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Low compression? Time to rebuild?

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dboyle23

10+ Year Contributor
297
14
Jun 10, 2010
Chicago, Illinois
I have been building up my gsx and recently installed a 14b w/7cm, 660cc's, and tuned with ECUFlash. Car was running GREAT for like 6 weeks.

Recently I have been getting misfires in cyl #1. I changed plugs and no help. I changed wires to different cylinders and still just on cyl #1. I did a compression test and got the following numbers from cyl 1 to 4: 140, 150, 160, 160.

The weather has been REALLY hot around here lately and I wondered if that can contribute to burning a valve? I don't have a fmic and was getting a few counts of knock, but nothing over 7. Could that be an issue?

I have some hks 264's in my garage waiting to go on, but I figured that with that 140 in there that I might buy a new head and get some nice springs and such and install the 264's. Then later, after its built, toss it on. What do you guys think? Do you think I should do something else? Maybe 272's?
 
Do a leak down test and find out where it's leaking.

Those numbers really aren't bad. My compression was under 100 on all cylinders and my talon still ran before I pulled the motor.
 
Well, it still runs, and runs decent. That misfire is making me scratch my head and makes the car hesitate a lot. I had the injectors in for like 2 months so I don't think it's that.

Could the 140 compression cause the misfire?
 
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