In Dec 07, after a good 1/4 on the G-Tech, I discovered I had some blow-by. I did a compression test and all had 130 - 133 psi except #3 was 110 psi. A couple of days later I did a leak down test on #3 but did not bother with the others. I got a reading of 30 psi with 95 psi supplied pressure and the leak was in the crankcase with the air exiting from the pcv in the driver's valve cover.

Last night I pulled the driver's side head after a long time passing. :nunchuk1:

Here are the pics. No damage I can see except for a shiny wear mark where I marked the pic. The mark is less than 3/16" wide and cannot be felt with my finger nail. No sign of any detonation? Broken ring? What do you think?

Attachment 48618

Attachment 48619

 

I would bet that when you pull that piston out you will see a broken middle ring land. I have seen that too many times. When you take off the rings, parts of the land will fall to the ground.

 

Thanks for your reply.

Do you happen to know what causes middle ring lands to break?

 

I have seen many of these broken. Most of these are on boosted engines. I had one happen on my N/A camaro with high compression. Apparently this happens with high cylinder pressures and high cylinder temperature.

 

Thanks Again!

I may have this engine apart sooner than later.

 

according to your g-tech, how much rwhp do you have?

 

Since my runs with the G-tech start from a launch the HP calculator does not seem to work properly. Seems like it looses the rpm signal. The last run I did told me I had 415 rwhp at 2485 rpm and that is close to the maximum rpm it recorded for the run. Not sure what is happening to the rpm signal but my Alky Control meth progressive control may be interfering with the signal.

 

yea second ring land is most likely broken...