I have a buddy that has a 01 WS6 with the 6 speed, a lid full exhaust, and et streets. When we took it to the track, the car seemed slugish to me. It only ran a best of 13.40's. to me thats slow for a 01 ws6 M6. Soon after it threw a code, and said misfire on #5 cylinder. So we did a compression check, and it would take like 10 seconds of cranking to get like 25 psi on the gauge, NOT GOOD

Well, he took it to his buddy, and took the heads off, and cant see anything. I think it needs a set of rings, or a new shortblock.

if there are any other idea's, or whatever, please let me know!!

thanks to all at LS1tech.com for all their help!

Charlie

 

piston could be cracked on that cylinder, if no blue smoke was seen when it missfired , than is not the rings, also check the condition of the head gasket around cylinder. Most likely cracked piston, sometimes cracks can't be seen by the naked eye, you need to magnify if with a baroscope. SINCE YOU ALREDY TOOK THE HEADS OFF, MAKE SHURE THE PISTON IS NOT CRACKED.

 

My first instinct would have been to do a leakdown test. You could hear if the air was blowing into the block or out one of the valve. That would have narrowed down the search. I guess you could check for an out of round cylinder, but I haven't heard of that problem with these engines. My guess is bent valves as it is a m6 and chances of a mist shift mechanical over rev are possible. Check the pushrods on that cylinder to see if they are straight and that the valves seal up. If that checks ok then the rings are shot or maybe a borken ringland on the piston.

 

i guess i will just have to head over and see it for myself. The car ran fine, but seemed low on power, and i guess it just took this long to get really bad...

ohh yea it did burn more than normal oil soon before the misfire code

thanks guys, give me something to look for when i go to the car.