rgonza

maybe you broke a apex seal in rear rotor do not start until perform compress check, Why because you can breake the rotor housing too.

sammytcl

iTrader: (1)

just did a compression test, the front got 90 psi, and the rear got almost zero! i think i need a new motor!

sammytcl

iTrader: (1)

should i rebuild the motor, buy a reman, or buy a brand new motor?

sammytcl

iTrader: (1)

we checked all hoses, no leak, how did i blow the motor?! can someone please advise some possible reasons? i don't want to blow it again once it gets fixed.

rgonza

wow you blow the apex seal that,s mean that you should need to replace the entire engine. because i 'm my blow first engine when we openen it we found a rotor damage, housing,ect..... when we goin down to mazda to buy the parts there are tooo expensive we opted to buy a used one .

zoomzoom_8

boost spike, too much compressed air, not enough fuel. You need to make sure your boost controller will stop the boost at the psi that your map is tuned for.

what did you use for your compression test? a conventional piston compression tester or a special rotary one? just wondering.

rgonza

It is the same tool for rotary and piston is reading scale is in PSIG. if reads less than 80 no way.

zoomzoom_8

not really, the piston type has a check valve, the rotary type does not and gives three pulses for all three compressions per rotor. the piston type only does on compression and the check valve makes the needle stay at that number so unless you remove the check valve, you could get a faulty reading, say a good reading on one compression but not know that you have a bad reading on the other compressions.

rgonza

the check valve is only to keep the hightes reading , we have in our shops both the only diffrences are tha mazda are electronics and it control the cranking by using internal timer but it have too an internal check valve to archive the highter value so how it keep the measure when remove it.

dannobre

iTrader: (3)

Pull the valve from the end...it's like one found in the valve stem of a tire ...Schreader Valve

You will then get three pulses per rotor....kinda fast but you get truer readings.

Good enough to see if your motor is F**Ked

zoomzoom_8

is it in the end of the hose or the gauge itself?

dannobre

iTrader: (3)

It depends. It's usually where the button to release the pressure is....

Richard Paul

iTrader: (5)

Mute point!!!! If he has 0 pressure then not even one pulse is there. The only reason for the special gauge is that you can see if one seal is bad. So if you can't even show one of them is working why bother?

dannobre

iTrader: (3)

^^ True....with 0 compression it doesn't matter....but I was only answering questions

With readings like that you might as well call Paul at Mazmart and see about getting a new engine......

rotarygod

Aftermarket turbo kits and ecu's don't come with an engine replacement warranty should something happen.

sammytcl

iTrader: (1)

I don't even think of any warranty issue as Mazda voided the whole warranty 6 months ago after my 1st transmission was broken. But I am still questioning the reason causing the blown motor. I had the boost reading at 7psi at max, a/f ratio at 11.2 at max when on boost, egt 1300 F at max, no boost controller connected, no vacuum leak, etc, the engine was flooded, and I was using interceptor with map tuned for California 91 octane. So what casue the blown motor? Maybe my motor already got some internal damage/pre-mature wear even before the turbo? Now I am ready to order a reman engine, but my concern is how to avoid the same incident after the new engine. One thing I realized on the map of interceptor was the super rich a/f in cranking and idle. Mazsport got the map from a CA forum member who dyno turned the car 2-3 weeks ago. I have the map checked by a local rotory tunner after the install but did not have a chance to fine tune it before blew the engine. Another observation was that yesterday, the engine crank/idle much much easier and better with the stock ecu alone!

brillo

I can't tell from this, did you alter the original Mazsport interceptor maps for your car? Did someone try to tune your car?

RX7TT

youre runs lean is supposed not more than 1200 d. f. with complete exhaust, and 91 oct gas maybe youre run the engine in detonation, this can cause a apex seals broken.

legokcen

There is a quick and easy way. I did this with my RX-7, should work the same.

Remove the 2 plugs from one of the rotors. With the fuel cut off, crank the car. You should hear 3 distinct, and strong "whoosh"es. Try this for both rotors. If you hear one stron whoosh and two "farts", it's a bad apex seal. If you hear one soft fart, it could be a bad side seal.

May not be state of the art, but it works.

rotarygod

Don't remove both plugs from each rotor. Only remove the trailing plugs. Make sure there is no fuel going to the engine by removing the fuse that disables this. Not sure which one it is on the RX-8. You'll know real quick if one rotor is different from the other.

Don't worry about what you're a/f ratio was. It on it's own is unimportant when it comes to detonation. Too many people rely on a/f ratio to tell them the whole story and it doesn't. Timing in relation to a/f ratio is what is important but you must know both. There could have been other reasons that caused this. There could have been a boost spike, there could have been intermitent spark, there could have been a sticking fuel injector, etc. Some of those aren't very plausible but it could happen. One possiblity is that the plugs got fouled from rich a/f but kept running. They could have had carbon build up on them which led to them staying "hot" igniting the incoming mixture early and causing ping much like a diesel engine glow plug lights them off. Again not saying this happened but using it more to illustrate the point that there are many things to consider other than just thinking it is necessarily an ecu issue. It may very well be but who knows?

rkostolni

If this happened to a piston engine, you could just rebuild it stronger. Too bad you can't do the same with the Renesis, at least not yet. Someone needs to develop some stronger seals.

BigOLundh

iTrader: (1)

Sorry to hear about your blown engine. This really s*cks. Fortunately, alot of the top subject matter experts are here to help. Hopefully you can diagnose what went wrong, which will help some of the rest of us.

brillo

we don't need stronger seals, the stock seals are plenty strong up to 500whp. We heard this from every rotary expert at sevenstock, the issue isn't seals, its proper tuning.... period.

People don't take the time to tune the engine properly.

PUR NRG

It takes more than just time to tune the engine. Unfortunately it also takes more than "just" experience. When Scott programmed the Interceptor he did so with what he considered a conservative map that should work fine with 91 octane. Unfortunately CA 91 octane is not the same as other state's 91 octane--it's much worse. Consequently all Interceptors in CA need to pull something like 5 degrees of timing from Scott's original map just to prevent detonation. (I'm probably the guy who provided Scott with the CA dyno info.)

If you didn't have a BOV then I can easily see a boost spike.
________
Side effects from depakote

adrian-1

Yes, the stock ecu will crank and idle much better than with the interceptor connected. The interceptor runs a bit richer at idle and there's other issues of cold starts being worse with the interceptor.
I believe it has to do with how the stock ecu controls the spark plugs at idle .... it's different from how the interceptor controls them.