<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FredoSP &raquo;</TD></TR><TR><TD CLASS="quote">time for a leakdown test...

As for mine .. approx 9.3:1 C/R

I got 215-220 psi per cylinder and 2%-3% leakdown (Thanks Chris @ NRG). Endyn </TD></TR></TABLE>

Why do you say do a leakdown Fred?

On my stock block D16 with 110k my numbers were like 210-215 across.

I have not tried a 2nd compression tester as this was the only one he brought with him. I am going to break it in a little more then do it again on 2 gauges this time.

 

This is a 78mm bore engine and the combustion chambers were opened up to match the bore.

Anyone want to buy some compression?

 

sounds very strong. my 9:1 motor was 210 straight across with no variation last time i check it .

 

I can't really think of any reason why it is so high unless I am at 14:1.

 

that sounds stupid high, i would try another gauge also
-jonny

 

Damn thats high

 

I was at ~270 when I had 10.8:1 compression.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mad Cow &raquo;</TD></TR><TR><TD CLASS="quote">I was at ~270 when I had 10.8:1 compression.</TD></TR></TABLE>

So I am not at 14:1 then. That is a good sign.

We will try a different gauge. Maybe that has a lot to do with it. Any you guys recommend?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ladysman &raquo;</TD></TR><TR><TD CLASS="quote">
On my stock block D16 with 110k my numbers were like 210-215 across.
</TD></TR></TABLE>

If this was done with the same guage, I'm going with your guage reading high. Stock D16 should be around 190 psi in excellent condition.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RyanCivic2000 &raquo;</TD></TR><TR><TD CLASS="quote">

If this was done with the same guage, I'm going with your guage reading high. Stock D16 should be around 190 psi in excellent condition.</TD></TR></TABLE>

Yeah, it probably is. Makes for a nice thread though.

I will let everyone know when we do it again.

 

When i had high CR pistons in my Dseries i threw 245 PSI with a bigger cam and my CR was at 11.7:1. With the stock cam it would've probably been around 260PSI

So your CR must be close to 12.

What pistons are you running,Head,block?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fjt &raquo;</TD></TR><TR><TD CLASS="quote">When i had high CR pistons in my Dseries i threw 245 PSI with a bigger cam and my CR was at 11.7:1. With the stock cam it would've probably been around 260PSI

So your CR must be close to 12.

What pistons are you running,Head,block?</TD></TR></TABLE>

Endyn 9.5 pistons 78mm bore
Z6 Block
Z6 head with welded and opened chambers.

 

Gauge is definitely way off if you had 210psi out of a 110k mile SOHC engine.

If your gauge WAS good, I'd feel really sorry for your rings.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HybridKOOP &raquo;</TD></TR><TR><TD CLASS="quote">Gauge is definitely way off if you had 210psi out of a 110k mile SOHC engine.

If your gauge WAS good, I'd feel really sorry for your rings.</TD></TR></TABLE>]

I dont think you can say his gauge is definitely way off..look at it this way your 110 mile stocker has 210psi so his 0 mile,flat topped,closed chambered motor should have more...

cliff notesnce he gets some miles on it it'll come down

 

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

I dont think you can say his gauge is definitely way off..look at it this way your 110 mile stocker has 210psi so his 0 mile,flat topped,closed chambered motor should have more...

cliff notesnce he gets some miles on it it'll come down </TD></TR></TABLE>

It has about 25 miles on it now. Probably less than that actually.

 

check the valve adjustment again

 

we are tomorrow night actually. Also checking head stud torque. Wouldn't a tighter valve adjustment increase it?

 

Is it even possible that the cam is off a tooth? I mean, in the sense that the intake valve is closing that much earlier allowing pressure to build that much sooner?

And yes, a tighter valve lash will push the valve farther off the seat. EDIT - which also means that the valve is lifted sooner which means pressure is bled off sooner.

Just a guess.


Modified by EE_Chris at 2:50 PM 6/14/2004

 

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

I dont think you can say his gauge is definitely way off..look at it this way your 110 mile stocker has 210psi so his 0 mile,flat topped,closed chambered motor should have more...

cliff notesnce he gets some miles on it it'll come down </TD></TR></TABLE>

I think you read a little too quickly. HIS sohc engine was the 210psi motor (and gauge), it was not mine. I would expect a sohc motor with that mileage to be more toward the 170psi range... which is why I stated that his gauge seems off by about 40psi...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">Is it even possible that the cam is off a tooth? I mean, in the sense that the intake valve is closing that much earlier allowing pressure to build that much sooner?

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

I am not sure. But, we have triple checked that it was at TDC. Guess we can do it again. With the block being decked and the head having a skim cut for straightness, I would assume it being retarded?

 

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

I think you read a little too quickly. HIS sohc engine was the 210psi motor (and gauge), it was not mine. I would expect a sohc motor with that mileage to be more toward the 170psi range... which is why I stated that his gauge seems off by about 40psi...</TD></TR></TABLE>

Off by 40 would be a good thing.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HybridKOOP &raquo;</TD></TR><TR><TD CLASS="quote">
I think you read a little too quickly. HIS sohc engine was the 210psi motor (and gauge), it was not mine. I would expect a sohc motor with that mileage to be more toward the 170psi range... which is why I stated that his gauge seems off by about 40psi...</TD></TR></TABLE>

opps...yeah,your right,too quickly cause I'm at work

 

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

opps...yeah,your right,too quickly cause I'm at work </TD></TR></TABLE>

I can't believe you look at this stuff at work.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ladysman &raquo;</TD></TR><TR><TD CLASS="quote">we are tomorrow night actually. Also checking head stud torque. Wouldn't a tighter valve adjustment increase it?</TD></TR></TABLE>

tighter will lower it cause it holds the valves open.....looser increases it.

 

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

tighter will lower it cause it holds the valves open.....looser increases it.</TD></TR></TABLE>

It may be way loose cause it is loud with that Zex cam.

Get back to work.