This is the inside of my cylinders/piston tops.

Less than 2000 miles on this motor.

Both rings are gapped at .024.

Slideshow

Comp:
1-192 re-tested the same on second round
2-165
3-170
4-155 first round, 165 after a squirt of oil
5-160
6-170
7-165
8-160

 

Explains your low cylinder

 

A few more pics.

 

#6 intake


#8 intake

 

Have you noticed any oil consumption?

 

Don't drive it enough between oil changes to notice. Only time I see any smoke is in my track vids when running it hard in boost.

Initially there was a lot of oil going into the intake when I had a catch can setup...can would fill up in no time. Ditched that for a breather tank setup a couple of years ago. I would have expected most crud that was there to burn off by now if it was soft like in the pics of the stuff on #4. Still being there indicates that oil is still entering the cylinder(s).

 

Yea my next question was how do you have your crankcase ventilation set up? If it was recirculated having crud in there doesnt suprise me.

 

#1


#1


#3


#5


#7

 

Leakdown results on cold motor. After messing around with the gauge and slight variations in piston position on 1 cylindeer, I would say some of these numbers could be a few % high. Total seal 1.5mm stainless top ring gapped at .024 and 1.5mm Napier 2nd gapped at .024. 3mm oil.

GM service manual for a stock engine says leakage should be under 25%.

Some of the cylinders with the best numbers actually have the most crud on them.

1- 20
2- 20
3- 12
4- 12
5- 18
6- 18
7- 15
8- 20

1-20____2-20
3-12____4-12
5-18____6-18
7-15____8-20

 

Digging through old pics. These are from the 1000 mile rebuild.