zeeshan

iTrader: (14)

front rotor seems to have no compression. i made a wot pass in 2nd gear , afr was pegged to 10.0:1, ignition timing was around 18 degrees and split was about -8, suddenly the car sounded like it was running on one rotor. checked for compression just using my hand, and there are strong pulses coming from the rear rotor, but really weak ones coming from the front rotor.

if this is how sensitive the rotary is, i'm going to the dark side. expect a major part out thread coming soon.

RotaryEvolution

iTrader: (30)

cya then, forced induction is the same for any vehicle but only slightly more sensitive in the rotary.

why were you WOT boosting a fresh engine with only 1 mile on it? you know you'll get flamed for that but i think you want it, except for this case it only furthers the bad name of the rotary engine.

keep in mind you can have rich AFRs but that means NOTHING! do you know that both injectors were firing at 100%? one can be working properly dumping fuel and keeping AFRs within target after mixing with the second rotor which could be running excessively lean. unless you either had the injectors serviced and the shop did in fact put the right injectors in the package to send back, your wideband is accurate and your injector clip didn't simply pop off at a really bad time then ANY motor probably would have let go under the same situation.

i feel your pain but don't blame the motor for something that probably isn't its fault. there is good reason why there is also a break in period. burrs in the rotor apex slot can bind a seal in boost where it would lap in normally with simple miles driven in other cases. we have no idea how liberal you were with your cleaning and spec'ing of the engine.

i see engines blow all the time while in the target AFR range, then after testing the injectors low and behold one is 15% out of spec. this won't show on your wideband, unless you have dual widebands(which no one does because they will cook to death).

i see all this bullshit all the time, people swapping to V8s for not being dilligent during rebuilds or maintenance. try something different if forced induction is obviously not for you, build a naturally aspirated 3 rotor.

there, now you have me ranting too..

MR_Rick

iTrader: (7)

Why would you go WOT on a motor that has 1 miles? That's stupid. ^ like stated above, could have been a lot of thing that = to operator error.

lastphaseofthis

iTrader: (8)

I agree. I always wait at least 20 miles before going WOT to redline. depending on new or used bearings/metal seals/housings.

zeeshan

iTrader: (14)

it wasn't a fresh motor. it was 29k mile used jdm motor which had 100psi compression roughly on both rotors. all injectors were serviced and balanced. the injector clips didn't pop off. the engine was running for a long time ~10hours idle + revving before it was taken for a cruise to be tuned.

same with other engines? i have to disagree. i have a turbocharged 4g64 9:1 that was beaten up worse than this (22psi on a 35r with aem ems).

MR_Rick

iTrader: (7)

Who did the compression test? I will never rust a JDM motor or a motor that I can't verify its history. Even on my Honda days I will not trust this after going through 2 motors in less than 3 month.

What mods are you running and how much boost?

moconnor

iTrader: (14)

I think you need to change the post title. This is not a 1 mile engine.

RotaryEvolution

iTrader: (30)

even worse thing to admit then and be pissed about. many threads have been disclosed about jspecs which have been sitting in the elements for years, then shelved, then set outside and buried 6 feet under, dug up, pressure washed off then wrapped and sent to you.

run time means nothing as well, have you ripped the motor apart to see what actually happened to it yet? i have had more than one customer who accidentally dropped a nut/bolt down the intake, ran the engine for 30-45 minutes perfectly fine then once they hit a bump with some throttle "hiccup, fart, pop!" the motor sounds like a lawnmower as the bolt/nut gets sucked in.

your 4g is argumentative how? we don't even know what caused this 15 year old shelf motor to fail..

listen, one time in my car i cracked a rear plate from overboosting. i pulled out the motor and replaced the rear iron, while the motor was out i fixed a leaky wastegate issue but failed to adjust the boost controller back down to compensate enough. i took the car out, made a right turn and went WOT, left a trail of oil down the street and right back into the bay that i just pulled out of. who could i be pissed at? the motor? no, i smacked myself and went back to work. **** happens, if you're smart enough you never make the same mistake twice and eventually all of that pain pays off.

zeeshan

iTrader: (14)

i verified the compression pulses myself when i went to go pick the engine up. i saw the car it came out of. gt3582 1.03 a/r t3, 550/1680cc injectors, 8.7psi (was just trying to tune one row of the boost comp map slowly)


what are the chances i flooded one rotor? 10:1 is pretty rich.

zeeshan

iTrader: (14)

after blowing my first engine due to the fuel atomization plates breaking, i was meticulous in making sure there was nothing that could fall or break. (i removed all atomization plates)

zeeshan

iTrader: (14)

MR_Rick

iTrader: (7)

Do another compression check and check your coolant levels. JDM engine could have good compression but a bad coolant seal that could have gave way when you when WOT, log shot but possible. You could also have a stuck injector flooring the front housing. When you felt the pulses, was there fuel coming out?

