RotorMotorDriver

iTrader: (1)

Well, I just picked up an 82 GS for my transplant into my 83 GSL (assuming the engine is decent). I havent personally seen it yet (my Dad went and got it), but I was told it has no exhaust, but it "runs strong". My Dad drove it home, and it was the guys "daily driver" so I should be ok (I hope). Im gonna pop a compression tester on it tonight and see what she reads. I read on here just the other day that piston compression testers dont read the total compression on each face because they dont have enough time to react or something, is this true? I just thought that anything over three 90 PSI bounces would be good for each rotor?? Anyway, another question...My Dad says the oil pressure gauge "doesnt work all the time". Could this just be a loose wire/connector? Or is this a really bad sign of a mechanical failure? If it could be wires/connectors, where should I look? And last, Im gonna put a new clutch in when I put everything back together...Where should I look to get a decent one? Preferably fairly cheap? Thanks.

~T.J.

damon

make sure that you are getting oil into the carb oil injection line

three even pulses at about 90 psi is correct

don't you have exhaust for the 83?

do you just want a clutch or race


reddy4fun

Directfreak

iTrader: (2)

Hey at least its running. - Whaddaya mean by No exhaust? Stock? Open Header?

You could do fine with less, I believe 90 PSI bounces is for near perfect compression. I don't recall what its supposed to be for 12A's.

Yep. Notorious for going bad and/or the connectors get filthy.

Lately I have heard some VERY good things about BNR Supercars 1st Gen Clutches (the link up on top), Mike P-28, Setzep and a few others have had supposedly awesome prices on some things (like clutches) through them.

Good Luck!

RotorMotorDriver

iTrader: (1)

Thanks. As far as exhaust goes, when I got the 83, the exhaust was already removed because the guy before me started pulling the engine, so I dont think its all there. If it is, Ill be happy. As far as the clutch, I just want something stock, maybe a little more grippy. I just saw a couple on Ebay...Good idea or not? One is a no name thing, and the other one is an "Exedy" kit. I like the price range though, ~$120. Thats what I need to spend...

~T.J.

damon

napa or the equal shoud suffice as far as clutch


if emissions arent a prob go to racinbeat and get a header and run strait or presilencer


gotta go for now be back tomarrow at about 9 am in ga

RotorMotorDriver

iTrader: (1)

Oh, and where should I check as far as connectors and what-not for the oil pressure gauge? Thanks.

~T.J.

RotorMotorDriver

iTrader: (1)

Found it...Is this true? What should the compression be on a 12A? Whats is "perfect" and what is "crap"? You know, like what are Mazdas specs for it? Thanks again...

~T.J.

4ohfour

for the comrpession test, just remove the holder p[in (the one that holds it at the highest recorded compression) and look fro 3 even spikes... if you ghet this, gointo a maxda dealer (i know i know) and use their compression tester, it'll print out a nice report for you.

cheers'

RotorMotorDriver

iTrader: (1)

Ok, well I did the "hold pin and read gauge" technique, and I got three even spikes, but none of them went over the 0 on the gauge...This might be bad. If I let the pin out, it will build compression to 50 PSI when the engine turns and uses all three rotor faces on both rotors. Why wont the gauge read over 0 when I do it with the pin in? The engine seems to run strong, it has 166K miles on it and its an 84, not an 82. It has a bad shutter valve that kinda makes it idle funny, but I corrected the timing, mixture, and idle speed as best i could, and she almost purrs like a kitten . Anyway, I will be using my old carb from the 83 when (if) I swap the engine, so the shutter valve isint that big of a deal. I will buy a new clutch when I put it in, and the engine will run, so I will be happy and my car will be on the road again . Assuming the compression thing isint something I should worry about ...

~T.J.

Directfreak

iTrader: (2)

Did you take out both spark plugs per rotor?

I am not sure of the process, but I believe you're supposed to leave some in.

79+80_rx-7

Is the 84, really crappy??? Why are you gonna yank the engine out??? just curious I wonder what it looks like, got any pics???


THANX LATERZ, Andrew

RotorMotorDriver

iTrader: (1)

I left in one plug on each rotor I tried...I put tester in leading with the trailing plugs still in, nothing. Tester in trailing with plugs in leading, nothing. Both rotors, nothing. And yes, the 84 is pretty rough, I get the engine/tranny/anything else I need, and my Dad gets body panels/interior plastics. The rest is up for whatever. It was a theft recovery that was bought for $50, and when it was stolen all the windows were broken out (now replaced by auction company) and it sat in the rain for a few weeks so the cloth/anything fabric covered is BAD. All the plastic stuff (dashboard, center console, gauge pod etc.) are all still good though, most of which may go to my Dad. If you need anything, let me know, I may be able to help you out.

~T.J.

PS - Once again, its an 84 GS. And Im keeping the manual window regulators and the wiper-less hath . Its cream with a black sunroof, and a white passenger door if you need either .

79+80_rx-7

good, if it is in that shape, make me feel a little better...... Hopefully, you can have a nice 83 GSL

RotorMotorDriver

iTrader: (1)

Ok, so doesn anyone know why my engine might say it has no compression? I havent tried the tester on another car to see if its the car or the tester...I was just wondering if any of you know why it might do this...

~T.J.

RotorMotorDriver

iTrader: (1)

So, does anyone even help anymore?? Anyone know why the engine might say no compression, and where should I look for the oil pressure wires/sender or whatever?

~T.J.

Directfreak

iTrader: (2)

Don't worry T.J.,

Obviously the engine has compression (it's running alright isn't it?) It's obviously something that you're probably doing wrong with the piston compression tester.

By the way, I have No experience in getting a compression reading from a rotary other than the "Phuh-Phuh-Phuh" sounds when I turn it over by hand.

Wish I could help you more.

FJ

It sounds like you measured correctly. As Directfreak said, if the engine is running, the gauge can't be correct.

The factory manual doesn't give ideal compression numbers, but it says 85 psi is the minimum. The same for 12A or 13B.
I had mine checked at the dealer many years ago, and had 145 psi, so maximum is higher than that.

I don't agree with the above remark that you quoted regarding the pressure being 30-40% low as a result of the needle bouncing and it doesn't have time to react. I don't know what he was referring to, but just release the pin and no more bouncing, it will show you the peak.
I measured mine recently and it bounced to about 115 equally. When I released the pin it settled about 4 psi higher. Not as accurate as a readout, but give or take 5 psi and it is still enough to have a good idea of the condition of the engine.
If your gauge doesn't have a release valve and you had unscrewed the fixed one, just replace it after comparing the bouncing value and measure the peak.
There is nothing special about the way the dealer tester measures the compression, it just gives a readout so that you can more accurately compare the maximum and minimum between rotor faces.

The oil pressure sender is directly under the oil filter. Round, about 1.5 inches in diameter. There is a capacitor connected to it in the harness. It is a cylinder about one inch by a half inch, mounted just to the front of the clutch slave. With a single wire on it. If it is leaky it may be causing the problem. You could disconnect it to see if that helps. Shouldn't cost much to replace if that's it.

-John.

FJ

We tried. What did you find?

-John.