I just got my motor back together and running yesterday. Today I checked the compression and it was 195 on all 4 cylinders. I read that you are suppose to gain compression with miles, as the rings seat. Is it normal for the compression to be almost up to par with 30 miles on it? My internals are CP 9:1 pistons and eagle rods with the Z6 head on the y7 block. Any thoughts or ideas? Are the rings seated?

 

Yeahs sounds real good, why do think you have problem readings sound perhaps a little to high. You disconnect the the fuel pump? Sounds like they are to me, still best to keep running it in.

 

well you have low comp pistons in there...your not using full sythetic are you for the break in? .. did you get on it when you had a chance? .. what i would do is .. do a little more breaking in..slowly get your revs up with out shifting hard...but 195 is very good actually...try to use regular oil.. and when you test compression remove the ECU fuse... with the spark plugs out and the throttle wide open

 

Spark plug was out, I am using nd 30 wieght,the fuel was shut off by removing the fuse and the throttle was held down. The car does not smoke at all! I have only driven it to 4000 rpm with maybe 1/2 throttle, so no, I have not "gotten" on it yet. I am not worried in a bad way, just cautious. I do not want to do another motor swap! This the third one in 6 months in my driveway! I figured out the gremlin that kept bustin ringlands in 4th gear but I am just not used to the sounds forged internals make.

 

yup alot of knocking with forged internals...

 

What do you mean by alot of knocking with forged internals? Just curious so i dont freak out when i drop my new motor in soon.

 

The motor sounds like a diesel truck!

 

you will just hear noise... like lose vlaves or something LOL closest i can think of what it sounds like

 

Seems a little high.. My z6 with 9:1 only had around 160psi all cylinders with around 100 miles on it. And an average of 173psi now with over 3,000 miles on it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 5thgencivic &raquo;</TD></TR><TR><TD CLASS="quote">Seems a little high.. My z6 with 9:1 only had around 160psi all cylinders with around 100 miles on it. And an average of 173psi now with over 3,000 miles on it.</TD></TR></TABLE>
same here , 9:1 cr 175 across the board

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 5thgencivic &raquo;</TD></TR><TR><TD CLASS="quote">Seems a little high.. My z6 with 9:1 only had around 160psi all cylinders with around 100 miles on it. And an average of 173psi now with over 3,000 miles on it.</TD></TR></TABLE>

My stock block Z6 was at 210 on 2 different gauges. Both were Snap-on if that makes a difference. Some may read higher than others.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ladysman &raquo;</TD></TR><TR><TD CLASS="quote">

My stock block Z6 was at 210 on 2 different gauges. Both were Snap-on if that makes a difference. Some may read higher than others.</TD></TR></TABLE>

Yea, but how many miles did you have on your motor? He has 30. I think my old stock block z6 was around 165 across with 110,000 on it It will definitely vary like you said, just seemed high to me.

 

i wouldnt worry so much as to what the compression is (within reason) but if all the cylinders are within close psi to eachother, which yours are. i dont think you have anything to worry about

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ITSTOCK &raquo;</TD></TR><TR><TD CLASS="quote">What do you mean by alot of knocking with forged internals? Just curious so i dont freak out when i drop my new motor in soon.</TD></TR></TABLE>

you got high silicon pistons man, they should be a bit quieter than normal forged ones since the piston to wall tolerance is closer to stock because they expand less. it sacrifices strength just slightly for the more 'streetable' design.

 

Your just jealous!

 

those compression numbers are right where they should be IMO . .

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 5thgencivic &raquo;</TD></TR><TR><TD CLASS="quote">

Yea, but how many miles did you have on your motor? He has 30. I think my old stock block z6 was around 165 across with 110,000 on it It will definitely vary like you said, just seemed high to me.</TD></TR></TABLE>

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