cracked apex seal symptoms?
 

I was driving tonight and the car detonated pretty badly in 2nd gear for about 1 second (sounded like detonation, car lost power, etc)... I let off, got back on the throttle and it sounded OK.

Drove it home and it felt OK, idle VAC was down a bit though (-15 instead of -20)..

it started getting worse and worse on the drive home, by the time I got into my town the idle was pretty rough and the car was down on power, idle vac was down to like -8...

when I pulled into my driveway it quit and refused to restart, and that's where I am now...

what do you think is going on here? cracked seal? who knows?
I guess i just have to wait till it's light out (I'm a little too worked up to sleep) and see... stupid night!

oh, I forgot to mension that the engine was making a funny noise at idle too, sounded kindof like a "scraping" noise or something..

Yup, you most likely blew a seal. To prove it take out the trailing spark plug of the front rotor and crank it. You should Psshhhh psshhhh psshhhh. If you hear something that sounds more like a galloping horse than steady pulses, that rotor has a blown seal. After you do the front, put the spark plug back in and repeat with the rear rotor.

it might not even sound like galloping, you need to put your finger near the holes to feel if the pulses are lighter.

if thats all to hard goto your local auto shop and buy a compression tester ($25AUD) and hold in the reset button and watch the pulses to see if they are all even. if they show up uneven your in crapsville like me and i say 'welcome'. :)

for more info check here:
http://rotaryresurrection.com/rotary...lder/comp.html

hope this helps ya bro.

Yeah, I know what a blown motor is.. this is my car's 4th engine ...

guess I just thought I'd post what happened...

So I got up this morning, feeling like shit.. opened the hood on the car, noticed the BOV had "blown off" lol. Hooked it back up. looked for any other obvious problems, couldn't find any. well I hopped in it, and fired it up... it sounded OK, not blown just not "right"... Idled fine but had a miss that seemed to go away above 3000RPM.
Took it for a spin, felt OK. Lots of power, etc. Just the idle was weird... lower RPM (750 from 1000) and lower vac (but normal for the rpm, like 16").
Drove to my garage in leamington and pulled the plugs...

it passes the "woosh" test with flying colors!
Even feeling infront of the plug holes, 3 even pulses on both rotors.

Hooked up my compression tester...

40-40-40 on the front
0-40-0 on the rear.
WTF!

So is it blown? Cracked seal? Goblins? wtf?

it feels like it has at least 90% of the power it did before, if not all... it's harder to start when hot though, it flooded on me twice in the driveway.. usually it never floods unless there's a problem.

Looks like the talon is coming on the road early, I guess. :(

So roughly how many days after the turbo was installed did this happen?

Possibly 18 days or so?

no, it's been at least a month... now I gotta decide what to do!

the car still runs and drives, its by far the nicest blown motor I've ever driven..

it still pulls like a mofo! if I'd never checked the compression I probably wouldn't know for a while.

so either I A: put the talon on the road and park it for the winter, do either a rebuild, jspec, or v8 swap over the winter.
b: pull the motor tomorrow, get jspec day after, install day after that. Enjoy! (and keep the s-afc on the right map this time).

What caused the detonation is me being stupid and forgetting to re-set the S-AFC, I had it set to stay on the lo-throttle map always to save gas on the expressway since it wanted to go into the boost map after about 110km/h... so yeah, me trying to save a few bucks in gas cost me big! Learn from my mistakes people, someone has to :)

Interesting how strong the engine is. That's 40-40-40psi on the front?

40-40-40 on the front
0-40-0 on the rear.
when you listen to it the exhaust is just a "little" bit off, my friends didn't think it was blown at all.

it'll still spin the tires through 2nd gear... I'm not kidding!

whatever route I pick, I'm getting an EMS.

More than stock boost + stock EMS != reliable!

watch out for that turbo!
 

sorry to hear it, but ... two low, one hi on the compression test sounds like an apex seal. Worry about driving it, especially hard, if you send that seal through your turbo, it ain't going to be pretty.

Dude!
4th motor???
Are you like stubborn or just like to blow these things up? :)


-Ted

Hint:
Anytime you boost a motor above stock, it must be reTUNED!

It's good that you posted this for the benefit of others..

ha...haha. Blown motors are fun...

Hey, I'm right there with you brother. Oddly, my compression tested at 85 front, 0-30 rear, and just like yours, felt nice and quick... Of course the idle was pretty crappy.

I say oddly, because I JUST got done tearing the block and looking at everything, and the front housing/irons are just as messed up as the rear :eek:... I wonder *why* the compression was so much better...?

Oh well, I enjoy rebuilding these motors. I just don't like that it's going to cost me $1500 to get the seals and "big" parts that I need (I.E. New housings and irons).

Good luck, you gonna do anything cool while it's apart (tweak your porting etc?)