iF THE CAR JUST DIED AND ITS NOT CRANKING OVER, YOUR ALTERNATOR IS MOST LIKELY THE PROBLEM.

Sorry for caps...to lazy to change it back.

 

in a post a few up it said to look for 70 psi, its one made by aaron cake, it says you are just looking for 70 psi throughout, and it had that

 

Well I wouldnt exactly go by his word as the bible. The FSM states the minimum requirement for a running engine as 85psi on all faces with no more than 20psi difference between them. I have seen and made engines run with less than 85psi, but they are so weak they're almost impossible to restart once warm.

 

The Mazda compression tester is the quickest and easiest way to determine the compression of a rotary engine. However, since these units are quite expensive, we can assume you don't have one. If you do, then obviously you wouldn't be reading this document so there's no real point in telling you how to use it. A simple tester can be made by using a standard automotive compression gauge. Remove the one way check valve, and install the tester into the leading (lower) spark plug hole in the front rotor. Make sure your battery is fully charged, remove the EGI fuse, then floor the pedal and crank the engine while an observer looks at the gauge. You are not looking for excellent numbers, just three even bounces above 70 PSI. If the rotor has lost one apex seal, you will get one strong bounce followed by two very low bounces. If all seals are damaged, then you will get three bounces that barely register on the gauge. Repeat for the other rotor.

 

[QUOTE=ItsTimesLyke;7057652] just three even bounces ABOVE 70 PSI.QUOTE]

key word

 

[quote=helghast7;7057703]

 

**** **** ****!!

 

guessing no one is looking to just help a kid out and give me an engine either..

 

Yes, because plenty of people helped us out when we were "kids" by "giving" us engines when we killed our own due to negligence.

Not trying to be a dick, but seriously...stop and think before you speak. You know the old saying...

"better to remain quiet and be thought a dumbass, then to open your mouth and remove all doubt."

 

lmfao god i need to write that down

 

thats why they tell you to check your oil every time you get gas.... it can save premature engine failure.

 

Whoa! RR's write-up (http://www.rotaryresurrection.com/2n...ion_check.html) says 30-35psi per bounce.....

I thought mine were fine after getting 40+ per side and 120+total. Granted this was with an AutoZone piston compressor but damn now doubt has creeped in again. Someone tell me that 70+ is a typo!

BTW, this site and the people in it rocks! One of the many reasons I went with an FC over a 240/Supra/MR2/Miata.

 

WHEN IN DOUBT CHECK THE FSM!!! :smiley_12

the fsm says 85 psi at 250 rpm ON EACH ROTOR FACE, if the rpm is around 200 then 70psi is acceptable. But note: this is on a WARM engine. so a cold engine at the same RPM might be just a little bit lower like +/- 10psi. and remember the deviation from face to face can be no greater then 21 psi.

 

you ppl confuse me.. one says 70 is **** another says too much.. which is right? on new news for anyone, i got new plugs and still wont fire up, when i turn the key smoke is coming from somewhere in the engine bay, anyone have input on that wat it could be or anything?

 

1) note battery strength. A weak battery will yield low compression results.

2) Remove both lower plugs and wires.

3) remove EGI fuse from engine fusebox.

4) have a friend floor the accelerator pedal, opening the throttle for more airflow

5) insert your tester into the leading hole

6) hold the valve on the side of the tester open

7) have your friend crank the car over for 5+ seconds.

8) observe the needle bounces. You should see 3 in succession without skips, even bounces, in roughly the 30-35psi range.

9) let out on the valve now, and let the tester reach an overall compression value for all 3 faces(highest of 3 will be displayed). 115+ is like new, 100-115 is healthy, 90-100 is getting weak(1 year or less in most cases) below 90 could blow at any moment.

10) repeat for opposite rotor. Note difference in overall compression between rotors, which should be no more than 20psi max


after reading this i did it wrong, wats it mean hold the valve and then let it go?

 

70psi IS bad, but not on the bounce readings. Then you can easily expect less than 60. The point of the bouncing is to check if the seals are worn EVENLY. The point of the test where you don't let it bounce is to check the actual compression.

 

You're comparing apples to oranges. The low psi per-bounce is for a piston gauge with the valve being held in...this means air is constantly venting, so of course the pressure never builds up much. This is what allows you to see each face.

Then you want to do a test with the valve in normal position, letting the chamber build up to a higher number. This number should be above 85.

I think it is pretty well explained there...how anyone could misinterpret it is beyond me?

 

What the FSM says about the compression doesn't apply here in the non-pro/dedicated mechanics world brotha! We use what's known as the 'finger-in-the-socket-hole' tool or just plain cheap piston compression testers.

-RR, I understood your instructions clearly. I was just confused when other people say that the psi should be 70+ per bounce when using the piston comp. tester.