I've been keeping an eye on my compression numbers since I rebuilt my motor. I did a light break in (no boost, stayed under 3000-3500rpms) At 0 miles it was 150psi arcoss. At 200miles it was 162-168 across. I just had my motor tuned ~500miles. At 800 miles it is 165 on cylinder 1. Well i decided to drop some oil in to see if it would change the numbers and it went up to 180-190 psi. I've been getting smoke coming out of my exhaust when i let up off the gas. I gapped the rings to cp specs. I had to use a je second ring though b/c the cp ring that came with it had too much of a gap (.024 when i wanted a .021). I had the block honed also. I dont understand how I could have blow-by already. What did i do wrong?

 

Did you have blow by before tuned?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by booscivic &raquo;</TD></TR><TR><TD CLASS="quote">Did you have blow by before tuned?</TD></TR></TABLE>
It would smoke alittle at idle. I do not know about driving it. I had just put on a new exhaust so i thought the smoke was from that. The car was running rich before it was tuned, so i'm thinking the rings did not seat right. The extra fuel could have washed the cylinders or something.
Would this be safe to run around on even though i'm getting blow-by since its tuned right now? Or am i going to need to get some new rings and retune it??

 

Did you have new valve guides installed?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by booscivic &raquo;</TD></TR><TR><TD CLASS="quote">Did you have new valve guides installed?
</TD></TR></TABLE>
nope, but that wouldn't have anything to do with the compression going up by adding oil would it?

 

did you file the piston rings?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by booscivic &raquo;</TD></TR><TR><TD CLASS="quote">did you file the piston rings?</TD></TR></TABLE>

I called earl up and he told me what to gap them at.

 

Did you double check where the ring gaps were before the pistons got went in the block?

Just a thought...

 

so what was the numbers on the others at 800 miles?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TURBO4drTypeR &raquo;</TD></TR><TR><TD CLASS="quote">Did you double check where the ring gaps were before the pistons got went in the block?

Just a thought...</TD></TR></TABLE>

yeah i checked them a few times and made sure i had all the gaps lined up on the pistons like the instructions showed.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C1CYA &raquo;</TD></TR><TR><TD CLASS="quote">so what was the numbers on the others at 800 miles?</TD></TR></TABLE>
~160-165

I'm just going to keep checking on the compression numbers and my oil level. The car still made some decent power so.... I donno we'll see what happens.

 

if they are all the same i would not worry or consistant with each other, the numbers sound about right for a 9.1 motor

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C1CYA &raquo;</TD></TR><TR><TD CLASS="quote">if they are all the same i would not worry or consistant with each other, the numbers sound about right for a 9.1 motor </TD></TR></TABLE>

the compression calc i used said my motor was around 10.1:1 b/c of the y8, z6 block, y8 headgasket and the 9:1 pistons. It should be 180-190 b/c that's what it was with my last rebuild. The compression numbers would not have gone up by adding the oil unless it sealed off something that the rings weren't. I'm not too worried about it. It still pulls nice and hard