RotaryEvolution

iTrader: (30)

i'll just give you an example of how much a 15% discrepency in low output from one injector can cause AFR wise.

say you have one injector firing 100% spray pattern producing a 9.5:1AFR, then you have a second rotor injector that has 15% low out put spraying 85% flow with an output of 11:1 AFR, your wideband will read the average of the 2 at 10.2:1.

of course it would have to be further than 15% out to cause a failure with your wideband reading 10.1:1 but i still listed it as a possibility anyways not knowing if you did have the injectors serviced or not.

MR_Rick

iTrader: (7)

This could have attributed to your problem I believe.

zeeshan

iTrader: (14)

i pressure tested the coolant system before putting it into the car
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/homemade-coolant-tester-953769/

the front rotor plugs were really wet when i pulled them out. i cranked the car a bit and a bit of fuel came out (i made sure to WOT the throttle to inject no fuel). after a while it all seemed pretty dry. but the pulses dont seem strong still.

i'll compression test it soon and get the numbers

RotaryEvolution

iTrader: (30)

doubtful, atomizers are mainly for fuel economy and a slight increase in torque(hah, i said torque).

adam c

iTrader: (2)

You bought an old engine and blew it apart. Very unlikely it had 29K. Very likely it sat around for a long time. Whats the point of this thread? To tell people not to buy JDM engines???

zeeshan

iTrader: (14)

front rotor 0-0-0
rear rotor 95-92-94

arghx

iTrader: (3)

you put a JDM junkyard motor in your car and then you wondered why it blew up. Old 3 piece apex seals is just asking for it on a single turbo.

arghx

iTrader: (3)

if you had pulled that motor apart it may have had a lot of good useable parts. it could have been a good base to build up properly. now you have a trashed rotor and a trashed housing at least

mono4lamar

iTrader: (32)

This unfortunate event could have been avoided if the setup was properly taken care of. A compression test, data-logging 0 psi and perhaps small increments in boost to isolate any weak wiring/defective injectors/fpr or even a bad batch of fuel.

Anyway, sell me the short-block. Sorry for your loss...

MR_Rick

iTrader: (7)

Seem that your motor was on it way out when you got it. Post picture when you take it apart. Would like to see the seal and housings.

t-von

iTrader: (8)

This right here! There are so many other factors that causes rotarys to blow that easily get over looked during rebuilds. If you never source the problem that took out the previous engine, I don't care if the newer engine is built by the hand of God, it's gonna suffer the same fate. I mean seriously I don't see how some rotary shops offer the warranty they do. Customer sends in a blown core for rebuild. Shop sends rebuilt engine back with 1 year warranty. Customer blows engine again because of improper flow differences between the injectors or a freyed wiring harness that cut power to one of the injectors. Customer try to send engine back for warranty repairs. Warranty get denied. Now customer is slamming the shop and the rotary to all his friends. Rotary's reputation gets worse due to customers own IGNORANCE. I'm with you Krack! I can keep on ranting too!

t-von

iTrader: (8)

The compression test really means nothing with an aged used rotary engine. The compression test will never tell you the state of carbon inside the engine. These engines are always carbon infested (especially after sitting up for years on end). The factory 3 piece apex seals also get very brittle. What do you think happens when carbon chunks finally fall of the rotor face and start jamming those brittle apex seals? The engine goes snap crackle and pop! If you don't check the used engines state of carbon before installation, your asking for trouble. Period! When I bought my 20b back in 2003, that was the 1st thing I did was remove the turbos to inspect for carbon build up. I've already had a 12a engine carbon lock before. Originally I was afraid to open the engine so I figured a way to clean out the carbon (which I did). Engine went from have no compression to having compression in the 90's on all three rotors. At that point, I was confident enough that if I ever got that engine running that nothing would be falling off any rotor face to destroy my engine.

bajaman

Pretty misleading thread title....