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-   -   i blew my motor. (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/i-blew-my-motor-654654/)

xfillthy 05-21-07 05:54 PM

i blew my motor.
 
on my way home last night my temp rose above 100 and the car overheated. someone had mixmatched the map sensor cables and when you try to start it you can hear the rotor hitting the housing.

pretty fucked but a lesson learned.

87 t-66 05-21-07 06:10 PM

"mixmatched the map sensor cables"

:wtf:

spot_skater 05-21-07 06:15 PM

Uhh...^:withstupi

Welcome to the club (of blown motors).

:)

James

Sideways7 05-21-07 06:19 PM

Sorry, but nothing in your post makes sense.
First of all, 100 degrees F (which I assume you are using since you are in Cali) is well below operating temps.
Second, there is no MAP sensor on the car.
Third, assuming you are talking about the AFM, there are no wires to "mixmatch". It is a plug. If its plugged in the car works, if not it doesn't.
Fourth, there is not a way the rotor can hit the housings unless the e-shaft snapped or something, which isn't really possible.

So will the car start? If so, how does it run? I suggest you do a compression check.

xfillthy 05-21-07 06:25 PM

i run haltech and there is a cable from the intake manifold that runs through the chassis thats the map sesnsor cable. somone connected that to the blow off valve.
and it spun a bearing

stylEmon 05-21-07 06:27 PM

temp rose above 100

I'd love to get those temps!

spot_skater 05-21-07 06:28 PM

Do you mean a vacuum hose?

Sideways7 05-21-07 06:36 PM

Ah, ok, now it makes more sense. No idea you had a haltech. Anyway, thats weird it spun a bearing. I don't recall hearing of that before on a rotary.

MaczPayne 05-21-07 07:10 PM

I think he meant 100C. Which is pretty hot since normal operating temp is around 190F or 86 C

rx7 FC TII 05-21-07 07:13 PM

welcome to the blown engine club...im 4 months in and falling into depression

mazda.junkie 05-21-07 07:15 PM

What a labor of love it is to have a 7

stevensimon 05-21-07 07:38 PM

welcome. i love it when i get to rebuild my motor. im still not buying the rotor crash into housing because of a spun bearing. it would if you broke a gear tooth on the stationary gear but that only happens at high rpm.

Radial GT 05-21-07 07:45 PM

The rotor may be slopping back and forth and hitting the cast irons, that can happen with a spun bearing. But no way is it hitting the rotor housing. That is quite strange that you spun a bearing due to overheating. If this had been on a microtech, it would have just richened the maps and it would have been fine (though it would have ran like poop). I am also in the club of loving to have a reason to rebuild the rotary. Pitty it is just as summer is starting. Cheers with that.


edit, if it was hooked to the BOV, than it was not BOV'ing right... all kinds of crazy here. You did not notice nothing strange about how it was running? Running badly, no BOV woosh, temp.

micah 05-21-07 07:53 PM


Originally Posted by stevensimon (Post 6963781)
welcome. i love it when i get to rebuild my motor. im still not buying the rotor crash into housing because of a spun bearing. it would if you broke a gear tooth on the stationary gear but that only happens at high rpm.

Couldn't a spun bearing, in theory, cause the SIDES of the rotor to scrape against the plates? I doubt he means the apex edge and the rotor housing.

I might be a complete asshole, but.... shouldn't somebody with a haltech...... nevermind....

finishline 05-21-07 07:53 PM


Originally Posted by rx7 FC TII (Post 6963708)
welcome to the blown engine club...im 4 months in and falling into depression

me too.
it's about 6 months now. :wallbash:

spot_skater 05-21-07 07:55 PM

I'm ten months...

stevensimon 05-21-07 08:12 PM


Originally Posted by micaheli (Post 6963834)
Couldn't a spun bearing, in theory, cause the SIDES of the rotor to scrape against the plates? I doubt he means the apex edge and the rotor housing.

I am a complete asshole...... nevermind....


yes it could cause the sides to scrape plates.. but he didnt say plates or irons, he said housings.

RETed 05-21-07 09:31 PM


Originally Posted by MaczPayne (Post 6963698)
I think he meant 100C. Which is pretty hot since normal operating temp is around 190F or 86 C

100C is about 212F, which isn't particularly very hot.
The motor should handle temps intermittently above 230F or so...105C?


-Ted

Sideways7 05-21-07 09:52 PM


Originally Posted by stevensimon (Post 6963902)
yes it could cause the sides to scrape plates.. but he didnt say plates or irons, he said housings.

Yes, but technically "plates" and "irons" are housings, at least according to Mazda.

An yeah, even 100 C isn't terribly hot. While it could possibly do damage, I doubt it would spin a bearing. I maxed out my temp gauge on my s4. It cooked the already dead coolant seals, but it didn't do anything else.
Also, try being down for 20 months with a blown engine.

xfillthy 05-21-07 11:14 PM

i dont know man but the engine is fucked and it ran pretty normal other than the fact that on the trip home it was 100c steady until my friend pointed it out we started to decelerate and the temp got up to 120 after i had turned the car off. cranked it and it sounded like someone was knocking on the door inside the motor.


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