IM looking into buying this rx7, its going to get a complete check up at a mazda dealer, what is good compression on stock motor? I want to know from people here cause they know best, so if someone can tell me whats good compression on a very very low mileage car lets say 14k miles. oringinal no mods what should compression be? its 1993 by the way

 

ugh, please search bro!

i typed in compression and this was like result number 6

https://www.rx7club.com/showthread.p...ht=compression

i was reading a thread and rotary res said mazda measures in kg/cm^2, which is 14.2 psi IIRC

so if it's an 8 on the mazda tester, then it's 8X14.2 psi and that's the compression

 

100 PSI is good. Take it to a rotary specialist if you can, unless there is someone at Mazda that actually have some real experience with these cars. Mazda mechanics are pretty much clueless when it comes to these cars, even though their company built it.

 

i have no choice but to use the dealer i should get the numbers thursday, I will post the numbers if you guys give me the go im flying out the next morning!!!

 

isn't 125 on all faces of both rotors factory spec? I think anything below 90 is getting time for a rebuild... and whats even more criticle is to make sure all the faces on both rotors are close to eachother

 

Read the links in the FAQ:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/faq-3rd-gen-other-useful-links-68640/

There's several guides on what to look for when buying an FD.

 

faces of the rotors yeah but generally they would all wear the same unless an apex was blown

there is not supposed to be much difference between *front and rear*

 

This is basic FAQ thread stuff here....

I wouldn't buy a car with numbers less than 7kg/cm^2 (100 psi), unless I was accounting for a worn engine. The compression test must be done PROPERLY, per the FSM.

PS - Don't be in a hurry to buy an FD....

 

it's a toss up. i did the same thing you did. the car was out of state and it had recently been inspected by a "reputable" mazda dealer. now this wasn't my first one so i knew what i was getting into, but the results came back positive and when i got the car it ran like ****. luckily (as i later found out) , the car has a fresh rebuild on engine and turbos, and the only problem were a couple of frayed wires. long story short, i did the same thing you are about to and got a really really good deal. it's your call. good luck

 

how come everyone is stealing my avatar?

 

I must have made a good choice huh?
j/k

 

I don't care even if the car has zero miles...I wouldn't touch it w/ a 10 foot pole unless a respected rotary specialist looked at it. Mazda dealerships have no idea what they're doing. And even if the motor is "fine," you have no idea how the turbos are...most Mazda techs have NO idea what the 10-8-10 boost pattern is lol. They just tell ya "oh yea she's fast... pulls hard, so she must be running good" lol.

~Ramy

 

yea mazda mechanics are morons...when they tested mine before i bought it they told me over the phone that it grinds going into 1st gear.....i just started laughing and asked them how fast were they going? they were like about 10-15 mph....just morons

 

Sorry? I MADE this avatar from a full size picture MYSELF! I guess we could have both done that, but that would mean you were nearly as cool as me... which i seriously doubt.

anyways...

why is that? is it just that he seems to be rushing into it and could find a better one... or do you hate FD's?!?

 

Of course I don't hate FDs....I've got well over $40k in the one sitting in my driveway....

I was responding to the "please hurry and reply right away" nature of the thread. It's a bad move to rush into just buying an FD because one is available...

 

lol, guess i f*cked up then! j/k no regrets

let us know how the compression test turns out btw

 

Dealerships are good at compression tests. You can check the boost pattern yourself.

Compression also depends on a few other things like temperature, and altitude, so you can't say 100PSI is good. When in reality even 80PSI could be 'good.'

 

Ambient temperature? No.

There are correction factors for barometric pressure and cranking rpm, so a PROPERLY done compression test will always equal "80psi sucks donkey *****".

 

I don't have anything useful to contribute to this thread, I just wanted to point out that this was one of the lamest thread titles EVER, and this simple question could have been answered by reading the FAQ. Sometimes I miss the gestapo mods of the Subaru forums.

-s-

 

/agree x1000

 

You're in the minority...but this thread has served it's purpose.