Compression test results
 

Hey guys

So looking to purchase a RX8, I found a 2004 with 67k

Thanks to this forum, I noticed the hard starts were taking about 4 seconds, so told the owner I wanted a compression test done

The results were ~
6.2, 6.4, 6.7, 9.2, 9.3, 8.9

Cant remember the second line

I've looked through the sticky graph but I"m not too sure what RPM they tested at, maybe someone will know. Are these results okay? They numbers seem to be quite apart?

Anyway the dealer said the compression was fine, and told the owner he must get new coils and a new starter ASAP ($1k)

Opinions?

At what rpms was the test performed?
It looks out of spec anyway.

How can those numbers be called fine? The 9's on the second rotor look good but if they were both ran at the same rpm and have that much of a difference between the 2 rotors I thought that was a fail.

Yea that's just terrible. I'm almost 100% sure that the test was done above 250rpm as well. You got this test done at a Mazda dealership? Which one?

Why new starter...O_o;

I thought out of spec was below 6.0:dunno:

Hi guys, I just got my 2004 RX8 a few weeks ago, I still haven't done a compression test? still to do. But I'm going to ask since it's been mension hear "why change the starter??" my starter is also weak sometimes it takes 3 seconds to turn on and sometimes it just doesnt start and it will start until the second try. So do I need to change the starter or will a new one be the same way??? sorry haven't read all the rules yet so don't jump on me... :-)

that much difference between one rotor and the other is unacceptable. its either a bad test or a bad rotor

Sorry just to clarify, the test produced six results which were layed out on the sheet of paper like this

6.2, 6.4, 6.7, 9.2, 9.3, 8.9
6.2, 6.4, 6.7, 9.2, 9.3, 8.9

so the higher numbers were a testing at a higher RPM.

I got the test done at Neftin Mazda Thousand Oaks, not too sure they knew what they were doing, especially after they all marvled at the immediate cold start but didnt seem too concerned when I raised issues about the long warm start.

By the way Itachi, if your going to put a new starter in definately do it yourself! Or if your in California I found a rotary place which will put it in for half the price of the dealership

so the results were
6......., 6....... @ RPM A
9......., 9....... @ RPM A + X

Is that correct?

Without the RPM, the tests results are meangingless. I would go back and complain and make them test the car again for free.

There is a factory spec with variance between rotors( a certain percentage) that is 33.3% roughly difference which is way too much....like said before bad test or bad engine.

Also he mentioned the car being started cold there, that can have an effect on numbers if the test was done then.

I would go complain as well, and make sure you arrive with on time with your car hot. Don't let them wait and let it sit for an hour or more tell them it needs to be done when its hot. You will have better compression when the engine is colder.

I believe he said we were reading the results wrong and the differences are very tight.

Truuuuue I forgot about that.