back.

I probably raped the engine already. It's all an assumption at this stage but when the apex seal was chipped I was in the middle of nowhere so I drove for 10mins back to the shop.

I wasn't running AI even though I have a water/meth kit installed ready to use. Because my plan and the general consensus seemed to be having the car tuned first then injecting water only for safety.

I know discussing apex seals is a bit like discussing religion but the engine was one of the brand new ones from Ray @ Malloy so I assume it is the latest version from Japan which is OK for 280hp. My car probably had 300-350whp at the time of the incident. Now from what I know and read over the years about these apex seals some people actually prefer OEM seals as they have a softer material and when the tune is right they can handle the power ok. Some even said harder seals are to compensate for bad tuning. Also read about harder seals being harsher on the housings etc. I will have to research harder for my next apex seals. Which ones are the newer apex seals you are talking about?

I haven't decided what to do at the moment but looks like my options are:
- Buy another brand new engine
- Buy a rebuild engine from a reputable shop
- Take apart the 3 damaged engines I have in my garage and try to build one good engine.

I was really shocked and have no idea what happened because everything was going so smooth. All values seemed ok, the car drove smooth. I know rotaries are fragile but didn't expect this from a near new engine with such low boost.

Maybe with my new engine I should run a newer better ECU for more control.

GTX35R @ 12psi, peaked at 15psi.

#3 Build an engine from good parts.

But read this first. 50k miles and still flat at the plug bores.

https://www.rx7club.com/3rd-generati...em-fix-989811/

Barry




Attachment 639374

Thanks Barry, I will look into this. I tried to build a safe setup but obviously it wasn't. I will be extra extra careful with my next engine and setup.

"some people actually prefer OEM seals as they have a softer material and when the tune is right they can handle the power ok. Some even said harder seals are to compensate for bad tuning. Also read about harder seals being harsher on the housings etc. I will have to research harder for my next apex seals. Which ones are the newer apex seals you are talking about?"

OE seals are fine for an OE power level.

OE power is 255 X .85 or 217 rwhp

if you are at 300 rwhp you are 38% above OE and the motor is generating significantly more combustion chamber pressure and heat.

ditch the OE apex seals and replace them w either Goopy or ALS both of which tend to bend, not break, if you encounter detonation. do check the turbine wheel on your turbo (i don't know what you are running) to see if it is injured. you will need to remove the hotside housing to inspect the wheel.

AI is essential and if your unit was operating you probably would not have the problem.

rotary motors are, IMO, capable of generating 550 rwhp w no significant degradation IF they are properly tuned, built and supported w proper subsystems.

your motor did not fail you. you failed your motor. this is not offered to you as a negative but rather as an instructive comment.

done right the rotary is worth the effort.

i am w Barry. you have a almost new motor w perhaps a couple of pieces not serviceable. take it apart, fix it, and get your AI working.

howard

More important than AI is fuel

I'm betting you lost fuel pressure and went lean

Nobody in their right mind would argue against anything that cools the engine and allows more boost/more power but I'll repeat it's not needed for low boost and is a PIA.

Saying the 13b is reliable at 500 HP with AI shouldn't be done until that 500 HP car is on a track competing against the corvettes, vipers and GTRs it would be classed with and doing it 10 weekends in a row.

"Saying the 13b is reliable at 500 HP with AI shouldn't be done until that 500 HP car is on a track competing against the corvettes, vipers and GTRs it would be classed with and doing it 10 weekends in a row."

sure, i'll buy that but most anyone who has seriously tracked an FD wouldn't be running at the 500 hp level since you can beat just about anything w approx 100 hp less... i should have better qualified my statement. i have a customer running around the 550 level doing a lot serious street racing ( a rolling blast thru a couple of gears). he has mowed down everything he has matched against and the motor is happy as a clam. used in this fashion i will stick by my (qualified) statement.

road racing is a totally diff story of course.

hc

Understood a reliable hot rod is a bit different than what I had in mind. We are simply coming from two different places.

I would like to clarify some points:

- I have a GTX35R which was running approx 13-14psi at the time of the engine failure. My wastegate springs are 12psi springs but boost gauge showed 15psi peak, settling at 13psi.
- Not sure what it translates to in whp but my guess would be 300-350whp.
- The fuel I was using unfortunately is 95 octane (probably equivalent to US 91 octane). We had 97 octane available until a few months ago but no more.
- I know Howard is one of the experts on AI on rotary engines. I have read his posts many times and talked to few other rotary experts/mechanics. There is a difference between using water injection after the tune and tuning with water. I am not against AI and I have a AEM water/meth injection kit with the biggest nozzle installed on my car already. Maybe my thinking was wrong but the only reason I did not tune with water is because of the risk of tuner making the tune more aggressive unintentionally due to increased limits. Instead I decided to get a safe tune first and then use water injection on top as added safety.

