checked compression 75 front 75 rear after 600 on rebuild
 

is this normal? the car runs like shit...
the 5th and 6th ports were closed down with templates on teh outside by the guy who rebuidl it.

the car only has 600 miles on it... but i was expecting something higher... the engine had been on for 10 minutes prior to chekcing compression, i took EGi fuse out and spark plug wires and took out the leading plugs. The 75 front 75 rear i got was after turning the engine over 5 times... well until the needle stoped getting higher anymore. ( When i read the compression after turning the engine over barely 3 times it gave a 60 psi reading) I also took all that crap on the bottom of the gauge house out but i cant seem to get that tiny needle out of it. (i took the spring and the metal thingys around it out though)

With used rotor housings and only 600 miles, 75 is a viable number, I would think...

yes used housings and used rotors new apex seals and blah blah... but they were in good condition.

Take more compression readings every couple hundred miles using the same testing procedures you're now using, if the numbers don't start "perking up" after the next couple of tests, then you'll know something's wrong...

yea i know from experience.

what do u mean you know from experience?

1) maybe your not doing it right... (i dont know havent done a compressiong check by myself yet)

2) what wayne said

3) hes prolly been what your going through??

you cant really get an accurate compression reading from a normal compression tester go to mazda and have them test it and get some real results

QUOTE??????????you cant really get an accurate compression reading from a normal compression tester go to mazda and have them test it and get some real results

can someone explain that to me,,,,,,i thought compressed air was,,,well compressed air no matter how it got compressed???

i just used an liquid filled compression guage that screws and seals into the plug hole,,,,,,,,,,,,are mazdas tests usually higher of lower than a normal tester??????

A piston engine tester just isn't cut out to do the work of compression testing on a rotary. I had a compression test done with a piston tester first...Readings were ~85FR, ~75RR. I went to RP and had a Mazda compression test done on it. I was at ~110FR, ~100RR. That's a BIG difference between the 2 testers. That's the difference between a healthy engine and an almost dead engine...

David

Granted, piston testers weren't designed with the rotary in mind. But you're not trying to get exact scientific lab results here, more of a "base" reading for comparisons at a later date. If you had that much of a discrepancy between gauges, that raises definite questions about the seviceability/calibration accuracies of your gauge. I've had no problems with mine...

Usually you can see used housing rebuilds (with poor to decent housings) start as low as 65psi, and after the first few hours of run time this will rise 10-15psi. Then it builds very slowly over the course of the next 2-4000 miles (depending on how marginal the housings were). I've seen rebuilds with these housings reach a max of 100-105psi with over 5k miles...but they still run just fine, and usually don't even flood unless you do something dumb. Check again at about 1500...if it hasnt gone up by then, you know your housings were pretty bad, and the engine won't ever develop to be anything desireable.

thank you kevin i appreciate ur concern and help

P7,

Glad to see you're still in the rotary game. You were about to chuck it a while back, yes?

I cannot see doing all the work of a rebuild and not replaceing the housings. The few hundred bucks are so worth it as an insurance. Just my two cents.

I hope your compression perks up.

Peace Out,

yeah im glad u remember me bro... I was a step close to being a ricer and get a civic... but I love the rotary so much... the sound the uniqueness. Im a big fan. thanx i hope it does too.

thats fine and dandy if you want to pay 100 bucks ..

i called mazda and said i wanted a compression test done, cause im just curious, and due said it would be 100 bucks ... JUST FOR THE COMPRESSION TEST

thats retarded

somebody needs to break into a dealer ship and snatch up one of thier "official" compression testers ... then make bootlegs and sell those bastards

thats really low comp i checked mine a year ago 120 each rotor 100 thousand miles on a piston tester.

I dont believe theres much difference between the mazda tester and the one you get at walmart,.. you just need an idea of how much compression the engine has. If it starts fine dont worry about it. My new rebuild reads 110 front rotor and 120 rear rotor on a piston compression checker with about 30 mins idle time and 1 mile of driving.

IF you ever want a test done I have a mazda digital tester...but by the time you account for your time and gas, you could have done one at your local dealer anyway. At least I'll let you see the results firsthand.

and here we go again
 

so anyways... my car wont start now and i heard weird noises trying to started... i checked compression and it reads 80 front 80 rear so im liek WTF??@ MATE.... i drove the car only maybe 30 miles... now i think the problem might lay in that im running a low independence wiring harness with out the transformer and with high dependence injectors with a n326 ecu i have a n327 also but i switched them out and nothing... could this maybe be my problem? the guy also left 1 or 2 wires empty on the connector that comes from the front into the ecu... ( he kinda hoemmade wires from teh CAs an dthe ignitors directly to the ecu) so yeha i have a 80 front 80 rear but the car wont start. i bought a new wiring for teh 88 high depence injectors il see if that works

Man you got all kinds of related crap going on with that eng, lol...

If she's flooding, that would explain your higher compression readings now, you're filling in any imperfections with fuel at this point...And it sounds like you have little idea what "flavor" of ECU you need for whatever harness setup you got going there...

And what's this "transformer" you're talking about?

Done forgot to make sure your battery is in peak condition and your have the accelerator pedal to the floor when you test your car dude. I over looked that on my rebuild and thought I fucked it up.

[QUOTE=Peruvianrx7]is this normal? the car runs like shit...
the 5th and 6th ports were closed down with templates on teh outside by the guy who rebuidl it.

... the engine had been on for 10 minutes prior to chekcing compression, i took EGi fuse out and spark plug wires and "TOOK OUT THE LEADING PLUGS". The 75 front 75 rear i got was after turning the engine over 5 times... QUOTE]

..i thought we were suppsed to leave those in and take out the trailing to hook uup the compresiion tester

yeah i've done what u said j200pruf everytime ive checked compression... anyways i got teh car to start again the CAS plug was dirt i reconected and it started... I let it warm up for 25 minutes at 900 rpms and rechecked compression save way i had before and it gave me 70 front 70 rear... I WAS LIKE WTF>@>?@?@@?

Read...
http://fc3spro.com/TECH/FAQ/compress.html

The numbers sound about right.

Get another 200 miles on the engine and retest.
This is about another tank of gas.

As long as the compression numbers are rising, you are still good.


-Ted