ok so im interested in buying an 03 cobra. the one i've been looking at was manufactured on 9-7-02, so it's one of the early ones. i had a compression test done on it today and all cylinders read between 170 and 175, except for cylinder number 7, which was right at 150. Im thinking since # 7 and 8 were the bad pistons with the head tick issue in the early 03s that maybe #7 consistently ran hotter than the rest and eventually scuffed up a ring?


anyhow, im wondering what is you alls opinions on the matter, pass it up, or is the motor still strong?


btw, it's your basic pullied eaton with exhaust, makes in the high 400s, and it has just below 50k miles, IIRC


thanks for the info!

 

by the book that motor is ok if your going just off of compression numbers. i believe its something like 20% difference between cylinders.

I personally along with alot of other people im sure. i dont like a difference of 10psi per cylinder.

also did you do this test cold? if so when its heated up you might get that cylinder to come up a little bit.

also take some thick oil and drop it down that cylinder through the spark plug hole. like a soda bottle cap amount. see if the numbers go up from that. If so its more likely to be rings.

also do the test with full throttle.

but i would not call that cylinder down. its within spec by the book. and probably due to the tick your talking about maybe its not fully closing the valves so some psi is bleeding off.

If everything else on the car checks out i wouldnt worry too much. but keep an eye on that cylinder.