Can you elaborate on that? What causes the sudden fuel pressure loss?

The tuner was next to me at the time and he knows that I wanted reliability first and was willing to sacrifice hp for it. I don't know if there is a way to know the exact cause of the problem (tune or mechanical failure) but I will share some photos once I open the engine.

This is exactly what happened in my case, rear rotor went lean & boom. Give your fuel system a once or twice over before and after your rebuild.

I am sorry to hear about your misfortune.

I know a lot of the local guys who do a lot of mods on their crs really want the car running now and quick. But typically I tune the car in the low boost rows and idle cells and get it running very smooth down low. I ask them to drive the car around for a while and make sure everything is running great and catch any leaks with the car. do a small vacuum run shake down.

I then tune the cars from no boost up row by row watching the inputs like you have done, and I trim fuel from a rich state to a lean state. I keep the upper rows super rich so if the car/or excited driver/wastegate doesn't open, it gets a ton of fuel.

I am not convinced that its the seals or the engine, but something around the engine (perhaps fuel related) which you need to figure out. If you drop another engine in and start going for it......wouldn't want it to happen again.

My fuel system has FIC 720cc primary injectors, FIC 2000cc secondary injectors, CJ-Motorsport primary and secondary rail, NipponDenso Supra intank fuel pump, external fuel filter and Aeromotive FPR. These should be sufficient the power my engine was making. Of course if something let go then the rest of the system is irrelevant.

I am very curious to know the cause of the problem and I hope I can find it otherwise it'll be a matter of time before the next engine gets damaged.

Alpsta,
Check your last logs.....
What were the AFRs around 8000 rpm?
What was the injector duty at 8000 rpm?
What was the highest knock value on the map?

Then disassemble the engine and check for damage....
Are any of the Apex seals chipped?
Are the apex seal faces flat when facing each other?
Do the housings have carbon spots on both sides of the plug holes?

Post pictures.
Barry

there should be a LOG , from the tune . as well as your current tune . Tell him you want that .. Or well you should of asked for it right then and there before he had a chance to delete it if it was his mistake .

there's no mystery here. you don't have enough fuel for the turbo.

http://imagizer.imageshack.us/v2/xq90/905/PkCmQE.jpg

your situation is an example of:

fuel rule number one:

always size your fuel for max air output from your turbo at 10.0 to 1

if you don't, a stuck wastegate spells doom. do not assume you can always control your turbo output.

note max output of the GTX35 at one pressure ratio (which is the "2" on the Y axis) is 67.

67 pounds of air at 14.7 psi

requires 6.7 pounds of fuel or 1.055 gallons per minute which is 3993 CC per minute net of lag and duty cycle into the motor.

you have 5440 nominal but you have to remove lag and an 85% max duty cycle.

5440 X .74 = 4025 cc

you have 4025 and you need 3993 to max out your turbo at 14.7 psi boost.

at 15 PSI and 43.5 static fuel pressure your fuel pump must produce 245 liters per hour.

at 13.5 volts your fuel pump will do 250 liters per hour before removing flow loss due to line and filter restriction.

The 250 at 58.5 psi is also at 13.5 volts. is your fuel pump hardwired into your car? if not, it is probably seeing just less than 12 V.

flow rises and falls w the square of the voltage...

for instance, if you were running at 13.5 V to the pump flow would be 250 L/H.

if the same pump was seeing 12.5 V flow would be 214 L/H or 3566 CC/Min

what is your V at the pump?

finally, your turbo can make 77 pounds of air... you need to resize your fuel system to work w that output even though you may not ever run at that level.

you need 4588 net CC/minute or 6200CC/min of nominal injector capacity.

max air on your turbo is at 2.85 pressure ratios or 27 psi.

your fuel pump must deliver 275 liters per hour at 27 psi. hard wire your pump and I suggest you use a Kenne Bell Boost A Pump (20 amp 13.5 base V) at plus 20% V gain.

my guess is a chipped apex seal, flattened corner seal springs and a cracked corner seal or two.
rotor housings may or may not be usable. If you had Goopy apex seals, it is unlikely they would be broken. i also believe that Atkins solid corner seals would increase your chances of being O K w re to CS.

most of your motor should be fine.

you can run another set of secondary injectors w a Ground Zero manifold and a separate driver module from AEM to remove the strain on the PFC injector drivers.

howard