My guess is that there was detonation that that cylinder which flattened the electrode to the tip and damaged the piston. Since the electrode was touching the tip there was 0 spark in that cylinder. No spark means that none of the fuel that entered the cylinder was ever burned. This created a situation called "fuel wash" which basically washed all of the oil from the cylinder walls allowing the rings to create the scratches. Any loose pieces of piston probably just bounced around creating little chip marks.

 

If you've been keeping up with the FI issues on this car you have to have known that 9.5lbs boost, 7000rpm, and stock internals weren't going to mix, right?

 

The same deal happened to my number 6 or 5 cylinder. The sparkplug tip was touching the diode, or 0 gap. I however didnt have anything break off and was very lucky. Im still leaning towards rod stretch.

 

I would lean towards bigend bolts/fasteners stretch rather than the rods.

David

 

GUYS...guys....you need to listen to some of the others...this is a DETONATION issue.

The huge pressure spike slammed shut the spark plug ground strap to zero gap...classic sign of detonation NOT "rod stretch" or whatever.

If the ring land is fractured as in Enron Exec's pictures, definitely detonation.

You might want to READ this on why there is scuffing:
http://www.streetrodstuff.com/Articl...ion/Page_3.php

On stock CR motors, you need to be running higher octane fuel, using water/alcohol injection, or if you don't mind sacrificing some power....serious retarding of the timing. Assuming you've figured out the fuel system and it's not running lean.

Gurgen was the "victim" of pre-ignition, while Booger and Enron Exec are victims of detonation.

 

I believe mine was detonation.....I was only pulling 5 degrees at 9.5 psi at 7,000rpm I had 95 octane in it . I t was cooler that night than I have ever ran , and the boost got a little higher . It went at about 6,800rpm....had about 100 yards to go in the 1/4 mile run . I recorded the 2 runs prior to that....so I dont think I was quite at 9.5psi yet . I was passing the 1/4 mile at 7,000rpm @ 108.5 mph

 

newbie question here.. Depending on the depth of the scratches, can't the block be bored out to save the block? Just in time for a bigger diameter piston upgrade.

 

We are doing built short blocks, email or PM me for details and pricing info

 

new here so bear with me.
First off sorry to hear about your problem. I noticed a ticking noise within 30 miles of my procharger install, but couldn't find a decernable cause, the car felt strong and I ran it that way for 6k miles. Had the car looked at by 3 people on different occasions, verdict = no signs of detonation. 3k miles in I hit the rev limiter for the first and last time, heard a bang, but the car continued to run great. I was progressively using more and more oil but no blue smoke (it's used oil since new). Had it compression tested, one cylinder down at 160psi and one plug had vitually no gap. Changed plugs and 2k miles later one oils up (in the low cylinder) The car is now awaiting strip down and I'll post results later. Strange thing is with all this going on the car was still a flyer.
Hope I haven't done a hijack.

 

Usually 10-20 thousandths overbore will take out the fine scratches. If they are too deep the block would have to be sleeved.

 

I saw Enron pics and mine wasnt as bad from what I could see through the scope .We will see when we get it apart